Effects of social relationships on mortality of the elderly: how do the influences change with the passage of time?

The purpose of this study was to determine the changes with time lapse in the influences of social relationship factors, in relation to mortality in the elderly. A baseline investigation was conducted in 1992 and survival conditions of 637 subjects aged 68-82 years were followed up for 12 years. The associations of social relationships with mortality were compared between the first and later half periods. The results showed that for men, close friends, group membership and finding life worth living were significantly associated with mortality in the first half period and the association disappeared in the later half; also in men, providing instrumental support was significantly associated in the 12-year period. In the first half, living arrangement was not significantly associated with mortality for men, and marital status and job were not for women, but in the later half, the association of those became apparent. The present study suggests that for men, the association of close friends, group membership and finding life worth living with mortality decreased with the passage of time while providing instrumental support had positive effects throughout the long term. The association of living arrangement increased for men, and marital status and job for women.