Sex Differences in the Associations of Handgrip Strength and Asymmetry With Multimorbidity: Evidence From the English Longitudinal Study of Ageing.

Abstract Objectives To determine the sex-specific associations of handgrip strength (HGS) and asymmetry with incident multimorbidity and examine whether these relationships differ by sex. Design Prospective cohort study. Setting and Participants Secondary analyses of data from the English Longitudinal Study of Ageing (ELSA, waves 2-8). The analytic sample included 3977 participants (51.4% female) aged ≥50 years who had data for HGS on both hands and were living without multimorbidity at baseline. Measures HGS was assessed with a handheld dynamometer. Individuals in the lowest tertile of sex-specific age-adjusted HGS were defined as having low HGS. The largest HGS readings from the nondominant and dominant hand were used to calculate HGS ratio [nondominant HGS (kg)/dominant HGS (kg)]. Those with HGS ratio 1.10 had any HGS asymmetry. Further, those with HGS ratio 1.10 had nondominant HGS asymmetry. Multimorbidity was defined as the coexistence of ≥2 chronic diseases. Cox proportional hazards regression models were conducted for analyses. Results Low HGS was associated with multimorbidity among older men [hazard ratio (HR) 1.20, 95% confidence interval (CI) 1.03-1.40] and women (HR 1.19, 95% CI 1.03-1.38). No significant effect modification by sex was observed (P-interaction = .71). HGS asymmetry increased the risk of multimorbidity in women only (HR 1.23, 95% CI 1.07-1.41). The relationship between HGS asymmetry and multimorbidity risk differed by sex (P-interaction = .01). Similarly, both dominant HGS asymmetry (HR 1.21, 95% CI 1.05-1.40) and nondominant HGS asymmetry (HR 1.32, 95% CI 1.03-1.68) were related to incident multimorbidity in women only. There was a significant interaction between dominant HGS asymmetry and sex (P-interaction = .02). Conclusions and Implications Examining HGS asymmetry in HGS test protocols can provide novel insights for the predictive power of HGS in the accumulation of diseases, particularly in women.