Association of handgrip strength weakness and asymmetry with later life pain risk in middle-aged and older individuals: Results from four prospective cohorts

Objectives

The burden of pain in middle-aged and older adults is considerable and significantly increases healthcare expenditures. We aimed to investigate the roles of handgrip strength (HGS) weakness and asymmetry in predicting pain across four nationally representative cohorts.

Methods

This longitudinal study utilized data from four major surveys: the Health and Retirement Study (HRS); the English Longitudinal Study of Ageing (ELSA); the Survey of Health, Ageing and Retirement in Europe (SHARE); and the China Health and Retirement Longitudinal Study (CHARLS). Multivariable cubic regression splines were employed to visually explore the nonlinear associations between HGS and pain in each cohort. The Cox proportional hazard model was applied to analyze the independent and combined relationship between HGS weakness and asymmetry and pain risk.

Results

We included 41,171 participants in the final analysis, with a mean follow-up period of 4.68 ± 2.61 years (50.7% female, mean age 64.3 ± 9.3 years). No nonlinear relationship was found between HGS and pain incidence (nonlinear p < 0.05 in ELSA and SHARE; >0.05 in CHARLS and HRS). After adjustment, the highest quartile groups had a significantly reduced risk of pain compared to the lowest quartile groups across all cohorts, with hazard ratios of 0.81 (0.74, 0.89) in CHARLS, 0.86 (0.77, 0.97) in HRS, 0.88 (0.77, 0.98) in ELSA, and 0.78 (0.73, 0.84) in SHARE. Participants with normal HGS had approximately 20% lower risk of pain compared to those with weak HGS. Each 5 kg increase in HGS was associated with decreased hazard ratios for pain: 0.95 (0.93, 0.97) in CHARLS, 0.97 (0.94, 0.99) in HRS, 0.96 (0.94, 0.99) in ELSA, and 0.94 (0.92, 0.95) in SHARE. The association between HGS asymmetry and pain risk was significant only in a few cohorts (HRS at 10%, 1.10 (1.03, 1.18); SHARE at 30%, 1.12 (1.05, 1.21)). No interaction effect between HGS weakness and asymmetry on pain risk was observed (all p-values for interaction >0.05).

Conclusions

Our findings suggest that HGS can be used as an independent predictor of pain in middle-aged and older European, American, and Chinese populations. However, our results do not support the use of HGS asymmetry as an independent predictor of pain risk. It is necessary to establish appropriate criteria for HGS asymmetry across different populations. The use of both weak HGS and asymmetry as predictors of health outcomes requires further validation in more diverse populations.