High Sodium Intake, as Assessed by Urinary Sodium Excretion, Is Associated with Nonalcoholic Fatty Liver Disease or Sarcopenia

BACKGROUND/AIMS: We explored whether high sodium intake, assessed by urinary excretion, determines the risk of sarcopenia and nonalcoholic fatty liver disease (NAFLD). METHODS: We analyzed 10,036 adult participants with normal kidney function from the Korea National Health and Nutrition Examination Survey (2008–2011). NAFLD was identified using the fatty liver index, and the muscle mass was evaluated using dual X-ray absorptiometry. The dietary sodium intake was estimated using Tanaka’s equation. RESULTS: The mean 24-hour urinary sodium excretion was 144.2±36.1 mmol/day (corresponding to 3.3 g/day Na) in the total population. The 24-hour urinary sodium excretion showed moderate accuracy in predicting NAFLD (area under the receiver operating characteristic, 0.702; 95% confidence interval [CI], 0.692 to 0.712). A cutoff value of 99.96 mmol/day (corresponding to 2.30 g/day Na) for urinary sodium excretion in predicting NAFLD showed 76.1% sensitivity and 56.1% specificity. The results of multiple adjusted models indicated that the participants with the highest urinary sodium excretion had a significantly higher risk of NAFLD (odds ratio, 1.46; 95% CI, 1.27 to 1.66; p<0.001) and sarcopenia (odds ratio, 1.49; 95% CI, 1.28 to 1.73; p<0.001) than those with the lowest urinary sodium excretion. The association between a higher 24-hour urinary sodium excretion and NAFLD was independent of sarcopenia. CONCLUSIONS: Participants with a high sodium intake, as assessed by sodium excretion, had a substantial risk of NAFLD and sarcopenia.