Stressful Life Events, Sexual Orientation, and Cardiometabolic Risk Among Young Adults in the United States

Exposure to a wide range of stressful life events—including high job strain (Bosma, Peter, Siegrist, & Marmot, 1998), care-giving for an ill family member (Lee, Colditz, Berkman, & Kawachi, 2003), loss of a loved one (Kaprio, Koskenvuo, & Rita, 1987), exposure to a life-threatening traumatic event (Kark, Goldman, & Epstein, 1995), and childhood adversities (Slopen, Kubzansky, McLaughlin, & Koenen, 2013)—has been consistently linked to risk for cardiovascular disease (CVD). Despite numerous studies documenting these relationships, several important gaps in the literature remain. First, the degree to which associations between stressful life events and CVD risk are consistent across the life course is largely unknown. Many behavioral (e.g., smoking, diet) and social (e.g., childhood adversity) risk factors for adult CVD emerge early in development (e.g., Adair & Dahly, 2005), suggesting that relationships between stressful life events and CVD risk might be evident in young adulthood. Scant research has examined this possibility. Indeed, the vast majority of work examining stressful life events and CVD risk has been conducted among middle-aged and older adults (Everson-Rose & Lewis, 2005). Second, the relationship between stressors and CVD risk is likely to vary across sociodemographic groups. For instance, psychosocial stressors, such as marital stress, are more strongly associated with CVD outcomes among women compared with men (Iso et al., 2002; Orth-Gomer et al., 2000). Further, the association between stressful events and subclinical CVD risk also varies by race/ethnicity (Slopen et al., 2010; Troxel, Matthews, Bromberger, & Sutton-Tyrrell, 2003). Although there is emerging evidence for sexual orientation disparities in CVD-related outcomes (Cochran & Mays, 2007; Conron, Mimiaga, & Landers, 2010; Everett & Mollborn, 2013; Hatzenbuehler, McLaughlin, & Slopen, 2013), we are unaware of studies that have examined whether the relationship between stressful life events and CVD risk varies by sexual orientation. For the current study, we sought to address these gaps in the literature. Differential vulnerability models (Nolen-Hoeksema & Girgus, 1994) provide a potential framework for understanding how sexual orientation could moderate the relationship between stressful life events and CVD risk. Specifically, differential vulnerability models posit that members of certain social groups are rendered more vulnerable to the negative effects of stressful life events because they have a lower threshold for developing adverse reactions to these events (Nolen-Hoeksema & Girgus, 1994). These preexisting vulnerabilities, in turn, are exacerbated by the heightened degree of stressful life events that socially disadvantaged groups experience compared with more advantaged groups. Why might lesbian, gay, and bisexual (LGB) individuals be more vulnerable to the negative health consequences of stressful life events than heterosexuals? Managing a stigmatized identity disrupts development of a variety of cognitive (e.g., negative self-schemas), emotion-regulation (e.g., maladaptive coping such as rumination and suppression), and neurobiological (e.g., hypothalamic–pituitary–adrenal axis-functioning) processes (Hatzenbuehler, 2009; Hatzenbuehler & McLaughlin, 2014; Inzlicht, McKay, & Aronson, 2006; Major & O’Brien, 2005). In turn, these biopsychosocial processes affect future susceptibility to poor health, including CVD risk (Everson-Rose & Lewis, 2005; Miller, Chen, & Cole, 2009; Repetti, Taylor, & Seeman, 2002). Differential vulnerability might also emerge due to differences in the developmental timing of exposure to stressors. Individuals who have been exposed to early life stressors are more likely to develop depression (Hammen, Henry, & Daley, 2000) and posttraumatic stress disorder (McLaughlin, Conron, Koenen, & Gilman, 2010) following exposure to stressors in adulthood than individuals who have not experienced early life stressors. Multiple studies have documented that LGB adolescents and young adults are more likely than their heterosexual peers to be victimized (Bontempo & D’Augelli, 2002), and to experience childhood maltreatment and homelessness (McLaughlin, Hatzenbuehler, Xuan, & Conron, 2012). This differential exposure might be directly linked to greater vulnerability to subsequent stressful life events. Based on differential vulnerability models (Nolen-Hoeksema & Girgus, 1994; Hammen et al., 2000), we hypothesized that stressful life events would be more strongly associated with cardiometabolic risk among LGB young adults compared with their heterosexual peers. In particular, for the reasons stated above, LGB young adults were expected to have more preexisting characteristics that render them more vulnerable to CVD risk; when these characteristics interact with stressful life events, LGB young adults may be more likely to develop cardiometabolic risk than heterosexuals. We examined this question using a cumulative CVD risk score, designed to characterize overall functioning across multiple measures of cardiovascular activity (Seeman et al., 2004). We opted to use a measure of cumulative CVD risk rather than examine individual biomarkers in light of allostatic load research, which suggests that adverse risk factors across multiple biological systems predict morbidity and mortality risk better than individual components (Poulter, 2003; Seeman, Epel, Gruenewald, Karlamangla, & McEwen, 2010). There is limited knowledge about the relationship between stressful life events and CVD risk in younger populations, particularly using a cumulative cardiometabolic risk score. Consequently, the study makes several unique contributions to the literature on stressful life events and CVD risk. We examined our research questions using the only existing data set (from the National Longitudinal Study of Adolescent Health; Add Health; Shin, Edwards, & Heeren, 2009; Brummett et al., 2013) with a representative sample of young adults that simultaneously measured sexual orientation, stressful life events over multiple waves, cardiometabolic biomarkers, and established CVD risk factors. This data set therefore offered us a rare opportunity to address the role of stressful life events in cardiometabolic risk among both LGB and heterosexual young adults in the United States.