Sex and education differences in the association between social frailty and mortality in older adults.

BACKGROUND: Social frailty in older adults is associated with an increased risk of adverse health outcomes, including mortality. However, limited evidence exists on whether this association differs by sex and education. METHODS: Participants were 965 community-dwelling adults (54.9% female) aged 70-90 years from the Sydney Memory and Ageing Study. Social frailty was assessed using a validated index incorporating seven psychosocial factors. Mortality was determined using death records and information from relatives. Analysis was performed using Cox Proportional Hazards regression with the fully adjusted model including age, physical and psychological frailty, education, smoking, alcohol, and physical health as covariates. RESULTS: Over 18 years, 689 participants died (347 women, 342 men). Among women, social pre-frailty, but not frailty, was associated with increased mortality risk compared with non-frailty (HR 1.40 [95% CI 1.07, 1.82]). This association was observed in women with fewer than 12 years of education in the partially adjusted model. Among men with low education, social frailty was associated with increased mortality risk in the partially adjusted model (HR 1.62 [95% CI 1.08, 2.42]), but not in the fully adjusted model. DISCUSSION: The association between social frailty and mortality differed by sex and education. The most consistent finding was an elevated mortality risk among women classified as socially pre-frail. CONCLUSION: Social vulnerability may be more informative in specific subgroups rather than as a universal mortality risk marker. These findings highlight the potential importance of identifying social pre-frailty and considering sex and educational differences when assessing risk in later life.