Diurnal salivary cortisol and nativity/duration of residence in Latinos: The Multi-Ethnic Study of Atherosclerosis.

Latino immigrants have lower prevalence of depression, obesity and cardiovascular disease than US-born Latinos when they are recently arrived in the US, but this health advantage erodes with increasing duration of US residence. Cumulative exposure to psychosocial stress and its physiological sequelae may mediate the relationship between nativity and duration of US residence and poor health. We used data from Latino cohort study participants ages 45-84 to examine cross-sectional (n=558) and longitudinal (n=248) associations between nativity and duration of US residence and features of the diurnal cortisol curve including: wake-up cortisol, cortisol awakening response (CAR, wake-up to 30min post-awakening), early decline (30min to 2h post-awakening) and late decline (2h post-awakening to bed time), wake-to-bed slope, and area under the curve (AUC). In cross-sectional analyses, US-born Latinos had higher wake-up cortisol than immigrants with fewer than 30 years of US residence. In the full sample, over 5 years the CAR and early decline became flatter and AUC became larger. Over 5 years, US-born Latinos had greater increases in wake-up cortisol and less pronounced flattening of the early diurnal cortisol decline than immigrants with fewer than 30 years of US residence. Immigrants with 30 or more years of US residence also had less pronounced flattening of the early decline relative to more recent immigrants, and also had a less pronounced increase in AUC. In sum, we saw limited cross-sectional evidence that US-born Latinos have more dysregulated cortisol than recently-arrived Latino immigrants, but over time US-born Latinos had slower progression of cortisol dysregulation.