Association Between Sodium Density and Grip Strength Among Older Korean Adults: A Nationwide Cross-Sectional Study

Purpose: Handgrip strength is a key diagnostic criterion for sarcopenia, and sodium is an essential mineral for muscle contraction. We investigated the association between grip strength and sodium intake using sodium density. Patients and methods: A total of 2982 older adults (aged >= 65 years) from the 2014-2016 Korea National Health and Nutrition Examination Survey were included. Dietary intake was assessed by a 24 hr dietary recall, and grip strength was measured using a digital grip strength dynamometer. Based on the recommendation of the Asian Working Group for Sarcopenia, low grip strength (dynapenia) was defined as <26 kg for men and <18 kg for women. Multivariable logistic regression was performed to estimate the adjusted odds ratio (OR) and 95% confidence interval (CI) and to investigate the association between the quartiles of sodium per calorie (mg/1000 kcal; sodium density) and dynapenia. Results: A total of 577 subjects (19.3%) had dynapenia. Subjects in the second quartile of sodium density had the lowest prevalence of dynapenia and were defined as the reference group. Among women, those in the highest quartile of sodium density showed a significantly higher risk for dynapenia (OR 1.51, 95% CI 1.10-2.07). ORs in the first and third quartiles of sodium density were 1.01 (95% CI 0.74-1.38) and 1.18 (95% CI 0.89-1.58), respectively. However, there was no association between sodium density and dynapenia in men. Conclusion: High sodium density was associated with dynapenia in older women. A balanced diet of minerals is important to preserve muscle strength among older adults.