Effect of urinary sodium-To-potassium ratio change on blood pressure in participants of the longitudinal health of adults study-ELSA-Brasil

Abstract

To assess the effect of changing the sodium to potassium (Na/K) ratio on blood pressure at 4 years of follow-up.The measurements were carried out under identical conditions in two study periods (2008-2010 and 2012-2014). Urinary excretion of sodium and potassium (mmol/L) over 12 nocturnal hours was used to calculate the Na/K ratio and categorized by quintile. The 24-hour sodium and potassium intake was estimated using a validated equation. The mean BP was calculated from 3 measurements after 5 minutes of rest. Of the 15,105 participants at baseline, 14,014 completed the first follow-up. Participants without validated urine collection (n=5,041), using antihypertensive medication (n=3,860) at either time points or reporting bariatric surgery during follow-up (n=45) were excluded. The differences between follow-up and baseline values were calculated for BP and the Na/K ratio. Analyses were stratified by sex and adjusted for confounding variables.Sodium intake did not change from baseline, but potassium intake increased by approximately 150mg in both sexes (P