Gender and socio-economic differences in physical activity and fitness among rural Bangladeshi adolescents: a cross-sectional study from the 15-year follow-up of MINIMat cohort.

Given the paucity of objective physical activity (PA) and fitness assessment among adolescents in low-income settings, the underlying gender and socio-economic disparities remain poorly understood. Hence, we aimed to examine the associations of gender, household wealth and maternal education with PA and fitness among adolescents of a rural birth cohort in southeast Bangladesh. This cross-sectional study utilized data collected during the 15-year follow-up of MINIMat (Maternal and Infant Nutrition Interventions in Matlab) cohort. In total, 2465 adolescents completed the household survey, and 2253 attended the subsequent PA and fitness assessment. Wrist-worn, triaxial accelerometers (dynamic range ±8G) were used to estimate sedentary time (ST), and total and intensity-specific PA. Valid accelerometry data (≥ 5 days with ≥ 600 min/day awake wear time) were available for 1872 adolescents. Fitness indicators assessed were: handgrip strength, standing long jump distance, and aerobic capacity (VO2max). We fitted multiple multivariable-adjusted linear regression models and derived predicted means. About 58% adolescents spent ≥ 60 min/day in moderate-to-vigorous PA. After adjusting for socio-demographic variables, ST was higher among girls than boys (644 vs. 635 min/day; p < 0.001), in adolescents from the wealthiest than the poorest households (648 vs. 631 min/day; p < 0.001), and in adolescents with educated mothers compared to those having mothers without formal education (646 vs. 636 min/day; p = 0.005). While boys engaged in more vigorous PA (4 vs. 1 min(s)/day; p < 0.001), moderate PA was higher among girls (66 vs. 64 min/day; p = 0.007). Moderate-to-vigorous PA did not vary by gender, but was higher among socio-economically disadvantaged adolescents than their peers from wealthier households. Predicted levels of weight-normalized grip strength (0.66 vs. 0.51), standing long jump distance (160.2 vs. 126.3 cm), and VO2max (34.8 vs. 33.2 mL/kg/minute) were higher among boys than girls. Adolescents from the wealthiest households had lower muscular fitness than those from the poorest households. We observed gender and socio-economic differences in PA and fitness, with girls and adolescents from relatively affluent and educated households demonstrating lower activity and fitness levels. Context-specific strategies tailored to gender and socio-economic disparities are needed to promote PA and fitness among rural adolescents in Bangladesh.