ARS | Publication request: Active commuting to school and association with physical activity and adiposity among US youth

Submitted to: Pediatric Academic Society
Publication Type: Abstract Only
Publication Acceptance Date: February 1, 2009
Publication Date: May 1, 2009
Citation: Mendoza, J.A., Watson, K., Nguyen, N., Cerin, E., Baranowski, T., Nicklas, T. 2009. Active commuting to school and association with physical activity and adiposity among US youth [abstract]. In: Proceedings of the Pediatric Academic Societies. Annual Meeting of the Pediatric Academic Societies, May 2-5, 2009, Baltimore, Maryland. 2009 CDROM.

Technical Abstract: Walking or bicycling to school, i.e., "active commuting", was associated with greater physical activity and lower adiposity. However, findings were mixed and may be due to small sample sizes, subjectively measured physical activity, or not controlling for dietary energy intake. Our objective was to examine (1) the relationship between active commuting and adiposity and (2) whether active commuting was associated with increases in moderate-to vigorous physical activity (MVPA), which in turn, could improve adiposity among a nationally representative sample of US youth. We hypothesized that active commuting would be inversely associated with adiposity and that greater physical activity would be responsible for that relationship. Cross-sectional analysis using multiple linear regression models on participants aged 12-19 years from the National Health and Nutrition Examination Survey, 2003-2004 (n=789 unweighted). The main exposure variable of active commuting was assessed by participant recall. BMI, waist circumference, and skinfolds were measured using standardized techniques. Moderate-to-vigorous physical activity (MVPA) was objectively measured by accelerometers. Dietary energy intake was a covariate and calculated from the mean of two 24-hour dietary recalls. Other covariates included age, gender, race/ethnicity, and poverty-to-income ratio. The product-of-coefficients method was used to test for mediation. 32.9% actively commuted greater or equal to 2 days/week. In multivariate models, controlling for covariates, active commuting was inversely associated with BMI z-score (std. beta=-0.07, p=0.046, R**2=0.05) and skinfolds (std. beta=-0.06, p=0.029, R**2=0.12). Active commuting was positively associated with overall daily MVPA (std. beta=0.12, p=0.024, R**2=0.31) and with before- and after-school MVPA (std. beta=0.20, p<0.001, R**2=0.20). Greater before- and after-school MVPA significantly explained the positive relationship between active commuting and waist circumference (Sobel p=0.048). Walking and bicycling to school was associated with greater physical activity and lower measures of adiposity among US youth. Pediatric clinicians and public health professionals should promote active commuting as an important modifiable behavior to target for pediatric physical activity promotion and obesity prevention interventions.