Abstract 008: Casual and 24-hour Urinary Sodium-to-potassium Ratio and Intakes of Sodium and Potassium Among Men and Women From Multi-ethnic General Populations: The Intersalt Study

Abstract

Background: Urinary sodium-to-potassium ratio may be more strongly related to blood pressure and cardiovascular disease than either urinary sodium or potassium alone. The casual urine sodium-to-potassium ratio is readily obtained, can provide prompt on-site feedback, and with repeated measurements may provide useful individual estimates of 24-hour urinary sodium-to-potassium ratio. The World Health Organization (WHO) has recently published guidelines for sodium and potassium intakes, but no generally accepted guideline prevails for favorable sodium-to-potassium ratio. Objective: Our primary aim was to compare the level of urinary Na/K ratio with the current recommended levels of Na and K intakes suggested in WHO guidelines. Methods: INTERSALT is an international study on associations of multiple urinary variables, with blood pressure (BP), based on standardized data on 24-hour and casual urinary electrolyte excretion in 10,065 individuals from 52 population samples in 32 countries. The associations between casual urinary sodium-to-potassium ratio and 24-hour urinary sodium and potassium excretion of individuals were assessed by correlation and stratification analysis. Results: Mean 24-hour sodium and potassium excretions were 156.0 mmol/24h and 55.2 mmol/24h; mean 24-hour urinary sodium-to-potassium ratio was 3.24. Pearson-r correlation coefficients of casual urinary sodium-to-potassium ratio with 24-hour sodium and potassium excretions were 0.42 and -0.34, respectively, and these were 0.57 and -0.48 for 24-hour urinary sodium-to-potassium ratio. The proportion of participants with estimated sodium chloride intake below the WHO recommended guideline of 85 mmol/day was 61.1% for those with casual urinary sodium-to-potassium ratio less than 1, and 96.3% where the 24-hour ratio was less than 1. For potassium, the proportion of people with potassium intake more than the WHO recommended guideline of 90 mmol/day was 21.3% where the casual urinary sodium-to-potassium ratio was less than 1 and 28.6% for the 24-hour urinary sodium-to-potassium ratio. Conclusions: Casual urinary sodium-to-potassium ratio less than 1 may be a useful indicator of adherence to the World Health Organization recommended levels of sodium intake, and to a lesser extent potassium intake in diverse different populations.