To describe the prevalence of ‘graded thinness’ in children aged 11, 13 and 15 years in eleven developed countries and to identify trends in the prevalence of ‘thinness’ (BMI < 17 kg/m2 at age 18 years) by age and gender.

Cross-sectional study using data collected through self-reported questionnaires.

Data were taken from the 1997/1998, 2001/2002 and 2005/2006 surveys of the Health Behaviours in School-aged Children (HBSC) Study.

Children and adolescents from ten European countries and the USA (n 158 000).

Prevalence of grades 1, 2 and 3 of thinness was higher among 11-year-old students compared with the 13- and 15-year-olds in all countries. A higher prevalence of thinness was observed in girls than in boys. Since 1998 the prevalence of thinness decreased steadily in Czech boys and girls, while it increased for French girls. In the total European sample of females, thinness decreased from 1998 to 2006 (χ2 for trend, P < 0·01). Age-adjusted logistic regression analysis showed that Czech boys and girls, and Flemish and American girls were less likely to be thin in 2006 than in 1998; while a noteworthy increment, even if borderline significant, was observed for French girls with a 41 % increase in the likelihood to be thin.

Our findings suggest that thinness is an important overlooked phenomenon with wide variation in prevalence and trends across developed countries. It deserves further longitudinal studies in a multinational context that could increase the understanding of the factors associated with thinness and contribute to developing preventive and nutritional programmes targeted at controlling obesity and chronic diseases, while monitoring thinness.

The increasing prevalence of childhood overweight is an important health issue. There is a need for longitudinal research among children in order to identify risk factors for childhood overweight. The objective of the present research was to identify potential sociodemographic and behavioural risk factors for development of childhood overweight among 3- to 6-year-old children.

Longitudinal study.

Sixteen pre-primary and primary schools.

BMI Z-scores at baseline and two follow-up measurements were calculated for 568 children. Sociodemographic, parental adiposity, familial composition, child's diet, physical activity and sedentary behavioural data were collected through questionnaires.

Several risk factors for the development of childhood overweight were found. Being an only child, lower maternal educational level, maternal and paternal overweight, more than 1 h screen time on weekdays and high soft drinks consumption were shown to be positively associated with the development of childhood overweight.

Although behavioural factors are important, our findings support the thesis that interventions on the prevention of childhood overweight should focus on high-risk groups, i.e. children from low socio-economic background or with high parental BMI. Interventions should address the whole family and take into account their lifestyle and structure.

The aim of the paper is to describe the formative evaluation of the feedback component of an online nutrition tailoring instrument, the Children's and Adolescents’ Nutrition Assessment and Advice on the Web (CANAA-W), among parents of schoolchildren.

Parents of pre-primary and primary-school children recorded their child's food intake over 3 d with CANAA-W and completed the evaluation questionnaire online. A subsample participated in focus group discussions.

Parents completed CANAA-W at home.

Forty-six parents completed the evaluation questionnaire. Seventeen parents participated in three focus group discussions.

Parents were enthusiastic: the majority (81 % or more) found the advice comprehensible, interesting, logical, useful, believable, well formulated, correct, personal, relevant, complete, attractive, containing enough and not too much information; they indicated that it is helpful to improve their children's eating habits and that they intend to use it. The qualitative analyses revealed that the respondents appreciated the confrontation with their child's diet and the visualization (i.e. traffic light colours, pictograms, food models, diagrams). The length of the feedback was rather a drawback, but it was useful nevertheless.

CANAA-W was well received by the parents; the scores on the feasibility questionnaire were high and the qualitative analyses showed that the confrontation with their child's diet, and attractive visualization of the most relevant feedback linked to more elaborated optional feedback, were well appreciated. The major challenge will be to convince parents who are less interested in food habits and less computer-literate to participate in this type of study.

To evaluate a web-based nutritional knowledge questionnaire for primary-school children.

Children's nutritional knowledge was assessed in five domains: healthy choices (twenty-seven items), estimated recommended portions/servings (eight items), nutrient content (five items), main food function (five items) and categorization of food items (eight items).

The questionnaires were completed in school.

