Lifestyle risk factors and racial and ethnic inequality in mortality: Decomposing differential exposure and vulnerability in the United States

We aimed to evaluate the contribution of lifestyle factors, including alcohol use and smoking, in explaining the association between race and ethnicity with all-cause mortality through differential exposure and differential vulnerability.

Data came from the 1997-2014 repeated cross-sectional, annual U.S. National Health Interview Survey (NHIS) linked to the National Death Index. NHIS evaluated race and ethnicity (non-Hispanic White, non-Hispanic Black, Hispanic, and Other), lifestyle risk factors (smoking, alcohol use, obesity, physical inactivity), and covariates (age, education, marital status, survey year). Causal mediation analysis using an additive hazard model was used.

415,764 adults (25-85 years) were followed for 8.8 years (SD:5.2). Relative to Whites, Blacks experienced 20.3 (men; 95%CI:17.4,23.2) and 14.8 (women; 95%CI:12.5,17.1) additional deaths per 10,000 person-years (py), largely because of a direct effect of race and ethnicity (i.e., independent of lifestyle factors overall, although less exposure to smoking provided a protective effect). Hispanics experienced 6.0 (men; 95%CI:3.6,8.3) and 17.9 (women; 95%CI:16.0,19.9) fewer deaths per 10,000py relative to Whites, of which 80% (men) and 42% (women) were explained by lifestyle factors (particularly less smoking). The overall effect of alcohol use was small for Blacks and Hispanics (relative to Whites) resulting from a deleterious effect of greater exposure to alcohol use among Blacks and Hispanics that was offset by a protective effect of greater resilience to the adverse effects of alcohol use. The unique pattern of differential exposure and vulnerability to each lifestyle risk factor will be discussed for each race and ethnicity.

The results demonstrate, for the first time, the role of differential exposure vs. vulnerability to lifestyle factors in relation to racial inequalities in mortality. Notably, smoking and alcohol use have unique effects on inequalities for different racial and ethnic groups. This information is central for formulating public health policies aimed at reducing racial and ethnic disparities in health.