Age-related increase and sex difference in the prevalence of handgrip strength asymmetry among Chinese middle-aged and older adults

In addition to weakness, asymmetry is increasingly recognized as an abnormal condition of handgrip strength (HGS), one which is associated with various adverse health outcomes in older adults. However, the influence of age and sex on the prevalence of HGS asymmetry remains unclear. The study population included adults aged 45 to 85 years from two waves of the China Health and Retirement Longitudinal Study (CHARLS), categorized by 5-year age groups. HGS ratio was calculated by dividing the maximal HGS (stronger HGS) by the highest HGS value obtained from the opposite hand (weaker HGS). HGS asymmetry was defined as an HGS ratio > 1.1, 1.2 or 1.3. Univariate and multivariate analyses were used to explore the associations of age and sex with HGS asymmetry. The prevalence of HGS asymmetry among Chinese middle-aged and older people, defined by an HGS ratio > 1.1, 1.2, and 1.3, was 42.7 %, 15.6 %, and 6.4 %, respectively. Regardless of the diagnostic threshold, the prevalence of HGS asymmetry increased with age (all, p value for trend <0.0001), starting primarily from 60 to 64 years. The risk of HGS asymmetry was significantly higher in women than in men, though this sex difference diminished after age 70. The age-related increase and sex difference in the risk of HGS asymmetry remained significant even after adjusting for multiple covariates. The prevalence of HGS asymmetry increases with age and is higher in women. HGS asymmetry may serve as an additional marker of muscle function decline and should be routinely evaluated in assessing sarcopenia and frailty, particularly among women and the oldest-old.