[15 years of the Kiel Obesity Prevention Study (KOPS). Results and its importance for obesity prevention in children and adolescents].

The Kiel Obesity Prevention Study (KOPS) has been performed since 1996 and aims to characterize determinants and to prevent overweight. A total of 15,251 children and adolescents aged 5-16 years were recruited, of whom 780 and 92, respectively, underwent school-based and family-based interventions. Long-term evaluation of the school-based intervention was available over 4 and 8 years, while family-based intervention was evaluated over 1 year. The prevalence of overweight was 18.8% for the whole KOPS cohort. Determinants of overweight were parental overweight and obesity, low socioeconomic status (SES), early life factors, and lifestyle factors. School-based intervention ameliorated the weight status of children of high SES and of normal weight mothers over the long-term. The intervention effect was small but within the expectable range as calculated from analysis of determinants. Alternative outcome variables (e.g., fat mass) and new evaluation approaches (e.g., excess gain in fat mass) gave no detailed information of the intervention success. Family-based intervention showed that even with this individual approach children of low SES could not be reached.