Explaining the effect of a 1-year intervention promoting physical activity in middle schools: a mediation analysis

OBJECTIVE: The aim of the present study was to examine the mediation effects of changes in psychosocial determinants of physical activity (attitude, social support, self-efficacy, perceived benefits and barriers) on changes in physical activity. DESIGN: One-year intervention study with baseline and 1-year post measures of physical activity habits and psychosocial correlates. SETTING: Fifteen middle schools. SUBJECTS: Boys and girls (n = 2840) aged 11-15 years completed the validated questionnaires during class hours. RESULTS: The product-of-coefficients test was used to asses the mediating effects. Self-efficacy for physical activity at school was found to be the only significant mediator of physical activity change. Specifically, self-efficacy for physical activity at school partly mediated the effect of the intervention on total and school-related physical activity change in the intervention group with parental support (P < 0.05). None of the other potential mediators, attitudes, social support, perceived benefits and perceived barriers, seemed to have had a positive effect. Even a suppressor effect was found for attitudes. Given that the effects of self-efficacy and attitudes were of opposite direction, the total mediated/suppressed effects of the intervention were not statistically significant. CONCLUSIONS: Positive changes in total and school-related physical activity in adolescents could be partly explained by increases in self-efficacy for physical activity at school through a physical activity intervention in middle schools with parental support. However, the suppressor effect of attitudes decreased this effect. As this is one of the first true mediation analyses in this age group, further research is needed to replicate the importance of these mediators.     

Environmental and psychosocial correlates of physical activity in Portuguese and Belgian adults

OBJECTIVES: To investigate differences in reported physical activity levels and in perceived environmental and psychosocial correlates of activity between Portuguese and Belgian adults; and to analyse the relative contribution of environmental and psychosocial variables in explaining physical activity within different contexts in Portugal and Belgium. DESIGN: Cross-sectional study. SETTING: One city in Portugal (Oeiras) and one in Belgium (Ghent). SUBJECTS: In total 526 participants, 247 from Portugal and 279 from Belgium, completed the long International Physical Activity Questionnaire and a validated questionnaire on environmental and psychosocial correlates. RESULTS: For the sum of all activities of at least moderate intensity, a significantly higher mean level of activity was found in Belgian adults (P < 0.001). However, comparable percentages of the Belgian (38%) and Portuguese (42%) samples did not meet the recommendation of 30 min per day. The variance explained by environmental factors was lower (1% to 8%) than by psychosocial factors (maximum 42%). Regression analyses showed activity-specific relations with environmental variables which were analogous in both countries. Walking/cycling for transportation and walking for recreation were related to social support from family and/or friends and to walkability and walking facilities in the neighbourhood. Recreational physical activity was mainly determined by social support, self-efficacy, and perceived benefits and barriers. CONCLUSIONS: Activity campaigns addressing psychosocial determinants are needed to encourage leisure-time activity, while a combination of neighbourhood design changes and encouragement of social support in walking is warranted to increase walking in different contexts.     

Habitual physical activity and body composition of black township adolescents residing in the North West Province, South Africa

OBJECTIVE: It is known that stunting and obesity affect a large proportion of children in the world, and these can be affected by the physical activity levels of the children. In the present study, we evaluated the association between physical activity, physical development and body composition in black adolescent children. DESIGN: Cross-sectional study. SETTING: Black township schools in the North West Province, South Africa. METHODS: Three-hundred and thirteen grade 8 children were included in the Physical Activity in Youth study. Anthropometric measurements, body composition measures and maturity level as assessed by Tanner stages were determined in these children. In addition, Previous Day Physical Activity Recall questionnaires were administered on the children to record the various activities they undertake daily. RESULTS: The demographic characteristics of the children showed a high level of homogeneity. A high prevalence of stunting (16.3%) was observed in the children, which was higher in boys than in girls (21.6 vs. 12.3%). Also prevalent was overweight/obesity (8.6%), but this was higher in girls than in boys (13.4 vs. 1.6%). The children also showed a reduction in levels of physical activity with advancement in maturity; furthermore, boys showed a more central form of fat deposition whilst girls showed more gynoid deposition. CONCLUSIONS: The study revealed that physical activity plays a role in determining body composition, and further indicated that physical activity is associated with favourable body composition measures. Children who were more active were likely to have less fat deposits.     

