School-based interventions to prevent overweight and obesity in prepubertal children:: process and 4-years outcome evaluation of the Kiel Obesity Prevention Study (KOPS)

Aim: To evaluate the feasibility and 4-year outcome of school-based health promotion on overweight among 6-10-year-old children. Methods: Four-year follow-up data of 344 children participating in health promotion (I) as part of the Kiel Obesity Prevention Study (KOPS) at age 6 years, compared with 4-year changes in 1420 non-intervention children (NI). Nutritional knowledge was assessed before and 3 months after intervention in 1996 and 2004. Outcome was characterized compared to reference values for (i) BMI, (ii) triceps skinfold (TSF) and (iii) waist circumference (WC). Results: Process evaluation showed an increase in knowledge after intervention. However, the prevalence of children with good nutritional knowledge before intervention doubled from 1996 to 2004 but similar intervention-induced increases in knowledge (+50%) were observed. When compared with NI I increased remission of overweight with no significant effect on incidence. The effect was most pronounced in girls. The effect was affected by definition of overweight: when compared with parameters of fat mass (TSF and WC), BMI was showing a stronger effect (remission in girls (Delta I - NI): BMI: +13.4%, TSF: +18.7%, WC: +20.7%). Conclusions: 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.