Effectiveness and Spillover of an After-School Health Promotion Program for Hispanic Elementary School Children

Objectives. 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 after-school 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. (Am J Public Health. 2011;101:1907-1913. doi:10.2105/AJPH.2011.300177)