Misperceptions, inactivity and maternal factors may drive obesity among Barbadian adolescents

OBJECTIVES: To describe (1) the prevalence of overweight and obesity and their association with physical activity; (2) the effect of different cut-off points for body mass index (BMI) on weight status categorisation; and (3) associations of weight status with perceptions of body size, health and diet quality. DESIGN: A cross-sectional study. SETTING: Secondary schools in Barbados. SUBJECTS: A cohort of 400 schoolchildren, 11-16 years old, selected to study physical education practices. RESULTS: Prevalence of overweight (15% boys; 17% girls) and obesity (7% boys; 12% girls) was high. Maternal obesity, as defined by the International Obesity Task Force (IOTF) BMI cut-off points, predicted weight status such that reporting an obese mother increased the odds of being overweight by 5.25 (95% confidence interval: 2.44, 11.31). Physical activity was inversely associated with weight status; however levels were low. Recreational physical activity was not associated with weight status in either category. Overweight subjects tended to misclassify themselves as normal weight and those who misclassified perceived themselves to be of similar health status to normal-weight subjects. The National Center for Health Statistics and IOTF BMI cut-off points produced different estimates of overweight and obesity. CONCLUSIONS: Our findings suggest that inadequate physical activity and ignorance related to food and appropriate body size are promoting high levels of adiposity with a strong contribution from maternal obesity, which may be explained by perinatal and other intergenerational effects acting on both sexes. Prevalence studies and local proxy tools for adiposity assessment are needed.     

Body mass index, physical activity and dietary behaviours among adolescents in the Kingdom of Tonga

OBJECTIVES: To compare the prevalence of overweight and obesity among adolescents using international and ethnic-specific cut-off points and to examine patterns of physical activity and dietary behaviours. DESIGN: Cross-sectional analytical study. SETTING: Schools on Tongatapu, Vava'u and Hapa'ai islands in the Kingdom of Tonga. SUBJECTS: A total of 443 school students aged 11-16 years underwent anthropometric measures of height and weight and provided self-reported measures of physical activity and dietary behaviours.Results Mean body mass index (BMI) was higher among girls than boys (23.7 kg m(-2) vs. 21.8 kg m(-2) and tended to increase with age. A total of 36.0% of boys and 53.8% of girls were overweight or obese using the international cut-off points, whereas 25.0% of boys and 37.6% of girls were classified in this way using Polynesian-specific cut-off points. Tinned mutton or beef was the food that most participants (56.9%) reported eating once or more per day. Over half of the young people did not eat taro, fruit or vegetables at least once per day. Regular physical activity outside of school hours was reported by 20.7% of respondents, and 58.2% watched 1 h or more of television per day. Physical activity participation was the only behaviour independently associated with a lower risk of overweight or obesity.Conclusions Using Polynesian-specific cut-off points for overweight and obesity the prevalence of these conditions was still among the highest found in adolescents. The prevalence of physical inactivity and poor dietary habits indicate that risk factors for chronic disease are well established during adolescence in Tonga.     

Why do boys eat less fruit and vegetables than girls?

