The relationship of psychosocial factors to total mortality among older Japanese-American men: The Honolulu Heart Program

OBJECTIVE: To examine the predictive value of psychosocial factors as risk factors for all-cause mortality. DESIGN: A community-based longitudinal cohort study: The Honolulu Heart Pro gram. SETTING: Population-based study conducted in Oahu, Hawaii. PARTICIPANTS: Three thousand four hundred and ninety-seven men age 71 to 93 were examined and followed prospectively for all-cause mortality for an av erage of 6 years. MEASUREMENTS: Psychosocial data were obtained using the Lubben Social Netwo rks Scale (LSNS). The LSNS consists of 10 items-family relationships (three items), relationships With friends (three items), and interdependent socia l supports and living arrangements (four items). We divided the LSNS score into quartiles for comparison, with the first quartile representing the low est social support and the fourth quartile representing the highest social support. RESULTS: A significant dose-response relationship was noted with LSNS score and total mortality: 33.8% in the first quartile died over the follow-up p eriod, 23.4% in the second, 18% in the third, and 15.7% in the fourth (P < .001). Six-year age-adjusted mortality rates were 66.2, 45.7, 37.8, and 33. 7 per 1,000 person years in the first, second, third, and fourth, respectiv ely (P < .001). Using age-adjusted Cox proportional hazards models, with th e first quartile of LSNS as the reference group, relative risk for mortalit y was 0.69 (95% confidence interval (CI) = 0.58-0.82), 0.57 (95% CI = 0.47- 0.70), and 0.52 (95% CI = 0.43-0.64) in the second, third, and fourth quart iles, respectively. Cox models were repeated, controlling for age and smoki ng status, and low LSNS scores remained significantly associated with highe r mortality (P =.0001). CONCLUSIONS: Our findings suggest that social networks were significantly i ndependently associated with 6-year all-cause mortality in this cohort of o lder Japanese-American men. Social interventions in old age may reduce earl y mortality.