A convenience sample of 576 Belgian children (aged 7–12 years) from fourteen primary schools completed the questionnaire once, 386 completed the questionnaire twice.

Healthy choices could be answered correctly by 73 % of the children, nutrients by 59 %, food categorization by 49 %, main function by 38 % and portion estimation by 36 %. Children's test–retest intra-class correlations were 0·75 for healthy choices, 0·33 for nutrients, 0·61 for food categorization, 0·44 for main function, 0·47 for portion estimation and 0·76 for the total scale. The intra-class correlation was lower in the youngest age group (grade 2: 0·51, grade 4: 0·65, grade 6: 0·66). The total score was significantly lower in the retest. The instrument was in general positively evaluated by the children.

The instrument is a promising, practical, inexpensive tool with acceptable test–retest reliability in fourth and sixth graders.

To investigate test–retest reliability of primary-school children's reports of food preferences and to investigate agreement with parental reports.

Children completed an online test and retest, one to two weeks later, during school hours; parents completed a paper-and-pencil or an online questionnaire at home. The children's preferences questionnaire contained 148 food items, reduced to twelve scales; the parental questionnaire contained seventy-eight items reduced to nine scales.

Children of fourteen primary schools in Belgium-Flanders.

In total 572 children participated; test–retest data were available for 354 children, children's tests could be matched to 362 parental reports.

Test–retest intraclass correlations were on average 0·73, ranging between 0·62 and 0·86; correlations between children's and parents’ reports were on average 0·50, ranging between 0·32 and 0·62. Retest preferences were significantly higher for more than half of the scales. Children reported higher preferences than their parents for milk & milk products, fruit and soft drinks, while parents reported higher preferences for bread & breakfast cereals, meat, snacks and sauces.

The results indicate that the test–retest stability was good; however, agreement between parents and children was rather low to moderate.

To examine the association between breakfast consumption and CVD risk factors in European adolescents.

Cross-sectional. Breakfast consumption was assessed by the statement ‘I often skip breakfast’ and categorized into ‘consumer’, ‘occasional consumer’ and ‘skipper’. Blood pressure, weight, height, waist circumference, skinfold thickness, total cholesterol (TC), HDL cholesterol (HDL-C), LDL cholesterol (LDL-C), TAG, insulin and glucose were measured and BMI, TC:HDL-C, LDL-C:HDL-C and homeostasis model assessment–insulin resistance index (HOMA-IR) were calculated.

The European Union-funded HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study.

European adolescents, aged 12·50–17·49 years, from ten cities within the HELENA study (n 2929, n 925 with blood sample, 53 % females).

In males, significant differences across breakfast consumption category (‘consumer’, ‘occasional consumer’ and ‘skipper’) were seen for age, BMI, skinfold thickness, waist circumference, cardiorespiratory fitness, systolic and diastolic blood pressures, TC:HDL-C, LDL-C:HDL-C, glucose, insulin, HOMA-IR and LDL-C; in females, for cardiorespiratory fitness, skinfold thickness, BMI, insulin and HOMA-IR. In overweight/obese males significant differences were also seen for TC and LDL-C, whereas no differences were observed in non-overweight males or in females regardless of weight status.

Our findings among European adolescents confirm previous data indicating that adolescents who regularly consume breakfast have lower body fat content. The results also show that regular breakfast consumption is associated with higher cardiorespiratory fitness in adolescents, and with a healthier cardiovascular profile, especially in males. Eating breakfast regularly may also negate somewhat the effect of excess adiposity on TC and LDL-C, especially in male adolescents.

The purpose of the present study was to evaluate the effects of a school-based, 2-year, multi-component intervention on BMI, eating and physical activity behaviour in Flanders, Belgium, targeting children aged 3–6 years in communities of high and low socio-economic status (SES).

Cluster-randomized controlled trial.

Thirty-one pre-primary and primary schools in three different intervention communities and three paired-matched (on SES profile) control communities in Flanders, Belgium.

BMI Z-scores at baseline and follow-up were calculated for 1102 children. Questionnaires with sociodemographic data and FFQ were available from 694 of these 1102 children.

