Beelden van eigen gezondheid bij jongeren 12
Transcription
Beelden van eigen gezondheid bij jongeren 12
Overweight and obesity in Dutch adolescents Associations with health lifestyle, personality, social context and future consequences: methods & tables N.J.A. van Exel X. Koolman G. de Graaf W.B.F. Brouwer Correspondence: Erasmus MC institute for Medical Technology Assessment (iMTA) PO Box 1738 3000 DR Rotterdam T 010 408 25 07 F 010 408 90 94 E n.vanExel@ErasmusMC.nl institute for Medical Technology Assessment 2005 Report number 06.82 Copyright. All rights reserved. Save exceptions stated by the law, no part of this publication may be reproduced in any form without the prior written permission of iMTA. ABSTRACT This report is part of a study that investigated adolescents’ health behaviour in relation to attitudes about their health lifestyle and their consideration of the future consequences of their behaviour. The study focussed on young adolescents in the age of 12 to 14 years, attending 1st or 2nd grade of secondary education. This report is meant to serve as a reference book for future output from the project by providing a description of the measures selected for inclusion in the “Health & Future” questionnaire, the study sample, the results of intermediate analyses of multiple-item scales as well as a full overview of the data collected, in relation to the main outcome variable “overweight”. ACKNOWLEDGEMENT We wish to acknowledge ZonMW (www.zonmw.nl) for funding the project (2100.0100), the members of the advisory board (Annex A) for their constructive contributions, and the schools and their pupils (Annex C) for their enthusiastic participation. AFFILIATIONS Job van Exel: Erasmus MC, institute for Medical Technology Assessment (iMTA) and Department of Health Policy & Management (iBMG). Xander Koolman: Erasmus MC, Department of Health Policy & Management (iBMG). Gjalt de Graaf: Vrije Universiteit Amsterdam, Faculty of Social Sciences, Department of Public Administration & Organisation Science. Werner Brouwer: Erasmus MC, institute for Medical Technology Assessment (iMTA) and Department of Health Policy & Management (iBMG). Contents 1 2 Introduction 5 1.1 Overweight and obesity 5 1.2 About the study 6 1.3 About this report 7 Methods 9 2.1 About the “Health & Future” questionnaire 9 2.1.1 Aim of the questionnaire 9 2.1.2 Selection of topics 9 2.1.3 Recruitment of schools and pupils 10 2.1.4 Administration of the questionnaire 12 2.2 3 Contents of the “Health & Future” questionnaire 12 2.2.1 About you (questions 1 to 8) 12 2.2.2 About your health (questions 9 to 14) 15 2.2.3 About your future (questions 15 to 22) 17 2.2.4 About home (questions 23 to 34) 19 2.2.5 About school (questions 35 to 43) 20 2.2.6 About your leisure time (questions 44 to 52) 20 2.2.7 About what you eat (questions 53 to 55) 21 2.2.8 About money (questions 56 to 63) 23 Results 25 3.1 Study population 25 3.1.1 Participating schools and number of respondents 25 3.1.2 Representativeness of the sample 26 3.2 Length, weight, BMI and prevalence of overweight and obesity 27 3.3 Variables 31 3.3.1 About you 31 3.3.2 About your health 32 3.3.3 About your future 33 3.3.4 About home 34 3.3.5 About school 36 3.3.6 About your leisure time 37 3.3.7 About what you eat 38 3.3.8 About money 40 References 43 Annex A Members advisory board 53 Annex B Validity and reliability of self-reported height and weight 55 Annex C Literature review 57 About you 57 About your health 58 About your future 61 About home 63 About school 65 About your leisure time 67 About what you eat 68 About money 70 Annex D International and national survey questionnaires reviewed 71 Annex E Questionnaire “Health & Future” [in Dutch] 73 Annex F Attitudes of youths about their health lifestyle (format A) 91 Annex G Attitudes of youths about their health lifestyle (format B) 93 List of tables Table 1 Big-Five personality dimensions and markers for 30-item short version ...............14 Table 2 Confirmatory factor analysis Big-Five personality dimensions ..............................16 Table 3 International Body Mass Index (BMI) cut-off points for overweight and obesity in adolescents; by gender and age ...........................................................................17 Table 4 Food Availability at Home Index (FAHI) scoring system........................................19 Table 5 Physical Activity Index (PAI) scoring system .........................................................20 Table 6 Healthy Eating Index (HEI) scoring system ...........................................................22 Table 7 Unhealthy Eating Index (UEI) scoring system .......................................................22 Table 8 Number of respondents per school (n=2,006) .......................................................26 Table 9 Reference population according to gender, age, education level, and ethnicity....27 Table 10 Length, weight and BMI .........................................................................................27 Table 11 Length, weight and BMI according to body image.................................................30 Table 12 Personal characteristics, BMI, overweight and obesity .........................................31 Table 13 Health, BMI, overweight and obesity .....................................................................32 Table 14 Future, BMI, overweight and obesity .....................................................................33 Table 15 Home environment, BMI, overweight and obesity .................................................34 Table 16 School environment, BMI, overweight and obesity................................................36 Table 17 Leisure time, BMI, overweight and obesity ............................................................37 Table 18 Eating behaviour, BMI, overweight and obesity.....................................................38 Table 19 Money, BMI, overweight and obesity.....................................................................40 List of figures Figure 1 Schematic overview of the Dutch education system .............................................10 Figure 2 Participating schools..............................................................................................25 Figure 3 Cumulative distribution of length, weight and BMI according to gender ................28 1 1.1 Introduction Overweight and obesity Obesity1 is one of the main current public health concerns in Western countries (Daniels et al. 2005; NHS HDA 2003; ILSI 2000; Seidell 1999), as it is associated with morbidity and mortality at least as much as smoking, alcoholism and poverty (Manson & Bassuk 2003; Sturm & Wells 2001). Recent studies have suggested that the prevalence of overweight and obesity among adolescents varies between 10-25% and 2-12%, respectively, depending on country, measure and definition (McCarthy et al. 2003). Overweight and obesity prevalence rates show a persistent, upward trend (NHS HDA 2003; Spurgeon 2002; Yarnell et al. 2001; Reilly et al. 1999). In addition, children and adolescents in the most overweight group are becoming heavier (Troiano & Flegal 1998). Though most young adolescents seem to have a basic perception of a healthy lifestyle (e.g., Watt & Sheiham 1999), they have relatively unhealthy lifestyles as compared to other age groups. From a public health perspective, they have therefore been categorised as a risk group (Daniels et al. 2005). The World Health Organization labelled the rapid increase in obesity over the past two decades as a global epidemic (WHO 1998), Swinburn and Egger (2004) described the trend as a “runaway weight-gain train”. Childhood obesity has been shown to have consequences for health and quality of life in both the short and longer term. In the short term, childhood obesity is associated with physical and psycho-social problems such as new-onset asthma, decreased health-related quality of life, lower body- and self-esteem, behavioural problems, and social isolation. In the longer term, childhood obesity is associated with an increased risk of adult obesity, with increased morbidity and mortality in adult life, including cardiovascular diseases, type 2 diabetes and certain cancers, as well as with significant social and economic consequences (see e.g., Flegal et al. 2005; Fonseca & Gaspar de Matos 2005; Wright et al. 2005; Janssen et al. 2004; Friedlander et al. 2003; Gilliland et al. 2003; Strauss & Pollack 2003; Strauss 2001; Graham et al. 2000; ILSI 2000; Stradmeijer et al. 2000; Gunnell et al. 1998; Averett & Korenman 1996; Mendelson et al. 1996; Gortmaker et al. 1993). For a more comprehensive review see, for instance, Skidmore & Yarnell (2004), Zametking et al. (2004), Reilly et al. (2003), Edmunds et al. (2001), NTFPTO (2000) and Dietz (1998). 1 Obesity is a condition in which weight gain, predominantly fat, has reached the point of endangering health (NHS HDA 2003). For adults, obesity is defined as a Body Mass Index (BMI; weight in kilograms divided by height in meters squared) of 30 kg/m2 or more (WHO 1998)). For children and adolescents, age- and gender-specific cut-off points have been established (Cole et al. 2000). 5 The primary causes of overweightness and obesity at young ages include sociodemographic factors like family income, social class and parental obesity, and unhealthy lifestyles, characterised by an imbalance between energy intake and expenditure (e.g., Bray & Champagne 2005; Vereecken et al. 2005; Bosch et al. 2004; Swinburn et al. 2004; Storey et al. 2003; Whitaker 2003; Wang 2001; ILSI 2000; McMurray et al. 2000; Rössner 1998). Komlos & Baur (2004) moreover hypothesised there may be a relation between trends in physical state, in terms of height and weight, and the biological standard of living, a person’s socio-economic and epidemiological environment that includes social inequality, and the quality of the health care system and social safety nets. Such assertions make clear that countering the increase in obesity rates may be no means be simple. Indeed, Swinburn and Egger (2004) argued that obesity seems to be perpetuated and accelerated in a series of vicious positive feedback cycles, including movement inertia, and mechanical and psychological dysfunction. Overall, they stated, there are too many accelerators and not enough brakes. Still, although this study must mainly be viewed as a quest to gather knowledge, this study was initiated in the hope that it may help to find new brakes or find better ways to use the existing ones. 1.2 About the study This study investigated adolescents’ health behaviour in relation to their attitudes about their health lifestyle and their consideration of future consequences of their behaviour, focussing on young adolescents in the age of 12 to 14 years, attending 1st or 2nd grade of secondary education. The study consisted of two phases. First, discourse analysis was conducted using Q-methodology to identify operant attitudes among youths about their health lifestyle, with a focus on overweightness. Q-methodology is a fairly novel method in health research in the Netherlands, but has been around for about 70 years and has been applied extensively in many fields including health research (Brown 1980; Stephenson 1935; Van Exel & De Graaf 2005; Cross 2005). In this Q-methodological study, youths rank-ordered statements on issues like eating behaviour, overweightness, health risks, health perceptions and motivations/obstacles for adopting a healthier lifestyle. Q-factor analysis revealed five attitudes: “carefree sporty”, “worrying dependent”, “contended independent”, “looks over matter”, and “indifferent solitary”. This Q-methodological study showed that youths were more or less non-interested in their own health, however because 6 of different reasons. For most youths, neither current nor future health was of major concern, because they felt physically fit, were generally satisfied and happy, or because they simply did not care. Some were primarily involved with their eating behaviour, because of concerns with the consequences on appearance or with being physically unfit or overweight. This preoccupation with eating some times appeared far from healthy. Only one of the five health lifestyle attitudes combined healthy eating and exercising behaviour. Most youths appeared to have little knowledge and many questions regarding (their) health and overweightness. This phase of the study was concluded, the results have been published in more detail elsewhere (Van Exel et al. 2005, 2006; De Graaf et al. 2006). Next, survey analysis was conducted to investigate associations of these five attitudes about health lifestyle with health behaviour, in terms of eating and exercising behaviour, and adolescents’ expectations and consideration of future consequences of their behaviour. Aim of this analysis is to explore possible alternative, target-group specific strategies for prevention of overweight and obesity among youths in the different discourses. This document reports on the second phase of the study. 1.3 About this report This report is meant to serve as a reference book for future output from the project (e.g., papers, presentations, et cetera) by providing: a comprehensive but concise description of the “Health & Future” questionnaire, a full overview of the data collected, in relation to the main outcome variable “overweight”, the results of intermediate analyses of multiple-item scales. Section two of this report accounts for the selection of measures, the data collection, and includes the results of intermediate analyses of multiple-item scales that were used in this study. Section three describes the study, discusses the representativeness of the sample, and reports descriptive statistics for all variables included in the “Health & Future” questionnaire, including bivariate correlarions with measures of the main outcome variable “overweight”. 7 8 2 2.1 Methods About the “Health & Future” questionnaire 2.1.1 Aim of the questionnaire The aim of the “Health & Future” questionnaire was to collect a coherent set of data that makes it possible to investigate associations of adolescents’ attitudes about health lifestyle with their actual eating and exercising behaviour, and their expectations and consideration of the future consequences of their behaviour. 2.1.2 Selection of topics A three-step strategy was adopted for the selection of topics and measures to be included in the “Health & Future” questionnaire. First, interviews were held with eight Dutch policy, research and field experts in the fields of adolescents, behaviour, health and overweightness or obesity, including members of the advisory board of this project (see Annex A). Next, a literature review was conducted in search of personal and contextual / environmental variables that may be associated with health lifestyle, health behaviour, overweight and obesity in adolescents (see Annex C). Finally, key international and national survey questionnaires (or study protocols) addressing the same target group and topics, identified through the review and interviews, were examined (see Annex D). Based on these resources, a long-list of topics was developed, and structured according to eight themes: 1. About you 2. About your health 3. About your future 4. About home 5. About school 6. About your leisure time 7. About what you eat 8. About money. Sets of questions were developed within each theme, as much as possible relying on available formats and formulations from existing, validated questionnaires (see Annex D) and former questionnaires developed by project team members (e.g., Brouwer & Van Exel 2005; Van Exel et al. 2004; Van Exel & Brouwer 2003). The draft questionnaire was discussed with 9 the advisory board, in terms of the selection of topics and corresponding questions, the appropriateness of the total set of questions for answering the research question, the feasibility of the questionnaire for the target group, and the recruitment of schools and pupils (see section 2.1.3). The revised final draft questionnaire was tested in a small convenience sample of adolescents in the target audience, which lead to some minor changes in language use. The final questionnaire is included in Annex E [in Dutch]. 2.1.3 Recruitment of schools and pupils The intended survey population was adolescents attending school at pre-vocational2 and general secondary3 education levels (see Figure 1). Dutch adolescents enter secondary school after eight years of primary education starting age 4. The different levels of secondary education prepare adolescents for middle vocational education or higher vocational / academic education (bachelor / master system). Some 817 thousand youths attended school at secondary education level in curriculum year 2004/2005, of whom about 351 thousand 1st and 2nd graders (CBS 2005). Figure 1 Schematic overview of the Dutch education system 2 3 i.e., VMBO beroepsgericht, theoretisch of gemengd. i.e., HAVO, VWO of Gymnasium. 10 In order to investigate adolescents’ health behaviour in relation to their attitudes about their health lifestyle and their consideration of future consequences of their behaviour, taking into consideration the main individual and contextual variables that are associated with overweight and obesity, the primary aim in the data collection was to have a fair distribution over smaller and larger schools in lower and higher urbanized areas throughout the country. Schools were approached for participating in the study based on the city of location, the size of the school and the education levels offered by the school. The aim was to recruit between 1,000 and 1,250 pupils (i.e., 50 classes of 20-25 pupils) from ten schools; 40 to 50 each (i.e., two classes) at three small schools, 80 to 100 each (i.e., four classes) at three middle sized schools, and 160-200 each (i.e., ten classes) at four large schools. The following approach was adopted: 1. 20 cities were selected, one larger and one smaller city in each of the ten provinces in the Netherlands. 2. A list of schools offering secondary education was collected from the telephone directory of each from city. 3. For each city two schools were randomly selected from this list, and information was retrieved regarding the size of the school and education levels offered through the internet or by telephone. 4. The list of schools was categorised according to the size of the school, based on number of 1st grade classes; up to 3 was classified as a small school, between 4 and 7 as a middle sized school, and more than 7 as a large school. 5. Within each category, schools were pre-selected based on city of location and education levels offered in order to ariive at a fair spread of schools across the country and a fifty-fifty distribution of classes between pre-vocational and general secondary education level. 6. The pre-selected schools were approached by telephone. If a school was not interested, a matching school was selected and approached (from the list in point 5, moving up with each refusal). 