School-Based Exercise Programs and Cardiometabolic Risk Factors: A Meta-analysis.

CONTEXT: The effects of school-based physical activity (PA) programs on different cardiometabolic risk factors and the most appropriate features of PA programs to achieve maximum effectiveness are unclear.

OBJECTIVE: To provide a comprehensive synthesis of the effectiveness of school-based PA interventions on cardiometabolic risk factors in children.

DATA SOURCES: We identified studies from database inception to February 22, 2018.

STUDY SELECTION: We selected studies that were focused on examining the effect of school-based PA interventions on cardiometabolic risk factors in children.

DATA EXTRACTION: Random-effects models were used to calculate the pooled effect size (ES) for the included cardiometabolic risk factors (waist circumference [WC], triglycerides, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, systolic blood pressure and diastolic blood pressure (DBP), and fasting insulin and glucose).

RESULTS: Nineteen randomized controlled trials (which included 11 988 children aged 3-12 years) were included in the meta-analysis. School-based PA programs were associated with a significant small improvement in WC (ES = -0.14; 95% confidence interval [CI]: -0.22 to -0.07; P < .001), DBP (ES = -0.21; 95% CI: -0.42 to -0.01; P = .040), and fasting insulin (ES = -0.12; 95% CI: -0.20 to -0.04; P = .003).

LIMITATIONS: Authors of few studies described the implementation conditions of their interventions in detail, and compliance rates were lacking in most studies. In addition, results by sex were provided in a small number of studies.

CONCLUSIONS: School-based PA interventions improve some cardiometabolic risk factors in children, such as WC, DBP, and fasting insulin.