To identify the association of individual and school environment factors with overweight among adolescents.

Cross-sectional study. Sociodemographic and behavioural information was collected using an anonymous self-administered questionnaire. Indicators on human and physical resources of the schools were based on information collected in interviews with school principals. Overweight was defined based on the BMI Z-score for age and sex recommended by WHO. Logistic regression models were used for statistical analysis.

Rio de Janeiro, Brazil.

By means of a two-stage (classrooms and students) probabilistic sampling, subjects comprised 1632 students enrolled in the last year of primary education of the municipal public school network, stratified by city region.

The mean prevalence of overweight at schools was 17·2 %, ranging from 0 % to 50 %. Adolescents more likely to be overweight were those who attended schools without knives and forks or ceramic/glass plates for students in the school refectory (prevalence odds ratio (POR) = 1·40; P = 0·04), those whose head of household had completed between 8 and 10 years of schooling (POR = 1·46; P = 0·03), those who did not live with both parents (POR = 1·24; P = 0·06) and those who had not practised physical activity outside school on at least 1 d in the 7 d before the study (POR = 1·56; P = 0·04).

Sociodemographic and behavioural variables of adolescents and school characteristics were associated with overweight, confirming individual and context effects on this health disorder. Studies such as the present one, identifying variables in context, may support actions to prevent overweight among adolescents.

Nutritional status has remained inadequate among disadvantaged mothers and small children in South Africa. Several supplementation programmes are administered through primary health clinics (PHC). The present study examined the perceptions of mothers who attend PHC and of the PHC staff on the purpose, management and eligibility of the vitamin A and nutritional supplementation components of the Nutrition Supplementation Programme (NSP).

Observational study based on anthropometry and questionnaires.

Random selection of ten urban and ten rural PHC from the Western Cape Province of South Africa.

Mothers (n 176) and their children (n 179) aged <5 years, and various PHC staff categories.

Half (56 %) of the households were classified as food insecure and about one-third of the children were malnourished, as evidenced by stunting, wasting or underweight. A majority of mothers complained about poor information related to the programmes. More than half of the children who were eligible for NSP were not included. In contrast, the staff felt that they managed both programmes well and problems with implementation were mostly attributed to clients.

In general, the mothers expressed more dissatisfaction and ignorance about the vitamin A programme and the NSP than was perceived by the staff. This apparent discrepancy might, at least in part, explain why these programmes do not work optimally.

To determine the effectiveness of the nutritional supplement developed for the Oportunidades programme on growth, prevalence of anaemia, morbidity and cognitive function of pre-school children.

In a randomised, placebo-controlled longitudinal trial, children were assigned to one of three experimental treatment groups: Oportunidades food supplement (OFS), powdered milk (PM) and placebo (PL). Treatments were administered daily for 6 months. Weight, height and Hb were measured in all participants before and after supplementation. Morbidity was assessed two times per week for 6 months using validated questionnaires. The Bayley Scale of Infant Development Test was administered at baseline and after 6 months.

Three marginal rural communities of the state of Queretaro, Mexico.

A total of 224 children, mean age 22·4 (sd 5·9) months, were recruited. After the 6-month intervention, 186 completed the study.

No differences were found in the adjusted changes of weight, height or anaemia between treatment groups and PL. No differences were found in the number of episodes of gastrointestinal or respiratory disease, nor were there any differences in cognitive performance between treatment and PL groups after 6 months of supplementation.

Daily supplementation of 12–24-month-old children with OFS has no additional benefits in growth, anaemia, morbidity or cognitive performance.