OBJECTIVE: To explore why boys eat less fruit and vegetables (F&V) than girls, using longitudinal data following pupils from the age of 12.5 to 15.5 years, including perceived accessibility, modelling, intention, preferences, self-efficacy and knowledge of recommendations as potential mediators. DESIGN/SETTING/SUBJECTS: A longitudinal study, based on data collected among the control schools within the intervention project 'Fruits and Vegetables Make the Marks'. This sample contains 896 6th and 7th graders from 20 randomly selected elementary schools within two Norwegian counties. Questionnaires were administered in May 2002 and May 2005 (when the participants were in 9th and 10th grade in 18 secondary elementary schools). RESULTS: In single mediation analyses all determinants mediated parts of the gender difference, but only preferences decreased the gender difference to a level below statistical significance. Preferences alone explained 81% of the gender difference. In the multiple mediation analyses, the six mediators together explained 91% of the gender difference, but only preferences and perceived accessibility contributed uniquely to the explanation, with 25% and 10% respectively. CONCLUSIONS: Preference appears as the strongest mediator of the difference in F&V intakes between boys and girls. Further research should explore why girls like F&V more than boys.     

Is overweight and obesity in 9-10-year-old children in Liverpool related to deprivation and/or electoral ward when based on school attended?

OBJECTIVES: To determine whether weight problems in children (overweight, obesity and overweight or obesity) were related to deprivation indices when attributed only according to electoral ward of the school attended. To determine whether children with weight problems were more likely to be found in some wards rather than others, and to compare the distribution for boys and girls. DESIGN: Retrospective, cross-sectional, observational study. SETTING: One hundred and six primary schools from all parts of Liverpool city. SUBJECTS: Five cohorts of 9-10-year-old children between 1998 and 2003. Main outcome measures: Body mass index (BMI) for each child to estimate proportions overweight, obese and overweight or obese according to international criteria. RESULTS: Between January 1998 and March 2003, the heights and weights of 7902 boys and 7514 girls were measured and BMI calculated. The prevalence of boys and girls categorised as overweight or obese was very high (1620, 20.6% and 1909, 25.7%, respectively). Prevalence was not related to deprivation and varied between wards only for the girls; some wards had very different prevalence rates for boys and girls (Picton: 59 boys, 23.4%; 106 girls, 36.6%). The most deprived ward did not have a remarkable prevalence of overweight or obesity (Speke: 32 boys, 15.3%; 40 girls, 19.8%). CONCLUSIONS: Obesity is a major problem and requires urgent action but targeting intervention on the basis of administrative areas may be very wasteful. Different factors seem to lead to obesity in boys and girls, and attention should be paid to the role of the physical environment.     

BRAC initiative towards promoting gender and social equity in health: a longitudinal study of child growth in Matlab, Bangladesh

OBJECTIVE: To explore the effect of BRAC (formerly Bangladesh Rural Advancement Committee) initiatives towards promoting gender and social equity in health among children of poor mothers who are BRAC members. DESIGN: A cohort of 576 children from the prospective study of a BRAC- International Centre for Diarrhoeal Disease Research, Bangladesh joint research project was analysed. Data were collected three times during 1995-1996 with approximately 4-month intervals. Stunting, defined as height-for-age below minus two standard deviations from the reference median, was the outcome health measure. The study children were stratified into three groups according to their mother's social and BRAC membership status: poor and BRAC member (BM), poor non-member (TG) and non-poor non-member (NTG). SETTING: Matlab, rural area of Bangladesh. SUBJECTS: Children aged 6-72 months. RESULTS: The overall prevalence of stunting was 76%; the highest prevalence was found among TG (84.6%) children and no significant difference was observed between BM and NTG children (67.3% and 69.4%, respectively). In all groups, a significantly larger proportion of girls was stunted compared with boys in the first round. Group-level analysis showed that stunting decreased among all children except BM boys at the end of third round, with the largest decline among BM girls. In contrast, stunting prevalence increased among BM boys. A similar trend was found in the individual-level analysis, where a larger proportion of BM girls recovered from stunting compared with other groups and no recovery was observed among BM boys. At the end of the third round, the nutritional status of BM girls was almost equal to that of the BM boys, while gender inequity remained large among TG and NTG children. CONCLUSION: The BRAC initiative appeared to contribute to a significant equity gain in health for girls, as well as to decreased differences in ill health between the poor and the non-poor.     