No significant effects were found on BMI Z-scores for the total sample. However, there was a significant decrease in BMI Z-score of 0·11 in the low-SES intervention community compared with the low-SES control community, where the BMI Z-score increased by 0·04 (F = 6·26, P = 0·01). No significant intervention effects could be found for eating behaviour, physical activity or screen-time. There were no significant interaction effects of age and gender of the children on the outcome variables.

Although no significant effects were found for BMI Z-scores in the total sample, this intervention had a promising effect in the low-SES community of reducing excess weight gain among young children.

To describe breakfast habits at food group level in European adolescents and to investigate the associations between these habits and sociodemographic factors.

Cross-sectional study.

Secondary schools from nine European cities participating in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study. Breakfast habits were assessed twice using a computer-based 24 h dietary recall. Adolescents who consumed breakfast on at least one recall day were classified as ‘breakfast consumers’ and adolescents who did not have anything for breakfast on either of the two recall days were considered ‘breakfast skippers’. A ‘breakfast quality index’ to describe breakfast quality was created based on the consumption or non-consumption of cereals/cereal products, dairy products and fruits/vegetables. The sociodemographic factors studied were sex, age, region of Europe, maternal and paternal education, family structure and family affluence.

Adolescents (n 2672, 53 % girls) aged 12–17 years.

The majority of the adolescents reported a breakfast that scored poorly on the breakfast quality index. Older adolescents, adolescents from the southern part of Europe and adolescents from families with low socio-economic status were more likely to consume a low-quality breakfast.

The study highlights the need to promote the consumption of a high-quality breakfast among adolescents, particularly in older adolescents, adolescents from southern Europe and adolescents from families with low socio-economic status, in order to improve public health.

The aim of the present study was to investigate dietary sources of Na and K intakes among Flemish pre-school children using multiple linear regression analyses.

Three-day estimated diet records were used to assess dietary intakes. The contribution to Na and K intakes of fifty-seven food groups was computed by summing the amount provided by the food group for all individuals divided by the total intake for all individuals.

A random cluster sampling design at the level of schools, stratified by province and age, was used.

A representative sample of 696 Flemish pre-school children aged 2·5–6·5 years was recruited.

Mean Na intake was above and mean K intake was largely below the recommendation for children. Bread (22 %) and soup (13 %) were main contributors to Na intake followed by cold meat cuts and other meat products (12 % and 11 %, respectively). Sugared milk drinks, fried potatoes, milk and fruit juices were the main K sources (13 %, 12 %, 11 % and 11 %, respectively). Although Na and K intakes were positively correlated, several food categories showed Na:K intake ratio well above one (water, cheeses, soup, butter/margarine, fast foods and light beverages) whereas others presented a ratio well below one (oil & fat, fruits & juices, potatoes, vegetables and hot beverages).

Flemish pre-school children had too high Na and too low K intakes. The finding that main dietary sources of Na and K are clearly different indicates the feasibility of simultaneously decreasing Na and increasing K intake among children.

To investigate the feasibility and impact of the Food-O-Meter, an Internet-based computer-tailored nutrition intervention in adolescents.

Participants in the intervention condition received the computer-tailored advice at baseline and at 1 month, those in the control condition received standardised advice. Effects were evaluated at 1 month (n 621) and at 3 months (n 558) using multi-level modelling.

Secondary schools in six European cities. Adolescents accessed the intervention in the school computer room under the supervision of teachers.

Classes with students aged 12–17 years in the schools participating in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) cross-sectional study were randomised into intervention and control schools.

In most participating centres the intervention was feasible and generally well appreciated, especially by girls. Technical problems and lack of motivation of the teachers hindered implementation in some centres. Overweight adolescents had higher scores for reading and using the advice than normal weight adolescents. After 1 month adolescents receiving the standardised advice reported an increase in fat intake, while fat intake in the intervention condition was stable (F = 4·82, P < 0·05). After 3 months, there was a trend in the total group for an intervention effect of the tailored advice on fat intake (F = 2·80, P < 0·10). In the overweight group there was a clear positive effect (F = 5·76, P < 0·05).

