The relationship between a frailty index and fall risk in middle-aged and older adults: Findings from three prospective cohort studies - CHARLS, ELSA and HRS.

BACKGROUND: Global population aging has made frailty a critical public health concern. While a frailty index (FI) is able to quantify frailty effectively, its association with fall risk needs further validation across diverse populations and cultural contexts.

METHODS: This study analyzed data from 24,526 participants aged ≥45 years from national cohorts in the China Health and Retirement Longitudinal Study, the English Longitudinal Study of Aging, and the US Health and Retirement Study. The association between a health deficit-based frailty index and self-reported falls over two years was assessed using a model with multivariable adjustment logistic regression, restricted cubic splines, and stratified analyses.

RESULTS: The mean baseline score on the frailty index was 0.1 in China Health and Retirement Longitudinal Study, 0.2 in English Longitudinal Study of Aging, and 0.4 in Health and Retirement Study. A significant positive association was observed between frailty score and fall risk after multivariable adjustment (P < 0.001), with adjusted odds ratios of 1.45, 1.51, and 1.86 per unit increase in score, respectively. A nonlinear dose-response relationship (P < 0.001) and significant sex interaction (P < 0.001) were identified, with a stronger association in men.

CONCLUSION: The frailty index is a significant predictor of fall risk in middle-age and older adults, with variations across countries and sexes, supporting its utility as a practical screening tool for targeted interventions to promote healthy aging.