The determinants of overweight and obesity among 10- to 15-year-old schoolchildren in the North West Province, South Africa - the THUSA BANA (Transition and Health during Urbanisation of South Africans; BANA, children) study

AIM: To investigate the determinants of overweight and obesity among 10- to 15-year-old schoolchildren in a population in the transitional phase in the North West Province of South Africa.METHODS: A cross-sectional survey was used to investigate weight status (anthropometric indicators) and determinants of overweight/obesity including dietary intake, physical activity and socio-economic status. A single, random sample (n=1257), stratified for gender, type of school and ethnic group, was used. Data were collected on demographics, family circumstances, habitual physical activity, dietary intake and anthropometry to evaluate weight status and body fat content. One-way analysis of variance, the generalised linear models procedure of SAS and the Tukey post hoc honest significant difference test were used to analyse the data.RESULTS: Few children were overweight or obese (7.8%) according to International Obesity Task Force (IOTF) standards (body mass index (BMI)-for-age). These standards were compared with other accepted standard values. Both Cole's IOTF/BMI-for-age standard and the sum of skinfold thicknesses standard classified normal-weight status similarly at a level of 92% (P<0.01) and were found to be useful in determining overweight/obesity. The prevalence rate was higher in females and white children, and was more apparent in urban areas, smaller households and children of parents with low- or high-income occupations. Boys and pre-menarcheal girls had mean body fat percentage in the normal/optimal range, whereas that of post-menarcheal girls was moderately high. Few variables showed a significant association with high body fat percentage: in boys, only the number of members in the household and physical activity levels over the weekend; in girls, only age. The overweight/obese boys mostly lived in smaller households, and the overweight/obese post-menarcheal girls were most inactive on both weekdays and weekends, and more overweight with increasing age.CONCLUSION: Smaller households, inactivity and increasing age for girls were found to be determinants that influence the development of overweight/obesity, while female gender and age post-menarche were identified as determinants of higher body fat content. For overweight/obesity prevention, the focus should be on pre-menarcheal girls, aged 10-13 years, using these determinants to identify overweight/obesity risk. Preventive programmes should aim to increase the physical activity of children to improve their current and future weight status.     

A comprehensive physical activity promotion programme at elementary school: the effects on physical activity, physical fitness and psychosocial correlates of physical activity

OBJECTIVE: To evaluate the effects of a comprehensive physical activity (PA) promotion programme in elementary schools on children's total PA levels, leisure-time PA, physical fitness and psychosocial correlates of PA. DESIGN: A pre-test-post-test design over two school years. SETTING AND SUBJECTS: Sixteen elementary schools (764 children, mean age: 11.2 +/- 0.7 years) were randomly assigned to the intervention condition (n = 8) and the control condition (n = 8). The intervention included a health-related physical education programme, an extracurricular PA promotion programme and classroom-based PA education lessons. In the total sample, leisure-time PA, psychosocial correlates of PA and physical fitness were measured using a PA questionnaire and the Eurofit test battery. In a sub-sample, total PA levels were measured using an accelerometer. RESULTS: According to accelerometer data, children's moderate PA and moderate-to-vigorous PA (MVPA) levels decreased less in the intervention schools than in the control schools (P < 0.01). The average time spent on MVPA decreased by 9 min per day in the intervention schools compared with 33 min per day in the control schools. Children in the intervention schools reported significantly more moderate PA in leisure time than the controls (P < 0.05). No overall improvement of physical fitness and no effects on the psychosocial correlates of PA were found. CONCLUSIONS: The comprehensive PA promotion programme was successful in preventing a decline in children's total activity levels. Furthermore, the intervention increased children's PA engagement in leisure time. Therefore, implementation needs to be encouraged.     

