摘要：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. Over the past decade, obesity rates have increased dramatically among children and adults in the United States. 1 Childhood excess weight is a strong predictor of adulthood excess weight, 2 and is associated with increased risk of common chronic diseases such as diabetes and cardiovascular disease. 3 Hispanic children and adolescents have higher incidences of overweight 4 and type 2 diabetes 5 than the national average and have lower rates of physical activity. 4 Without effective interventions, current trends in obesity will likely continue unabated. A meta-analysis of 64 intervention studies of childhood obesity found that few included appreciable numbers of Hispanic participants, 6 and none of these resulted in improvements in body mass index (BMI). 6 The majority of interventions examined in the meta-analysis were school-based programs conducted during the school day. 6 Schools have several well-known advantages for youth-targeted behavior change interventions. Almost all children attend school; schools have appropriate facilities for intervention activities and strong credibility within the community. However, school districts face increasing pressures for students to perform well on standardized examinations and are unable to release class time for health promotion activities. After-school activities provide a viable alternative for health promotion. An estimated 8.4 million youths in the United States participate in some form of after-school activity, and an additional 18.5 million families reported they would be interested in after-school activities if they were available. 7 Hispanic children are more likely than the national average to participate in after-school programs (21% vs 15% of school-aged children). 8 Despite the apparent need for and interest in after-school activities, few after-school health promotion programs have been evaluated and published. 9 – 18 In none of these studies were a majority of participants Hispanic. Therefore, we developed, implemented, and evaluated a culturally tailored health education and physical activity after-school program for a population of predominantly Hispanic elementary school children.
