Persistent musculoskeletal pain and subsequent falls in China: Evidence from CHARLS with exploratory frailty mediation analyses

BACKGROUND: Musculoskeletal pain (MSP) is prevalent among middle-aged and older adults and may increase fall risk through functional decline, but evidence on pain persistence and the potential role of frailty in China remains limited. METHODS: This study utilized data from the 2011 and 2015 China Health and Retirement Longitudinal Study (CHARLS), involving 13,057 participants in 2011 and a cohort of 7390 who reported no falls in 2011 and completed the 2015 follow-up. Among them, 1046 had persistent MSP identified using standardized CHARLS pain items. Participants indicated body pain locations, with MSP noted if pain was present anywhere. Baseline MSP was recorded in 2011, and persistent MSP was reported in both 2011 and 2015. Falls were self-reported. Survey-weighted logistic regression analyzed associations, while mediation analyses used baseline MSP (2011) as exposure and frailty in 2015 as a mediator, employing a counterfactual framework to decompose effects, interpreted cautiously due to standard assumptions and a two-year fall recall window. Baseline characteristics were compared between included and excluded participants to evaluate potential selection bias. RESULTS: In the longitudinal cohort, 1072 incident falls were recorded, with a higher fall rate among participants with persistent MSP than among those without (25.69 % vs 12.48 %). Adjusted models showed baseline MSP increased fall risk (OR 1.36, 95 % CI 1.15-1.60), with a stronger link for persistent MSP (OR 2.08, 95 % CI 1.70-2.54). Similar trends were observed for multisite pain. Mediation analysis indicated frailty partially mediated the effect of baseline MSP on falls, accounting for about 29 % of the effect, though results were interpreted cautiously due to the two-year fall recall period. CONCLUSIONS: In middle-aged and older Chinese adults, MSP increases fall risk, particularly with ongoing pain. Frailty might partly explain this risk, indicating the importance of combining pain management with anti-frailty measures for fall prevention.