The Food-O-Meter should be developed further. The results were modest but clear for percentage energy from fat, specifically in the overweight group. Adaptations based on new research are needed to enhance the reliability and effectiveness of the intervention.

To identify the correlates of the home food environment (parents’ intake, availability and food-related parenting practices) at the age of 10 years with dietary patterns during childhood and in adolescence.

Primary-school children of fifty-nine Flemish elementary schools completed a questionnaire at school in 2002. Four years later they completed a questionnaire by e-mail or mail at home. Their parents completed a questionnaire on food-related parenting practices at baseline.

Longitudinal study.

The analyses included 609 matched questionnaires.

Multi-level regression analyses were used to identify baseline parenting practices (pressure, reward, negotiation, catering on demand, permissiveness, verbal praise, avoiding negative modelling, availability of healthy/unhealthy food items and mothers’ fruit and vegetable (F&V) and excess scores) associated with children’s dietary patterns (F&V and excess scores).

Mother’s F&V score was a significant positive independent predictor for children’s F&V score at baseline and follow-up, whereas availability of unhealthy foods was significantly negatively associated with both scores. Negotiation was positively associated with children’s follow-up score of F&V, while permissiveness was positively associated with children’s follow-up excess score. Availability of unhealthy foods and mother’s excess score were positively related to children’s excess score at baseline and follow-up.

Parental intake and restricting the availability of unhealthy foods not only appeared to have a consistent impact on children’s and adolescents’ diets, but also negotiating and less permissive food-related parenting practices may improve adolescents’ diets.

To explore the relationship between several physical activity (PA) and dietary behaviours and BMI Z-score and to investigate the relationship between changes in these variables and in the BMI Z-score over a 4-year period from childhood to adolescence.

Longitudinal study in which children were included in the fifth grade and measured for four consecutive years. Dietary and PA behaviours as well as height and weight were measured by means of self-reported validated questionnaires.

Fifty-nine Flemish elementary schools.

The baseline sample consisted of 51·9 % boys and the mean age was 10 (sd 0·4) years. During the first measurement year (2002), data on 1670 fifth graders were gathered. These measurements were repeated after 1 (n 1557), 2 (n 1151) and 3 (n 807) years.

Significant inverse relationships with BMI Z-score were observed for frequency of breakfast consumption (β = −0·033, se = 0·012) and frequency of sports participation (β = −0·011, se = 0·004) across four time points. Significant inverse relationships between changes in BMI Z-score and changes in frequency of sports participation (β = −0·011, se = 0·006) and hours of physical education (PE; β = −0·052, se = 0·023) were observed, meaning that decreases in sports participation and hours spent in PE were associated with increases in BMI Z-score.

The present study provides an important insight into different dietary and PA behaviours related to (changes in) BMI Z-score during the transition from childhood to adolescence.

To describe the development of a short questionnaire including a wide range of personal, social and environmental constructs in relation to a healthy diet in an adolescent population.

The questionnaire was developed based on the literature, past experiences and feedback from a small pilot study (n 10). Test and retest (2 weeks later) of the questionnaire was done to investigate test–retest reliability. Data of four non-consecutive 24 h recalls were collected to investigate the predictive validity with food (fruit, vegetables, milk, snacks, soft drinks), nutrient (fibre, ascorbic acid, Ca, percentage energy from fat) and energy intakes.

At home, in the presence of a student.

Convenience sample of fifty-five Belgian-Flemish adolescents approached by university students for course credits.

Test–retest correlations of the constructs ranged between 0·51 and 0·78. Eleven of the eighteen final constructs were significantly associated with one or more of the five selected food items, all in the expected direction. Most significant associations with the food items were found for taste, perceived peers’ behaviour and availability of soft drinks at home. Fresh fruit and soft drinks were correlated with most constructs (seven) followed by snacks (five). Concerning energy and the selected nutrient variables, the findings were less clear.

The results are promising: the test–retest stability was moderate to good; most of the psychosocial constructs were significantly associated with one or more of the selected dietary variables. Future work in a larger sample of European adolescents is warranted.

