Browsing by Subject "Sleep health"

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Influences of sleep health, psychological stress, and hair cortisol on cardiometabolic health and depressive symptoms
(2023-08-07) Woo, Jihun; Steinhardt, Mary; Loukas, Alexandra; Tanaka, Hirofumi; Whittaker, Tiffany A
This dissertation examined the influences of sleep health, psychological stress, and hair cortisol concentration on cardiometabolic health and depressive symptoms among African-American adults with type 2 diabetes. Study 1 examined the association of sleep health with A1C and depressive symptoms. Sleep health was assessed using the RuSATED (regularity, satisfaction, alertness, timing, efficiency) framework which incorporates both self-reported and objectively measured sleep data. Study 1 found that the composite sleep health score was associated with a lower likelihood of having depressive symptoms and there was a negative linear association between the composite sleep health score and depressive symptoms. Additionally, irregular sleep, poor subjective sleep satisfaction, and lower alertness during the day were significantly associated with a higher likelihood of having depressive symptoms. However, A1C was not associated with the composite sleep health score or individual sleep dimensions. Study 1 findings suggest that optimizing multidimensional sleep health may help decrease depressive symptoms among African-Americans adults with type 2 diabetes and longitudinal research is needed to establish the causal association between sleep health and depressive symptoms. Study 2 examined the longitudinal association between psychological stress and metabolic syndrome (MetS) severity and the mediating roles of sleep health and hair cortisol concentration. A parallel mediation model was used to test the direct association between psychological stress (baseline) and MetS severity (12-month follow-up) and indirect associations through sleep health and hair cortisol concentration (6-month follow up). Study 2 found that psychological stress was not associated with MetS severity, sleep health, or hair cortisol concentration. Both sleep health and hair cortisol concentration were not significantly associated with MetS and neither variable mediated the association between psychological stress and MetS severity. Poor subjective sleep satisfaction was positively associated with psychological stress and MetS severity in an unadjusted model, but it did not mediate the association between psychological stress and MetS severity. The non-significant study findings may be attributed to the psychological stress measurement which did not account for chronic psychological stressors including discrimination that may have greater long-term effects on adverse health outcomes among African-Americans. Study 2 findings underscore the importance of further exploration into the complex interplay among different types of psychological stress, different aspects of multiple sleep dimensions, and hair cortisol concentration with respect to long-term cardiometabolic health outcomes. Taken together, both studies address gaps in prior research by employing more comprehensive measurements and valuable insights into the unique experiences of psychological stress, sleep health, hair cortisol concentration, and MetS severity among African-Americans who are often underrepresented in health science research. The dissertation studies highlight the importance of optimizing multiple sleep dimensions in decreasing depressive symptoms and a potential beneficial role of sleep satisfaction in mitigating MetS severity among African-American adults with type 2 diabetes.