Social isolation, rather than loneliness, is associated with cognitive decline in older adults: the China Health and Retirement Longitudinal Study

BACKGROUND: Social isolation and loneliness have each been associated with cognitive decline, but most previous research is limited to Western populations. This study examined the relationships of social isolation and loneliness on cognitive function among Chinese older adults. METHODS: This study used two waves of data (2011 and 2015) from the China Health and Retirement Longitudinal Study (CHARLS) and analyses were restricted to those respondents aged 50 and older. Social isolation, loneliness, and cognitive function were measured at baseline. Follow-up measures on cognitive function were obtained for 7761 participants (mean age = 60.97, s.d. = 7.31; male, 50.8%). Lagged dependent variable models adjusted for confounding factors were used to evaluate the association between baseline isolation, loneliness, and cognitive function at follow-up. RESULTS: Loneliness was significantly associated with the cognitive decline at follow-up (episodic memory: β = -0.03, p < 0.01; mental status: β = -0.03, p < 0.01) in the partially adjusted models. These associations became insignificant after additional confounding variables (chronic diseases, health behaviors, disabilities, and depressive symptoms) were taken into account (all p > 0.05). By contrast, social isolation was significantly associated with decreases in all cognitive function measures at follow-up (episodic memory: β = -0.05, p < 0.001; mental status: β = -0.03, p < 0.01) even after controlling for loneliness and all confounding variables. CONCLUSIONS: Social isolation is associated with cognitive decline in Chinese older adults, and the relationships are independent of loneliness. These findings expand our knowledge about the links between social relationships and the cognitive function in non-Western populations.