School Poverty Level Moderates the Effectiveness of a Physical Activity Intervention.

Purpose: To explore whether school poverty level and funding modified the effectiveness of an evidence-based Comprehensive School Physical Activity Program called Health Empowers You! implemented in elementary schools in Georgia.

Design: Secondary data analysis of a multi-level, cluster-randomized controlled trial.

Setting: 40 elementary schools in Georgia in 2018-2019.

Subjects: 4^th grade students in Georgia.

Measures: Intervention schools implemented the Health Empowers You! program to increase school-day physical activity. The outcome was average daily moderate-to-vigorous physical activity, school free-reduced price lunch (FRPL) percentage and per pupil expenditures were effect modifiers.

Analysis: Separate linear mixed regression models estimated the effect of the intervention on average daily moderate-to-vigorous physical activity, with interaction terms between intervention status and (1) school FRPL percentage or (2) per pupil expenditures.

Results: The effect of the intervention was significantly higher in schools with higher FRPL percentage (intervention*school % FRPL β (95% CI): .06 (.01, .12)), and was modestly, but not statistically significantly, higher in schools with lower per pupil expenditures.

Conclusion: Findings support the use of the Health Empowers You! intervention, which was effective in lower income schools, and may potentially reduce disparities in students' physical activity levels.