The influence of socioeconomic characteristics on active travel in US metropolitan areas and the contribution to health inequity.

Background: The prevalence of chronic disease in the US adult population varies across socioeconomic groups in the USA where approximately six in 10 adults have a chronic condition. Walking or cycling reduces the risk to many of these diseases and is influenced by the built environment, accessibility, and safety. Methods: We performed multivariate logistic and linear regression on the Health-Oriented Transportation model parameters using the 2009 and 2017 US National Household Transportation surveys, restricted to adults in major metropolitan areas. Model covariates included socioeconomic and environmental characteristics. Results: Using odds ratios (OR) adjusted for model covariates, we observe several significant variables in 2009 and 2017. Residents of households with no cars were more likely to walk or cycle than those with two cars; OR=5.4 (4.8, 6.0). Residents of households in a census block with population density greater than 2,5000 persons/square mile were more likely to walk or cycle than those with a population density of 2000-3999; OR=2.6 (2.3, 2.8). Individuals with a graduate or professional degree were more likely to walk or cycle than those with a high school degree; OR=2.1 (1.9, 2.2). Individuals that self-report as Black or African American, or Asian are less likely to walk or cycle than White; OR=0.60 (0.56, 0.66), OR=0.70 (0.65, 0.75). The proportional increase in all-cause mortality from estimated reductions in physical activity for African American, Asian, and Hispanic populations were 1.0%, 0.7%, 0.8%, respectively. Conclusions: Access to automobiles and the surrounding population density are primary factors in the decision to walk or cycle. After adjusting for these and other factors, members of low-income, low-education, Black or African American, and Asian populations in US metropolitan areas are less likely to walk or cycle than high-income, high-education, or White populations and the discrepancy in physical activity is likely to contribute to health inequity.