Effects Of A Two-year School-based Daily Physical Activity Intervention On Cvd Risk Factors

Abstract

PURPOSE: To investigate changes in children's cardiovascular disease (CVD) risk profile following a two-year school-based teacher-led 60-minute controlled daily physical activity (PA) intervention. METHODS: In total, 259 children (age 9.3±0.3 years) were invited to participate, of whom 256 participated. The intervention group (63 boys, 62 girls) carried out 60-minute teacher-controlled daily physical activity over two school years. The control group (62 boys, 69 girls) had the normal amount of physical education (45 minutes twice each week) in school. One hundred seventy-four children successfully completed both the baseline and the post-intervention tests in six defined CVD risk factors and were thus included in the analyses where the main outcome was change in clustering of CVD risk factors (Δcluster). The CVD risk factors included were systolic blood pressure, peak oxygen uptake, triglyceride, total cholesterol to high-density lipoprotein cholesterol ratio, waist circumference and the homeostasis model assessment for insulin resistance. All 174 subjects were pooled at baseline and Z-scores (value-mean/SD) were constructed and summed. The effect of the intervention on the Δcluster (of the six CVD risk factors) was analyzed with a linear multiple regression adjusted for sex and location. Body mass and height were collected from all 256 children at baseline, and there was no difference in height or weight between those with valid test (174) or those excluded (82). RESULTS: The intervention group had a significantly more beneficial development in their clustered CVD risk profile (P=0.001) compared to the control group (Δcluster (of 6 CVD RF) was 1.9 (1.0 to 2.8) (mean; 95%CI). CONCLUSION: A daily school-based physical activity intervention can significantly modify children's clustered CVD risk profile beneficially if the intervention is sufficiently long and includes a substantial amount of daily physical activity.