7. Schools that were interested in participating in the study were sent an information package regarding the aim and the set-up of the study. An appointment was made for call back. 8. With the schools that agreed to participate, agreements were made regarding the number of questionnaires to send, a contact person for the study, and time and procedure for administration of the questionnaires. Steps 6 and 7 were repeated until ten schools agreed to participate. 11 To increase response, pupils were informed that there would be a raffle of prizes among respondents returning a completed questionnaire: a first prize of €100 and five prizes of €20 among respondents from all schools, and a €10 prize among respondents from each class. 2.1.4 Administration of the questionnaire The contact person at each school received a package for each class recruited, containing 30 questionnaires, a stamped envelope with mail back address, and instructions for the teacher(s) administering the questionnaire. The contact person distributed the packages among the selected teacher(s) and went through the instructions with them. The instructions for the teachers, apart from a few practical details, emphasised three issues. First, teachers were emphatically requested to ask pupils, on the day before administering the questionnaire, to weigh and measure themselves at home the next morning, before coming to school. Second, teaches were asked to organize the school desks like is usually done for written exams, so that pupils would work individually and have sufficient privacy. Third, teachers were asked to emphasise to their pupils, before distributing the questionnaire, that anonymity was guaranteed and that neither the school nor the teacher would have access to information contained in individual questionnaires. The sheet containing personal information necessary for the raffle was attached as backpage to the questionnaire. After completion, pupils separated this backpage from the main questionnaire, and handed both in separately. 2.2 Contents of the “Health & Future” questionnaire The “Health & Future” questionnaire (see Annex E) consisted of eight clearly demarcated sections, corresponding to the themes identified in the selection of topics (see 2.1.2). Here, we briefly introduce the questions that were included in each section, including an account of the measures used, some data consideration issues, and results of intermediate analyses of any multiple-item scales. 2.2.1 About you (questions 1 to 8) This section of the questionnaire asked adolescents about personal characteristics: gender, age, country of birth, education level, grade (1st or 2nd), attitude about health lifestyle, happiness and personality. 12 Normal age in 1st and 2nd grade of secondary school is 12 to 14. In the questionnaire there were five answer categories to age (question 2), ranging from 11 to 15. For ease of presentation, in any tables where age is included as a categorical variable the ages of 11 and 12 will be aggregated under the label “12-”, and the ages of 14 and 15 will be aggregated under the label “14+”. Actual ages will be used in all analyses. Ethnicity was assessed using the common definition by the Dutch National Bureau of Statistics (CBS): if both parents were born in the Netherlands, the adolescent is classified as being autochthonous; if at least one of the parents was born outside the Netherlands, the adolescent is classified as being allochthonous. Within the allochthonous population a further distinction is made between those from western and non-western origin, the latter defined as originating from Africa, Latin America, Asia (excl. Indonesia and Japan) or Turkey. The survey population included adolescents attending two secondary education levels, namely pre-vocational and general secondary education (see section 2.1.3). Unless stated otherwise, education level is included as a categorical variable distinguishing between prevocational and general secondary education levels in all tables and analyses; sub-levels are ignored. Adolescents’ attitude about their health lifestyle (question 6) was assessed using the results of a Q-methodological study, conducted in the first phase of this study (see section 1.2). The five operant attitudes about health lifestyle among adolescents in 1st and 2nd grade of secondary school were: “carefree sporty”, “worrying dependent”, “contended independent”, “looks over matter”, and “indifferent solitary”. Attitude membership was assessed in two ways. The large majority of questionnaires included the format presented in Annex F, which asked adolescents to elicit which of the attitudes about health lifestyle fitted them best. A small sample, half of the adolescents in one of the large schools, received a questionnaire including the format presented in Annex G, which asked them to elicit to which extent each of the attitudes about health lifestyle fitted them (five answer categories, ranging from “not at all” to “very well”). Happiness (question 7) was assessed using a visual analogue scale ranging from 0 “very unhappy” to 10 “very happy”, on which respondents were asked to indicate how happy they generally feel. 13 Personality (question 8) was assessed using a short version of the Dutch translation of Goldberg’s adjective 100 list for the Big-Five personality dimensions (Goldberg 1992; Gerris et al. 1998). The Big-Five dimensions, more easily remembered by the acronym OCEAN, are: ‘openness to experience’ (O), ‘conscientiousness’ (C), ‘extraversion’ (E), ‘agreeableness’ (A), and ‘neuroticism’ (N). This 30-item short version was used before in similar study populations (De Bruijn et al. 2005; Gerris et al. 1998; Scholte et al. 1997). Furthermore, this 30-item short version is part of the Family Survey of the Dutch Population (De Graaf, De Graaf, Kraaykamp & Ultee 2000) and has been used in publications using data from this survey (e.g., Bekkers 2005; Bekkers & De Graaf 2002). Respondents were presented 30 general human traits, six for each Big-Five personality dimension (see Table 1), and asked to indicate to what extent these traits applied to themselves (seven answer categories, ranging from “not at all” to “definitely”). Table 1 Big-Five personality dimensions and markers for 30-item short version Openness to experience Conscientiousness Extraversion Agreeableness Neuroticism (O) (C) (E) (A) (N) Artistic Careful Bashful * Agreeable Anxious Complex Neat Introverted Cooperative Fearful Creative Organized Quiet Helpful High-strung Deep Sloppy Reserved Kind Irritable Imaginative Systematic Talkative * Pleasant Nervous Innovative Thorough Withdrawn Sympathetic Touchy Source: Gerris et al. (1998). Note: * two markers were missing in questionnaire due to a print failure. Because the validity of this set of markers for the Big-Five personality dimensions was demonstrated before (De Bruijn et al. 2005; Bekkers 2005; Bekkers & De Graaf 2002; Gerris et al. 1998; Scholte et al. 1997), we proceeded straightaway with confirmatory factor analysis using a five-factor criterion.4 The final selection of markers used for attribution of youths to personality dimensions was reached in four consecutive steps: (1) Five factors were extracted from 28 markers (explained variance 48.7%; communalities 0.265-0.683; Kaiser-Meyer-Olkin sampling adequacy 0.861). Three markers showed factor-loadings >.30 on more than one factor and were excluded from further analysis: fearful (N), systematic (C) and withdrawn (E). 4 Confirmatory factor analysis is used to confirm the findigns of earlier exploratory factor analysis, i.e., that scale items (here: markers) load on to the anticipated factor (here: personality dimensions) and correlate weakly with the other factors (Bowling 1997). 14 (2) Five factors were extracted from 25 markers (explained variance 49.3%; communalities 0.260-0.693; KMO sampling adequacy 0.837). Two markers showed factor-loadings >.30 on more than one factor and were excluded from further analysis: complex (O) and nervous (N). (3) Five factors were extracted from 23 markers (explained variance 51.3%; communalities 0.255-0.697; KMO sampling adequacy 0.834). Two markers showed factor-loadings >.30 on more than one factor and were excluded from further analysis: careful (C) and high-strung (N). (4) Five factors were extracted from 21 markers (explained variance 52.2%; communalities 0.258-0.720; KMO sampling adequacy 0.809; see Table 2). Scale reliability ranged from .57 for neuroticism (N) to .80 for conscientiousness (C). 2.2.2 About your health (questions 9 to 14) This section of the questionnaire addressed some key health and health perception variables: health status, chronic health conditions, length, weight, body image, and smoking behaviour. Health status (question 9) was assessed using a visual analogue scale ranging from 0 “worst conceivable health condition” to 10 “best conceivable health condition”, on which respondents were asked to indicate how healthy they generally feel. The questionnaire included self-report measures of length and weight (questions 10 and 11). The reliability of self-reported values of length and weight is often contested, especially in this age group (see Annex B for a discussion). Generally, self-reported values lead to underestimation of body mass at the individual level, and of the prevalence of overweight and obesity at the population level. We attempted to reduce the inaccuracy of self-reported values by asking all teachers emphatically to instruct their pupils, on the day before administering the questionnaire, to weigh and measure themselves at home the next morning, before coming to school (see section 2.1.4). Although this specific instruction may have helped to reduce the information problem of adolescents in growth not knowing their actual length and weight, it will not help to overcome other possible reasons for reporting a height or weight that deviates from the actual value. To emphasise the importance of reporting true values and as a means to check for possible bias, a question was added asking respondents to indicate whether they were “pretty certain” or “not so certain” of their self-reported length and weight: 75% indicated they 15 Table 2 I. II. Confirmatory factor analysis Big-Five personality dimensions Openness to experience (O) Conscientiousness (C) III. Extraversion (E) IV. Agreeableness (A) V. Neuroticism (N) Artistic Openness to experience (O) Conscientiousness (C) Extraversion (E) Agreeableness (A) Neuroticism (N) communalities 0.703 0.072 0.077 0.061 -0.043 0.511 Creative 0.710 0.108 0.008 0.149 -0.050 0.541 Deep 0.468 0.028 0.134 0.156 0.166 0.289 Imaginative 0.636 -0.131 -0.146 0.096 0.121 0.467 Innovative 0.429 0.103 -0.071 0.233 0.063 0.258 Neat 0.068 0.832 0.042 0.143 0.025 0.720 Organized 0.072 0.767 0.013 0.194 0.076 0.638 Sloppy 0.105 -0.799 0.043 0.073 0.185 0.691 Thorough 0.167 0.719 0.119 0.194 0.067 0.601 Introverted -0.015 -0.019 0.733 -0.164 0.180 0.597 Quiet -0.013 0.142 0.775 -0.091 0.028 0.630 Reserved 0.041 -0.007 0.739 -0.034 0.146 0.570 Agreeable 0.121 0.099 -0.225 0.458 -0.189 0.320 Cooperative 0.095 0.144 0.016 0.747 0.107 0.600 Helpful 0.096 0.182 0.029 0.704 0.120 0.554 Kind 0.047 0.052 -0.100 0.688 -0.098 0.498 Pleasant 0.200 0.005 -0.053 0.640 -0.051 0.455 Sympathetic 0.230 0.039 -0.082 0.563 -0.003 0.377 Anxious 0.046 0.064 0.236 0.094 0.581 0.408 Irritable 0.131 -0.051 -0.047 -0.141 0.753 0.608 Touchy 0.022 -0.015 0.194 -0.012 0.772 0.635 Mean Explained variance Scale reliability (Cronbach's alpha) 0.522 9.5% 12.3% 9.1% 13.1% 8.2% .59 .80 .67 .73 .57 16 were pretty certain of their length, 76% of their weight. Those not so certain of their length tended to report lower values (p<.01), while those not so certain of their weight tended to report higher values (p<.01). Nevertheless, BMI values - our key variable of interest - did not differ significantly (p<.01) between those that are pretty certain of both their length and weight, and those that are not so certain of one or both parameters. Overweight and obesity were assessed by calculating BMI values and by using international gender and age specific cut-off points (Table 3). Table 3 International Body Mass Index (BMI) cut-off points for overweight and obesity in adolescents; by gender and age Age Girls Boys Overweight Obese Overweight Obese 11 20.74 25.42 20.55 25.10 12 21.68 26.67 21.22 26.02 13 22.58 27.76 21.91 26.84 14 23.34 28.57 22.62 27.63 15 23.94 29.11 23.29 28.30 Source: Cole et al. 2000 Body image (question 12) was assessed by asking “What do you think of your own body?”, with five possible answer categories that ranged from “much too thin” to “much too thick”, with “exactly right, actually” as middle answer category. Furthermore, we asked respondents whether they had one or more chronic conditions or disabilities (question 13) and about their smoking behaviour during the last four weeks (question 14). 2.2.3 About your future (questions 15 to 22) This section included a series of questions aiming to assess adolescents’ appreciation and expectations of their future and the future consequences of their behaviour. As this seems to be a fairly novel subject area in this age group, we will discuss the approach and measures chosen more extensively. Adolescents’ appreciation of their future was assessed using four different measures. The first measure was Strathman et al.’s (1994) 12-item “consideration of future consequences” 17 (CFC) scale.5 Two researchers independently translated the CFC scale into Dutch and simplified the wording to make the scale it more comprehensible for young adolescents (in conformance with Cauffman & Steinberg 2000). Both versions were compared with the aid of a third researcher, and combined into a Dutch CFC scale for adolescents (CFCDA; question 15). Respondents were asked to indicate for each statement how characteristic it is of them on a Likert-type scale ranging from 1 (extremely uncharacteristic) to 5 (extremely characteristic). Possible scores therefore range from 12 to 60, with higher scores indicating higher consideration of future consequences. For ease of interpretation and comparability with other measures used in this study, final scores on the CFCDA were re-scaled to represent a range between 0 “lowest” and 10 “highest” consideration of future consequences. The second measure (question 17), that we have called “meaning of future life”, asked respondents how important it is to them what their life will be like in 2, 5 and 25 years from now, with four possible answer categories that ranged from “very important” to “not at all important”. The third measure (question 18) asked respondents to make a series of trade-offs between money values now and in the future, i.e., 2, 5 and 25 years from now. Answers were used to calculate adolescents’ discounting rates. This is a fairly standard economic approach, but novel in this context. The fourth measure (question 19) asked * long live the here and now respondents to consider three investments that would yield a better health at age 70 or extend their live with 3 years: improve their dietary behaviour, exercise 30 minutes per day more, and take an injection that would make them pretty sick for the next week. Adolescents’ expectations of their future was assessed by asking for their life expectancy (question 16) and expected health status at the age of 40 and 70 (questions 20 and 21). For all questions regarding the future we used carefully specified and mutually consistent ages and timelines. The anchor ages chosen were 40 and 70 years, rounded numbers that were expected to correspond fairly with the age of this target group’s parents and grandparents. Previous research has shown that people tend to use close family members as reference for eliciting expectations regarding their future health and life expectancy (e.g., 5 See also: http://www.missouri.edu/~psyas/cfc.pdf 18 Brouwer & Van Exel 2005). Furthermore, the timeline of 25 years corresponds to the first anchor age, more or less the age of their parents. The time line of 5 years more or less coincides with the end of the secondary school period, and was expected to be a more common focus for this target group when talking about “the future”. The timeline of 2 years was added because, after the interviews in the phase of the study (see section 1.2), we expected this to be a fair approximation of “distant future” in the perception of many adolescents. 2.2.4 About home (questions 23 to 34) The aim of this section was to gain insight in the characteristics of adolescents’ home situation, and its role in health attitudes, behaviours and future expectations. The questions concerned the composition of the household, the country of birth and employment status of both parents, perception of relative family wealth, religious upbringing, availability at will of healthy and unhealthy foods, whether they are allowed to smoke or drink alcohol at home, a set of statements assessing the adolescent-parents relationship, parenting style, and happiness at home. Analogous to the approach of Watt & Sheiham (1998), a Food Availability at Home Index (FAHI) was constructed in order to assess adolescents’ access to unhealthy food at home. Table 4 presents the questions selected and the scoring system used. FAHI scores range between 0 and 10, higher scores indicate higher access to unhealthy food at home. FAHI scores were negatively associated (p<.01) with mother having a job, perceived relative family wealth, religious upbringing, and the health belief statement “I eat healthy” (question 22). Table 4 Food Availability at Home Index (FAHI) scoring system Item Do you have these products at home and are you allowed to have one if you feel like it? (question 30, statements C - G) Answer caregories Score 1. Biscuit Yes No 2 0 2. Candy / chocolate Yes No 2 0 3. Chips / nuts / popcorn Yes No 2 0 4. Snacks Yes No 2 0 5. Soft drink (not light / sugar-free) Yes No 2 0 Analogous to the approach of Kremers et al. (2003), a fourfold typology of parenting style (PS) was constructed, based on the interaction between parental involvement (I) and 19 parental strictness (S) (question 33, statement A “My parents are interested in what I do or what I am concerned with” and statement C “My parents are strict”): authoritative (high I; high S; 24% of respondents), authoritarian (low I; high S; 2%), indulgent (high I; low S; 71%), and neglectful (low I; low S; 3%). 2.2.5 About school (questions 35 to 43) The aim of this section was to gain insight in the characteristics of adolescents’ school environment, and its role in health attitudes, behaviours and future expectations. The questions concerned travel mode and travel time to school, school performance, bullying, availability of healthy and unhealthy foods at school and close to school, where they go to after school, who is home when they come home from school, and happiness at school. 