biostudies-literatureUnknown23(1)Xie X<h4>Background</h4>Rapid urbanization is underway in China. However, the impact of urbanization on frailty remains unclear. This study aims to investigate the relationship between urbanization and frailty among middle-aged and older adults.<h4>Methods</h4>We analyzed nationally representative data from the China Health and Retirement Longitudinal Study (CHARLS) spanning 2011 to 2018. After applying inclusion and exclusion criteria, 10,758 non-frail individuals at baseline were analyzed. The exposure of interest was the comprehensive urbanization level. Urbanization level (0.072-0.689) was assessed using the entropy method. Frailty was assessed using the frailty index (FI), which ranges from 0 to 100. Frailty was defined as FI ≥ 25, and the urbanization-frailty association was assessed usinBMC medicine171https://www.ebi.ac.uk/biostudies/studies/S-EPMC11934686biostudies-literatureAssociation between urbanization levels and frailty among middle-aged and older adults in China: evidence from the CHARLS.PMC11934686Sun LXie XQue JSun TYang FfalseAssociation between urbanization levels and frailty among middle-aged and older adults in China: evidence from the CHARLS.<h4>Background</h4>Rapid urbanization is underway in China. However, the impact of urbanization on frailty remains unclear. This study aims to investigate the relationship between urbanization and frailty among middle-aged and older adults.<h4>Methods</h4>We analyzed nationally representative data from the China Health and Retirement Longitudinal Study (CHARLS) spanning 2011 to 2018. After applying inclusion and exclusion criteria, 10,758 non-frail individuals at baseline were analyzed. The exposure of interest was the comprehensive urbanization level. Urbanization level (0.072-0.689) was assessed using the entropy method. Frailty was assessed using the frailty index (FI), which ranges from 0 to 100. Frailty was defined as FI ≥ 25, and the urbanization-frailty association was assessed usin2025-01-01T00:00:00Z2025 Mar2025-06-25T03:04:37.1Z2025-06-25T03:04:37.1ZS-EPMC119346864012874310.1186/s12916-025-03961-y