Correlates of childhood obesity in Athens, Greece

OBJECTIVE: Childhood obesity is a growing public health problem. We have examined the association between sociodemographic profile and eating and physical activity patterns with overweight among primary-school students in Athens, Greece. DESIGN: Cross-sectional study. SETTING: Eleven primary schools in the greater Athens area, Greece. SUBJECTS: A total of 633 children aged 10-12 years (50 % boys, 50 % girls) were interviewed in person during spring 2003. Multivariate logistic regression was used to investigate the association between eating and physical activity patterns and overweight (> or =85th sex- and age-specific BMI centile). Results are presented as odds ratios and 95 % confidence intervals. RESULTS: Overweight was more common among girls than among boys (OR=1.73; 95% CI 1.11, 2.69) and substantially less common among children born outside Greece (OR=0.46; CI 0.22, 0.95). Reported physical activity (per 1.5 h per day) was unrelated to overweight (OR=0.97; CI 0.85, 1.12) but patent physical inactivity, operationalised as time spent watching television or working/playing with the computer (per 1.5 h per day) was a highly significant predictor of overweight (OR=1.20; CI 1.05, 1.36). Composition of diet was unrelated to overweight but the daily number of eating occasions, controlling for total energy intake, was significantly inversely associated with overweight (OR=0.61; CI 0.48, 0.76). CONCLUSIONS: The principal factor underlying overweight among children in Athens appears to be the extended inactivity imposed by modern childhood lifestyles. An intriguing finding is that spreading a given energy intake over several eating occasions was inversely associated with the likelihood of childhood obesity.     

Reliability and validity of a questionnaire to measure personal, social and environmental correlates of fruit and vegetable intake in 10-11-year-old children in five European countries

OBJECTIVES: To investigate the internal consistency of the scales and the test-retest reliability and predictive validity of behaviour theory-based constructs measuring personal, social and environmental correlates of fruit and vegetable intake in 10-11-year-old children. DESIGN: Test-retest with one-week interval. SETTING: Five European countries: Norway, Spain, Denmark, Portugal, Belgium. SUBJECTS: Three hundred and twenty-six children completed the questionnaire during class hours. RESULTS: For the total sample across all countries, the test-retest reliability was good to very good (intra-class correlation coefficient (ICC) >0.60) for 12 out of the 15 fruit constructs and also for 12 out of the 15 vegetable constructs. Acceptable ICCs, ranging between 0.50 and 0.59, were found for the remaining constructs. Test-retest reliability was comparable across countries. Only in Portugal were some significantly lower ICCs found for some constructs (knowledge and barriers related to fruit, general self-efficacy related to fruit and vegetables) compared with the other countries. Cronbach's alpha values were moderate to high (range 0.52 to 0.89) with the exception of the general self-efficacy scale, which had a value below 0.50 for both fruit (alpha=0.42) and vegetables (alpha=0.49). Spearman correlations with intake ranged between -0.16 and 0.54 for personal determinants and between 0.05 and 0.38 for environmental determinants. Compared with other studies, predictive validity can be considered moderate to good. CONCLUSIONS: The questionnaire provides a reliable, valid and easy-to-administer tool for assessing personal, social and environmental factors of potential influence on fruit and vegetable intake in 10-11-year-olds.     

Exploration of possible correlates of nutrition awareness and the relationship with nutrition-related behaviours: results of a consumer study

OBJECTIVES: To unravel the concept of nutrition awareness, as it relates to risky personal nutrition-related behaviours, and to assess the sociodemographic and psychosocial correlates of nutrition awareness. DESIGN: Data were collected in a cross-sectional study with the aid of a face-to-face interview-assisted questionnaire that was based on the Precaution Adoption Process Model and Stages of Change Model. SETTING: Dutch consumer homes. SUBJECTS: Six hundred and three Dutch adults aged 18 to 80 years, selected from a panel. RESULTS: Our model explains nutrition awareness well (explained variance 53.7%). Psychosocial correlates were involvement with nutrition, health awareness, association with healthy food, perceived relevance of eating less fat, association with necessity, perceived relevance of vitamins, and perceived attributes of independent organisations. Sociodemographic correlates were gender and age. The relationship between nutrition awareness and nutrition-related behaviours proved to be very complicated. CONCLUSIONS: The value of our study is that it unravels the concept of nutrition awareness. Understanding the correlates of nutrition awareness can contribute to a more effective application of behavioural change models. Our results support increasing involvement with nutrition through personalising and tailoring to the motivational stage.     