2.2.6 About your leisure time (questions 44 to 52) The aim of this section was to gain insight in how adolescents spend their leisure time, and its role in health attitudes, behaviours and future expectations. The questions concerned the number of good friends, time spent on several sedentary and non-sedentary behaviours on school and weekend days, membership of a sports club (and if so, hours training and participation in competition), statements regarding reasons for exercising, solitude and boredom, and happiness during leisure time. Analogous to the approach of Watt & Sheiham (1998), a Physical Activity Index (PAI) was constructed in order to assess adolescents’ level of physical activity. Table 5 presents the questions selected and the scoring system used. PAI scores range between 0 and 10, higher scores indicate higher levels of physical activity. Table 5 Physical Activity Index (PAI) scoring system Item Answer caregories Score 1. How do you usually travel to/from school? By bike or walking By schoolbus, public transport, car or otherwise 2 0 2. Are you member of a sports club? Yes No 2 0 3. Do you participate in a sports competition? Yes No 2 0 4. On average, how much time do you spend playing outside on weekdays? More than 2 hours per day / Between 1 and 2 hours per day One hour or les per day / Not at all 2 0 5. On average, how much time do you spend playing outside on weekenddays? More than 2 hours per day / Between 1 and 2 hours per day One hour or les per day / Not at all 2 0 20 PAI scores correlate statistically significantly and in expected directions with all of six statements about playing sports (Likert-type scale, “totally agree” - “totally disagree”; question 50), correlation coefficients however were moderate to low: “When I play sports, that is because I enjoy it” (-; p<.01); “When I play sports, that is because I want to keep fit” (-; p<.01); “When I play sports, that is because I want to look good” (-; p<.05); “When I play sports, that is because I meet friends then” (-; p<.01); “When I play sports, that is because I want to become one of the best” (-; p<.01); and “When I play sports, that is because my parents oblige me” (+; p<.01). PAI scores also correlate statistically significantly (p<.01) and in expected directions with five out of seven health belief statements (Likert-type scale, “totally agree” - “totally disagree”; question 22), correlation coefficients however were moderate to low: “I eat healthy” (-); “I exercise enough to stay fit” (-); “Living healthy makes me feel better” (-); “If I live unhealthy I may incur all sorts of diseases in the future” (-); and “If I live unhealthy, I may die sooner” (-). 2.2.7 About what you eat (questions 53 to 55) The aim of this section was to gain insight in adolescents’ eating behaviour. Van Assema et al. (2002) suggested that most often used food frequency questionnaires have only limited capacity to make a valid assessment of adolescents fruit and vegetable intake. Brener et al. (2002) assessed the test-retest reliability of a large range of self-report measures included in the YRBSS (see also section 2.1.2), and found the reliability of nearly all items to be at least moderate, and of nearly half to be substantial. Notably, dietary and physical activity behaviours had relatively low reliability. They argued that nutrition and physical activity may be less salient to adolescents and therefore recalled less reliably, but that inconsistent responses may also be related to variability in these behaviours among adolescents. Matheson et al. (2002) agreed that self-report questionnaires may result in sizable errors in quantitative estimates 21 of food and energy intakes, but argued they are appropriate for ranking children's relative intakes. The questions concerning eating behaviour have therefore been focussed on two salient issues. First, the questionnaire asked about the frequency of consumption of a variety of unhealthy snacks and the context of snacking in terms of location and activities (questions 53, 54). Second, the questionnaire asked about frequency of eating breakfast, lunch, and dinner at the table together with the family, and the frequency of consumption of a variety of target (un)healthy food types: milk, soft-drinks (not light), fruit and vegetables. Analagous to the approach of Watt & Sheiham (1998), a Healthy Eating Index (HEI) and an Unhealthy Eating Index (UEI) were constructed in order to assess adolescents’ eating behaviour. Table 6 and Table 7 present the questions selected and the scoring system used. HEI and UEI scores range between 0 and 10, higher HEI scores indicate healthier eating, higher UEI scores indicate unhealthier eating. Table 6 Healthy Eating Index (HEI) scoring system Item Answer caregories 1. How often do you eat breakfast? Every day / Often, but not every day Once or twice a week / (Almost) Never 2 0 Every day / Often, but not every day Once or twice a week / (Almost) Never 2 0 3. How often do you drink milk? Every day / Often, but not every day Once or twice a week / (Almost) Never 2 0 4. How often do you eat fruit? Every day / Often, but not every day Once or twice a week / (Almost) Never 2 0 5. How often do you eat vegetables? Every day / Often, but not every day Once or twice a week / (Almost) Never 2 0 (more than only something to drink or a snack) 2. How often do you eat dinner at the table, together with your family? Score (more than only something to drink or a snack) (salad / cooked vegetables) Table 7 Unhealthy Eating Index (UEI) scoring system Item Answer caregories 1. How often do you eat cookies / cakes? Every day / Often, but not every day Once or twice a week / (Almost) Never 2 0 2. How often do you eat sweets / chocolate? Every day / Often, but not every day Once or twice a week / (Almost) Never 2 0 3. How often do you eat chips / nuts / popcorn? Every day / Often, but not every day Once or twice a week / (Almost) Never 2 0 4. How often do you eat snacks? Every day / Often, but not every day Once or twice a week / (Almost) Never 2 0 Every day / Often, but not every day Once or twice a week / (Almost) Never 2 0 (like hamburger, French fries, pizza) 5. Hof often do you drink soft drinks (regular, not light)? Score 22 HEI and UEI scores were not correlated. HEI and UEI scores correlated statistically significantly (p<.01) with PAI scores, correlation coefficients however are low; healthier eating is associated with higher levels of physical activity, unhealthier eating with lower levels of physical activity. HEI scores correlate statistically significantly (p<.01) and in expected directions with six out of seven health belief statements (Likert type from “totally agree to totally disagree; question 22) , correlation coefficients however are low: “I eat healthy” (-); “I exercise enough to stay fit” (-); “Living healthy makes me feel better” (-); “If I live unhealthy I may incur all sorts of diseases in the future” (-); “If I live unhealthy, I may die sooner” (-); and “If I were regularly ill, I would start living healthier” (-). HEI scores correlate statistically significantly and in expected directions with two of six statements about playing sports (Likert type from “totally agree to totally disagree; question 50), correlation coefficients however are low: “When I play sports, that is because I enjoy it” (-; p<.01); and “When I play sports, that is because I want to keep fit” (-; p<.01). UEI scores correlate statistically significantly (p<.01) and in expected directions with five out of seven health belief statements (Likert type from “totally agree to totally disagree; question 22) , correlation coefficients however are low: “I eat healthy” (+); “Living healthy makes me feel better” (+); “If I live unhealthy I may incur all sorts of diseases in the future” (+); “If I live unhealthy, I may die sooner” (+); and “If I were regularly ill, I would start living healthier” (+). Contrary to HEI scores, UEI scores do not correlate with the statement “I exercise enough to stay fit”. UEI scores correlate statistically significantly and in expected directions with two of six statements about playing sports (Likert type from “totally agree to totally disagree; question 50), correlation coefficients however are moderate to low: “When I play sports, that is because I want to keep fit” (+; p<.01); and “When I play sports, that is because I meet friends then” (-; p<.05). 2.2.8 About money (questions 56 to 63) The aim of this section was to gain insight in the size of adolescents’ monthly budget, where they get their money from (pocket money, job), how they spend it, and the influence of any spending restrictions imposed by parents and competing popular activities (e.g., mobile phones, music, clothing, cosmetics, alcoholic drinks, smoking) on the amount of money spent on sweets and snacks. 23 24 3 3.1 3.1.1 Results Study population Participating schools and number of respondents Ten smaller and larger schools in lower and higher urbanized areas throughout the country were recruited to participate in the study (see Figure 2); completed questionnaires were received from 2,006 pupils, with school proportions ranging between 2 and 18 percent (see Table 8). Figure 2 Participating schools Note: numbers correspond to those in Table 8. 25 Table 8 Number of respondents per school (n=2,006) School City 1 Agnieten College - Carolus Clusius Zwolle 263 (13) 2 Bornego College Heerenveen 362 (18) 3 Carmel College Salland Raalte 4 CSG De Lage Waard Papendrecht 5 CSG Dingstede Meppel 6 Gomarus Scholengemeenschap Gorinchem 285 (14) 7 Hondsrug College Emmen 145 (7) 8 Ichthus College Veenendaal 148 (7) 9 Jacobus Fruytier scholengemeenschap Apeldoorn 317 (16) 10 Sint Laurens College Rotterdam 215 (11) Total 3.1.2 N (%) 34 (2) 183 (9) 54 (3) 2006 (100) Representativeness of the sample Table 9 presents proportions in the reference and study populations according to gender, age, education level, grade and ethnicity. As Table 9 makes clear, the study sample deviates from the reference population on all selected variables, but most importantly with respect to education level and grade: General secondary education is considerably over-represented; higher education level is associated with higher proportions of female pupils (47.5% VMBO; 52.7% HAVO; 55.0% VWO) and Dutch ethnicity (76.6% VMBO; 83.5% HAVO; 87.1% VWO). 1st grade is over-represented; this is associated with lower age (12.8 in 1st; 13.7 in 2nd). Regarding the other variables: Female gender is slightly over-represented; this difference is associated with the bias on education level. Older ages are over-represented; this can partly be explained by difference in reference date between the reference population (1st of October) and the study sample (second half of May); furthermore, this difference is associated with the bias on grade. Dutch ethnicity is over-represented; in part, this difference is associated with bias the in education level. 26 Table 9 Reference population according to gender, age, education level, and ethnicity CBS 2005 (%) Variable This study (%) Gender Female Male 49.2 50.8 53.0 (+3.8) 47.0 (-3.8) Age 12 13 14 30.1 a 45.9 23.9 15.0 (-15.1) 51.0 (+5.1) 34.0 (+10.1) Education level Pre-vocational (VMBO) General secondary (HAVO/VWO) 52.7 b 47.3 41.6 (-11.1) 58.4 (+11.1) Grade First Second 49.9 50.1 56.7 (+6.8) 43.3 (-6.8) Ethnicity Dutch Other 78.3 21.7 90.2 (+11.9) 9.8 (-11.9) Note: a Source: MinOCW 2006. 3.2 b approximation based on adolescents in third grade. Length, weight, BMI and prevalence of overweight and obesity Table 10 presents self-reported length and weight, and BMI based on these values (for a discussion of the validity and reliability of self-reported values, see Annex B). Self-reported length systematically exceeded mean values from standard growth charts for adolescent length-for-age (TNO/LUMC 1998), with larger differences at younger ages. When looking at age- and gender-specific mean length and weight, boys’ self-reported weight was higher and girls’ self-reported weight was lower than values from standard growth charts for adolescent weight-for-length (TNO/LUMC 1998). Figure 3 shows cumulative distributions of self-reported length, weight and BMI according to gender. Table 10 Length, weight and BMI Variable Mean (SD) 95% CI Min - max Percentiles th 1.20 - 1.99 5 10th 50th 90th 95th 1.52 1.56 1.66 1.77 1.80 Length 1.66 (0.1) 1.66 - 1.67 - girls 1.65 (.01) 1.65 - 1.66 1.32 - 1.88 1.54 1.57 1.65 1.74 1.76 - boys 1.68 (.01) 1.67 - 1.68 1.20 - 1.99 1.52 1.55 1.67 1.80 1.83 Weight 51.8 (9.4) 51.4 - 52.3 35 - 118 39 41 51 64 69 - girls 51.4 (8.7) 50.9 - 51.9 35 - 118 39 41 50 62 65 - boys 52.2 (9.9) 51.6 - 52.9 35 - 111 39 40 51 65 70 BMI 18.6 (2.6) 18.5 - 18.7 11.6 - 37.2 15.1 15.6 18.4 21.9 23.1 - girls 18.7 (2.6) 18.6 - 18.9 11.6 - 37.2 15.2 15.8 18.4 22.0 23.3 - boys 18.5 (2.5) 18.3 - 18.7 12.0 - 30.6 15.0 15.6 18.3 21.7 22.9 27 100% 80% Cumulative Percent 1,93 1,90 1,88 1,86 1,84 1,82 1,80 1,78 1,76 1,74 1,72 1,70 1,68 1,66 1,64 1,62 1,60 1,58 1,56 1,54 1,52 1,50 1,48 1,46 1,44 1,42 1,39 1,35 1,20 111 96 88 85 83 79 81 77 75 73 71 69 67 65 63 61 59 57 55 53 51 49 47 45 43 39 41 37 35 100% girls boys 80% Cumulative Percent 100% 80% Cumulative Percent Figure 3 Cumulative distribution of length, weight and BMI according to gender [including gender-specific cut-off points (age 13; see Table 3) for overweight and obesity (in bold)] 60% 40% 20% girls 0% boys Length (meters) 60% 40% 20% girls 0% boys Weight (kilograms) 60% 40% 20% 0% 28,4 25,6 24,3 23,4 22,9 22,4 21,9 21,5 21,2 21,0 20,6 20,3 20,1 19,8 19,6 19,4 19,1 18,8 18,6 18,4 18,2 17,9 17,7 17,5 17,3 17,0 16,8 16,5 16,3 16,0 15,8 15,5 15,2 14,9 14,2 11,6 Body Mass Index (BMI) 28 Using gender- and age-specific international BMI cut-off points for overweight and obesity in adolescents (Cole et al. 2000; Table 3), prevalence of overweight was 7.6%, and of obesity 0.7%. These rates are fairly low as compared to recent reference values (TNO 2006), but comparable to those reported for Dutch adolescents of 12 to 15 years in 1997 (Hirasing et al. 2001). Recent reference values include 10.5% / 1.5% for girls and 10.6% / 1.2% for boys in 2nd grade of secondary education in curriculum year 2003/2004 from a regional study, and 16.2% / 2.9% for girls and 15.7% / 3.0% for boys aged 12 to 14 years in 2002-2004 from a representative sample in a national study (TNO 2006). To assess whether the sample bias (see section 3.1.2) affects the prevalence rates of overweight and obesity, in particular with respect to the variables education level and ethnicity, two sets of weights were calculated through direct standardisation. A first set of weights was based on education level and grade (range from 0.81 to 1.90). A second set on education level, grade and ethnicity (range from 0.74 to 4.63). Weighing the data, however, had no significant effect on the prevalence of overweightness and obesity. There are two main reasons why this weighing procedure may not have led to prevalence rates that are more in conformance with the higher values observed in other studies. First, when weighing data it is assumed that the observations that are exploded are representative of the corresponding sub-population. This may not be the case. Second, it is possible that the low prevalence rates are the result of selection bias. The ten participating schools may constitute a relatively slim selection from the total population. Finally, we investigated the association of length, weight and BMI with body image (see Table 11). BMI values based on self-reported height and weight seem to be largely consistent with adolescents’ body image. Irrespective of the fact whether the sample is biased or slim, quantile regression (Koenker & Bassett 1978) will be applied as primary method for subsequent multivariate analysis of the data. Quantile regression is an appropriate technique when differences in association are expected between parts of the distribution of the outcome variable and the explanatory variables. Quantile regression therefore seems very suitable for analysis of the correlates of overweight, as our primary interest goes out to the attitudes, health behaviour and consideration of future consequences of the at risk group, i.e. adolescents in the 80th centile of the BMI distribution. Quantile regression has been used for this purpose before (Kobayashi & Kobayashi 2006; Wei et al. 2006; Sturm & Datar 2005; Kan & Tsai 2004; Zimmermann et al. 2004; Herpertz-Dahlmann et al. 2003; Smith et al. 2003). 29 Table 11 Length, weight and BMI according to body image Total Height N % Mean SD Much too thin A bit too thin Exactly right, actually A bit too thick Much too thick 25 238 1068 580 62 86.2% 98.8% 98.9% 99.0% 93.9% 1.64 1.66 1.66 1.67 1.68 (0.1) (0.1) (0.1) (0.1) (0.1) 1.43 1.40 1.20 1.40 1.50 Total 1973 98.6% 1.66 (0.1) 27 233 1047 572 62 93.1% 96.7% 96.9% 97.6% 93.9% 45.5 46.1 50.1 56.2 66.0 (10.4) (6.5) (8.0) (8.5) (15.3) 35 35 35 37 44 Total 1941 97.0% 51.8 (9.3) Much too thin A bit too thin Exactly right, actually A bit too thick Much too thick 24 230 1036 567 59 82.8% 95.4% 95.9% 96.8% 89.4% 15.8 16.7 18.0 20.2 23.0 Total 1916 95.7% 18.6 Weight Much too thin A bit too thin Exactly right, actually A bit too thick Much too thick BMI Girls Min Max Boys N % Mean SD Min Max N % Mean SD Min Max 1.88 1.86 1.92 1.99 1.99 16 97 530 356 45 94.1% 99.0% 98.5% 98.9% 97.8% 1.64 1.65 1.65 1.66 1.68 (0.1) (0.1) (0.1) (0.1) (0.1) 1.50 1.45 1.32 1.47 1.55 1.88 1.80 1.86 1.87 1.80 9 141 536 223 16 75.0% 98.6% 99.3% 99.1% 84.2% 1.66 1.66 1.67 1.68 1.68 (0.1) (0.1) (0.1) (0.1) (0.1) 1.43 1.40 1.20 1.40 1.50 1.87 1.86 1.92 1.99 1.99 1.20 1.99 1044 98.6% 1.65 (0.1) 1.32 1.88 925 98.5% 1.67 (0.1) 1.20 1.99 73 72 90 96 118 17 94 522 349 44 100.0% 95.9% 97.0% 96.9% 95.7% 42.5 45.1 49.2 55.3 63.8 (9.2) (5.5) (6.8) (7.6) (15.1) 35 35 35 38 47 73 58 83 84 118 10 139 523 222 17 83.3% 97.2% 96.9% 98.7% 89.5% 50.6 46.7 50.9 57.5 71.0 (10.8) (7.1) (8.9) (9.6) (15.2) 36 35 35 37 44 72.0 72.0 90.0 96.0 111.0 35 118 1026 96.9% 51.4 (8.7) 35 118 911 97.0% 52.3 (10.0) 35 111.0 (2.0) (1.5) (1.9) (2.4) (4.2) 11.6 12.1 12.0 12.8 17.0 20.3 20.8 28.4 30.6 37.2 16 93 514 345 43 94.1% 94.9% 95.5% 95.8% 93.5% 15.2 16.5 18.0 20.1 22.6 (1.8) (1.3) (1.8) (2.3) (4.4) 11.6 13.7 13.0 15.1 17.0 19.8 19.5 26.4 29.1 37.2 8 137 520 221 15 66.7% 95.8% 96.3% 98.2% 78.9% 16.8 16.8 18.0 20.3 24.1 (2.0) (1.6) (2.0) (2.5) (3.2) 15.1 12.1 12.0 12.8 18.1 20.3 20.8 28.4 30.6 29.1 (2.6) 11.6 37.2 1011 95.5% 18.7 (2.6) 11.6 37.2 901 96.0% 18.5 (2.5) 12.0 30.6 30 An additional advantage is that for quantile regression it is not necessary to classify adolescents into (over)weight categories. Assuming that BMI values based on self-reported height and weight are valid representations of actual values, but systematically underestimate measured values, analysing the data as a distribution partly mitigates the problem of the low observed overweight and obesity prevalence rates in this sample. An issue to account for in the interpretation of results, however, is that adolescents in the heaviest quartiles of measured weight tend to underreport weight by significantly more than those in lighter quartiles, so that effect sizes most probably will constitute an underestimation. Furthermore, as is commonly done, logit and generalised ordered logit analysis will be applied to data categorised according to age and gender specific cut-off points for overweight and obesity (see were pretty certain of their length, 76% of their weight. Those not so certain of their length tended to report lower values (p<.01), while those not so certain of their weight tended to report higher values (p<.01). Nevertheless, BMI values - our key variable of interest - did not differ significantly (p<.01) between those that are pretty certain of both their length and weight, and those that are not so certain of one or both parameters. Overweight and obesity were assessed by calculating BMI values and by using international gender and age specific cut-off points (Table 3). Table 3). This will primarily be done to obtain results that are comparable to other studies. 