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

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 <0.90 or >1.10 had any HGS asymmetry. Further, those with HGS ratio <0.90 had dominant HGS asymmetry, whereas 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.