Socioeconomic and Regional Disparities in Handgrip Strength: A Cross-sectional Analysis of Three Aging Cohorts

This cross-sectional study examined the associations of education and body mass index (BMI) with handgrip strength among older adults from the United States, China, and Europe, and quantified education-related inequalities across these populations. We used data from the National Health and Nutrition Examination Survey (NHANES, 2011-2014, n=5,267), the China Health and Retirement Longitudinal Study (CHARLS, 2015, n=16,631), and the Survey of Health, Ageing and Retirement in Europe (SHARE, Wave 6, 2015, n=21,997). Participants were community-dwelling adults aged 50-80 years. Handgrip strength was measured using handheld dynamometers, with maximum values used for analysis. Education was harmonized into three categories (Low, Middle, High). Multivariable linear regression, the Slope Index of Inequality (SII), and association decomposition were employed. European older adults exhibited the highest crude grip strength (mean 34.3 kg), followed by Chinese (31.0 kg) and American (28.8 kg) counterparts. Higher education was significantly associated with greater grip strength in all cohorts. Education-related inequality was greatest in China (SII=4.22, 95% CI: 3.91-4.52) and smallest in the United States (SII=1.67, 95% CI: 1.26-2.08). The educational effect was strongest among European males (3.48 kg) and weakest among Chinese females (0.79 kg). BMI exhibited a suppression pattern rather than mediation, with negative proportional contributions in NHANES (-7.4%) and SHARE (-4.8%). Sensitivity analyses confirmed the robustness of these findings. Considerable cross-national heterogeneity exists in education-related grip strength disparities, with the educational advantage most pronounced in Europe and least effective in China, particularly among women.