Association between body mass index and disability among older population in China: analysis of 2011–2020 data from the China Health and Retirement Longitudinal Study

A nonlinear U-shaped relationship between BMI and ADL disability risk was observed among Chinese adults aged 60-69 and older female adults, suggesting that both high and low BMI are associated with increased ADL disability risk. Despite limitations such as baseline-only BMI measurements, observational study design, potential residual confounding, and limited generalisability beyond Chinese older adults, these findings highlight the importance of routine BMI screening and targeted weight management strategies to help prevent or delay the onset of ADL disability in older adults.