Objective A growing number of studies have associated various measures of social integration, the diversity of social roles in which one participates, with alterations in hypothalamic-pituitary-adrenocortical (HPA) functioning. The pathways through which social integration may be linked to HPA functioning, however, are as yet unknown. The present study examined whether daily social interactions, affective responses, health behaviors, and personality help explain the association between social integration and diurnal cortisol slope. Methods A sample of 456 healthy, employed adults (53.9% female, 82.0% white, 72.2% bachelor’s degree or greater, mean age of 42.86 years) completed a 4-day ecological momentary assessment protocol that measured cortisol, social interactions, affect, sleep, and physical activity at frequent intervals throughout the day. Social integration was measured at baseline. Results Regression results controlling for age, sex, race, and education indicated that more socially integrated individuals showed steeper cortisol slopes (B = −0.00253, p = .006). Exploratory analyses suggested that the consistency (i.e., reduced variability) in nightly sleep midpoint partially explained this association (B = −0.00042, 95% confidence interval = −0.00095 to −0.00001). Personality, mood, social interaction patterns, and nonsleep health behavior differences did not account for the association between social integration and HPA activity. Conclusion This study replicates previous findings linking social integration and HPA functioning, and it examines patterns of nightly sleep as possible pathways through which the association may operate. Results have implications for understanding mechanisms for health risk and for development of future interventions.

ObjectiveSocially integrated individuals are at lower risk of cardiovascular disease morbidity and mortality compared with their more isolated counterparts. This association may be due, in part, to the effect of social integration on nocturnal blood pressure (BP) decline or “dipping,” a physiological process associated with decreased disease risk. However, the pathways linking social integration with nocturnal BP dipping are unknown. We sought to replicate the association between social integration and BP dipping, and to test whether sleep characteristics (duration, regularity, continuity) and/or daily social interactions (frequency, valence) helped to explain the association.MethodsA total of 391 healthy midlife adults completed an actigraphy assessment protocol that measured sleep. During four actigraphy assessment days, participants also completed ambulatory BP monitoring and ecological momentary assessment protocols that measured BP and social interactions at regular intervals throughout the day. Social integration was assessed via a questionnaire.ResultsLinear regression controlling for age, sex, race, education, and body mass index indicated that higher levels of social integration were associated with greater nocturnal BP dipping, as indicated by a smaller ratio of night/day mean arterial pressure (β = −0.11, p = .031). Analyses of indirect effects suggested that this association was explained, in part, by greater sleep regularity among more integrated individuals. We did not find evidence for other hypothesized indirect effects.ConclusionsThis was the first study to investigate sleep and social mechanisms underlying the link between social integration and nocturnal BP dipping. Because sleep regularity is modifiable, this pathway represents a potential intervention target to promote nocturnal BP dipping.

Stress exposure is linked to elevated blood pressure, which increases risk for cardiovascular disease (Spruill, 2010; WHO, 2013). Stress exposure may be especially harmful when concentrated in one particular domain (i.e., low stressor diversity) (Koffer, et al., 2016). Using a diversity index, we test whether high stressor exposure and low stressor diversity is associated with high resting blood pressure. Participants (N=391, aged 40-64 years) completed four days of hourly self-report of stressful experiences (e.g., work task demand, non-work task demand, arguments, interpersonal tension), with clinic blood pressure separately assessed. Linear regression results indicate older adults experienced lower stressor diversity (B = -0.003, p =.003). Further, higher stressor exposure with lower stressor diversity related to higher diastolic blood pressure (B= -7.21, p=.046). Experiencing high stress concentrated in one domain may increase risk of high blood pressure. We discuss how low stressor diversity may help explain age-related risk of cardiovascular disease.

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