3.3 Variables 3.3.1 About you Table 12 Personal characteristics, BMI, overweight and obesity Variable Category Value BMI th Mean 90 Proportion Proportion overweight obese Gender Female Male 1062 (53) 942 (47) 18.7 18.5 22.0 21.7 .067 .085 .005 .010 Age 1213 14+ 301 (15) 1023 (51) 682 (34) 18.0 18.4 19.1 20.7 21.7 22.7 .072 .073 .082 .011 .007 .006 Country of birth Netherlands Other 1910 (95) 96 (5) 18.6 18.6 21.9 21.7 .076 .078 .008 - Ethnicity Dutch Allochthonous, western Allochthonous, non-western 1809 (90) 74 (4) 117 (6) 18.6 18.9 19.1 21.8 22.6 22.8 .072 .129 .109 .006 .014 .018 31 Variable Category Value BMI th Mean 90 Proportion Proportion overweight obese Education Pre-vocational General secondary 825 (42) 1157 (58) 18.8 18.5 22.2 21.5 .091 .062 .013 .004 Grade First Second 1137 (57) 867 (43) 18.3 19.0 21.5 22.2 .075 .077 .011 .002 Attitude about health lifestyle Carefree sporty Worrying dependent Contended independent Looks over matter Indifferent solitary (39) (22) (14) (24) (2) 18.2 19.6 18.4 18.6 19.5 21.1 23.8 21.3 21.9 23.6 .048 .156 .059 .059 .185 .003 .023 .004 .037 Happiness a Mean or lower Above mean 601 (30) 1376 (70) 19.0 18.4 22.7 21.5 .115 .059 .012 .005 Personality b Neuroticism (+) (-) 875 (50) 867 (50) 18.5 18.8 21.4 22.2 .057 .100 .001 .013 Extraversion (+) (-) 921 (53) 821 (47) 18.6 18.7 21.8 22.0 .074 .085 .003 .011 Openness to experience (+) (-) 851 (49) 891 (51) 18.6 18.7 22.1 21.8 .087 .071 .006 .008 Conscientiousness (+) (-) 833 (48) 909 (52) 18.8 18.5 22.1 21.6 .094 .065 .008 .007 Agreeableness (+) (-) 812 (47) 930 (53) 18.8 18.5 22.1 21.7 .093 .067 .009 .006 722 398 250 445 29 Note: a descriptive statistics happiness (mean (SD); 95%CI; min-max): 7.94(1.27); 7.88-7.99; 1-10. versus negative personality-factor loaders. 3.3.2 b positive About your health Table 13 Health, BMI, overweight and obesity Variable Category Value BMI Mean 90th Proportion Proportion overweight obese Health status a Mean or lower Above mean 783 (39) 1205 (61) 19.1 18.3 22.8 21.3 .116 .051 .012 .004 Body image Much too thin A bit too thin Exactly right, actually A bit too thick Much too thick 29 241 1080 586 66 (1) (12) (54) (29) (3) 15.8 16.7 18.0 20.2 23.0 19.7 18.6 20.4 23.1 28.0 .023 .157 .517 .002 .009 .121 Chronic condition No Yes, low burden Yes, high burden 1719 (86) 265 (13) 19 (1) 18.6 19.0 20.0 21.8 22.2 28.3 .071 .096 .222 .007 .004 .111 Smoking No Yes, now and then Yes, every day 1833 (92) 121 (6) 50 (2) 18.6 19.0 19.9 21.8 21.9 24.4 .072 .080 .196 .002 .022 Note: a descriptive statistics health status (mean (SD); 95%CI; min-max): 7.69(1.27); 7.64-7.75; 0-10. 32 3.3.3 About your future Table 14 Future, BMI, overweight and obesity Variable CFCDA a Category Value BMI Mean 90th Proportion Proportion overweight obese Mean or lower Above mean 859 (43) 1146 (57) 18.5 18.7 21.8 21.9 .077 .074 .006 .008 Life expectancy b Mean or lower Above mean 941 (53) 827 (47) 18.7 18.5 22.0 21.5 .082 .063 .006 .009 Meaning of future c life… … in 2 years (+) (-) 1765 (89) 226 (11) 18.7 18.2 21.9 21.4 .074 .086 .006 .014 … in 5 years (+) (-) 1827 (92) 162 (8) 18.7 18.2 21.9 21.4 .077 .060 .007 - … in 25 years (+) (-) 1761 (88) 229 (12) 18.6 18.6 21.9 21.4 .075 .070 .007 .005 Discounting rate 2 years Up to 5% 5 to 12% 12 to 22% 22 to 58% 58 to 124% over 124% 418 208 288 615 285 181 (21) (10) (14) (31) (14) (9) 18.9 18.8 18.2 18.5 18.5 18.8 22.3 22.2 21.1 21.7 21.9 21.2 .094 .080 .051 .071 .074 .089 .010 .015 .004 .003 .004 .018 Discounting rate 5 years Up to 15% 15 to 38% 38 to 58% 58 to 119% over 119% 786 578 388 140 102 (39) (29) (19) (7) (5) 18.7 18.5 18.5 18.6 19.4 21.9 21.3 21.9 22.3 22.9 .077 .072 .062 .093 .125 .009 .004 .003 .008 .031 Discounting rate 25 years Up to 20% 20 to 32% 32 to 45% over 45% 1524 235 108 132 (76) (12) (5) (7) 18.6 18.4 18.5 19.3 21.8 21.4 22.2 23.4 .072 .061 .067 .154 .006 .004 .010 .024 Invest in a better health at age 70 Dietary behaviour (y) (n) 1521 (76) 468 (24) 18.7 18.5 21.9 21.5 .074 .072 .010 - Exercising (y) (n) 1371 (69) 624 (31) 18.6 18.6 21.7 22.1 .068 .090 .008 .007 Injection (y) (n) 1039 (52) 957 (48) 18.7 18.6 21.8 21.9 .077 .072 .009 .005 Dietary behaviour (y) (n) 1282 (64) 706 (36) 18.6 18.7 21.8 22.1 .071 .083 .010 .003 Exercising (y) (n) 1225 (62) 761 (38) 18.4 18.7 21.7 22.1 .067 .090 .010 .003 Injection (y) (n) 929 (47) 1060 (53) 18.5 18.7 21.6 22.0 .061 .088 .009 .006 Invest in 3 years life extension Health expectancy at age… … 40 d Mean or lower Above mean 1120 (56) 877 (44) 19.1 18.3 22.2 21.4 .095 .052 .007 .008 e Mean or lower Above mean 1064 (53) 928 (47) 18.9 18.4 22.2 21.3 .095 .052 .007 .008 … 70 Statements health lifestyle & future health f “I eat healthy” (+) (-) 1662 (83) 333 (17) 18.5 19.2 21.7 23.1 .063 .135 .006 .016 “I exercise enough to stay fit” (+) (-) 1747 (88) 248 (12) 18.5 19.7 21.5 23.8 .064 .165 .004 .030 33 Variable Category Value BMI th Mean 90 Proportion Proportion overweight obese “Living healthy makes me feel better” (+) (-) 1757 (89) 222 (11) 18.6 18.6 21.9 22.0 .075 .075 .006 .020 “If I live unhealthy I may incur all sorts of diseases in the future” (+) (-) 1500 (76) 484 (24) 18.6 18.7 21.9 21.9 .074 .079 .008 .004 “If I live unhealthy I may die sooner” (+) (-) 1363 (68) 632 (32) 18.6 18.7 21.8 22.1 .073 .083 .009 .003 “If I want, I can easily live healthier than I do now” (+) (-) 1332 (67) 651 (33) 18.6 18.7 21.8 22.1 .072 .086 .009 .005 “If I were regularly ill, I would start living healthier” (+) (-) 1411 (71) 585 (29) 18.5 18.6 21.9 21.9 .075 .076 .007 .009 Note: descriptive statistics: mean (SD); 95%CI; min-max. a 5.69(1.26); 5.63-5.74; 0.8-9.4. A higher score indicates a higher consideration of future consequences. b 85.6(13.9); 85.0-86.3; 10-200. c (very) important d e f versus (completely) unimportant. 7.26(1.23); 7.21-7.31; 1-10. 6.28(1.51); 6.21-6.35; 0-10. (totally) agree versus (totally) disagree. 3.3.4 About home Table 15 Home environment, BMI, overweight and obesity Variable Category Family composition Country of birth… BMI Value th Mean 90 Proportion Proportion overweight obese Two biological parents (y) (n) 1753 (87) 253 (13) 18.6 19.0 21.9 22.3 .072 .101 .007 .013 Single parent (y) (n) 154 (8) 1852 (92) 19.4 18.6 23.0 21.8 .142 .070 .021 .006 Only child (y) (n) 127 (6) 1879 (94) 18.8 19.1 21.8 22.9 .071 .143 .007 .017 … mother Netherlands Other 1869 (93) 137 (7) 18.6 19.2 21.8 22.9 .071 .141 .006 .023 … father Netherlands Other 1861 (93) 145 (7) 18.6 18.9 21.8 22.6 .073 .111 .006 .022 Employment status Mother employed (y) (n) 1332 (67) 665 (33) 18.6 18.7 21.8 22.0 .070 .086 .006 .008 Father employed (y) (n) 1912 (96) 74 (4) 18.6 18.9 21.9 21.8 .077 .060 .008 - (Much) Wealthier About as wealthy (Much) Less wealthy 459 (23) 1369 (69) 162 (8) 18.4 18.7 19.2 21.3 22.0 23.5 .059 .075 .126 .011 .005 .020 Religious upbringing Yes, Catholic Yes, Protestant Yes, Islamic Yes, other No 110 1202 44 124 512 (6) (60) (2) (6) (26) 18.3 18.7 20.4 18.5 18.5 22.2 21.9 27.3 21.5 21.5 .100 .074 .216 .051 .071 .009 .004 .081 .017 .006 Food availability at will Milk (y) (n) 1912 (96) 82 (4) 18.6 18.7 21.9 21.7 .076 .080 .008 .000 Fruit (y) (n) 1978 (99) 27 (1) 18.6 19.5 21.9 24.5 .075 .136 .007 .045 Family wealth a 34 Variable Category Value BMI th Mean 90 Proportion Proportion overweight obese Biscuit (y) (n) 1510 (76) 489 (24) 18.6 18.7 21.8 22.0 .072 .086 .005 .015 Candy / chocolate (y) (n) 1133 (57) 857 (43) 18.5 18.8 21.4 22.3 .060 .096 .003 .014 Chips / nuts / popcorn (y) (n) 835 (42) 1152 (58) 18.5 18.7 21.5 22.0 .065 .083 .002 .011 Snacks (y) (n) 489 (25) 1498 (75) 18.5 18.7 21.4 22.0 .062 .080 .004 .008 Soft drink (not light / sugar-free) (y) (n) 1651 (83) 344 (17) 18.6 18.6 21.8 22.2 .074 .081 .006 .016 (-) (+) 896 (45) 1107 (55) 18.9 18.5 22.1 21.5 .090 .064 .013 .003 Food Availability at Home Index (FAHI) b,c Smoking at home Never Sometimes Always 1579 (80) 266 (13) 139 (7) 19.2 18.7 18.6 22.9 21.9 21.9 .106 .082 .073 .008 .004 .008 Drinking at home Never Sometimes Always 536 (27) 1291 (65) 172 (9) 19.1 18.6 18.6 22.8 21.7 22.0 .094 .067 .089 .006 .003 .016 Statements relationship parents d “My parents are interested in what I do or what I am concerned with” (+) (-) 1902 (95) 93 (5) 18.6 19.1 21.8 22.3 .074 .111 .006 .033 “My parents give me a compliment when I do good” (+) (-) 1856 (93) 140 (7) 18.6 18.9 21.9 22.7 .073 .113 .007 .015 “My parents are strict” (+) (-) 512 (26) 1467 (74) 18.4 18.7 21.4 22.0 .058 .083 .004 .009 “I am generally satisfied about my relationship with my mother” (+) (-) 1816 (92) 167 (8) 18.6 18.7 21.9 21.8 .075 .077 .007 .006 “I am generally satisfied about my relationship with my father” (+) (-) 1765 (90) 205 (10) 18.6 18.9 21.9 22.1 .073 .093 .006 .016 Parenting style Authorative Authoritarian Indulgent Neglectful 479 32 1405 60 (24) (2) (71) (3) 18.4 18.6 18.7 19.4 21.4 21.5 22.0 24.9 .060 .031 .080 .158 .004 .007 .053 Happiness at home e Mean or lower Above mean 810 (41) 1186 (59) 18.8 18.5 22.1 21.8 .087 .068 .010 .005 Note: a categories “Much wealthier” and “Wealthier” were aggregated into “(Much) Wealthier”, and “Much less wealthy” and “less wealthy” into “(Much) Less wealthy”. b mean or lower versus above mean. c descriptive statistics (mean (SD); 95%CI; min-max): 5.66(3.25); 5.51-5.80; 0-10. A higher score indicates a higher availability at will of unhealthy food at home. d (totally) agree versus (totally) disagree. e descriptive statistics (mean (SD); 95%CI; min-max): 8.50(1.44); 8.43-8.56; 0-10. 35 3.3.5 About school Table 16 School environment, BMI, overweight and obesity Variable Category BMI Value th Mean 90 Proportion Proportion overweight obese Usual travel mode to school Walking Cycling Public transport / school bus Car (as passenger) 32 1692 264 13 (2) (85) (13) (1) 19.2 18.6 19.0 20.5 22.0 21.8 22.9 - .067 .069 .117 .222 .033 .006 .004 .222 Travel time to a school Mean or lower Above mean 1192 (60) 803 (40) 18.6 18.7 21.9 21.9 .080 .070 .011 .003 School performance Very good Good Satisfactory Unsatisfactory Very unsatisfactory (14) (49) (28) (9) (1) 18.5 18.5 18.7 19.1 18.8 21.6 21.6 22.2 22.7 21.6 .076 .064 .078 .136 .111 .015 .006 .006 .006 .000 Teased at school Never Sometimes Often 1668 (83) 285 (14) 45 (2) 18.6 18.7 19.4 21.7 22.6 24.1 .066 .118 .195 .004 .018 .049 Food availability at school Milk (y) (n) 1507 (76) 488 (24) 18.6 18.4 21.8 21.9 .072 .085 .005 .012 Fruit (y) (n) 99 (5) 1883 (95) 18.4 18.6 21.4 21.9 .042 .077 .010 .007 Healthy sandwiches (y) (n) 658 (33) 1327 (67) 18.3 18.7 21.3 22.0 .061 .083 .009 .006 Biscuit (y) (n) 1333 (67) 658 (33) 18.6 18.5 21.9 21.5 .077 .070 .007 .006 Candy / chocolate (y) (n) 1946 (97) 55 (3) 18.6 18.4 21.8 22.6 .075 .098 .007 - Snacks (y) (n) 830 (45) 1156 (58) 18.2 18.8 21.3 22.2 .054 .091 .006 .008 Soft / energy drinks (y) (n) 1943 (97) 56 (3) 18.6 18.1 21.8 22.1 .075 .092 .007 - Biscuit (y) (n) 1932 (97) 68 (3) 18.6 18.7 21.8 22.2 .075 .078 .007 .015 Candy / chocolate (y) (n) 1949 (97) 50 (3) 18.6 18.4 21.8 22.3 .075 .085 .007 - Snacks (y) (n) 1836 (92) 163 (8) 18.6 18.5 21.8 21.9 .075 .076 .006 .019 Soft / energy drinks (y) (n) 1952 (98) 46 (2) 18.6 18.4 21.8 22.2 .076 .066 .007 - Food availability near school 275 970 557 173 21 Usual destination after school Home To a friend’s home Hang around with friends Other place / activity b 1780 87 95 36 (89) (4) (5) (2) 18.6 18.6 18.4 19.3 21.9 21.4 21.6 23.7 .076 .049 .083 .139 .007 .056 Home after school Mother only Father only Both Neither 1381 70 305 234 (69) (4) (15) (12) 18.6 17.8 18.6 18.9 21.8 20.6 21.9 22.3 .075 .030 .075 .089 .006 .015 .007 .009 36 Variable Category Happiness at school c Value Mean or lower Above mean BMI 782 (39) 1216 (61) th Mean 90 18.7 18.6 22.0 21.8 Proportion Proportion overweight obese .085 .070 .012 .004 Note: descriptive statistics: mean (SD); 95%CI; min-max. a 31.8(21.5); 30.8-32.7; 1-120 [maximized]. b relatives, baby-sitter, after-school centre, sports or hobby club, job. c 7.66(1.43); 7.59-7.72; 0-10 3.3.6 About your leisure time Table 17 Leisure time, BMI, overweight and obesity Variable Category Value BMI th Proportion Proportion overweight obese Mean 90 16 (1) 232 (12) 1746 (88) 19.5 18.8 18.6 25.7 22.6 21.8 .143 .100 .072 .071 .009 .007 (-) (+) 1131 (57) 864 (43) 18.6 18.7 21.8 22.0 .070 .084 .007 .008 (-) (+) 1370 (69) 624 (31) 18.6 18.7 21.8 22.1 .074 .082 .005 .012 … TV, video, DVD a,d (-) (+) 1036 (52) 958 (48) 18.7 18.6 22.0 21.8 .079 .073 .003 .012 … PC, web, games a,e (-) (+) 1057 (53) 938 (47) 18.6 18.6 21.8 22.0 .071 .082 .006 .009 … Phone, SMS a,f (-) (+) 791 (40) 1204 (60) 18.6 18.7 21.9 21.9 .083 .072 .005 .009 … Play (sports) (-) 965 (48) 18.9 22.7 .103 .010 (+) 1031 (52) 18.4 21.3 .051 .005 (-) (+) 975 (49) 1017 (51) 18.7 18.5 22.0 21.7 .076 .076 .007 .007 Number of good friends None One or two Three or more Weekly time spent on… … homework a,b … reading outside a,c a,g … Other hobby’s a,h Member of sports club i No Individual sport Team sport Both 835 573 465 100 (42) (29) (24) (5) 18.9 18.5 18.3 18.3 22.3 21.8 21.3 21.2 .098 .064 .053 .053 .010 .004 .002 .021 Weekly hours training j,k Mean or lower Above mean 810 (71) 324 (29) 18.5 18.3 21.6 20.9 .067 .039 .006 - Participate in competition j No Yes 339 (30) 797 (70) 18.6 18.3 21.8 21.3 .060 .058 .009 .003 (-) (+) 946 (47) 1059 (53) 19.0 18.3 22.8 21.3 .107 .048 .013 .002 “When I play sports, that is because I enjoy it” (+) (-) 1875 (95) 95 (5) 18.6 18.9 21.8 23.1 .073 .116 .006 .023 “When I play sports, that is because I want to keep fit” (+) (-) 1798 (91) 169 (9) 18.6 18.1 21.9 21.2 .077 .044 .006 .006 “When I play sports, that is because I want to look good” (+) (-) 1423 (73) 538 (27) 18.6 18.4 21.8 21.8 .077 .070 .007 .007 Physical Activity Index (PAI) a,l Statements exercising m 37 Variable Category Value BMI th Mean 90 Proportion Proportion overweight obese “When I play sports, that is because I meet friends then” (+) (-) 1316 (67) 650 (33) 18.5 18.7 21.7 22.0 .075 .076 .003 .014 “When I play sports, that is because I want to become one of the best” (+) (-) 599 (31) 1358 (69) 18.3 18.7 21.2 22.0 .068 .079 .007 .006 “When I play sports, that is because my parents oblige me” (+) (-) 185 (9) 1777 (91) 18.7 18.6 22.1 21.8 .083 .074 .007 Statements leisure time “In my leisure time I am alone” n “In my leisure time I am bored” n Happiness leisure time o (Very) Often Sometimes Rarely Never 200 772 760 225 (11) (39) (38) (11) 18.7 18.8 18.5 18.6 22.3 22.1 21.5 22.0 .086 .088 .059 .080 .010 .009 .004 .009 (Very) Often Sometimes Rarely Never 103 635 798 432 (5) (32) (41) (22) 19.8 18.7 18.5 18.7 24.2 22.0 21.5 22.0 .130 .084 .061 .079 .050 .003 .007 .005 827 (42) 1150 (58) 18.8 18.5 22.5 21.5 .099 .060 .007 .007 Mean or lower Above mean Note: descriptive statistics (mean (SD); 95%CI; min-max). a mean or lower versus above mean. b 5.71(3.76); 5.55-5.88; 0-18. c 4.08(3.80); 3.91-4.25; 0-18. d 8.08(3.80); 7.83-8.32; 0-18. e 8.35(5.65); 8.10-8.59; 0-18. e 3.51(3.84); 3.34-3.67; 0-18. f 8.88(5.46); 8.63-9.13; 0-18. g 7.97(5.40); 7.73-8.20; 0-18. i comparable to national figures for this age group (SCP 2003). j members only. k 4.19(4.49); 3.93-4.46; 0-60. l 6.42(2.91); 6.30m n 6.50; 0-10. (totally) agree versus (totally) disagree. categories “Very often” and “Often” were aggregated into o “(Very) Often”. 8.59(1.19); 8.54-8.64; 2-10. 3.3.7 About what you eat Table 18 Eating behaviour, BMI, overweight and obesity Variable Category BMI Value th Mean 90 Proportion Proportion overweight obese Eating in-between meals… (what) …biscuit (Almost) Never Once or twice per week Regularly, but not daily Daily 250 369 555 809 (13) (19) (28) (41) 19.2 18.7 18.6 18.4 22.9 22.1 22.1 21.3 .115 .088 .079 .054 .021 .011 .004 .004 … candy or chocolate (Almost) Never Once or twice per week Regularly, but not daily Daily 211 485 626 657 (11) (25) (32) (33) 19.4 19.1 18.3 18.3 23.4 22.2 21.3 21.3 .140 .095 .057 .059 .020 .009 .005 .005 … chips, nuts or popcorn (Almost) Never Once or twice per week Regularly, but not daily Daily 336 1036 448 156 (17) (52) (23) (8) 19.0 18.6 18.4 18.3 22.6 21.8 21.8 21.1 .111 .065 .078 .054 .012 .007 .005 .007 … snacks (Almost) Never Once or twice per week Regularly, but not daily Daily 721 1068 152 37 (36) (54) (8) (2) 18.9 18.5 18.5 18.1 22.1 21.6 21.6 21.0 .093 .064 .085 .029 .013 .004 .029 38 Variable Category Value BMI th Mean 90 Proportion Proportion overweight obese Eating in-between meals… (where) …on the way to or from school (Almost) Never Once or twice per week Regularly, but not daily Daily 1568 215 105 57 (81) (11) (5) (3) 18.7 18.5 18.1 18.6 22.0 21.2 21.3 2.9 .079 .054 .061 .057 .007 .010 .019 … during breaks at school (Almost) Never Once or twice per week Regularly, but not daily Daily 336 510 385 742 (17) (26) (20) (38) 19.1 18.5 18.6 18.5 22.9 21.6 21.8 21.4 .116 .060 .079 .063 .016 .011 .006 … when coming home from school (Almost) Never Once or twice per week Regularly, but not daily Daily 131 328 561 947 (7) (17) (29) (48) 18.7 18.9 18.7 18.5 22.0 22.2 22.3 21.5 .082 .086 .091 .061 .016 .009 .008 … when watching TV or behind computer (Almost) Never Once or twice per week Regularly, but not daily Daily 706 536 448 264 (36) (27) (23) (14) 18.8 18.9 18.3 18.1 21.9 22.7 21.5 2.9 .072 .109 .053 .051 .008 .008 .002 .012 … in the street, downtown (Almost) Never Once or twice per week Regularly, but not daily Daily 1158 491 247 67 (59) (25) (13) (3) 18.7 18.6 18.4 18.0 21.9 21.8 21.7 21.0 .081 .064 .065 .063 .004 .011 .009 .016 … at the sports club (Almost) Never Once or twice per week Regularly, but not daily Daily 1321 382 186 71 (67) (19) (9) (4) 18.8 18.4 18.2 18.1 22.0 21.7 2.6 21.2 .083 .063 .052 .058 .009 .006 .014 … breakfast (Almost) Never Once or twice per week Regularly, but not daily Daily 156 147 155 1517 (8) (7) (8) (77) 19.2 18.7 18.6 18.6 22.9 22.3 21.8 21.8 .134 .086 .083 .067 .013 .007 .008 … lunch (Almost) Never Once or twice per week Regularly, but not daily Daily 91 167 250 1467 (5) (8) (13) (74) 19.1 18.8 18.5 18.6 23.6 21.9 22.0 21.8 .153 .076 .072 .072 .012 .006 .013 .006 … dinner, with the family at the dining table (Almost) Never Once or twice per week Regularly, but not daily Daily 70 75 120 1707 (4) (4) (6) (87) 19.1 18.5 18.4 18.6 23.6 22.3 21.5 21.8 .138 .087 .061 .073 .009 … milk (Almost) Never Once or twice per week Regularly, but not daily Daily 433 219 332 990 (22) (11) (17) (50) 18.6 18.8 18.9 18.5 22.0 22.1 22.0 21.6 .092 .072 .083 .068 .002 .014 .010 .007 … soft drink (not light / sugar-free) (Almost) Never Once or twice per week Regularly, but not daily Daily 262 484 456 770 (13) (25) (23) (39) 19.1 18.8 18.5 18.4 22.6 22.0 22.0 21.3 .112 .069 .077 .067 .016 .009 .009 .003 Eating meals… 39 Variable Category Value BMI th Mean 90 Proportion Proportion overweight obese … fruit (Almost) Never Once or twice per week Regularly, but not daily Daily 158 376 630 803 (8) (19) (32) (41) 18.5 18.6 18.8 18.6 21.4 21.8 22.0 21.9 .073 .069 .087 .070 .003 .013 .007 … vegetables (Almost) Never Once or twice per week Regularly, but not daily Daily 54 145 584 1186 (3) (7) (30) (60) 18.8 18.9 18.6 18.6 22.8 21.9 21.9 21.9 .148 .068 .066 .078 .019 .015 .009 .005 Healthy Eating Index (HEI) a,b (-) (+) 1136 (57) 843 (43) 18.7 18.5 22.1 21.6 .086 .061 .007 .007 Unhealthy Eating Index (UEI) a,c (-) (+) 1064 (54) 924 (46) 18.9 18.3 22.2 21.2 .089 .059 .013 .001 Note: descriptive statistics (mean (SD); 95%CI; min-max). a mean or lower versus above mean. b 8.11(2.11); c 8.02-8.20; 0-10. A higher score indicates more healthy eating. 