Environmental quality modifies the relationship between county-level leisure-time physical inactivity and obesity in the U.S.
Citation:
Gray, C., L. Messer, K. Rappazzo, J. Jagai, A. Patel, M. Jimenez, S. Deflorio-Barker, AND D. Lobdell. Environmental quality modifies the relationship between county-level leisure-time physical inactivity and obesity in the U.S. International Society of Environmental Epidemiology, Sydney, New South Wales, AUSTRALIA, September 24 - 28, 2017.
Impact/Purpose:
The purpose of this study was to examine how the environment modifies relationship between physical inactivity and obesity. This study used the Environmental Quality Index
Description:
Background/Aim More than one-third of U.S. adults are obese, making them vulnerable to multiple poor outcomes including diabetes, heart disease, cancer, and death. Physical inactivity is a well-established mechanism contributing to obesity that can be promoted or hindered by numerous environmental factors. We aim to examine how cumulative environmental quality may modify the inactivity-obesity relationship. Methods We used county-level Behavioral Risk Factor Surveillance System (BRFSS) data for our exposure (2009 leisure-time physical inactivity (LTPIA)) and outcome (2010 obesity). We linked BRFSS data to the Environmental Quality Index (EQI), a composite measure of variables from five environmental domains (air, water, land, built, and sociodemographic) across all U.S. counties from 2000-2005. We estimated the county-level association (N=3,137 counties) between LTPIA and obesity across tertiles of the EQI using multi-level linear regression models, with random intercept for state, and adjusted for county percent minority and rural-urban status. Because obesity is modified by sex, we modeled overall as well as sex-specific estimates from the BRFSS data. We report estimates as prevalence differences (PD) and 95% confidence intervals (CI). Results Before stratification, adjusted associations between LTPIA and obesity were 0.51% (0.48, 0.54) overall, 0.44% (0.42, 0.47) for males, and 0.56% (0.53, 0.60) for females. In stratified results, the PD increases substantially from the best (PD=0.34% [0.29, 0.40]) to worst (PD=0.64% [0.60, 0.69]) tertile of environmental quality in the overall population. We observed similar trends in males from best (PD=0.24% [0.19, 0.29]) to worst (PD=0.60% [0.56, 0.65]) quality environments, as well as in females from best (PD=0.45% [0.39, 0.51]) to worst (PD=0.65% [0.61, 0.70]) quality environments. Conclusions We found that poor environmental quality exacerbates the county-level association between physical inactivity and obesity. Research and programs aimed at improving obesity through physical activity may benefit from considering this relationship. This abstract does not reflect EPA policy.