Abstract 12829: Sodium Excretion and Risk of Cardiovascular Disease: A 20-year Follow-up Study

Abstract

Introduction: Effects of sodium intake and cardiovascular (CV) events from prospective cohort studies have been conflicting. The present study aims to estimate the effect of sodium excretion on cardiovascular disease in Chinese population. Methods: Data from the PRC-USA Collaborative Study of Cardiovascular and Cardiopulmonary Epidemiology were used in the analyses, including 880 men and women ages 35-59 years at baseline from 4 urban and rural population samples in Beijing and Guangzhou of China. Three timed 8-hour overnight urine samples were collected for each participant; the average of 3 times urinary sodium measurements were used. The association of urinary sodium categorized by tertiles with CV events was tested by Cox proportional hazards multivariable models. Results: At baseline, the mean (SD) estimated 8-hour overnight excretion for sodium was 63.48 (33.66) mmol. After a median follow-up of 20.25 years, the total CV outcome occurred in 64 (7.3%) participants, including 15 coronary heart disease (CHD) events (acute myocardial infarction, sudden cardiac death, or CHD death) and 52 stroke. From lowest (<44.28 mmol/8h) to highest (>=72.28 mmol/8h) tertile of sodium excretion, the cumulative incidence was 4.1%, 6.8%, and 10.9% for total CV events and 3.4%, 5.4%, and 8.9% for stroke. Compared with the lowest sodium excretion group, the Hazard Ratios (HRs) and 95% CI after adjustment for age, gender, site, type of work, smoke, alcohol drinking and serum total cholesterol for total CV outcome were 1.764 (0.853-3.647) and 2.745 (1.390-5.419) in middle (44.28-72.28 mmol/8h) and the highest sodium excretion groups, respectively. Furthermore, the HRs and 95% CI for stroke were 1.756 (0.789-3.912) and 2.737 (1.296-5.777) in middle and the highest sodium excretion groups, respectively. However, the association of sodium excretion with total CV outcome and stroke was not significant both in middle and the highest groups when we additionally adjusted for baseline systolic blood pressure. Conclusions: Higher urinary sodium excretion is associated with increased risk of CV events and stroke, but this relationship is not independent of baseline blood pressure levels.