Links Between Socioeconomic Status, Daily Depressive Affect, Diurnal Cortisol Patterns, and All-Cause Mortality.

OBJECTIVE: Socioeconomic status (SES) remains a robust risk factor for mortality. Various theoretical models postulate that lower SES is associated with higher negative affect, which then initiates a cascade of physiological disturbances that contribute to illness and early mortality. However, few studies have explicitly investigated the interplay between psychological and biological factors in determining SES disparities in mortality. This study examined the role of daily negative affect and cortisol secretion in explaining the SES-mortality link in a large sample of US adults. METHODS: Using data from the Midlife in the United States study (n = 1735, mean [standard deviation] age = 56.40 [12.10] years, 56.4% female), we tested longitudinal associations between SES, daily negative affect, daily cortisol levels, and all-cause mortality 13 years later. Daily negative affect was classified into three clusters reflecting depressive affect, anxiety, and anger. RESULTS: Higher SES was linked to a lower risk of all-cause mortality (hazard ratio = 0.94, 95% confidence interval = 0.90 to 0.97). Furthermore, there was a sequential link between higher SES and lower mortality through lower daily depressive affect and a steeper ("healthier") diurnal cortisol slope (indirect effect = -0.0007, 95% confidence interval = -0.0014 to -0.0002). Daily anxiety and anger were not associated with cortisol levels or mortality (p values > .05). CONCLUSIONS: These findings suggest that daily negative emotional experiences and the hypothalamic-pituitary-adrenal axis functioning may constitute important psychological and physiological pathways underlying the link between SES and all-cause mortality.

Diurnal Cortisol in a Sample of Socioeconomically Disadvantaged Chinese Children: Evidence for the Shift-and-Persist Hypothesis.

OBJECTIVE: Low socioeconomic status (SES) is one of the most well-established social determinants of health. However, little is known about what can protect the health of individuals (especially children) living in low-SES circumstances. This study explored whether the psychological strategy of "shift-and-persist" protects low-SES children from stress-related physiological risks, as measured through blunted (unhealthy) diurnal cortisol profiles. METHODS: A sample of 645 children (aged 8-15 years) from low-SES backgrounds and having at least one HIV-positive parent completed a battery of psychological scales. Diurnal cortisol assessments included collection of saliva samples four times a day for 3 days, from which three cortisol parameters (cortisol at awakening, cortisol awakening response, and cortisol slope) were derived. RESULTS: Higher levels of shift-and-persist, considered as a single variable, were associated with higher cortisol at awakening (B = 0.0119, SE = 0.0034, p < .001) and a steeper cortisol slope (B = -0.0007, SE = 0.0003, p = .023). These associations remained significant after adjusting for covariates and did not vary by age. In supplementary analyses, where shifting and persisting were treated as separate variables, the interaction between these two coping strategies significantly predicted cortisol at awakening (B = 0.0250, SE = 0.0107, p = .020) and the cortisol slope (B = -0.0022, SE = 0.0011, p = .040), suggesting that the combination of shift-and-persist is important for predicting diurnal cortisol profiles. CONCLUSIONS: Our findings demonstrate that shift-and-persist is associated with healthier diurnal cortisol profiles among socioeconomically disadvantaged children and introduce the possibility that this coping strategy is protective against other stressors, such as those uniquely faced by children in our study (i.e., being affected by parental HIV).

Discrimination and anger control as pathways linking socioeconomic disadvantage to allostatic load in midlife.

OBJECTIVE: Recent evidence suggests that experiences of discrimination contribute to socioeconomic status health disparities. The current study examined if the experience and regulation of anger-an expected emotional response to discrimination-serves as an explanatory factor for the previously documented links between socioeconomic disadvantage (SED), discrimination, and allostatic load. METHODS: Data were drawn from the second wave of the Midlife in the United States (MIDUS) study and included 909 adults who participated in the biomarkers subproject. RESULTS: Results revealed that perceived discrimination was associated with higher levels of allostatic load. Furthermore, we found evidence that perceived discrimination and anger control sequentially explained the relationship between SED and allostatic load, such that greater discrimination was associated with lower levels of anger control, which, in turn accounted for the effects of discrimination on allostatic load. These results remained significant after controlling for negative affect, positive affect, other forms of anger expression, as well as demographic covariates. CONCLUSIONS: Our findings suggest that low anger control may be an important psychological pathway through which experiences of discrimination influence health.

Socioeconomic status, perceived control, diurnal cortisol, and physical symptoms: A moderated mediation model.

Social class is a robust predictor of health, with risk for disease and mortality increasing towards the lower end of the socioeconomic (SES) spectrum. While certain psychological characteristics, such as high sense of control, can protect low-SES individuals from adverse health outcomes, very few studies have investigated the biological mechanisms underlying these relationships. In this study, we tested whether sense of control mitigated the associations between SES and cortisol activity, and SES and physical health in daily life (i.e., number and severity of physical symptoms). Next, we tested whether individual differences in cortisol secretion would act as a mechanism by which SES and perceived control influenced physical health. In a large national sample from the Midlife in the United States (MIDUS) survey, we found that SES interacted with perceived control in predicting morning cortisol levels, cortisol slopes, number of physical symptoms, and severity of physical symptoms. Specifically, SES disparities in these health outcomes were more pronounced among individuals reporting low levels of perceived control than among individuals endorsing high levels of perceived control. Further, we found that a flatter cortisol slope mediated the link between lower SES and greater number and severity of physical symptoms for those individuals who reported lower levels of perceived control, but not for individuals reporting higher levels of perceived control. These findings suggest that perception of greater control may act as a buffer against the effect of low SES on health-related physiological processes.

Life satisfaction moderates the impact of socioeconomic status on diurnal cortisol slope.

The association between SES and health is well established; however, only a handful of studies have investigated the relationship between SES and daily cortisol parameters. Further, within this small literature, virtually no studies have looked at psychological factors that might mitigate this relationship. In this study, we tested whether life satisfaction--the overall subjective affective assessment of one's own life--acts as a protective factor against cortisol dysregulation driven by low-SES. Among a large sample (N=1325) of individuals from the Midlife in the United States (MIDUS) survey, we found that low-SES individuals with high levels of life satisfaction had a cortisol circadian profile similar to those of high-SES individuals. In contrast, low-SES individuals reporting low life satisfaction experienced attenuated morning cortisol concentrations and a flatter ("less healthy") diurnal cortisol slope. Although more studies are needed to investigate the constellation of psychological resources and processes through which life satisfaction exerts its effects, the current work shows that the general affective evaluation of one's own life acts as a buffer against the detrimental effect of low-SES on health-related physiological processes.

Effects of socioeconomic status on maternal and child positive behaviors in daily life among youth with asthma.

OBJECTIVE: Socioeconomic disadvantage is associated with poorer behavioral and emotional outcomes in children with asthma. This study investigated the associations between maternal income and education and naturalistically observed behaviors and affect during everyday parent-child interactions. METHODS: 53 predominantly low-income youth with asthma, aged 10-17 years, wore a naturalistic event-sampling device, the Electronically Activated Recorder, for 4 days to assess mother and child positive behaviors and affect in daily life. RESULTS: Maternal education, but not income, was positively associated with child positive behaviors, displays of mother and child positive affect, and increased maternal responsiveness. Maternal positive affect and maternal responsiveness mediated the effect of maternal education on child positive affect. CONCLUSIONS: Our findings suggest that maternal education has an important influence on the socioemotional adjustment of youth with asthma and point to the importance of investigating the independent influence of socioeconomic status components on everyday parent-child interactions.