Social relationships and their biological correlates: Coronary Artery Risk Development in Young Adults (CARDIA) study

Objective: Analyses test the hypothesis that aspects of social relationships (quantity of ties, social support and social strain) are associated with differences in levels of biological risk across multiple major physiological regulatory systems and consequently overall multi-systems risk (i.e., allostatic load [AL]). Methods: Data are from the Coronary Artery Risk Development in Young Adults (CARDIA) study a bi-ethnic, prospective, multi-center epidemiological study, initiated in 1985-1986 to track the development of cardiovascular risk in young adulthood (N = 5115). At the year 15 follow-up when participants were between 32 and 45 years of age, additional social and biological data were collected; biological data used to assess AL were collected at the Oakland, CA and Chicago, IL sites (N = 844). Results: Social strains were most strongly and positively related to overall AL (Cohen's d =.79 for highest vs. lowest quartile), and to each of its component biological subsystems, independent of social ties and support as well as sociodemographics and health behaviors. Social ties and emotional support were also negatively related to AL (Cohen's d =.33 and d =.44 for lowest vs. highest quartiles of ties and support, respectively) though controls for social strains reduced these associations to non-significance. Social support and social strain were more strongly related to overall AL than to any of its component subscales while social ties were less strongly related to AL and to its component subscales. There was no evidence that effects differed by sex, age or ethnicity. Conclusions: Findings focus attention on the particularly strong relationship between social strains and profiles of biological risk and support the cumulative impact of social factors on biological risks, showing larger effects for cumulative AL than for any of the individual biological systems. (C) 2014 Elsevier Ltd. All rights reserved.