Association between intake of sodium, potassium, sodium-to-potassium ratio, and blood pressure among US adults.

High dietary sodium and low potassium intake is associated with high blood pressure (BP). The current study aimed to determine if the sodium-to-potassium ratio is more strongly associated with low (130-139/80-89 mm Hg) and high (≥140/90 mm Hg) BP thresholds among US adults than either sodium or potassium alone. A total of 30,776 patients aged ≥20 years with complete blood pressure participated in the National Health and Nutrition Examination Survey (NHANES) from 2003 to 2018. Demographic information and health characteristics were compared between men and women using the chi-square test for categorical variables and independent samples t-test for continuous variables. Logistic regression was performed to investigate the association of the odds ratios (OR) of different levels of sodium, potassium, and sodium-to-potassium ratio. After multivariable adjustment (age, gender, Body mass index, Smoking, education, Race, Alcohol, total energy intake, and physical activity), no relationship has been observed between high versus low sodium-to-potassium ratio and BP threshold of 130-139/80-89 mm Hg (odds ratio [OR]: 1.02, 95% confidence interval [CI]: 0.92-1.12). Higher sodium-to-potassium ratio (OR=1.24; CI: 1.11-1.38) and dietary intake of potassium (OR=0.66; CI: 0.55-0.80) showed significant association in reducing the BP threshold of ≥140/90 mm Hg. In dose-response analysis, higher BP ≥140/90 mm Hg was inversely associated with higher potassium intake. Furthermore, the sodium-to-potassium ratio showed higher odds in predicting the BP of patients aged ≤60 years, underweight, nonsmokers, and non-alcohol users. The study confirms an inverse association between higher potassium intake and higher BP threshold. The Doses-response analyses showed sodium-to-potassium ratio is a better predictor of BP thresholds than sodium or potassium alone.