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.
David Geffen School of Medicine at UCLA, Los Angeles, CA, United States. Electronic address: tseeman@mednet.ucla.edu.
Teresa E
TE
Seeman
Davis School of Gerontology, University of Southern California, Los Angeles, CA, United States.
Tara L
TL
Gruenewald
Department of Psychology, Carnegie Mellon University, Pittsburgh, PA, United States.
Sheldon
S
Cohen
Department of Social and Behavioral Sciences, Harvard School of Public Health, Harvard University, Boston, MA, United States.
David R
DR
Williams
Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States.
Karen A
KA
Matthews
D000293:Adolescent; D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data; D003324:Coronary Artery Disease / Q000453:epidemiology* / Q000503:physiopathology / Q000523:psychology*; D005260:Female; D005500:Follow-Up Studies; D015438:Health Behavior; D006801:Humans; D007398:Interpersonal Relations; D008297:Male; D011446:Prospective Studies; D012919:Social Behavior; D012944:Social Support; D014481:United States / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data; D055815:Young Adult
Allostatic load; Biology; Social relationships; Social strains; Social support