Association of Salt Intake with Muscle Strength and Physical Performance in Middle-Aged to Older Chinese: The Guangzhou Biobank Cohort Study

Older people have higher amounts of sodium accumulation in skeletal muscles than younger people, indicating the possible role of salt intake on muscular and physical function. This large population-based cross-sectional study examined the association of salt intake with muscle strength and physical performance in 4867 participants with an average age of 60.4 (standard deviation = 7.7) years. Information on salt intake was collected from self-reports. Absolute and relative grip strength (AGS and RGS), timed up-and-go test (TUGT), and falls were considered the indicators of muscle strength and physical performance. Linear and logistic regression were used to examine the associations of salt intake with AGS, RGS, TUGT score, and falls, adjusting for demographic and lifestyle factors, body mass index, self-rated health, and self-reported hypertension. Higher salt intake was independently associated with lower grip strength and a higher TUGT score. Versus light salt intake, the adjusted beta (95% confidence interval (CI)) of AGS(max), RGS(max), and TUGT scores in those with salty taste were -0.53 (-0.97, -0.08) kg, -0.04 (-0.06, -0.02) kg per kg/m(2), and 0.08 (0.02, 0.14) s, respectively. A non-significant association was found between salt intake and falls. In sex-stratification analysis, the association remained in women but became non-significant in men. Our results suggest that avoiding high-salt diets may play a role in preserving muscle strength and physical function in the elderly, especially in women.