Cross-cultural comparison of growth, maturation and adiposity indices of two contrasting adolescent populations in rural Senegal (West Africa) and Martinique (Caribbean)

OBJECTIVES: To stress the importance of social and environment (nutritional) factors in determining the growth spurt during puberty and the risk of excessive adiposity, two contrasting adolescent populations, one from a rural area of Senegal (West Africa) and the other from Martinique (French West Indies), were compared. DESIGN: Cross-cultural comparison of contrasting populations. Adolescents from Senegal belonged to a cohort followed up since 1995. Adolescents from Martinique participated in a cross-sectional nutritional survey that covered the entire island. SUBJECTS: A total of 507 adolescents (mean age: 14.3+/-0.7 years) from Senegal (319 girls and 188 boys) and 703 adolescents from Martinique (351 boys and 352 girls) were surveyed. RESULTS: Differences in growth and maturation were striking: boys in Martinique were 22.7 kg heavier and 20.1 cm taller than boys in Senegal. Differences were less important for girls but still evident: 12.6 kg in weight and 10.5 cm in stature. In Senegal, there were virtually no overweight adolescents, but 18% of girls and 50% of boys could be considered as malnourished. In Martinique, 19% of girls and 23% of boys were overweight or obese. Adolescent girls from Martinique were also sexually more mature than adolescent girls from Senegal. When comparisons were repeated after Senegalese girls reached menarche, differences in weight and body mass index disappeared, but Senegalese girls were still shorter than girls from Martinique. CONCLUSIONS: Adolescents are extremely susceptible to nutritional changes and their particular situation needs to be incorporated into nutritional prevention programmes.     

Validation of the Spanish version of the physical activity questionnaire used in the Nurses' Health Study and the Health Professionals' Follow-up Study

OBJECTIVE: The objective of this analysis was to test the validity of the estimates of energy expenditure and sedentary lifestyle obtained through a self-administered questionnaire of physical activity for Spanish-speaking people adapted from US questionnaires (Nurses' Health Study and Health Professionals' Follow-up Study) using a triaxial accelerometer (RT3 Triaxial Research Tracker) as the reference. DESIGN AND SETTING: Validation study, calculating the non-parametric correlation coefficients between the level of physical activity and sedentary lifestyle collected by the self-administered questionnaire and the triaxial accelerometer measurements. Percentage of misclassification and kappa coefficients were also calculated. SUBJECTS: The study population consisted of a sample of 40 obese women who were participants of the SUN (Seguimiento Universidad de Navarra) project (a prospective cohort study among Spanish university alumni). They were selected because of their peculiar metabolic characteristics, in the search for a sub-optimal scenario for validity. RESULTS: Physical activity during leisure time (estimated as MET-h week(-1)) derived from the self-administered questionnaire moderately correlated with kcal day(-1) assessed through the accelerometer (Spearman's rho = 0.507, 95% confidence interval (CI) 0.232, 0.707). The Spearman correlation between the ratio of sedentary lifestyle to physical activity obtained through the questionnaire and the direct estimation (RT3) was -0.578 (95% CI -0.754, -0.325). The kappa index was 0.25 (P = 0.002) when assessing the cross-classification into quintiles and 0.41 for the dichotomous estimation of a sedentary lifestyle. Only 2.5% of participants were misclassified by the questionnaire more than two quintiles apart from the estimates of the RT3. CONCLUSIONS: The moderate values obtained for correlation in a sub-optimal scenario for validity and the low percentage of extreme misclassification suggest the validity of the questionnaire to assess physical activity in Spanish-speaking women aged 20-50 years.     

