Association between dietary sodium intake and disease burden and mortality in Koreans between 1998 and 2016: The Korea National Health and Nutrition Examination Survey

BACKGROUND/OBJECTIVES: Sodium intake is positively associated with blood pressure, which may increase the risk for cardiovascular disease (CVD). Therefore, we assessed the disease burden of CVD attributable to sodium intakes above 2,000 mg/day and prospectively investigated the association between dietary/urinary sodium levels and the risk of all-cause and CVD-mortality using the Korea National Health and Nutrition Examination Survey (KNHNES). SUBJECTS/METHODS: A total of 68,578 and 33,113 participants were included for comparative risk assessment (CRA) analysis and mortality analysis, respectively, and mean follow-up time for mortality was 5.4 years. CRA analysis was used to quantify attributable incidences of stroke, ischemic heart disease (IHD), and deaths attributable to sodium intake between 1998 and 2016. Cox proportional hazard regression model was used to determine the association between sodium intake and all-cause and CVD-mortality. RESULTS: Mean dietary sodium intake decreased over time, reaching 3,647 mg/day in 2016. Similarly, the population attributable fractions of stroke and IHD, and the number of CVD-associated deaths attributable to high sodium intake/excretion also decreased. In terms of association with mortality, when participants were grouped into quartiles (Q) by energy-adjusted sodium intake, those in Q2 had a lower risk of all-cause mortality than those in Q1 with lower intakes. The risk of CVD-associated mortality was higher only in females with high sodium intake in Q4 than those in Q1. CONCLUSIONS: This nationwide data indicates that, in line with previous studies of multiple cohorts, both low and high sodium intakes may be associated with an increased risk of mortality; therefore, the optimal sodium intake for Koreans needs to be revised.