4.69(2.62); 4.58-4.81; 0-10. A higher score indicates more unhealthy eating. 3.3.8 About money Table 19 Money, BMI, overweight and obesity Variable Category BMI Value th Mean 90 Proportion Proportion overweight obese Monthly allowance a from parents Mean or lower Above mean 1477 (77) 450 (23) 18.6 18.9 21.8 22.3 .071 .098 .007 .009 Monthly earnings b Mean or lower Above mean 1312 (70) 552 (30) 18.5 19.1 21.7 22.3 .075 .087 .010 .004 Do your parents let Yes you decide where Largely you spend your Sometimes money on? No 577 1039 329 37 (29) (52) (17) (2) 18.6 18.7 18.5 18.8 21.5 22.1 21.8 23.0 .058 .086 .070 .088 .005 .010 .029 Are you allowed to spend it on candy or snacks? No Yes 756 (38) 1208 (62) 18.7 18.5 22.3 21.5 .098 .061 .012 .004 Do you save? No Yes 269 (14) 1712 (86) 18.8 18.6 21.5 21.9 .063 .078 .008 .007 Mean or lower Above mean 1190 (74) 418 (26) 18.5 18.9 21.8 22.2 .077 .082 .006 .007 Monthly savings c,d Savings purpose c Specific objective (n) (y) 910 (53) 792 (47) 18.6 18.5 21.9 21.9 .076 .078 .009 .005 Money to fall back on (n) (y) 720 (42) 982 (58) 18.5 18.6 21.9 21.8 .076 .077 .010 .005 Just what I have left (n) (y) 1234 (73) 468 (27) 18.6 18.5 22.0 21.7 .083 .060 .008 .004 My parents oblige me (n) (y) 1533 (90) 169 (10) 18.5 18.6 21.8 22.2 .075 .092 .006 .012 40 Variable Monthly amount spent on… Category Value BMI th Mean 90 Proportion Proportion overweight obese … candy, biscuits e,f (-) (+) 1245 (64) 705 (36) 18.5 18.8 21.8 22.1 .070 .082 .008 .007 … snacks e,g (-) (+) 1302 (67) 629 (33) 18.6 18.7 21.9 21.7 .074 .077 .010 .002 (-) (+) 1752 (91) 167 (9) 18.6 19.0 21.9 22.3 .075 .082 .008 .006 … cigarettes e,i (-) (+) 1819 (95) 96 (5) 18.6 19.2 21.9 22.9 .074 .101 .007 .011 … clothing, shoes e,j (-) (+) 1559 (82) 352 (18) 18.6 18.8 21.8 22.1 .074 .081 .008 .006 … CD’s, DVD’s e,k (-) (+) 1525 (80) 390 (20) 18.6 18.7 21.7 22.3 .070 .097 .005 .016 … cosmetics e,l (-) (+) 1447 (75) 473 (25) 18.6 18.8 21.8 22.1 .077 .069 .007 .009 … mobile phone e,m (-) (+) 1313 (68) 614 (32) 18.6 18.8 21.8 22.2 .075 .079 .009 .005 … alcoholic drinks e,h Note: descriptive statistics (mean (SD); 95%CI; min-max). a 23.50(29.39); 22.19-24.82; 0-500. b 23.98(53.36); 21.55-26.40; 0-1000. c savers only. d 25.73(34.84); 24.04-27.43; 0-500. Monthly earnings from allowance and jobs, proportion that indicated to save, and the amount saved per month are comparable to national averages reported by the Dutch National Institute for Budget Information (NIBUD 2005). e mean or lower versus above f g h i mean. 2.78(4.04); 2.60-2.96; 0-50. 1.74(7.71); 1.40-2.08; 0-300. 0.72(4.33); 0.53-0.91; 0-100. 0.66(5.02); 0.43-0.88; 0-120. j 10.2(44.3); 8.22-12.2; 0-1500. k 3.12(16.8); 2.36-3.87; 0-600. l 2.46(6.08); 2.19-2.74; 0-100. m 5.77(10.9); 5.28-6.26; 0-160 41 References Ackard DM, Neumark-Sztainer D, Story M, Perry C. Overeating among adolescents: prevalence and associations with weight-related characteristics and psychological health. Pediatrics 2003;111(1):67-74 Ackard DM, Neumark-Sztainer D, Story M, Perry C. Parent-child connectedness and behavioral and emotional health among adolescents. Am J Prev Med 2006;30(1):59-66 Adams K, Sargent RG, Thompson SH, Richter D, Corwin SJ, Rogan TJ. 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Am J Clin Nutr 2004;79(5):838843 51 52 Annex A Members advisory board Jaap Seidell Vrije Universiteit Amsterdam, Faculteit der Aard- en Levenswetenschappen, Voeding en Gezondheid / Kenniscentrum Overgewicht (www.overgewicht.org) Jolien Pon Stichting Gezond Gewicht / Dikke Vrienden zomerkamp (www.gezondgewicht.nl) Karen van Reenen Nederlandse Hartstichting / Heart Dance Awards (www.heartdanceaward.com) Saskia van Dorsselaer Trimbos Instituut / HBSC panelonderzoek (Health Behaviour in School-Aged Children; www.hbsc.org) Isabel Ferreira, Hans Brug Erasmus MC, iMGZ / ENDORSE project (determinantenonderzoek naar overgewicht onder jongeren; www2.eur.nl/fgg/mgz) 53 54 Annex B Validity and reliability of self-reported height and weight Many studies investigated the validity and reliability of self-reported height and weight in adolescents, and the subsequent classification of adolescents into (over)weight categories on the basis of accepted cut-points for body mass index. Fortenberry (1992) found that adolescents over-reported their height by 0.5 cm (females) / 0.6 cm (males), and underreported their weight by 1.5 kg (females) / 1.2 kg (males). Adolescents in the heaviest quartiles of measured weight underreported weight by significantly more than those in lighter quartiles. There were no differences in the accuracy of height or weight reports when subjects were grouped by height quartile. In conclusion, Fortenberry suggested that although the bias in self-report could affect results of survey research; the magnitude of such an effect would likely be small. Himes and Faricy (2001) observed that biases in reporting stature and weight were consistently negative, with intra-class coefficients between measured and self-reported dimensions within age and gender groups ranging from 0.57 to 0.91 for stature and from 0.85 to 0.98 for weight, respectively. Strauss (1999) observed that the correlation between self-reported and actual weight of young adolescents ranged from 0.87 to 0.94, and between self-reported and actual height from 0.82 to 0.91. Self-reported weights were significantly lower than measured weights for girls compared to boys, and differences between actual and self-reported weight were significantly greater for obese children compared with non-obese children. Nevertheless, the use of self-reported weight and height resulted in the correct classification of weight status in 94% of children. Brener et al. (2003) administered self-reported height and weight twice, 2 weeks apart, and compared these with measured values. Differences between self-reported values were small, and highly correlated with their measured counterparts. Adolescents over-reported their height by 2.7 inches and underreported their weight by 3.5 pounds; resulting mean BMI values based on self-reported values (23.5 kg/m2) underestimated BMI based on measured values (26.2 kg/m2) by 2.6 points, as well as the prevalence of overweight (14.9% and 26.0%, respectively). Wang et al. (2002) found that self-reported heights were significantly higher than measured heights, and self-reported weights significantly lower than measured weights. There were no differences between boys and girls in the accuracy of self-reported height or weight, but bias was much higher in overweight or obese adolescents than normal/underweight adolescents. The resulting percentage misclassification of overweight or obesity was 30%. They 55 suggested efforts to improve the accuracy of self-reporting are needed for self-report measures in adolescents to be reliable. Elgar et al. (2005) found that self-reported and measured height and weight were highly correlated, but that underreporting of body weight by an average of .52 kg contributed to underestimation of the prevalence of overweight and obesity: 13.9% was identified as overweight and 2.8% as obese based on self-reported data, while measured data showed rates of 18.7% and 4.4%, respectively. Body mass index (BMI) and body dissatisfaction predicted bias in self-reported weight. Galan et al. (2001) observed under-reporting of weight by 0.07% for males and 0.79% for females, and of height by 0.51% for males and 0.98% for females. Although the correlation between self-reported and objective BMI was 0.87 for males and 0.90 for females, the prevalence of high BMI (≥85th percentile) was underestimated by about 34%. Consequently, they suggest, analysis of BMI based on self-report as a continuous variable entails a small margin of error, but that its use as a categorical variable involves a considerable underestimate of the prevalence of high BMI. Flood et al. (2000) found that self-reported weights and heights led to misclassification of relative weight status: 62% of males and 47% of females were classified as overweight or obese based on measured weights and heights, compared with 39% and 32% based on selfreport. Himes et al. (2005) found that self-reported stature, weight and BMI on the average were valid representations of actual values, but argued that the prevalence of overweight based on self-reported data systematically underestimate measured values. Black et al. (1998) compared the accuracy of self-reported body weight of two groups of people, a group that was explicitly informed that body weight would be measured immediately following questionnaire completion, and a group that was not informed. They found that people from the group that was informed reported more accurately and with consistent accuracy across the weight range, whereas the accuracy of people from the uninformed group decreased as body weight increased. 56 Annex C Literature review The computerized literature databases Medline and Scopus were searched, using the following keyword combinations: Overweight, obesity Child, adolescent, youth, young people Health attitude, health behaviour, physical activity, sedentary behaviour, fruit, vegetables, snacks, soft-drinks Home, family, school, peers Personality, self-esteem, body-image, happiness, well-being Availability, family meals, vending machines, pocket money. About you Many studies have addressed gender differences in health behaviour (e.g., Inchley et al. 2005; De Vries et al. 2002; Van Mens-Verhulst & Moerman 2002; Neumark-Sztainer & Hannan 2000) De Bruijn et al. (2005b) found the Big-Five personality dimensions to be associated with healthy behaviours. Agreeableness was positively associated with vegetable consumption, openness to experience with vegetable and fruit consumption, and extraversion with sportsrelated physical activity. Based on a meta-analysis of studies addressing the relation between conscientiousness-related traits and health behaviours, Bogg and Robberts (2004) concluded that these traits were negatively associated with risky health behaviours and positively with beneficial health behaviours. Klein-Hessling et al. (2005) observed that selfefficacy is associated with health protective behaviours, and stress experiences and maladaptive coping with health risk behaviours. Braet and Ipema (1997) hypothesised that neuroticism may be associated with emotional eating, in particular in obese girls older than 12. Craeynest et al. (2005) investigated explicit and implicit attitudes towards food and physical activities among obese and non-obese adolescents. They found no differences in the explicit attitude towards food and physical activity between the groups. Obese adolescents had a more pronounced positive implicit attitude towards both health and unhealthy food, but there was no difference in implicit attitude towards sedentary, moderate and high intense physical activities. 57 Falkner et al. (2001) examined associations of weight status with social relationships, school experiences, psychological well-being, and some future aspirations. Compared to normal weight peers, obese girls were less likely to hang out with friends, more likely to report being held back a grade, to consider themselves poor students, and to report serious emotional problems, hopelessness, or a suicide attempt in the last year; obese boys were less likely to hang out with friends, more likely to feel that their friends do not care about them, to report having serious problems in the last year, to consider themselves poor students, and to expect to quit school. Erickson et al. (2000) asked themselves whether overweight children were more unhappy than normal weight children, and only found a relationship between depressive symptoms and BMI in preadolescent girls, that seemed to be explained by an excess of overweight concerns. About your health Friedman and Brownell (1995) presented a list of potential risk factors for psychological problems in obese individuals based on a literature review, including social / environmental and cognitive factors. Social / environmental risk factors concerned societal pressure to be thin, teasing and discrimination history, reactions to weight by family and peers and peer interpersonal relationships; cognitive factors concerned body image dissatisfaction and distortion, and self-concept. Obesity is associated with poorer psychosocial functioning, even compared with other chronic diseases, because of its visibility and negative evaluation – as a sign for lacking self-control, absent intention for self-restraint, or offence against esthatic ideals (Warschburger 2005). Stradmeijer et al. (2000) found that overweight adolescents displayed lower body-esteem scores than their normal weight peers, had lower selfperceptions of their physical appearance, athletic competence, social acceptance, and global self-worth (see also Mendelson et al. 2001, 1996; Mendelson & White 1982). Watt and Sheiham (1999) found that the main reason for a sample of 13-14 year olds to change their dietary pattern was a desire to improve appearance, with health and other considerations being less important. Ryan et al. (1998) observed a high level of dissatisfaction with body weight in a sample of schoolgirls aged 15 years: 59% reported that they wanted to be slimmer and 68% had previously tried to lose weight. Dissatisfaction was expressed by overweight, normal weight and even underweight girls, reporting the use of unhealthy weight control practices including random avoidance of staple foods, fasting, smoking and purging, in their pursuit of the 'perfect' female figure. Watt and Sheiham (1999) found that girls were more likely to perceive themselves overweight than boys, and that four out of five young people who perceived themselves overweight actually were not, based on self-reported height and weight. Griffin et al. (2004) found that significantly more girls than boys were 58 affected by fear of fatness. In a qualitative study, Wills et al. (2006) observed that acceptance of body size and shape was fairly common among overweight and obese young adolescents, contradicting the common perceptions that overweight and obesity are associated with body dissatisfaction and that young adolescents strive for thinness and have a fear of fatness. Sobal et al. (1995) found that female secondary school students were more concerned about their own body weight than male peers, while males emphasized thinness in partners more than did females and showed lower comfort in dating very overweight partners. Honjo and Siegel (2003) observed that perceived importance of being thin among young female adolescents was associated with future smoking initiation. Some studies suggest a negative correlation between obesity and smoking behaviour (Gruber & Frakes 2006; Chou et al. 2004), while Flegal et al. (1995) found that smoking cessation was associated with significant weight gain. Classen and Hokayem (2005) found overweight or obesity to be associated with self-reported depression among youth, in particular among girls. Pesa et al. (2000) observed that overweight female adolescents seem to suffer from low self-esteem but that this may be explained by body image, supporting earlier evidence that the effect of shape and weight on self-esteem among adolescents is not so much related to actual body mass but to perceptions of being overweight and body image dissatisfaction. Kelly et al. (2005) found that adolescent girls with high body satisfaction were more likely to report parental an peer attitudes that encouraged healthy eating and exercising to be fit, and less likely to report weight related concerns and behaviours. Sarlio-Lahteenkorva et al. (2003) found girls frequently reported feelings of over- and underweight, while boys were mostly satisfied with their current weight; low self-esteem was associated with feelings of overweight among girls and underweight among boys. According to McCreary and Sasse (2000), much of the existing research on disordered eating has centred on the drive for thinness, which is most commonly observed in girls. Hill and Silver (1995) asked girls and boys to rate four silhouettes representing a thin and a heavy girl and boy, and found that the overweight body shapes were associated with poor social functioning, impaired academic success, and low perceived health, healthy eating and fitness, and a greater perceived relevance of weight among girls. Staffieri (1967) asked boys to assign 39 adjectives of behaviour/personality traits to three silhouettes representing extreme endomorph (fat), mesomorph (muscular) and ectomorph (thin) body types. The fat body type was associated with socially unfavourable and aggressive adjectives, the thin body type with personally unfavourable and socially submissive adjectives, and the muscular body type with favourable adjectives. Cohane and Pope (2001) reviewed the literature of body image in boys. Boys generally displayed less overall body concern than girls, many reported dissatisfaction with their bodies, often associated with reduced self-esteem, and boys frequently wanted to be bigger, but most studies failed to distinguish between bigness due to 59 increased muscle and due to fat. The male standard of bodily attractiveness, thus, appears to be bigger, bulkier, and more muscular; whereas girls typically want to be thinner, boys more commonly desire to be physically big (Courtenay 2003; Pope et al. 1999; Guggenheim 1977). Therefore, males more often think they are underweight, and nearly half of overweight males think their weight is normal (McCreary 2002; McCreary & Sadava 2001). Adams et al. (2000) observed that young adolescent males selected significantly larger body size silhouettes for ideal adult body size than females, and expressed less personal concern about weight. Television viewing also plays a role in constructing and internalizing negative stereotypes of overweight and obese individuals, possibly contributing to poorer self-and peer-perceptions. Greenberg et al. (2003) analysed 10 prime-time fictional programs and observed that overweight and obese television characters were mostly associated with specific negative characteristics. Fouts and Burggraf (2000) conducted a content analysis of 18 prime-time television situation comedies and found that below-average weight females were overrepresented, that the heavier the female character, the significantly more negative comments were made about or to her, usually