Associations between the built environment and body mass index in the Mexican American Mano A Mano Cohort

Abstract

Background: Obesity is highly prevalent in Mexican American adults. Studies on the role of the built environment in relation to obesity among this population are scarce.

Objectives: To investigate cross-sectional associations between multiple components of the built environment, and Body Mass Index (BMI) as well as obesity status among Mexican American adults enrolled in the Mano a Mano Cohort (MAC) study in Houston, Texas.

Methods: We calculated BMI from measured height and weight among 9534 Mexican American adults (aged 20-60) who participated in the baseline survey during 2008-2013. Several metrics of exposure to the built environment (physical activity environment, land use, and food environment) were generated using Geographic Information System and Google Maps based on participants' residential address. Generalized linear regression and logistic regression models were used to estimate associations between exposure to the built environment, a continuous BMI variable and categorical BMI variables (<30, ≥30 and ≥35), respectively.

Results: Among all built environment exposure variables investigated, road density (total road length per km²) [0.21 (0.06, 0.36) as coefficient (95% CI)], intersection density (intersection links per km²) [0.74 (0.21, 1.28)], networked distance (km) [-0.29 (-0.47, -0.10)], and walking time (mins) [-0.02 (-0.04, -0.01)] to the nearest parks had statistically significantly linear associations with BMI. Those variables were found to have statistically significant associations with BMI ≥ 35 in logistic regression models, the odds ratio was 1.08 (1.02, 1.14) for road density, 1.31 (1.07, 1.60) for intersection density, 0.91 (0.85, 0.98) for networked distance, and 0.99 (0.99, 1.00) for walking time. None of the built environment exposure variables were found to be associated with BMI ≥ 30.

Conclusions: Living in areas with high density of roads exhibited significant associations with increased BMI, in particular BMI ≥ 35, among enrolled Mexican American adults in the MAC study.

Keywords: Built environment; Mexican American; Population-based study.