Sleep and Diurnal Cortisol Patterns: Cultural Prediction and Moderation Among Latino College Students

Abstract

Sleep is a bioregulatory mechanism that promotes healthy physiological stress processes. Little research has examined daily links between sleep and diurnal cortisol patterns in minoritized youth populations, or explored whether such links are predicted by developmentallysalient cultural factors. Using a strengths-based approach to understanding cultural neurobiology, we examined individual (e.g., familism values) and institutional (i.e., changes in co-ethnic concentration) predictors of diurnal cortisol patterns, and whether cultural factors moderated daily links between sleep and cortisol. Methods: Salivary cortisol was collected five times a day in conjunction with actigraphy sleep across three weekdays in a sample of 180 Latino first-year college students (Mage=18.95; 64.4% female). High school and college institutional characteristics and self-reported cultural values were also collected. Results: Three-level growth curve analyses revealed greater sleep duration one night was linked with higher waking cortisol (γ=.119, p<.01), lower cortisol awakening responses (CAR; γ=-.070, p=.01), and steeper cortisol slopes (DCS; γ=-.035, p<.01) the next day. Experiencing more congruent campus contexts, but not familism, was associated with greater CAR (γ=.251, p<.05), on average. Familism values moderated day-to-day associations; greater sleep duration one night was associated with steeper DCS the next day for individuals reporting low (b=-.053, p=.003) or average levels of familism (b=-.036, p=.001). Conclusion: Findings illustrate cultural neurobiological processes as longer sleep was linked with healthier diurnal profiles in Latino college students and individual cultural values and exposure to coethnic peers served as protective and promotive factors, respectively.