Demographics and anthropometrics impact benefits of health intervention: data from the Reduce Obesity and Diabetes Project

Objective: To determine the efficacy of a 4-month school-based health, nutrition and exercise intervention on body fatness and examine possible effects of demographic and anthropometric covariates. Methods: Height, weight, waist circumference and body composition were measured in a diverse population of 644 NYC middle school students (mean ± SD age 12.7 ± 0.9 years; 46% male; 38% Hispanic, 17% East Asian, 15% South Asian, 13.5% African American, 8.5% Caucasian, 8% other) during the fall and spring semesters. Year 1 participants (n = 322) were controls. Experimental participants (year 2, n = 469) received a 12-session classroom-based health and nutrition educational programme with an optional exercise intervention. Results: Groups were demographically and anthropometrically similar. The intervention resulted in significant reductions in indices of adiposity (ΔBMI z-scores [−0.035 ± 0.014; p = 0.01], Δ% body fat [−0.5 ± 0.2; p < 0.0001] and Δwaist circumference [−0.73 ± 0.30 cm; p < 0.0001]). Intervention effects were greater (p = 0.01) in men (ΔBMI z-score = −0.052 ± 0.015) versus women (0.022 ± 0.018), participants who were obese (ΔBMI z-score −0.083 ± 0.022 kg m⁻²) versus lean (−0.0097 ± 0.020 kg m⁻²) and South Asians (Δ% body fat −1.03 ± 0.35) versus total (−0.49 ± 0.20%) participants (p = 0.005). Conclusion: A 4-month school-based health intervention was effective in decreasing measures of adiposity in middle school students, particularly in men, participants who were obese and South Asians.