title: Social integration is associated with fibrinogen concentration in elderly men.
abstract: OBJECTIVE
  The objective of this study was to determine whether social integration is associated with plasma concentrations of fibrinogen in an elderly population.
  
  
  METHODS
  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.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Society, Human Development and Health, Harvard School of Public Health, 677 Huntington Ave., Boston, MA, USA. eloucks@hsph.harvard.edu
authors.forename: Eric B
authors.initials: EB
authors.lastname: Loucks
authors.forename: Lisa F
authors.initials: LF
authors.lastname: Berkman
authors.forename: Tara L
authors.initials: TL
authors.lastname: Gruenewald
authors.forename: Teresa E
authors.initials: TE
authors.lastname: Seeman
mesh_terms: D000367:Age Factors; D000368:Aged; D002318:Cardiovascular Diseases / Q000209:etiology / Q000523:psychology*; D003430:Cross-Sectional Studies; D005191:Family Characteristics; D005260:Female; D005340:Fibrinogen / Q000032:analysis*; D033062:Friends; D006801:Humans; D007398:Interpersonal Relations; D008137:Longitudinal Studies; D008297:Male; D017533:Marital Status; D012307:Risk Factors; D012737:Sex Factors; D012931:Social Environment; D012934:Social Isolation; D012944:Social Support; D029181:Spirituality
chemical_list: D005340:Fibrinogen