The role of breakfast in nutrient intake of urban schoolchildren

OBJECTIVES: To ascertain the breakfast habits of 10-15-year-old schoolchildren and to assess the quality of this meal as well as its relationship to the food consumption pattern for the full day. DESIGN: Cross-sectional survey. SUBJECTS AND SETTING: Eight hundred and two schoolchildren, boys and girls, aged 10-15 years, belonging to different urban schools located in Secunderabad, Andhra Pradesh, India. METHOD: The breakfast eating patterns of the children were studied and their impact on growth was assessed, using dietary recalls and anthropometric measurements. RESULTS: Only 42.8% of the children ate breakfast regularly. Over half of the children skipped breakfast, ranging from daily to once in two weeks. The energy and protein composition of breakfasts eaten by the children indicated that those who did not skip breakfast met one-quarter to one-third of their total daily energy and protein requirements. Mean nutrient intakes calculated from 24-hour recalls revealed that the children's diets were inadequate compared with the recommended values for energy and protein. The inadequate energy intake was reflected in a high incidence of malnutrition in both boys and girls; 40.3% of the boys and 32.1% of the girls studied were found to be underweight. Protein intake was also inadequate among boys and girls, although a higher percentage of children met their protein requirements. CONCLUSIONS: Over half of the schoolchildren studied skipped breakfast frequently, the main reason being getting up late. Children who consumed breakfast had higher daily intakes of energy and protein than children who skipped breakfast. These data confirm the importance of breakfast to overall dietary quality and adequacy in school-aged children.     

Correlates of fruit and vegetable intake among Norwegian schoolchildren: parental and self-reports

OBJECTIVES: To identify correlates of 6th and 7th graders' (age 10-12 years) fruit and vegetable intake, to investigate parent-child correlations of fruit and vegetable intake, and to compare parents' and children's reports of children's accessibility, skills and preferences with respect to fruit and vegetables. DESIGN: The results presented are based on the baseline survey of the 'Fruits and Vegetables Make the Marks Project', where 38 schools participated. SETTING: Fruit and vegetable intake was measured by food frequency questions. Theoretical factors, based on Social Cognitive Theory, potentially correlated to intake were measured, including behavioural skills, accessibility, modelling, intention, preferences, self-efficacy and awareness of 5-a-day recommendations. SUBJECTS: In total, 1950 (participation rate 85%) 6th and 7th graders and 1647 of their parents participated. RESULTS: Overall, 34% of the variance in the pupils' reported fruit and vegetable intake was explained by the measured factors. The strongest correlates to fruit and vegetable intake were preferences and accessibility. The correlation between the children's and their parents' fruit and vegetable intake was 0.23. The parents perceived their children's accessibility to be better than what was reported by the children (P<0.01), while the children reported their skills to be better than what was perceived by their parents (P<0.01). CONCLUSION: The results from this study clearly point to a need for nutrition interventions aimed at parents. An important next step will be to investigate whether the identified correlates predict future fruit and vegetable intake, and whether they mediate any changes in intake in an intervention study.     

Ethnic differences in body mass index and associated factors of adolescents from minorities in Oslo, Norway: a cross-sectional study

OBJECTIVES: To examine ethnic differences in body mass index (BMI), food habits and physical activity, and determine the factors contributing to differences in BMI. DESIGN AND METHOD: In 2000-2001, 7343 (response rate 88%) 15- and 16-year-old students, enrolled in lower secondary schools in Oslo, participated in the cross-sectional Oslo Health Study. Of these participants, 1719 were defined as ethnic minorities. RESULTS: Significant gender and ethnic differences in mean BMI were observed. Of the ethnic minority adolescents, 5.8% were underweight (<5th percentile of the US Centers for Disease Control and Prevention (CDC)/National Center for Health Statistics (NCHS) reference distribution) and 9.1% were overweight (>85th percentile of the US CDC/NCHS reference distribution). BMI was not significantly associated with either socio-economic factors or physical activity. Food habits and physical activity differed with ethnicity but not with socio-economic factors. An ordinal regression showed that girls from East Asia (odds ratio (OR) 0.4) and boys from sub-Saharan Africa (OR 0.4) had lower BMI than the Western group. Among girls, higher BMI was associated with less frequent consumption of chocolates and sweets, full-fat milk and breakfast (OR 2.4, 1.7 and 1.7, respectively). Higher BMI, for both boys and girls, was associated with current and past dieting (OR 3.7 and 4.2, respectively). CONCLUSIONS: Adolescent food habits and physical activity varied by gender and ethnicity but not with socio-economic factors. BMI was associated with ethnicity, gender and food habits, but no significant relationship was observed with socio-economic factors or physical activity. Ethnicity, in addition to gender, should be taken into consideration when studying BMI and associated factors among adolescents.     

