Effectiveness and spillover of an after-school health promotion program for hispanic elementary school Children

We evaluated the effectiveness and spillover of an after-school health education and physical activity program among Hispanic elementary school children. Methods. In fall 2008, students in third through fifth grades in 6 schools in El Paso, Texas (n=901), were randomized to intervention (n=292 participants) or control (n=354) classrooms (4 unknown). Intervention classrooms also contained a spillover group (n=251) that did not join the after-school program but that completed measurements and surveys. The intervention was a 12-week culturally tailored after-school program meeting twice a week. Four-month outcomes were body mass index, aerobic capacity, and dietary intentions and knowledge. We calculated intervention exposure as the proportion of afterschool participants per classroom. Results. Intervention exposure predicted lower body mass index (P=.045), higher aerobic capacity (P=.012), and greater intentions to eat healthy (P=.046) for the classroom at follow-up. Intervention effectiveness increased with increasing proportions of intervention participants in a classroom. Nonparticipants who had classroom contact with program participants experienced health improvements that could reduce their risk of obesity. Conclusions. Spillover of beneficial intervention effects to nonparticipants is a valuable public health benefit and should be part of program impact assessments.