Trends in prevalence, associated comorbid burden, and subsequent mortality of social isolation: A gender perspective

BACKGROUND: Gender differences in social isolation have not been thoroughly characterized. This study aimed to estimate the gender differences in the trends in the prevalence of social isolation, evaluate the gender-based differences in its comorbid burden, and examine their subsequent associated mortality by gender. METHODS: This nationwide cohort study used data from the China Health and Retirement Longitudinal Study. Social isolation was measured using 4 dichotomized indicators. The Cochran-Armitage trend test and multivariate Poisson regression models were constructed to analyze the trends in social isolation and the longitudinal associations between social isolation and mortality by gender. All analyses were weighted to account for the multistage, probability-proportional-to-size sampling scheme of the project. RESULTS: A significant downward trend in social isolation was observed in men, with a weighted prevalence of 19.4 % (95 % confidence interval (CI): 17.7, 21.3) in 2011 and 14.1 % (95 % CI: 12.9, 15.4) in 2018 (P for trend <0.001). In contrast, a stable trend in social isolation was noted in women, with a weighted prevalence of 24.0 % (95 % CI: 22.5, 25.6) in 2011 and 24.1 % (95 % CI: 22.7, 25.6) in 2018 (P for trend = 0.154). A steeper increase in age-adjusted Charlson Comorbidity Index (ACCI) and number of comorbidities was observed in women compared to men (P for gender-by-social isolation score interaction <0.001). Over a 9-year follow-up period, females with social isolation had more than double the risk of mortality (incidence rate ratio (IRR): 2.03, 95 % CI: 1.64, 2.52), while males with social isolation had only a 58 % increased IRR (95 % CI: 1.30, 1.94) of all-cause mortality (P for interaction = 0.031). CONCLUSION: Several gender differences in social isolation were observed, including the higher prevalence, heavier comorbid burdens, and a stronger association with mortality noted in women.