UC San Diego

BACKGROUND: Local area immigrant fraction is strongly and positively correlated with local life expectancy in the United States. The aim of the study was to determine the relationship between local area immigrant fraction and local prevalence of coronary heart disease (CHD) and stroke. METHODS: Cross-sectional study design, with ZIP code as the unit of observation. Demographic data was obtained from the American Community Survey, and linked to indicators of health access (e.g., insurance, annual check-ups, cholesterol screening), obesity, behavior (smoking, exercise), and cardiovascular outcomes data from the 2020 Population Level Analysis and Community Estimates. Multivariable regression and path analyses were used to assess both direct and indirect relationships among variables. FINDINGS: CHD prevalence was lower in the second (3.9% relative difference, 95% CI: 3.1-4.5%), third (6.5%, 95% CI: 5.8-7.1%), and fourth (14.8%, 95% CI: 14.1-15.8%) quartiles of immigrant fraction compared to the lowest (p-trend <0.001). These effects remained robust in multivariable analysis following adjustment for indicators of access, obesity, and behavioral variables (p-trend <0.0001). For stroke, only the highest quartile demonstrated a significant difference in prevalence (2.1%, 95% CI: 1.2-3.0% with full adjustment). In CHD path analysis, ∼45% of the association of immigrant fraction was direct, and ∼55% was mediated through lower prevalence of deleterious behaviors (e.g., smoking). In stroke path analysis, the effect was entirely mediated through indirect effects. INTERPRETATION: In the United States, ZIP codes with higher immigrant fractions have lower prevalence of cardiovascular diseases. These associations are partially mediated through differences in health behaviors at the community level. FUNDING: NIH (K08CA252635, P30AG0059304, K24HL150476), Stanford University, Rutgers University.