by men, and that negative comments were significantly associated with audience laughter. Similarly, Fouts and Vaughan (2002) conducted a content analysis of 27 different prime-time television situation comedies, and found that above-average weight males were underrepresented, that the heavier the male character, the more negative references he made about his own body shape/weight, and that his negative comments about himself were significantly associated with audience reactions. Harrison (2000) investigated relationships between children’s television viewing and interpersonal attraction to television characters, fat stereotyping, body shape standards and eating disorder symptomatology, and found that the time boys spent watching television was associated with the likelihood of associating negative stereotypes to overweight females. Tiggemann and Slater (2004) demonstrated that the content of music videos that emphasized appearance and featured thin and attractive women had negative consequences for adolescent female's body image. Also in Tiggeman et al. (2000) adolescent females reported experiencing media pressure to be thin, but indicated that this did not necessarily mean they were dissatisfied with their bodies. Friedlander et al. (2003) found that overweight children have increased odds of low scores for several health-related quality-of-life domains, including psychosocial health, self-esteem, and physical functioning. Swallen et al. (2005) found that overweight or obese adolescents were more likely to have a functional limitation, had significantly worse self-reported health, and young adolescents of 12 to 14 years were significantly more likely to be depressed and to report low self-esteem and poor school/social functioning compared with normal weight 60 peers. Williams et al. (2005) found that child and parent-proxy reported health-related quality of life scores were similar and decreased with increasing child weight. Associations were found with physical and social functioning subscale scores, but not with emotional and school functioning. Wake et al. (2002) observed that parental concern about their child's weight was strongly associated with their child's actual BMI. Schwimmer et al. (2003) compared the health-related quality of life (HRQoL) of children and adolescents who are healthy, obese, or diagnosed as having cancer. Compared with healthy children and adolescents, obese children and adolescents reported significantly lower HRQoL in all domains, similar to those diagnosed as having cancer. Parent proxy report showed that the child or adolescent's weight was inversely correlated with HRQoL, physical functioning, social functioning, and psychosocial functioning. Fallon et al. (2005) also found overweight to be associated with poorer quality of life in adolescence, both from self- and parent-proxy reports. According to Warschburger (2005), overweight and obesity are associated with functional impairments (including breathing and joint difficulties), may lead to psychosocial strain (including negative self-esteem, increased anxiety and depression), and that overweight and obese children report lower levels of HRQoL. Neumark-Sztainer et al. (1998) highlighted chronic illness as one of the main risk factors for inadequate food intake patterns. Fonseca and Gaspar de Matos (2005) observed that overweight adolescents were significantly more likely to describe themselves as not healthy. Will et al. (2006) conducted in-depth interviews with normal weight, overweight and obese teenagers and found that they rarely mentioned any healthrelated consequences of their own or others' fatness; wearing 'nice' clothes and being slowed down were raised as considerations by girls and boys, respectively. About your future Although there is some evidence suggesting that being overweight or obese may have a lasting effect on life satisfaction and future life aspirations (e.g., Ball et al. 2004), there are few studies addressing future expectations of adolescents in relation to overweightness. Davis et al. (2004) argued that overeating and overweight is not just a passive response to salient environmental triggers and powerful physiological drives, but is also about inability to advantageously assess future consequences of current choices. They found greater decision-making impairments - in terms of ability to inhibit short-term rewards when the longterm consequences are deterious - in healthy adult women with high BMI, even greater than in previous studies with drug addicts. Adolescent risk-taking behaviour is often attributed to their ignorance, misunderstanding or underestimation of adverse outcomes. Mann et al. (1989) argued that although by the age of 15 years many adolescents show a reliable level of decision-making competence, young 61 adolescents (12-14 years) are less able to create options, identify a wide range of risks and benefits, foresee the consequences of alternatives, and gauge the credibility of information from sources with vested interests. Others have also demonstrated the immature judgement of young adolescents as compared to middle / late adolescents and adults (Cauffmann & Steinberg 2000; Steinberg & Cauffmann 1996). Quadrel et al. (1993) reviewed the literature on the “adolescent invulnerability hypothesis”, that poses that adolescents perceive themselves invulnerable to the threats associated with risk behaviours, and investigated differences in the cognitive decision-making processes of adolescents and adults. Both from the review and their own study they found no evidence that adolescents were less competent in decision-making than adults. They displayed similar knowledge of the possible consequences of risk behaviours and made similar judgments of their and others’ risk levels, both showing overconfidence in their level of knowledge and optimism regarding their personal vulnerability. Millstein and Halpern-Felsher (2002) found that adolescents tended to overestimate personal health behaviour-linked risks more than younger adults, and were less likely to see themselves as invulnerable. Steinberg (2004) suggested that the greater propensity of adolescents to take risks is not due to age differences in risk perception or appraisal, but to a disjunction between novelty and sensation seeking and the development of self-regulatory competence (in terms of thinking before acting, choosing between alternative courses of action differing in level of risk, and interrupting a risky behavioural trajectory that is already set in motion). Komlos et al. (2004) hypothesized that recent trends in obesity may be partly related to an increase in the marginal rate of time preference, the rate at which people are willing to trade current for future benefits. Weight control requires people to forego current consumption and to invest time and effort – and perhaps money - in exercise, for the sake of potential future health benefits. A higher discounting rate may then be associated with higher food intake, less physical activity and, consequently, with weight gain. They argued international evidence suggests that such a relationship is plausible. Borghans and Goldsteyn (2006) support the idea that the increasing incidence of overweight may be related to increasing individual discounting rates over time, as evident from rises in credit card debts, gambling and the development of more hedonic lifestyles. They found some evidence that differences in overweight are associated with the way people discount future health benefits, depending on the choice of proxy for the discount rate, but no evidence that these proxies changed over time, so that the increase in BMI was more likely explained by shifts in other parameters. Other authors also discussed the positive association between overweight / obesity and time preference, time-inconsistent choice, myopic choice or impatience (Finke & Huston 2003; Huston & Finke 2003; Offer 2001). Kan and Tsai (2004) found evidence of a relationship in the general population between individuals' knowledge concerning the health risks of obesity and their tendency to be obese. 62 Dohmen et al. (2005a, 2005b) found evidence of heterogeneity of risk attitudes across individuals; women were more risk averse than men, willingness to take risks was negatively related to age, individuals with highly educated mothers were less risk averse. Individual risk preference was however reasonably stable across domains. About home Steinberg (1987) observed that youngsters living with both natural parents were less susceptible to pressure from their friends to engage in deviant behaviour than youngsters living in other family structures, while youngsters growing up in stepfamilies - in the presence of an additional adult - were equally at risk for involvement in deviant behaviour as were their peers growing up in single-parent households. Lundborg (2006) found that living in a single parent household had significant effects for health risk behaviours like smoking and illicit drug use. Watt and Sheiham (1999) found that young people from lower social class groupings were more likely to be less healthy eaters, and that boys were less healthy eaters than girls. Among others, Vereecken et al. (2005), Stamatakis et al. (2005), Storey et al. (2003) and Wang (2001) observed associations between socio-economic status or family income / wealth and food habits of young adolescents and the prevalence of obesity. Friestad and Klepp (2006) found a relation between socio-economic status and a composite measure of health enhancing behaviour. Eisenberg et al. (2004) investigated the association between frequency of family meals and multiple indicators of adolescent health and well-being, and found that eating family meals enhances adolescent health and well-being. Neumark-Sztainer et al. (2003, 2004) found that family meal patterns, including frequency, priority, structure and atmosphere of family meals, potentially play an important role in promoting positive dietary intake among adolescents. Patrick and Nicklas (2005) argued that adolescents eating patterns are strongly influenced by both physical and social characteristics of mealtime structure, including availability and easy access to healthy and unhealthy types of food, portion size, whether families eat together, TV-viewing during meals, the source of foods (e.g., take-away, home-cooking), and parents’ attitudes and time constraints. Kremers et al. (2003) explored the possible influence of parenting style, the emotional climate within which child development and socialization occurs (Darling & Steinberg 1993), on adolescent food choice patterns. They used a two-dimensional classification of parenting style, based on the interaction of parental involvement / responsiveness (I) and parental strictness / control (S), resulting in a fourfold typology of parenting styles: authoritative (high I; high S), authoritarian (low I; high S), indulgent (high I; low S), and neglectful (low I; low S). 63 Fruit consumption as well as fruit-specific cognitions were most favourable among adolescents who were being raised with an authoritative parenting style, while children of parents with indulgent parenting styles consumed more fruit than adolescents from authoritarian or neglectful homes. Patenting styles were associated with adolescents’ gender, age and religiosity. Lau et al. (1990) explored the influence from parents and peers on young adults' health beliefs and behaviour concerning drinking, diet, exercise, and wearing seat belts. They argued that parental influence is strong and enduring, but distinguished three “windows of vulnerability”, critical periods in which individuals were particularly open to the influence from socializing agents. The first period of vulnerability is adolescence, when individuals typically seek independence from parents. In combination with higher exposure to alternative health beliefs, norms and behaviours from peers, this individualization process may be associated with increased (health) risk seeking. Ackard et al. (2006) discussed the importance of parent-child connectedness: adolescents' perceptions of low parental caring, difficulty talking to their parents about problems, and valuing their friends' opinions for serious decisions were significantly associated with compromised behavioural and emotional health. Mellin et al. (2002) examined the potential impact of familial factors on unhealthy behaviours and psychosocial difficulties among overweight adolescents. Overweight adolescents reported engaging in significantly more unhealthy behaviours and experiencing more psychosocial distress than their nonoverweight peers, but among the overweight youth, higher levels of reported family connectedness and parental expectations and moderate levels of parental monitoring were associated with the lowest levels of unhealthy behaviours and psychosocial distress. According to Neumark-Sztainer et al. (1998) low socioeconomic status, minority status, and low family connectedness were some of the main risk factors for inadequate food intake patterns. Fonseca et al. (2002) found that the main protective factors associated with adolescents engaging in extreme weight control behaviours included high parental expectations, maternal presence, and connectedness with friends and other adults for boys, and family connectedness, positive family communication, parental supervision/monitoring, and maternal presence for girls. Classen and Hokayem (2005) investigated the influence of a range of child and mother variables on the likelihood that a child will become an obese or overweight youth, and found significant effects for the mother’s BMI, education level, number of children and employment status. The likelihood of being overweight or obese in youth increased with mother’s BMI, decreased with her education level and number of children, and was higher when she worked more than 35 hours per week. Swinburn et al. (1999) developed a conceptual model for helping characterize elements of adolescents´ environment influencing food intake and physical activity as obesogenic 64 (promoting fatness) or leptogenic (promoting leanness). This two-dimensional framework dissects the environment into size (micro and macro) by type: physical (what is available), economic (what are the costs), political (what are the "rules"), and socio-cultural (what are the attitudes and beliefs). Ferreira et al. (2005) adopted this framework for a literature review of potential environmental determinants of physical activity in children and adolescents. Most convincing evidence was found for home environmental factors, especially parental support and encouragement and indicators of socio-economic status. Van der Horst et al. (2005) did the same for potential environmental determinants of selected dietary behaviours in children and adolescents. Here also, most studies focussed on the micro-environmental, household level, in particular on socio-cultural and economic factors; parental fat and energy intakes are associated with intakes of their offspring, and higher parental education and authorative parenting styles are associated with higher fruit and vegetable intakes of their offspring. In a study by Watt and Sheiham (1999), young people indicated that availability of healthy foods and encouragement and support from close family were most helpful factors in promoting positive changes in dietary pattern, next to own willpower. Popkin et al. (2005) reviewed the literature on the ways the environment, conceived as the external context in which individual make decisions, affects diet, physical activity, and obesity. They argued there is a significant association of the availability of food sources and physical activityrelated facilities with individual-level health behaviour, but also an inequitable distribution of such facilities, with high minority, low educated populations at strong disadvantage. GordonLarsen et al. (2006) support these findings; they found lower-SES and minority groups had reduced access to facilities, which in turn was associated with decreased physical activity and increased overweight. Brug and Van Lenthe (2005) argued there still is a lack of convincing evidence for the role of environmental factors as determinants of physical activity and nutritional behaviour, in particular regarding the interaction with individual factors. About school Friedman and Brownell (1995) highlighted teasing about physical appearance as a potential risk factor for psychological problems in obese individuals, in particular when teasing becomes internalized as thoughts and views about oneself. A range of studies (e.g., Elgar et al. 2005; Janssen et al. 2004; Neumark-Sztainer et al. 2002) indeed reported that overweight and obese school-aged children were more likely to be victims as well as perpetrators of bullying than their normal-weight peers. In a study by Eisenberg et al. (2003), 15-30% of adolescents reported weight-based teasing by peers or family members. Teasing about body weight was found to have profound effects on young people's psychosocial well-being, as it was associated with low body satisfaction, low self-esteem, high depressive symptoms, and 65 suicide ideation and attempt. Strauss and Pollack (2003) found that many overweight adolescents are socially marginalized. In a study by Fonseca and Gaspar de Matos (2005), a significantly greater proportion of obese/overweight versus non-overweight youth reported difficulty in making friends. Not in the last place this may be related to the proximity effect or courtesy stigma, the tendency for individuals who associate with stigmatized individuals to face negative interpersonal and professional outcomes (Hebl & Mannix 2003). Obese people are stigmatised (Myers & Rosen 1999; Ryan et al. 1998), more than almost all other social groups (Klaczynski et al. 2004). As a result of this threat, non-stigmatized adolescents may avoid or break off contact with those who are stigmatized because of their overweightness or obesity. Chen and Brown (2005) asked college students to rank order six drawings of potential sexual partners, including an obese partner, partners with various other disabilities, and a healthy partner. They found that the least-preferred partners were obese, in particular among men. Halpern et al. (2005) examined associations among body mass, involvement in romantic relationships, and dieting among adolescent females. They observed that for each one point increase in BMI, the probability of having a romantic relationship decreased by 67%, while involvement in a nonsexual romantic relationship was associated with a significant increase in the likelihood of dieting. Bell and Swinburn (2004) found that a substantial proportion of total energy intake was consumed at school, and that energy-dense foods and beverages were over-represented in the school environment: biscuits, snack bars and fruit/cordial drinks brought from home and fast food, packaged snacks, and confectionary sold at canteens. Sanigorski et al. (2005) studied the lunchbox contents of schoolchildren: though an encouraging 68% of children had fruit in their lunchboxes, over an alarming 90% had energy-dense, micronutrient-poor snacks ('junk food'). Bell et al. (2005) observed that children and adolescents obtain a considerable proportion of their daily energy intake from foods and beverages that do not fit the requirements of a healthy diet, but found no clear association with weight status. NeumarkSztainer et al. (2005) found that food-related policies and the food environment at school (i.e, open/closed campus during lunchtime, availability and hours of operation of vending machines, type of food sold in vending machines) had a significant impact on students’ lunch and snacking patterns. Also French et al. (2003) argued that he availability of healthful foods and beverages in schools as well as school food policies that foster healthful food choices among students need greater attention. Anderson and Butcher (2005) investigated the effect of school food policies on students body mass, and estimated that the increase in availability of junk foods in schools can account for about one-fifth of the increase in average BMI among adolescents over the last decade. 