The objective of this study was to determine whether social integration is associated with plasma concentrations of fibrinogen in an elderly population.
Participants (ages 70–79; n = 375 men and 425 women) were part of the MacArthur Successful Aging Study, a longitudinal study from three community-based cohorts in the United States, who have relatively high physical and cognitive functioning. Social integration was measured using a social integration score, which assessed marital status, number of contacts with family and friends, frequency of religious service attendance, and participation in voluntary organizations. Fibrinogen concentrations were measured in plasma using an automated clot-rate assay. Cross-sectional multivariate logistic regression analyses were performed.
Social integration was significantly associated with elevated concentrations of fibrinogen (>336 mg/dL) in men after adjusting for smoking, alcohol consumption, physical activity, body mass index, comorbidity, physical functioning, depression, age, race, and education (odds ratio [OR] = 2.29, 95% confidence interval [CI] = 1.07–4.89, p = .03 for having elevated fibrinogen in the least integrated quartile versus the most integrated quartile). There was no significant association between social integration and fibrinogen in women (multivariate-adjusted OR = 0.57, 95% CI = 0.27–1.21, p = .15).
Social integration is associated with fibrinogen concentrations in elderly men. This provides evidence of a biologic mechanism that may help explain the observed associations between social integration and mortality in men. There may be gender differences in the physiological pathways by which social integration influences health.
OR = odds ratio; CI = confidence interval.
From the Department of Society, Human Development & Health, Harvard School of Public Health, Boston, Massachusetts (E.B.L., L.F.B.); and the Division of Geriatrics, Department of Medicine, UCLA School of Medicine, Los Angeles, California (T.L.G., T.E.S.).
Address correspondence and reprint requests to Eric B. Loucks, PhD, Department of Society, Human Development and Health, Harvard School of Public Health, 677 Huntington Ave., Boston, MA. E-mail: email@example.com
Received for publication August 19, 2004; revision received December 8, 2004.
This research was support by NIA grants AG-17056 and AG-17265, grants from the John D. and Catherine T. MacArthur Foundation, a research fellowship from the Harvard Center for Society and Health, and a personnel award from the Heart and Stroke Foundation of Canada.