Stress Biomarkers and Latinos' Exposure to the United States.

Abstract

Background: Latino immigrants to the United States (US) have better health and mortality outcomes than US-born Latinos, but this health advantage erodes with increasing duration of US residence. Public health scholars have theorized that chronic stress mediates the relationship between exposure to the US environment and poor health among Latinos, but there is little literature examining biological mechanisms by which this occurs. Methods: Informed by literature on structural determinants of health and the racialization of Latinos in the US, I examine links between life history, stress biomarkers and risk of poor health among Latinos. First (Aim 1), I use data from Latino participants in an ancillary study to the Multi-Ethnic Study of Atherosclerosis (MESA Stress) to examine cross-sectional and longitudinal relationships between nativity/duration of US residence and diurnal patterns in salivary cortisol, a stress hormone. Second (Aim 2), I use MESA Stress data to examine cross-sectional and longitudinal relationships between nativity/duration of US residence and leukocyte telomere length (LTL), a marker of stress-mediated cellular aging. Lastly (Aim 3), I use birth-certificate data to evaluate population-level effects of a major immigration raid on risk of low birthweight (LBW, a stress-sensitive birth outcome) among infants born to Latina mothers in the state of Iowa. Results: Among MESA Stress participants, US-born Latinos and Latino immigrants with longer US residence had higher waking cortisol (cross-sectionally) and slower flattening of the diurnal cortisol curve (longitudinally) than more recently-arrived immigrants. While there were no cross-sectional differences in LTL according to nativity or duration of US residence, US-born Latinos and Latino immigrants with longer US residence had faster 10-year LTL shortening than more recently-arrived immigrants. Lastly, in the 37 weeks following a major immigration raid, immigrant and US-born Latina mothers in Iowa were at higher risk of having a LBW infant than Latina mothers during the same period one year earlier, while White mothers did not exhibit an increase in risk of LBW. Conclusions: These findings extend the literature about biological pathways by which the structural position of Latinos in the US may contribute to declines in health that accompany increasing exposure to the US environment.