In the Health Behaviour in School-Aged Children (HBSC) survey, the frequency of consumption of a limited number of food items – focusing on fibre, calcium and less healthy items – is queried using a 15-item food-frequency questionnaire (FFQ). The present study was conducted to assess the reliability and relative validity of the HBSC FFQ among school pupils in Belgium.

To assess the reliability of the FFQ, 207 pupils aged 11–12 years and 560 pupils aged 13–14 years completed the questionnaire twice, with a test–retest interval of 6 to 15 days. To assess the relative validity of the FFQ, in a first study data were collected as part of the Flemish HBSC 2000 survey: 7072 pupils (11–18 years) completed the FFQ and a 24-hour food behaviour checklist (FBC). In a second study, 101 pupils (11–12 years) completed the FFQ and a 7-day food diary (FD).

Reliability – weighted kappa values between test and retest ranged from 0.43 to 0.70, percentage agreement from 37 to 87%, and Spearman correlations from 0.52 to 0.82. Relative validity – comparison of the FBC with the percentage of respondents who should have consumed the food items on a random day, computed from the FFQ, showed good agreement between the FFQ and the FBC for most items. Only for cereals, diet soft drinks and other milk products were considerably higher food frequencies than expected found from the FBC. Comparison of the FFQ with the FD showed overestimation for all but three food items (cheese, soft drinks and chips). Spearman correlations ranged between 0.10 for crisps and 0.65 for semi-skimmed milk.

The HBSC FFQ is a reliable questionnaire that can be used for ranking subjects for most food items, although one must consider the overestimation when the FFQ is used for estimating prevalences.

To evaluate the effects of a middle-school healthy eating promotion intervention combining environmental changes and computer-tailored feedback, with and without an explicit parent involvement component.

Clustered randomised controlled trial.

Fifteen West-Flemish (Belgian) middle schools.

A random sample of 15 schools with 2991 pupils in 7th and 8th grades was randomly assigned to an intervention group with parental support (n = 5), an intervention group without parental support (n = 5) and a control group (n = 5). In these 15 schools an intervention combining environmental changes with computer-tailored feedback was implemented. Fat and fruit intake, water and soft drinks consumption were measured with food-frequency questionnaires in the total sample of children.

In girls, fat intake and percentage of energy from fat decreased significantly more in the intervention group with parental support, compared with the intervention alone group (all F>3.9, P < 0.05) and the control group (all F>16.7, P < 0.001). In boys, there were no significant decreases in fat intake (F = 1.4, not significant (NS)) or percentage of energy from fat (F = 0.7, NS) as a result of the intervention. No intervention effects were found in boys or in girls for fruit (F = 0.5, NS), soft drinks (F = 2.6, NS) and water consumption (F = 0.3, NS).

Combining physical and social environmental changes with computer-tailored feedback in girls and their parents can induce lower fat intake in middle-school girls. However, to have an impact on the consumption of soft drinks and water, governmental laws that restrict the at-school availability of low-nutritive products may be necessary.

Several environmental factors influence adolescents' food habits and television (TV) viewing is thought to be one of these factors. The purpose of the present study was to describe sociodemographic differences in TV viewing and to examine associations of TV viewing with the consumption of sweets, soft drinks, fruit and vegetables in different countries.

Data were collected from 162 305 young people completing the 2001/02 Health Behaviour in School-Aged Children survey, a World Health Organization cross-national study on health and health behaviours among 11–, 13– and 15–year-old school pupils. Analyses of variance were used to examine sociodemographic differences in TV viewing and logistic regression analyses to examine associations between TV viewing and food habits.

Large differences were found between countries in reported daily TV viewing time, from an average of 2.0 h in Switzerland to 3.7 h in Ukraine. The results indicate that those most likely to watch TV are boys, 13-year-olds and pupils of lower socio-economic status. Those who watched more TV were more likely to consume sweets and soft drinks on a daily basis and less likely to consume fruit and vegetables daily, although the latter associations were not so apparent among Central and Eastern European countries.

Given the high TV viewing rates among adolescents and the association with less healthy food options, many young people are at increased risk of overweight or obesity. Interventions to modify TV viewing behaviour are needed. The findings underscore the importance of tackling socio-economic differences.