Effects of a three-year intervention. The Copenhagen School Child Intervention Study

Introduction: This study assessed short-term and long-term effects of a 3-yr controlled school-based physical activity (PA) intervention on fatness, cardiorespiratory fitness (V̇O _2peak) and CVD risk factors in children. Methods: The study involved 18 schools (10 intervention and 8 controls) and included a follow-up 4 yr after the end of intervention. The analyses included 696, 6-to 7-yr-old children at baseline, 612 postintervention (age 9.5 yr) and 441 at follow-up (age 13.4 yr). The intervention consisted of a doubling of the amount of physical education (PE; from 90 to 180 min•wk), training of PE teachers, and upgrading of PE and playing facilities. Anthropometrics and systolic blood pressure (SBP) were measured. V̇O _2peak was directly measured, and PA was assessed using accelerometry. Fasting blood samples were analyzed for CVD risk factors. A composite risk score was computed from z-scores of SBP, triglycerides, total cholesterol-to-HDL cholesterol ratio, homeostatic model assessment (HOMA score), skinfolds, and inverse V̇O _2peak. Results: The HOMA score of the intervention group boys had a smaller increase from baseline to postintervention compared with control boys (P = 0.004). From baseline to follow-up intervention group boys had a smaller increase in SBP compared with control boys (P = 0.010). There were no other significant differences between groups. Conclusions: This 3-yr school-based PA intervention caused positive changes in SBP and HOMA score in boys but not in girls, and no effects were seen in PA, V̇O _2peak, fatness, and the other measured CVD risk factors. Our results indicate that a doubling of PE and providing training and equipment may not be sufficient to induce major improvements in CVD risk factors in a normal population.