66 According to Evenson et al. (2003), travel to and from school can be an important and regular source of physical activity for youth. Kremers et al. (2004) found that 37% of Dutch adolescents always used a bike for transport, and 42% occasionally. De Bruijn et al. (2005a) found that bicycle use was more likely among adolescents that were native Dutch, went to school in a less-urbanized city, and had a more positive intention and perceived stronger behavioural control and subjective norm towards bicycle use. Falkner et al. (2001) examined associations of weight status with social relationships, school experiences, psychological well-being, and future aspirations, in terms of expectations regarding educational, occupational and financial success. Falkner et al. found that obese boys and girls were less likely to hang out with friends, were more likely to consider themselves poor students, and obese boys were more likely to expect to quit school. Pesa et al. (2000) observed overweight adolescents to have higher grades, but lower school connectedness. Neumark-Sztainer et al. (1998) highlighted poor school achievement as one of the main risk factors for inadequate food intake patterns. About your leisure time Childhood obesity is associated with insufficient (vigorous) physical activity and more time spent on sedentary behaviours like TV/video viewing, video/computer game use and reading/doing homework - the “couch-potato” hypothesis (e.g., Elgar et al. 2005; Patrick et al. 2004; Vandewater et al. 2004; Berkey et al. 2003a; Giammattei et al. 2003; Utter et al. 2003; Eisenmann et al. 2002; Gordon-Larsen et al. 2002; Faith et al. 2001; Strauss et al. 2001; McMurray et al. 2000; Robinson 1999; Gortmaker et al. 1996). The evidence regarding the association between sedentary behaviour and obesity is mixed. Marshall et al. (2004) reviewed empirical evidence of associations of media use – TV/video viewing, video/computer game use - with body fatness and physical activity. They conclude that there were statistically significant effects in expected directions, but that these effects were small and that the relationship between sedentary behaviour and health was unlikely to be explained using single markers of inactivity. Gordon-Larsen et al. (2002) found there are important gender and ethnic differences in the associations between sedentary behaviour, physical activity and overweightness. Faith et al. (2002) investigated the effect weight criticism during physical activity by family and peers, and found it to be associated with reduced sports enjoyment, perceived activity compared with peers, and mild-intensity leisure activity. Forshee et al. (2004) observed a strong negative association between BMI and participation in team sports or exercise programs for young adolescent males and females. Vandewater and Huand (2005) argued that the relationship between television viewing and weight status differs greatly for different children, and that parental weight status is an 67 important moderator of this relationship. Elkins et al. (2004) investigated associations between participating in after school sports activities and body mass, and found that participation in an increasing number of athletic activities was associated with lower weight status. They however observed considerable variations between different sports, potentially related to the level of vigorous activity or practice sessions each sport provides and selfselection of overweight adolescents to sports in which their weight is an advantage (or less a disadvantage). Strauss et al. (2001) observed that adolescents are largely sedentary. Physical activity was correlated with self-efficacy and social influence, and was an important component in the development of self-esteem. There is also evidence of an interaction between sedentary behaviours and unhealthy energy intake. Many authors reported a positive association between time watching TV/videos and unhealthful dietary behaviour. Matheson et al. (2004) found that a significant proportion of children’s daily energy intake is consumed during television viewing, and although the fat content of the foods consumed during television viewing did not differ significantly from that of the foods consumed with the television off, less soda, fast food, fruit, and vegetables were consumed with the television on. Boynton-Jarrett et al. (2003) also found an inverse relation between time watching TV/videos and playing video games and fruit and vegetable consumption. Worth noting is that, from all this evidence, it appears there is a difference in the association with overweightness between more passive types of sedentary behaviour, like TV/video viewing, and more active types, such as reading/doing homework and video/computer game use. In the same line, Utter et al. (2003) found that leisure time physical activity was not associated with TV/video viewing, but was positively associated with computer use and time spent reading/doing homework. Gardner and Steinberg (2005) investigated peer influence on risk taking, risk preference, and risky decision making, and found that adolescents took more risks, focused more on the benefits than the costs of risky behaviour, and made riskier decisions when in peer groups than alone. Lundborg (2006) found significant peer effects for potentially health damaging behaviours like binge-drinking, smoking and illicit drug use. About what you eat Childhood obesity is associated with consumption of sugar-sweetened (soft) drinks, packaged meals and fast foods (e.g., Bray & Champagne 2005; Elgar et al. 2005; Berkey et al. 2004; James et al. 2004; Giammattei et al. 2003; Dietz 2001; Ludwig et al. 2001). Neumark-Sztainer et al. (1998) listed the main risk factors for inadequate food intake patterns, which include: low socioeconomic status, minority status, chronic illness, poor school achievement, low family connectedness, weight dissatisfaction, and overweight. 68 Ackard et al. (2003) found associations between overeating, being overweight or obese, and a number of adverse behaviours and negative psychological experiences, but could not ascertain whether overeating was an early warning sign of additional psychological distress or a potential consequence of compromised psychological health. Martens et al. (2005) investigated the relative importance of personal and social environmental predictors of the consumption of fruit, high-fat snacks and breakfast, and observed that adolescents' attitudes were the most important determinants of different health-related eating behaviours. Guggenheim et al. (1977) observed that teenagers generally have well-informed opinions on good nutrition and on the causes and prevention of obesity, but that overweight teenagers appeared to be more conscious of their food intake than under- and normal-weight peers. Neumark-Sztainer et al. (2003) found that frequency of family meals was positively associated with intake of fruits, vegetables, grains, and calcium-rich foods and negatively associated with soft drink consumption. In a study among schoolchildren in nine European countries, Sandvik et al. (2005) found that children generally held a positive attitude towards fruit and vegetable intake, had a more positive attitude towards fruit than towards vegetables, and girls were more positive than boys. They perceived their social environment as supportive towards fruit and vegetable intake, and reported availability of fruit and vegetables to be (very) good at home but low at school and during leisure time activities. De Bruijn et al. (2004) found that snacking behaviour was inversely associated with female gender and a more positive intention, a more positive attitude, and stronger perceived behavioural control towards restricting snacking. French et al. (2001) found that frequency of fast food restaurant use was positively associated with intake of total energy, percent energy from fat, daily servings of soft drinks, cheeseburgers, french fries and pizza, but also with student employment, television viewing, home availability of unhealthy foods, and perceived barriers to healthy eating, while it was inversely associated with daily servings of fruit, vegetables and milk, and with students' own and perceived maternal and peer concerns about healthy eating. Forshee and Storey (2003) found no association between BMI and consumption of regular carbonated soft drinks, a positive association with consumption of regular carbonated soft drinks, and a negative association with drinking milk. These findings were confirmed by Forshee et al. (2005, 2004). In a longitudinal study of the effect skipping breakfast on weight, Berkey et al. (2003b) found that overweight children who never ate breakfast lost weight compared to overweight children who ate breakfast nearly every day, while normal weight children who never ate breakfast gained weight relative to peers who ate breakfast nearly every day. Elgar et al. (2005) reported associations between obesity and skipping breakfast. 69 Friedman and Brownell (1995) suggested that health risk attitudes or behaviours related to obesity should be considered jointly, because risk factors may interact and exacerbate each other. Schuit et al. (2002) investigated the degree of clustering of common lifestyle risk factors, as co-occurrence of such behaviours can help identify high-risk groups. They found that risk factors like smoking, low vegetable/fruit consumption, excessive alcohol intake and low physical activity tended to aggregate, particularly in young adults. Friestad and Klepp (2006) also argued in favour of composite measures of health behaviours, rather than studying single forms of health-enhancing and health-compromising behaviour. Kremers et al. (2004) focused on the clustering of motivations underlying energy balance-related behaviours among adolescents. They found that attitude, subjective norm, perceived behavioural control and intention measures related to energy-dense snacks, the use of highfat sandwich fillings, fruit consumption, active transport and physical activity during leisure time clustered more strongly than the behaviours themselves. Nelson et al. (2005) investigated physical activity and sedentary behaviour patterning and identified seven homogeneous groups of adolescents with similar behaviours. About money Roberts et al. (2003) investigated associations between more open relationships between parents and their children, and the influence of children on parental decision-making concerning the consumption of sweet snacks and drinks. They found that the child’s influence declined with the parent’s age, but that parental efforts to limit their children's intake of sweet snacks and drinks were undermined by access to money, which allowed the child to out-manoeuvre his or her parents. Scragg et al. (2002) found that cigarette smoking in young adolescents was positively associated with pocket money amount. Van Reek et al. (1994) observed an association between pocket money and adolescent drinking. 70 Annex D International and national survey questionnaires reviewed 1. Health Behaviour in School-Aged Children (HBSC; www.hbsc.org): a cross-national research study among young people attending school, aged 11, 13 and 15 years old. HBSC was initiated in 1982, the sixth survey was conducted in 2001/2002, and there are now 41 participating countries (predominantly Europe and US). All national survey questionnaires share a core set of questions looking at individual and social resources, health behaviours and health outcomes. 2. Global School-based Student Health Survey (GSHS; www.who.int): a school-based survey among young people aged 13 to 15. GSHS, an initiative of the World Health Organization, uses a self-administered questionnaire to obtain data on young people's health behaviour and protective factors related to the leading causes of morbidity and mortality among children and adults worldwide. Key topics addressed include alcohol and drug use, sexual behaviours, dietary behaviours, physical activity, and mental health. 3. Youth Risk Behavior Surveillance System (YRBSS; www.cdc.gov): a school-based surveys among 9th through 12th grade students, that was developed in 1990 to monitor priority health risk behaviours, often established during childhood and early adolescence, that contribute markedly to the leading causes of death, disability, and social problems among youth and adults. These behaviours include tobacco, alcohol and other drug use, unhealthy dietary behaviours, inadequate physical activity, and sexual behaviours. 4. Dutch National Youth Survey (Nationaal Scholierenonderzoek [NSO]; www.scp.nl): a school-based survey aimed at obtaining data on behaviour, health, opinions and attitudes to finances, lifestyle and the future of school-going adolescents in the Netherlands. NSO was initiated in 1984, the seventh survey was conducted in 2001/2002. 5. Electronic Monitor and Education (Elektronische Monitor en Voorlichting [E-MOVO]; www.ggd.nl): a web-based survey conducted by the East-Netherlands Regional Public Health Service. E-MOVO collects data on behaviour and health among school-going adolescents and uses the data to provide respondents with individualized feedback and links to web-based information on relevant health issues. 6. Rotterdam Youth Monitor (RYM; www.ggd.rotterdam.nl): a monitoring program of the Rotterdam Municipal Health Service aimed at assessing the physical, mental and social development of all children born in the city at 7 different occasions in their development. 7. Dutch Obesity Intervention for youTh (DOit; www.doitproject.com): a randomized controlled trial investigating the effectiveness of a school-based program aimed at weight gain prevention in adolescents. 71 72 Annex E Questionnaire “Health & Future” [in Dutch] VRAGENLIJST GEZONDHEID & TOEKOMST Dit is een onderzoek naar hoe Nederlandse scholieren in klas 1 en 2 van het voortgezet onderwijs denken over hun gezondheid nu en in de toekomst. Lees de vragen goed door en beantwoord ze zo eerlijk mogelijk. Denk niet te lang na en kies gewoon het antwoord dat het beste bij je past. Het gaat ons om jouw mening, er zijn dus geen goede of foute antwoorden. Deze vragenlijst is ANONIEM, jouw antwoorden worden NIET door iemand op school gelezen. Volledig ingevulde vragenlijsten doen mee voor een HOOFDPRIJS VAN €100 en vijf prijzen van €20. Daarnaast wordt in iedere klas nog €10 verloot. Heb je nog vragen? Stel ze gerust! Job van Exel 010-4082507 n.vanExel@ErasmusMC.nl 73 OVER JOU 1. Ben je een meisje of een jongen? ○ meisje ○ jongen 2. Hoe oud ben je? ○ 11 ○ 12 ○ 13 ○ 14 ○ 15 3. Waar ben je geboren? ○ Nederland ○ Suriname ○ De Antillen of Aruba ○ Turkije ○ Marokko ○ anders, namelijk ________________ 4. Welk schooltype volg je? ○ VMBO, beroepsgericht ○ VMBO, theoretisch of gemengd ○ HAVO ○ HAVO / VWO ○ VWO (en Gymnasium) 5. In welke klas zit je? ○ ○ G&T05.nr brugklas tweede klas 6. Welke beschrijving past het best bij jou? Bij mij past nummer Mijn uiterlijk vind ik eigenlijk best wel heel belangrijk. Ik het er vaak met mijn vrienden / vriendinnen over. Je kunt dus wel zeggen dat ik best veel bezig ben met hoe ik er uitzie. Natuurlijk is je uitstraling ook wel belangrijk. Iemand kan dik zijn en toch overal bijhoren. Of knap zijn, maar een bitch. Als het over gezondheid gaat, denk ik met name na over gezond eten, want als je slecht eet ga je er minder mooi uitzien. 2 1 Ik maak me niet zo druk over mijn gezondheid of mijn uiterlijk. Ik ben tevreden met mijn eigen lichaam, niet te dik en niet te dun. Het leven draait niet om uiterlijk, uitstraling is veel belangrijker. Het gaat erom dat je je goed voelt en daar heeft uiterlijk niet zoveel mee te maken. Gezondheid interesseert me eigenlijk niet zo. Ik weet wel dat bepaalde dingen niet zo gezond zijn, maar daar trek ik me niet al teveel van aan. 5 Ik denk best wel eens na over mijn gezondheid, meestal over wat gezond eten is en wat niet. Ik vind dat ik eigenlijk gezonder zou moeten eten, vooral niet teveel eten en snoepen. Maar ik vind het moeilijk om goed te letten op wat ik eet. Het liefst wil ik niet al teveel opvallen en er gewoon bij horen. Ik vind het onzin als anderen zeggen dat dik zijn je eigen schuld is. Als je dik bent hoor je er gewoon bij. 7. het best 3 WAT PAST HET BEST BIJ JOU? 4 Ik zit eigenlijk niet zo lekker in mijn vel en voel me vaak niet zo fit. Ik doe niet veel met leeftijdsgenoten en voel me op school niet op mijn gemak. Ik ben veel tijd kwijt aan gamen, computeren en TV kijken. Ik beweeg te weinig, want ik vind sporten niet zo leuk. Ik ben nu eenmaal meer een zitzak dan een sportfreak. Ik eet de meeste dingen wel, maar het interesseert me eigenlijk niet zo of wat ik eet wel of niet gezond is. Ik sport veel en graag, gewoon omdat ik sporten leuk vind. Gymles is dus een van de hoogtepunten van de schoolweek. Met mijn gezondheid ben ik niet zo bezig, maar ik voel me eigenlijk best gezond. Ik denk niet zoveel na over wat nou gezond of ongezond eten is en ik vind niet dat ik gezonder zou moeten eten. Op school heb ik het prima naar mijn zin. Ik zit eigenlijk best wel lekker in mijn vel. Geef je geluk een cijfer. Zet hieronder een kruisje op de plaats die het beste klopt met hoe gelukkig jij je over het algemeen voelt. De ‘0’ betekent “heel ongelukkig”. De ‘10’ betekent “heel gelukkig”. F F F F F F F F F F 0 1 2 3 4 5 6 7 8 9 heel ongelukkig G&T05.nr F 10 heel gelukkig 8. Hieronder staan een aantal eigenschappen. Kruis aan in welke mate jij deze eigenschappen bezit. helemaal niet prettig fantasierijk prikkelbaar schuchter slordig terughoudend onderzoekend zenuwachtig zorgvuldig stil hulpvaardig snel geraakt spraakzaam ordelijk gesloten veelzijdig vriendelijk nauwkeurig vernieuwend behulpzaam ongerust aangenaam artistiek angstig netjes teruggetrokken systematisch sympathiek nerveus creatief G&T05.nr ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ niet ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ meer niet deels niet meer wel dan wel deels wel dan niet ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ wel ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ helemaal wel ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ OVER JE GEZONDHEID 9. Geef je gezondheid een cijfer. Zet hieronder een kruisje op de plaats die het beste klopt met hoe gezond jij je over het algemeen voelt. De ‘0’ betekent de slechtste gezondheid die je je kunt voorstellen. De ‘10’ betekent de beste gezondheid die je je kunt voorstellen. F F F F F F F F F F F 0 1 2 3 4 5 6 7 8 9 10 slechtste gezondheid beste gezondheid 10. Hoeveel weeg je (zonder kleren aan)? Mijn gewicht weet ik… 11. Hoe lang ben je (zonder schoenen aan)? Mijn lengte weet ik… kilo ○ vrij zeker 1 meter en ○ vrij zeker ○ niet zo zeker centimeter ○ niet zo zeker 12. Wat vind je van je eigen lichaam? ○ veel te dun ○ een beetje te dun ○ eigenlijk precies goed ○ een beetje te dik ○ veel te dik 13. Heb je last van één of meer langdurige ziekten, aandoeningen of handicaps? ○ nee ○ ja, maar ik kan de meeste dingen gewoon doen ○ ja, en ik kan veel dingen niet gewoon doen 14. Heb je de afgelopen vier weken gerookt? ○ ○ ○ G&T05.nr nee ja, af en toe ja, elke dag OVER JE TOEKOMST 15. Passen deze uitspraken bij jou? helemaal niet niet a. ik denk na over hoe mijn leven later zal zijn, en probeer met de dingen die ik nu doe mijn toekomst te verbeteren ○ ○ ○ ○ ○ b. ik doe vaak dingen waarvan ik misschien pas over een paar jaar plezier heb ○ ○ ○ ○ ○ c. ik doe alleen wat ik nu leuk vind. wat er later gebeurt zie ik dan wel weer ○ ○ ○ ○ ○ d. ik doe alleen iets als ik er nu meteen plezier van heb ○ ○ ○ ○ ○ e. ik kies graag voor de gemakkelijke oplossing ○ ○ ○ ○ ○ f. ik wil best nu iets doen wat ik minder leuk vind, als ik daar later plezier van heb ○ ○ ○ ○ ○ g. ik vind het belangrijk goed te weten welke dingen slecht voor je kunnen zijn, ook als je daar pas veel later iets van merkt ○ ○ ○ ○ ○ h. ik denk dat het beter is om iets te doen dat heel belangrijk is voor later, dan iets dat een beetje belangrijk is voor nu ○ ○ ○ ○ ○ dat sommige dingen slecht kunnen zijn voor later, daar maak ik me niet zo druk om. dat los ik later dan wel op, voor het te erg wordt ○ ○ ○ ○ ○ j. nu minder leuke dingen doen omdat dat beter is voor later vind ik niet nodig. over de toekomst maak ik me later wel druk ○ ○ ○ ○ ○ k. ik doe alleen wat ik nu leuk vind. problemen in de toekomst los ik dan wel weer op. ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ i. l. nu dingen doen waarvan ik weet dat ik ze leuk vind is voor mij belangrijker dan dingen doen waar ik misschien later een keer plezier van heb 16. Hoe oud denk je te worden? G&T05.nr ____ jaar een heel goed beetje goed 17. Hoe belangrijk vind jij het, hoe het met je zal gaan… heel niet helemaal niet belangrijk belangrijk belangrijk belangrijk … over 2 jaar? … over 5 jaar? … over 25 jaar? ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ 18. Wat heb je liever? a. ik heb liever €100 nu dan €110 over 2 jaar ○ ja ○ ja ○ ja ○ ja ○ ja ○ ja ○ ja ○ ja ○ ja ○ ja ○ ja ○ ja ○ nee ○ nee ○ nee ○ nee ○ nee ○ nee ○ nee ○ nee ○ nee ○ nee ○ nee ○ nee a. nu gezonder eten zodat je een betere gezondheid hebt als je 70 jaar bent ○ ja ○ nee b. nu iedere dag 30 minuten extra bewegen zodat je een betere gezondheid hebt als je 70 jaar bent ○ ja ○ nee c. nu een prik waarvan je een week goed ziek bent zodat je een betere gezondheid hebt als je 70 jaar bent ○ ja ○ nee d. nu gezonder eten zodat je later 3 jaar ouder wordt ○ ja ○ ja ○ nee ○ nee ○ ja ○ nee b. ik heb liever €100 nu dan €125 over 2 jaar c. ik heb liever €100 nu dan €150 over 2 jaar d. ik heb liever €100 nu dan €250 over 2 jaar e. ik heb liever €100 nu dan €500 over 2 jaar f. ik heb liever €100 nu dan €200 over 5 jaar g. ik heb liever €100 nu dan €500 over 5 jaar h. ik heb liever €100 nu dan €1.000 over 5 jaar i. ik heb liever €100 nu dan €5.000 over 5 jaar j. ik heb liever €100 nu dan €10.000 over 25 jaar k. ik heb liever €100 nu dan €100.000 over 25 jaar l. ik heb liever €100 nu dan €1.000.000 over 25 jaar 19. Zou je dit doen? e. nu iedere dag 30 minuten extra bewegen zodat je later 3 jaar ouder wordt f. nu een prik waarvan je een week goed ziek bent zodat je later 3 jaar ouder wordt G&T05.nr 20. Geef een rapportcijfer aan je gezondheid als je 40 jaar oud bent. Zet een kruisje op de plaats die het beste klopt met hoe gezond jij verwacht te zijn als je 40 jaar bent. De ‘0’ betekent de slechtste gezondheid die je je kunt voorstellen. De ‘10’ betekent de beste gezondheid die je je kunt voorstellen. F F F F F F F F F F F 0 1 2 3 4 5 6 7 8 9 10 slechtste gezondheid beste gezondheid 21. Geef een rapportcijfer aan je gezondheid als je 70 jaar oud bent. Zet een kruisje op de plaats die het beste klopt met hoe gezond jij verwacht te zijn als je 70 jaar bent. De ‘0’ betekent de slechtste gezondheid die je je kunt voorstellen. De ‘10’ betekent de beste gezondheid die je je kunt voorstellen. F F F F F F F F F F F 0 1 2 3 4 5 6 7 8 9 10 slechtste gezondheid beste gezondheid 22. Gezond leven betekent dat je gezond eet (drie maaltijden op een dag / weinig tussendoortjes / voldoende groente en fruit) en genoeg beweegt of sport om fit te blijven. Wat vind je van deze uitspraken? helemaal mee eens mee eens niet mee eens helemaal niet mee eens a. ik eet gezond F F F F b. ik beweeg genoeg om fit te blijven F F F F c. als ik gezond leef dan voel ik mij beter F F F F d. als ik nu ongezond leef dan kan ik later allerlei ziektes krijgen F F F F e. als ik nu ongezond leef dan kan ik eerder doodgaan F F F F f. als ik dat wil dan kan ik makkelijk gezonder gaan leven dan ik nu doe F F F F g. als ik vaak ziek zou zijn dan zou ik gezonder gaan leven F F F F G&T05.nr OVER THUIS 23. Met welke mensen woon jij in één huis? Kruis alles wat van toepassing is aan ○ eigen moeder ○ pleegmoeder, stiefmoeder of partner vader ○ eigen vader ○ pleegvader, stiefvader of partner moeder ○ zus(sen) ○ broer(s) ○ anders, namelijk ________________ 24. Waar is je moeder geboren? ○ Nederland ○ Suriname ○ De Antillen of Aruba ○ Turkije ○ Marokko ○ anders, namelijk ________________ 25. Waar is je vader geboren? ○ Nederland ○ Suriname ○ De Antillen of Aruba ○ Turkije ○ Marokko ○ anders, namelijk ________________ 26. Heeft je moeder betaald werk? ○ ja ○ nee G&T05.nr 27. Heeft je vader betaald werk? ○ ja ○ nee 28. Hoe rijk is jullie gezin in vergelijking met andere gezinnen in Nederland? ○ veel rijker ○ rijker ○ ongeveer even rijk ○ minder rijk ○ veel minder rijk 29. Word jij thuis opgevoed met een bepaald geloof? ○ ja, Rooms-Katholiek ○ ja, Protestant (zoals Hervormd of Gereformeerd) ○ ja, Islamitisch ○ ja, anders ○ nee, niet gelovig opgevoed 30. Hebben jullie deze producten thuis en mag je die pakken als je er zin in hebt? a. melk b. fruit c. koek (zoals sultana, liga, ontbijtkoek) d. snoep / chocola e. chips / nootjes / popcorn f. snacks (zoals hamburger, friet, kroket, pizzabroodje) g. frisdrank of energiedranken 31. Mag je thuis roken of zou het mogen? ○ altijd ○ soms ○ nooit G&T05.nr ○ ja ○ ja ○ ja ○ ja ○ ja ○ ja ○ ja ○ nee ○ nee ○ nee ○ nee ○ nee ○ nee ○ nee 32. Mag je thuis alcoholhoudende drank drinken of zou het mogen? ○ altijd ○ soms ○ nooit 33. Geef aan wat je van deze uitspraken vindt. helemaal mee eens mee eens niet mee eens helemaal niet mee eens a. mijn ouders hebben belangstelling voor wat ik doe of wat mij bezig houdt F F F F b. mijn ouders geven mij een compliment als ik iets goed doe F F F F c. mijn ouders zijn streng F F F F d. ik ben meestal tevreden over de relatie met mijn moeder F F F F e. ik ben meestal tevreden over de relatie met mijn vader F F F F 34. Geef je geluk THUIS een cijfer. Zet hieronder een kruisje op de plaats die het beste klopt met hoe gelukkig jij je over het algemeen thuis voelt. De ‘0’ betekent “heel ongelukkig”. De ‘10’ betekent “heel gelukkig”. F F F F F F F F F F 0 1 2 3 4 5 6 7 8 9 heel ongelukkig OVER SCHOOL 35. Hoe ga je meestal van huis naar school? ○ lopend ○ op de fiets ○ met het openbaar vervoer ○ ik word met de auto gebracht / gehaald ○ anders, namelijk ____________________ G&T05.nr F 10 heel gelukkig 36. Hoe lang doe je er meestal over van huis naar school? minuten 37. Als je denkt aan je laatste rapport, hoe waren dan je schoolprestaties? ○ zeer goed ○ goed ○ voldoende ○ onvoldoende ○ zeer onvoldoende 38. Hoe vaak ben je in de laatste maand op school gepest? ○ nooit ○ soms (minder dan één keer per week) ○ vaak (één keer per week of meer) 39. Kun jij onderstaande producten bij jou op school kopen (bijvoorbeeld in de kantine of uit een automaat)? a. melk b. fruit c. gezonde broodjes (bijvoorbeeld met kaas of vleeswaren) d. koek (zoals sultana, liga, ontbijtkoek) e. snoep / chocola f. snacks (bijvoorbeeld hamburger, friet, kroket, pizzabroodje) g. frisdrank of energiedranken ○ ja ○ ja ○ ja ○ ja ○ ja ○ ja ○ ja ○ nee ○ nee ○ nee ○ nee ○ nee ○ nee ○ nee 40. Kun jij onderstaande producten ergens vlakbij school kopen (bijvoorbeeld bij een supermarkt of tankstation)? a. koek (zoals sultana, liga, ontbijtkoek) b. snoep / chocola c. snacks (bijvoorbeeld hamburger, friet, kroket, pizzabroodje) d. frisdrank of energiedranken G&T05.nr ○ ja ○ ja ○ ja ○ ja ○ nee ○ nee ○ nee ○ nee 41. Waar ga je meestal naar toe als je uit school komt? ○ naar huis ○ naar een vriend / vriendin thuis ○ met vrienden / vriendinnen ergens naartoe of een beetje rondhangen ○ naar een oppas, opvang of huiswerkbegeleiding ○ anders, namelijk ____________________ 42. Als je na school naar huis gaat of zou gaan, wie is er dan thuis? ○ mijn moeder (of pleegmoeder / stiefmoeder / partner vader) ○ mijn vader (of pleegvader / stiefvader / partner moeder) ○ beide ○ geen van beide 43. Geef je geluk OP SCHOOL een cijfer. Zet hieronder een kruisje op de plaats die het beste klopt met hoe gelukkig jij je over het algemeen op school voelt. De ‘0’ betekent “heel ongelukkig”. De ‘10’ betekent “heel gelukkig”. F F F F F F F F F F 0 1 2 3 4 5 6 7 8 9 heel ongelukkig OVER JE VRIJE TIJD 44. Hoeveel goede vrienden of vriendinnen heb je op dit moment? ○ geen ○ één ○ twee ○ drie of meer G&T05.nr F 10 heel gelukkig 45. Hoeveel tijd besteed je OP EEN SCHOOLDAG gemiddeld aan de volgende dingen? helemaal 1 uur of meer dan 1 à 2 uur niet minder 2 uur a. huiswerk maken F F F F b. lezen (krant, tijdschrift, strip, boek) F F F F c. televisie / video / DVD kijken F F F F d. computeren (internet, games, chatten, playstation) F F F F e. telefoneren / SMS’en F F F F f. spelen of sporten buiten of op straat F F F F g. andere hobby F F F F 46. Hoeveel tijd besteed je OP EEN WEEKEND DAG gemiddeld aan de volgende dingen? helemaal 1 uur of meer dan 1 à 2 uur niet minder 2 uur a. huiswerk maken F F F F b. lezen (krant, tijdschrift, strip, boek) F F F F c. televisie / video / DVD kijken F F F F d. computeren (internet, games, chatten, playstation) F F F F e. telefoneren / SMS’en F F F F f. spelen of sporten buiten of op straat F F F F h. andere hobby F F F F 47. Sport je bij een vereniging of club? ○ nee (ga verder met vraag 0) ○ ja, ik doe aan ____________________________________________ (naam sport(en), bijvoorbeeld voetbal / hockey) 48. Hoeveel uur per week train je voor deze sporten? Bij elkaar gemiddeld uur per week 49. Doe je voor één of meerdere sporten mee aan competitiewedstrijden? ○ nee ○ ja G&T05.nr 50. Als ik sport, doe ik dat omdat… helemaal mee eens mee eens niet mee eens helemaal niet mee eens a. …ik sporten leuk vind F F F F b. …ik fit wil blijven F F F F c. …ik er goed wil uitzien F F F F d. …ik daar vrienden en vriendinnen tegenkom F F F F e. …ik bij de beste in mijn sport wil horen F F F F f. …ik dat moet van mijn ouders F F F F 51. In mijn vrije tijd… heel vaak vaak soms zelden nooit a. …ben ik alleen F F F F F b. …verveel ik mij F F F F F 52. Geef je geluk IN JE VRIJE TIJD een cijfer. Zet hieronder een kruisje op de plaats die het beste klopt met hoe gelukkig jij je over het algemeen in vrije tijd voelt. De ‘0’ betekent “heel ongelukkig”. De ‘10’ betekent “heel gelukkig”. F F F F F F F F F F F 0 1 2 3 4 5 6 7 8 9 10 heel ongelukkig heel gelukkig OVER WAT JE EET 53. Hoe vaak eet jij TUSSENDOORTJES? (bijna) nooit 1 of 2 vaak, elke keer maar niet dag per week elke dag a. koek (zoals sultana, liga, ontbijtkoek) F F F F b. snoep / chocola F F F F c. chips / nootjes / popcorn F F F F d. snacks (zoals hamburger, friet, kroket, pizzabroodje) F F F F G&T05.nr 54. Als je tussendoortjes neemt, wanneer doe je dat dan meestal? (bijna) nooit 1 of 2 vaak, elke keer maar niet dag per week elke dag a. op weg naar / van school F F F F b. in de pauze op school F F F F c. als ik thuis kom van school F F F F d. als ik TV kijk / computer F F F F e. op straat / in de stad F F F F f. bij de (sport)club of (sport)vereniging F F F F 55. Hoe vaak eet of drink jij…? (bijna) nooit 1 of 2 vaak, elke keer maar niet dag per week elke dag a. ontbijt (meer dan iets te drinken of een tussendoortje) F F F F b. lunch (meer dan iets te drinken, een tussendoortje of F F F F c. avondeten, samen met je familie aan tafel (meer F F F F d. melk F F F F e. frisdrank (niet light) F F F F f. fruit F F F F g. groente (salade / gekookte groente) F F F F snack) dan iets te drinken, een tussendoortje of snack) OVER GELD 56. Hoeveel geld (bijvoorbeeld zakgeld of kleedgeld) krijg je van je ouders? Ik krijg gemiddeld ____ Euro per maand 57. Hoeveel geld verdien je met bijbaantjes? Ik verdien gemiddeld ____ Euro per maand G&T05.nr 58. Mag je van je ouders zelf beslissen wat je met je geld doet? ○ ja ○ grotendeels ○ soms wel en soms niet ○ nee 59. Mag je van je ouders dit geld uitgeven aan snoep of snacks (zoals hamburger, friet, kroket, pizzabroodje)? ○ nee ○ ja 60. Spaar je? ○ nee (ga verder met vraag 0) ○ ja 61. Hoeveel spaar je? Ik spaar gemiddeld ____ Euro per maand 62. Waarom spaar je? Kruis alles wat van toepassing is aan ○ voor een speciaal doel (bijvoorbeeld een stereo, MP3-speler) ○ om iets achter de hand te hebben als ik geld nodig heb ○ geen reden, ik hou gewoon geld over ○ omdat het moet van mijn ouders 63. Hoeveel van je eigen geld besteed je gemiddeld per maand aan…? a. snoep / chocola / koek / chips ____ Euro per maand b. snacks (zoals hamburger, friet, kroket, pizzabroodje) ____ Euro per maand c. alcoholhoudende dranken ____ Euro per maand d. sigaretten / shag ____ Euro per maand e. kleding en schoenen ____ Euro per maand f. CD’s / DVD’s e.d. ____ Euro per maand g. cosmetica, make-up, kapper, e.d. ____ Euro per maand h. mobiele telefoon ____ Euro per maand G&T05.nr Scheur deze bladzijde los van de vragenlijst en lever deze apart in bij je leraar VUL HIERONDER JE NAAM EN JE KLAS IN ZODAT WE JE KUNNEN TERUGVINDEN ALS JE IN DE PRIJZEN VALT! NAAM: __________ KLAS: ____ VOND JE HET LEUK OM MEE TE DOEN? WIJ DOEN VAKER DIT SOORT ONDERZOEK. WIL JE NOG EENS MEEDOEN? VUL DAN JE GEGEVENS IN! NAAM: _________________ ADRES: _________________________ STRAAT EN HUISNU MMER ______ _____________ POSTCODE WOONPLAATS Je bent aan het einde van de vragenlijst gekomen. Hartelijk dank voor het meedoen! G&T05.nr Q Annex F Attitudes of youths about their health lifestyle (format A) The way I look is very important to me. I discuss my looks a lot with my friends. It is fair to say I am pretty involved with my appearance. Of course, personality is also important. Someone can be overweight and still belong to the group, or be beautiful but still be a bitch. When I think about my health, I am particularly concerned with what I eat, because when you eat unhealthy you look worse. 2 1 I do not worry too much about my health or my looks. I am satisfied with my body as it is, not too overweight and not too thin. In life it is not about how you look, it is about who you are. It is important to feel good, and looks have little to do with that. I am not really interested in my health. I can tell healthy from unhealthy foods but, for the most part, I eat what I like. 5 Sometimes I think about my health, usually about what I should or should not eat. I really should eat healthier, in particular I shouldn’t eat too much and eat less snacks. However, I find it difficult to watch what I eat. I’d rather not attract too much attention at school and simply belong to the group. I think it is nonsense to say that being overweight is your own fault. Only being overweight, does not make you different form others. 3 WHICH DESCRIPTION FITS YOU MOST? I do not feel so good in general, and often do not feel fit physically. I do not do much with peers and do not feel at ease at school. I spend a lot of time playing computer games and watching TV. I exercise little, because I do not enjoy it. I am simply more a ‘couch-potato’ than a ‘sport freak’. I eat most types of food, but I do not really care whether what I eat is healthy or not. 4 I often play sports, simply because I love doing it. Gym class therefore is one of the high points of the school week. I do not think much about my health, but I actually feel pretty healthy. I give little thought to whether food is healthy or not and I do not feel I should live healthier. I feel at ease at school. Actually, I feel pretty good in general. 91 92 Annex G Attitudes of youths about their health lifestyle (format B) DOES THIS DESCRIPTION FIT YOU? I do not worry too much about my health or my looks. I am satisfied with my body as it is, not too overweight and not too thin. In life it is not about how you look, it is about who you are. It is important to feel good, and looks have little to do with that. I am not really interested in my health. I can tell healthy from unhealthy foods but, for the most part, I eat what I like. The way I look is very important to me. I discuss my looks a lot with my friends. It is fair to say I am pretty involved with my appearance. Of course, personality is also important. Someone can be overweight and still belong to the group, or be beautiful but still be a bitch. When I think about my health, I am particularly concerned with what I eat, because when you eat unhealthy you look worse. I do not feel so good in general, and often do not feel fit physically. I do not do much with peers and do not feel at ease at school. I spend a lot of time playing computer games and watching TV. I exercise little, because I do not enjoy it. I am simply more a ‘couch-potato’ than a ‘sport freak’. I eat most types of food, but I do not really care whether what I eat is healthy or not. I often play sports, simply because I love doing it. Gym class therefore is one of the high points of the school week. I do not think much about my health, but I actually feel pretty healthy. I give little thought to whether food is healthy or not and I do not feel I should live healthier. I feel at ease at school. Actually, I feel pretty good in general. Sometimes I think about my health, usually about what I should or should not eat. I really should eat healthier, in particular I shouldn’t eat too much and eat less snacks. However, I find it difficult to watch what I eat. I’d rather not attract too much attention at school and simply belong to the group. I think it is nonsense to say that being overweight is your own fault. Only being overweight, does not make you different form others. not at all not a little well very well not at all not a little well very well not at all not a little well very well not at all not a little well very well not at all not a little well very well 93