Perceptions of weight and associated factors of adolescents in Jiangsu Province, China

OBJECTIVE: To describe perceptions of weight of adolescents and associated factors. DESIGN: Cross-sectional survey in 2002. SETTING: Eight public middle schools in two distinct socio-economic areas of Jiangsu Province, China. SUBJECTS: Eight hundred and twenty-four adolescents (aged 12-14 years) and 628 of their parents. METHODS: Self-administered questionnaires for students and their parents were used to collect the data. Height and weight of the students were measured. RESULTS: One-third of the girls perceived themselves as overweight, while only 8.9% were actually overweight or obese according to the World Health Organization definition. On the other hand, 15.0% of the girls considered themselves underweight, while 5.6% were underweight according to the definition. Among the boys, one-fifth of those defined as overweight perceived their weight as normal. Furthermore, 23.9% perceived themselves as underweight when in fact only 4.9% were classified as underweight according to the definition. About one-quarter of the students dieted in the past year. Adolescents who perceived themselves to be overweight dieted and skipped breakfast more often. They also had lower intake frequencies of animal foods, Western foods and milk/yoghurt. No disparity was observed in the intake frequency of fruits and vegetables between the groups of different weight perception. Parents' weight norms seemed to favour overweight in both genders, but especially among boys. CONCLUSIONS: Both overweight and underweight concerns were common among girls, while a higher body weight was favoured by normal-weight boys and their parents. Distorted weight perceptions in adolescents, as well as dieting, are problems that need appropriate intervention.     

Food habits and physical activity patterns among Palestinian adolescents: findings from the national study of Palestinian schoolchildren (HBSC-WBG2004)

OBJECTIVE: To describe the food habits and physical (in)activity patterns and to investigate the relationship with sociodemographic factors among Palestinian adolescents. DESIGN AND SUBJECTS: The Palestinian Health Behaviour in School-aged Children (HBSC) is a cross-sectional survey of grades 6, 8, 10 and 12. Students completed a modified version of the international HBSC questionnaire. A total of 8885 students were included in this analysis; 53% were from the West Bank and 47% from the Gaza Strip. RESULTS: Adolescents in the West Bank consume more fruit, meat, chicken, sweets and soft drinks, but less vegetables than adolescents in Gaza (P<0.01). Girls reported more daily consumption of fruit, vegetables and sweets than boys (P<0.001), and less consumption of soft drinks, milk, meat and chicken (P<0.01). Boys were physically more active than girls (P<0.01), whereas girls reported doing more homework (P<0.001). Both boys and girls reported less physical activity with increasing age (P<0.001). Consumption of fruit and milk was positively associated with both parents' education, while consumption of meat, chicken and soft drinks was positively associated with mother's education only. Having breakfast on schooldays was positively associated with the father's education. Physical activity and television viewing were associated with the mother's education (P<0.01). The parents' level of education had no effect on vegetable consumption and dieting status. CONCLUSION: This study indicated that there are problems with Palestinian adolescents' eating, dieting and physical activity. Regional, gender and parental socio-economic status differences should be taken into account in developing interventions. More detailed studies are needed with more elaborate instruments about food habits and physical activity of adolescents.