Effectiveness of a School Drinking Water Promotion and Access Program for Overweight Prevention

BACKGROUND AND OBJECTIVE Drinking water promotion and access shows promise for preventing weight gain. This study evaluated the impact of Water First, a school-based water promotion and access intervention on changes in overweight.METHODS Low-income, ethnically diverse elementary schools in California's Bay Area were cluster-randomized to intervention and control groups. Water First includes classroom lessons, water stations, and schoolwide water promotion over 1 school year. The primary outcome was overweight prevalence (BMI-for-age-and-sex >= 85th percentile). Students (n = 1249) in 56 fourth-grade classes in 18 schools (9 intervention, 9 control) from 2016 to 2019 participated in evaluation at baseline, 7, and 15 months. Data collection was interrupted in 8 additional recruited schools because of coronavirus disease 2019.RESULTS Of 1262 students from 18 schools, 1249 (47.4% girls; mean [SD] age, 9.6 [0.4] years; 63.4% Hispanic) were recruited. From baseline to 7 months, there was no significant difference in changes in overweight prevalence in intervention schools (-0.2%) compared to control schools (-0.4%) (adjusted ratio of odds ratios [ORs]: 0.7 [confidence interval (CI): 0.2-2.9] P = 0.68). From baseline to 15-months, increases in overweight prevalence were significantly greater in control schools (3.7%) compared to intervention schools (0.5%). At 15 months, intervention students had a significantly lower change in overweight prevalence (adjusted ratio of ORs: 0.1 [CI: 0.03-0.7] P = .017) compared to control students. There were no intervention effects for obesity prevalence.CONCLUSIONS Water First prevented increases in the prevalence of overweight, but not obesity, in elementary school students.