Abstract 13118: Urinary Sodium and Potassium Excretion are Associated With Blood Pressure among Adults in the United States

Abstract

Introduction: One in three US adults has hypertension, a major risk factor for cardiovascular disease. We aimed to assess the associations between 24-h urinary excretion of sodium, potassium, and sodium-potassium ratio with blood pressure and hypertension status among US adults. Hypothesis: We hypothesized that urine sodium excretion and urine sodium-potassium ratio would be positively and urine potassium excretion would be inversely associated with blood pressure and hypertension. Methods: Cross-sectional data on up to two 24-h complete urine collections were analyzed from 765 non-institutionalized participants aged 20-69 y in the 2014 US National Health and Nutrition Examination Survey (NHANES). Urine collection started and stopped in the NHANES mobile examination center. Approximately half of participants had two complete collections; usual sodium and potassium excretion, and sodium-potassium ratio, were estimated using measurement error models accounting for day-to-day variability. Analyses adjusted for age, sex, race/ethnicity, body mass index, history of cardiovascular disease, diabetes, chronic kidney disease, smoking status, and physical activity, as well as the complex survey design. Results: In fully adjusted linear regression models, sodium excretion was positively associated with systolic (4.43 mmHg per 1000 mg/day, 95% CI 2.31,6.56) and diastolic (1.93 mmHg, 95% CI 0.34,3.51) blood pressure. Sodium-potassium ratio was also positively associated with systolic blood pressure (2.86 mmHg per .5 unit increase, 95% CI 1.15,4.56), and potassium excretion was inversely associated with systolic blood pressure (-3.39 mmHg per 1000mg/day increase, 95% CI -6.05,0.72). Adjusted odds ratios for hypertension, for excretion in the highest compared to the lowest quartiles, were 4.34 (95% CI 1.37,13.79) for sodium and 0.39 (95% CI 0.17,0.88) for potassium. Results were robust in sensitivity analyses restricted to persons not taking antihypertensive medications. Conclusions: Using a nationally-representative sample of US adults and a “gold-standard” urine biomarker, these data further support the strong relationship of higher sodium and lower potassium excretion with higher blood pressure and hypertension risk.