Low muscle strength and mortality: Key risk factors in the National Health and Nutrition Examination Survey retrospective cohort study

People progressively lose muscle strength with aging, a process that can be accelerated by malnutrition, comorbidities, and physical inactivity. Low muscle strength has been linked to increased mortality risk. This study aimed to investigate the association between low muscle strength and all-cause mortality and to identify key risk factors using handgrip strength as a measure in a large adult cohort. Participants aged ≥20 years with available handgrip strength data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014 cycles were included. Among 8608 participants, 3747 were alive and 384 (55.2%) deceased males, and 4178 were alive and 299 (44.8%) deceased females. Categorical variables were compared using the χ2 test, and continuous variables were analyzed using a complex samples general linear model. Univariate and multivariate Cox regression analyses estimated the relative risk of all-cause mortality, and the Kaplan-Meier method with log-rank test assessed survival differences. Multivariate Cox regression indicated that low muscle strength increased the risk of all-cause mortality (adjusted hazard ratio, 1.656; 95% confidence interval, 1.039-2.640; P = .035). Other significant factors included age ≥ 65 years, male sex, low income, underweight, physical inactivity, diabetes mellitus, cancer, and chronic kidney disease (CKD). While muscle strength limitations were comparable between males and females (P > .05), older adults and participants with CKD exhibited markedly lower strength. These findings highlight the importance of maintaining muscle strength, particularly among older adults and individuals with chronic diseases such as CKD, diabetes, and cancer, as a potential strategy to support healthy aging and longevity. Further research is warranted to examine whether interventions that enhance muscle strength can reduce mortality risk.