Association Between Estimated 24-Hour Urinary Sodium and Potassium Excretion and Cardiovascular Risk and Events: Findings from the Isfahan Cohort Study.

Abstract

Background: Sodium and potassium intake are key determinants of cardiovascular (CV) health, largely through effects on blood pressure. Most studies have focused on serum levels or dietary estimates, with limited evidence linking urinary excretion to CV outcomes.

Objective: To examine associations between estimated 24-hour urinary sodium and potassium excretion and cardiovascular risk factors and events in Iranian adults.

Methods: In this historical cohort study, 1,953 participants from the Isfahan Cohort Study with random morning urine samples (2013) and two-year follow-up were included. Sodium and potassium excretion were estimated using the Tanaka formula. Cox proportional hazards models assessed associations between tertiles of excretion and incident CV events, adjusting for demographic, clinical, lifestyle, and medication variables.

Results: Higher sodium excretion was associated with male sex, higher BMI, blood pressure, plasma sodium and potassium, better dietary quality (lower global dietary index score), and greater physical activity. Higher potassium excretion was associated with younger age, male sex, higher BMI and triglycerides, higher plasma electrolytes, lower smoking prevalence, and higher diabetes prevalence. No significant associations were observed between sodium or potassium excretion and CV events in adjusted models. Hazard ratios for higher sodium tertiles were consistently > 1.0, suggesting a nonsignificant trend toward increased risk. Potassium excretion showed a nonlinear pattern, with the middle tertile having the highest hazard ratio.

Conclusions: Estimated urinary sodium and potassium excretion were linked to several cardiometabolic risk factors but not to short-term CV events. Longer follow-up and more accurate intake assessments are needed to clarify their role in CV risk prediction.