Research Methods and Procedures:Within a cluster-sampled quasi-randomized controlled trial, 1764 children at 6 and 10 years of age were assessed between 1996 and 2005 in 32 primary schools in Kiel, North Germany. Six nutrition units followed by 20-minute running games were performed within the first year at school. Prevalence, incidence, and remission of overweight were main outcome measures. Results: The 4-year change in BMI was ϩ11.6%, with increases in prevalence of overweight and obesity from 5.2% to 11.1% and 3.9% to 5.1%, respectively. Cumulative 4-year incidence of overweight and obesity was 9.2% and 3.1%, respectively. Intervention had no effect on mean BMI. The effect on prevalence was significant in children from families with high socioeconomic status [odds ratio (OR), 0.35; 95% confidence interval (CI), 0.14 to 0.91] and marginally significant in children of normal-weight mothers (OR, 0.57; 95% CI, 0.33 to 1.00). Cumulative 4-year incidence of overweight was lower only in intervention children from families with high socioeconomic status (OR, 0.26; 95% CI, 0.07 to 0.87). Remission of overweight was most pronounced in children of normal-weight mothers (OR, 5.43; 95% CI, 1.28 to 23.01). Prevalence of underweight was unchanged. The intervention had minor but favorable effects on lifestyle. Discussion: A school-based health promotion has sustainable effects on remission and incidence of overweight; it was most pronounced in children of normal-weight mothers and children from families with high socioeconomic status. There was no effect on obesity. The data argue in favor of additional measures of prevention.

School-based health promotion has sustainable effects on nutritional knowledge and remission of overweight being most pronounced in girls. The effect of intervention was most pronounced using TSF and WC as criteria of overweight.

AIMS:Prevention of obesity is a public health agenda. There are only few longitudinal studies on prevention of overweight in children. The Kiel Obesity Prevention Study (KOPS) intends to characterise the determinants of childhood overweight and the effect of preventive measures within schools as well as within families. METHODS: Between 1996 and 2005, KOPS investigated 4997 German 5-7 and 4487 9-11-y-old children or 41 and 37% of the total population of all first and fourth graders in 32 primary schools in Kiel (248 000 inhabitants), northwest Germany. Main outcome measures were nutritional status, health habits and risk factors of disease. In addition, health promotion was performed each year in three schools for all first graders and their teachers (nutrition education and active school breaks) together with a family-oriented approach in families with obese and preobese children. Up to now, the children were followed for 4 y and were reinvestigated at age 10 y. RESULTS: The KOPS population was representative for all 5-7 and 9-11-y-old children in Kiel. The prevalence of overweight/ obesity (Z90th/97th BMI reference percentile) was 7.0/5.8 and 11.3/6.3% in 5-7 and 9-11-y-old children, respectively. Parental overweight, a low socio-economic status and a high birth weight were identified as main risk factors for overweight in prepubertal children. The first results of the interventions show that obesity prevention was possible, but there were limited success rates in boys and children from low social class. CONCLUSION: Faced with the environmental contributors to the obesity problem societal rather than individual responsibilities are evident. This idea suggests that dissecting and tackling the obesogenic environment is necessary to complement school-and family-based interventions.

There have been only a few controlled studies on the prevention of overweight and obesity in children and adolescents. These studies differ in relation to strategy, setting, duration, focus, variables of outcome and statistical power, and therefore do not allow general conclusions to be made about the value of preventive measures. All school-based interventions aimed at the prevention of overweight and obesity show some improvement of health knowledge and healthrelated behaviours. Short-term effects on nutritional state seem to be more pronounced in girls than in boys. School-based interventions can reduce the incidence of overweight. There is evidence that families of intermediate and high socio-economic status as well as intact families benefit more from treatment than families sharing other characteristics. Selected prevention in obese children is most successful when children are treated together with their parents. However, there are social barriers limiting the success of family-based interventions. Although some positive effects have been reported, simple interventions in a single area (e.g. a school health education programme) are unlikely to work on their own. The development of effective preventive interventions probably requires strategies that affect multiple settings simultaneously. At present there is no concerted action, rather many strategies in health promotion that are followed in isolation. Faced with the epidemic of overweight there is a need for national campaigns and action plans on childhood overweight and obesity. It is tempting to speculate that this strategy will also increase the value of isolated approaches (e.g. in schools and families).Childhood overweight: Prevention of overweight: Determinants of overweight

The average age of smoking onset has decreased further in the 1978-1992 birth cohorts.