Diurnal Cortisol Profiles of Stress and Hardiness in Sexual Minority Young Adults

3 Dedication . 5 Acknowledgments. 6 List of Tables . 8 List of Figures . 9 Introduction . 10 Models of Stress and Health . 11 Daily Diary Methods in Studies of Sexual Minority Stress and Health . 17 Psychological Hardiness . 18 Aims and Hypotheses . 20 Methods. 21 Analysis.32 Results . 37 Discussion.60 References . 68 8 List of Tables Page Table 1. Bivariate correlations of cortisol, key variables, and covariates.30 Table 2. Characteristics of participants by study arm.39 Table 3. Endorsement of minority stressors.42 Table 4. Endorsement of negative events.52 Table 5. Endorsement of positive events.56 9 List of Figures Page Figure 1. Flow chart of DASH study from April 2015 to June 30, 2016.22 Figure 2. Average diurnal cortisol slopes.46 Figure 3. Temporal changes in raw salivary cortisol predicted by challenge.50 Figure 4. Total cortisol output predicted by negative events.54 Figure 5. Total cortisol output predicted by positive events.58 Figure 6. Temporal changes in raw salivary cortisol predicted by positive events.59 10 Introduction Minority stress is prevalent in the lives of sexual minorities (Katz-Wise & Hyde, 2012), and associated with poor self-reported health (e.g., Figueroa & Zoccola, 2016). Further, research has shown that everyday stressors may be detrimental to health over time in general populations (for review, see Almeida, 2005). Yet, the mechanisms linking stress to poor health in sexual minorities remain poorly understood. To explore these mechanisms, it is important to examine objective markers that may link stress to poor health. One such marker is the stress hormone cortisol. Cortisol receptors are found throughout the body, allowing cortisol to regulate multiple physiological systems (Hoehn et al., 2010). Thus, identifying how stress processes may influence cortisol has widereaching consequences for sexual minorities. Accordingly, the current study tested the association between minority stress and general negative events and cortisol in the daily life of sexual minority young adults. Additionally, resiliency factors that promote health have been under-examined in sexual minority populations (Herrick et al., 2014). Only preliminary cross-sectional work implies that psychological hardiness, or a personality composite consisting of a sense of control over one’s life, commitment to engaging in life and seeing stressors as challenges to overcome, is negatively associated with anxiety, depression, and somatic complaints in sexual minorities (Figueroa & Zoccola, 2015). Thus, the present project also aimed to explore how psychological resilience may and daily positive events influence cortisol in the everyday life of sexual minority adults. 11 Models of Stress and Health Minority Stress Meta-analytic work on minority health suggests that stressors unique to minority populations, or minority stressors, may play an important part in the stress-health association in minority populations (Pascoe & Smart Richman, 2009). The minority stress model of stress and (mental) health (MSM; Meyer, 1995,2003) posits that minority stress may lead to poor health outcomes in minority populations, via two pathways: 1) external processes such as overt discrimination and 2) internal processes such as internalization of negative stereotypes associated with the minority status. Researchers have found that these pathways may lead to poor health both directly and indirectly. Specifically looking at the indirect pathways, it has been found that minority stress may lead to poorer health behaviors (e.g., smoking) as well as heightened or dysregulated physiological stress responses (e.g., exaggerated cortisol output) which in turn may lead to poor health (Pascoe & Smart Richman, 2009). Although minority stress occurs at multiple levels (e.g., systemic discrimination or interpersonal discrimination), minority stress at the interpersonal level is especially prevalent and consistently associated with self-reported poor health (e.g., Figueroa & Zoccola, 2016; Wise & Hyde, 2012). For example, a recent meta-analysis of 164 studies from 1992-2009 examining lifetime victimization experiences of sexual minority individuals found that 55% of sexual minority men and women experienced verbal harassment, 41% experienced discrimination, and 45% experienced sexual harassment due to their sexual orientation (Katz-Wise & Hyde, 2012). Similarly, in a seven-day paper and pencil diary study of 69 sexual minority adults (51% women, 86% Caucasian; 12 Mage = 31), participants reported an average of two heterosexist hassles (e.g., discrimination due to sexual orientation) across the week with a range of 0 to 8 events (Swim, Pearson, & Johnston, 2007). Thus, minority stress appears to be prevalent in the lifetime as well as everyday lives of sexual minority adults. Minority Stressors and Health To date, only a few studies have tested the association between minority stress and self-reported physical health (e.g., Figueroa & Zoccola, 2016; Frost, Lehavot & Meyer, 2013). For example, in an online sample of 277 sexual minority adults, greater perceived discrimination from family and friends was associated with greater somatic complaints (e.g., headaches), and poorer general physical health, controlling for general stressors (Figueroa & Zoccola, 2016). Although the literature examining minority stress and physical health is limited, it appears that there is a direct association between minority stress and poor (self-reported) physical health in sexual minorities. Nevertheless, to the author’s knowledge, the association between minority stress and physical health (subjective or objective) in sexual minorities has not been examined in daily life. Physiological stress responses to minority stress are proposed to mediate the association between minority stress and poor health in sexual minorities (e.g., Pascoe & Smart Richman, 2009). Previous work has found that perceived stress reactivity (i.e., a subjective measure of stress reactivity in a variety of different domains) partially mediated the association between perceived discrimination and self-reported health outcomes (Figueroa & Zoccola, 2016). Yet, in order to fully examine the pathways between minority stress and health, researchers must also examine objective 13 physiological measures of stress responses as they may be important mediators in the association between stress and health in sexual minority individuals. Stress, Cortisol, and Health One such possible biological mediator is cortisol. Cortisol, a glucocorticoid hormone synthesized from cholesterol in the adrenal cortex, and the primary end-product of the Hypothalamic-Pituitary-Adrenal (HPA) axis, is released in response to psychosocial stress (Kirschbaum & Hellhammer, 1989). A psychosocial stressor can trigger the HPA axis to release a cascade of hormones with the eventual release of cortisol (Kemeny, 2003). The primary functions of cortisol are to increase blood sugar through gluconeogenesis (i.e., a mechanism by which blood glucose levels are maintained in the human body), suppression of the immune system, and aiding of the metabolism of fat, protein, and carbohydrates (Hoehn et al., 2010). Cortisol receptors are located throughout the entire body, therefore cortisol has the ability to widely act upon tissue in the body (e.g., preparing the body physiologically to respond to stressors; Charmandari, Tsigos, & Chrousos, 2005). Cortisol normally follows a stable biological rhythm throughout the day. In general, cortisol typically rises sharply in the morning upon awakening (the rise in cortisol that occurs 3045 minutes after awakening is known as the cortisol awakening response or CAR) then steadily declines throughout the day (cortisol slope; Wust et al., 2000). Cortisol can also be measured by assessing daily output, or total exposure to cortisol throughout the day, which is usually calculated as the area between ground and cortisol values taken throughout the day (area-under-the-curve, with respect to ground: AUCG). Flat or b