Changes in handgrip strength and incident edentulism among middle-aged and older adults in China: a longitudinal analysis of CHARLS

Abstract Background Evidence on whether changes in muscle strength precede complete tooth loss remains limited. We examined the association between handgrip strength changes during 2011–2015 and incident edentulism during 2015–2018 in Chinese middle-aged and older adults. Methods This longitudinal analysis used the 2011, 2015 and 2018 waves of the China Health and Retirement Longitudinal Study. Participants were aged ≥ 45 years in 2011, reported retaining natural teeth in both 2011 and 2015, and had oral outcome data in 2018. Grip strength decline was calculated as the 2011 value minus the 2015 value. Changes in low grip strength status were classified as persistently non-low, recovered, incident low, or persistently low. Multivariable logistic regression estimated odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for baseline grip strength and sociodemographic, lifestyle and health characteristics. Supplementary analyses used natural cubic splines, change quartiles, multiple imputation and modified Poisson regression. Results Among 7005 participants in the complete-case analysis, 439 (6.3%) reported incident edentulism in 2018. Each standard deviation (7.36 kg) greater decline in grip strength was associated with an adjusted OR of 1.26 (95% CI 1.12–1.42). Compared with persistently non-low grip strength, the ORs were 1.54 (1.14–2.09) for incident low grip strength, 1.75 (1.08–2.85) for persistently low grip strength, and 1.10 (0.67–1.81) for recovered grip strength. There was no statistical evidence of nonlinearity (P = 0.794). Estimates were consistent after multiple imputation (OR 1.26, 1.11–1.42) and in modified Poisson regression (risk ratio 1.23, 1.10–1.38). Conclusions Greater grip strength decline over four years was associated with subsequent self-reported edentulism among adults who retained natural teeth in 2015. Incident and persistently low grip strength were also associated with edentulism. These findings extend longitudinal evidence linking changes in muscle strength to oral health and support further investigation of their shared determinants.