Associations among social isolation, living alone, and cardiovascular mortality: The Otassha study

Living alone is potentially associated with cardiovascular mortality; however, the effects of social interactions have not been fully considered. This study examined whether social isolation and living alone were independently associated with cardiovascular mortality and whether living alone modified the association between social isolation and cardiovascular mortality in community-dwelling older adults.

Community-dwelling older adults residing in Itabashi Ward, Tokyo, who participated in the postal survey, were enrolled. Social isolation was defined based on the frequency of interaction with others.

The main outcome was cardiovascular mortality, obtained from the Itabashi Ward office database. Cox proportional hazards models were used to examine the association between social isolation and living alone, independently of cardiovascular mortality, and to test whether living alone modified the association between social isolation and cardiovascular mortality.

In total, 4144 older adults (mean age 72 years; 46% men) were included in the analyses. During follow-up (median 96 months), 95 cardiovascular deaths occurred. Social isolation was independently associated with cardiovascular mortality (hazard ratio 2.20; 95% confidence interval 1.43-3.39), although living alone was not (hazard ratio 0.88; 95% confidence interval 0.52-1.49). Living alone did not significantly modify the association between social isolation and cardiovascular mortality (p for interaction = 0.06).

Social isolation was associated with cardiovascular mortality in older adults, independent of living arrangements. These results highlight the importance of considering social interactions in addition to living arrangements when stratifying cardiovascular risks for older adults.