Age-period-cohort analysis of dietary sodium, potassium, and sodium-to-potassium ratio in Korea

Abstract

OBJECTIVES: Excessive sodium and insufficient potassium consumption are major dietary contributors to hypertension (HTN) and cardiovascular diseases. The sodium-to-potassium ratio is a known predictor of blood pressure (BP) and HTN. This study evaluated 16-year-trends in dietary sodium, potassium, and the sodium-to-potassium ratio, and their associations with BP and HTN in Korea.METHODS: Data from 76,484 participants aged 19-79 years were obtained from the Korea National Health and Nutrition Examination Survey conducted in 2007-2022. Sodium and potassium intake were assessed using 24-hour recalls, and the sodium- to-potassium ratio was calculated. All values were energy-adjusted using the residual method. Age-period-cohort (APC) models were used to analyze temporal trends. Associations with BP and HTN were examined using multivariate linear and logistic regression models, adjusting for confounders.RESULTS: Energy-adjusted sodium intake decreased across all age groups, and potassium slightly increased in the recent 5 years, though both remained suboptimal relative to recommendations. APC analyses showed increasing potassium intake with age and a reversed U-shape cohort pattern. The sodium-to-potassium ratio decreased with age and calendar year but increased in recent cohorts. A higher sodium-to-potassium ratio was strongly associated with elevated systolic (β=0.028, p<0.001) and diastolic BP (β=0.036, p<0.001), and increased odds of HTN (odds ratio, 1.19; 95% confidence interval, 1.07 to 1.33). A linear association appeared when the sodium-to-potassium ratio exceeded 1.00 in the spline model.CONCLUSIONS: Despite improvements, sodium intake remains excessive, and potassium insufficient, particularly in younger adults and recent cohorts. Public health interventions should prioritize reducing sodium and promoting potassium-rich foods to reduce cardiovascular risk.