Sex differences in the frailty phenotype and mortality in the I-Lan longitudinal aging study cohort

Background: Frailty is a common geriatric syndrome related to multiple adverse outcomes. Sex differences in its prevalence and impact on mortality remain incompletely understood. Methods: This study was conducted with data from the I-Lan Longitudinal Aging Study, in which community-dwelling subjects aged > 50 years without coronary artery disease or diabetes were enrolled. Sex disparities in phenotypically defined frailty and sex–morality predictor interactions were evaluated. Sex- and frailty-stratified analyses of mortality were performed. Results: The sample comprised 1371 subjects (51.4% women, median age 61 years). The median follow-up period was 6.3 (interquartile range, 5.8–7.0) years. The frailty prevalence did not differ between men (5.3%) and women (5.8%). Frail individuals were older and less educated and had poorer renal function than did non-frail individuals. Body composition trends differed between sexes, regardless of frailty. Relative to non-frail men, frail men had significantly lower body mass indices (BMIs; 24.5 vs. 23.4 kg/m², p = 0.04) and relative appendicular skeletal muscle masses (7.87 vs. 7.05 kg/m², p < 0.001). Frail women had significantly higher BMIs (25.2 vs. 23.9 kg/m², p = 0.02) and waist circumferences (88 vs. 80 cm, p < 0.001) than did non-frail women. Frailty was an independent mortality predictor for men only [hazard ratio (95% confidence interval) = 3.395 (1.809–6.371), p_{sex–frailty interaction} = 0.03]. Conclusion: Frailty reflected poorer health in men than in women in the present cohort. This study revealed sex disparities in the impact of frailty on mortality among relatively healthy community-dwelling older adults.