Racial and Ethnic Differences in the Association Between Food and Physical Activity Environments and Adult Obesity in the United States: A Multilevel Analysis

Background Adult obesity remains a critical public health issue in the United States, with marked disparities across racial and ethnic groups. Racially and ethnically diverse communities may experience food and physical activity environments differently, yet less is known about whether these county-level environmental associations vary by racial and ethnic composition.Methods We conducted a retrospective cross-sectional ecological study using multilevel modeling of data from 3,143 U.S. counties across 50 states and the District of Columbia. Variables from the closest available years (2014-2024) were harmonized into a single cross-sectional analytic dataset. County- and state-level measures of food and physical activity environment indicators were examined in relation to adult obesity prevalence, with cross-level interactions tested between racial/ethnic population composition and key environmental indicators (e.g., fast-food density, grocery access, supercenter prevalence, low-income low-access rates). Cross-level interaction models were estimated to examine whether associations between food and physical activity environment indicators and adult obesity prevalence varied by county racial and ethnic composition, including American Indian Alaska Native (AIAN), Asian, Hispanic, Non-Hispanic Pacific Islander (NHPI), Non-Hispanic Black (NHB), and Non-Hispanic White (NHW) populations.Results Significant interaction patterns were observed for counties with higher Hispanic, NHB, NHPI, and NHW population composition, whereas AIAN and Asian interaction terms were not statistically significant. The association between fast-food restaurant density and adult obesity prevalence varied across counties with differing proportions of Hispanic residents. Additional significant interactions were observed between NHB population composition and grocery stores, convenience stores, and supercenters, as well as between NHPI population composition and supercenter availability and low-access, low-income households. A significant interaction involving convenience store density was also observed for NHW population composition.Conclusions Associations between food environments and adult obesity vary by racial and ethnic composition. Geographic, environmental, and racial/ethnic context should be incorporated into public health strategies aimed at promoting health equity and reducing obesity disparities.