Population-based association between urinary excretion of sodium, potassium and its ratio with albuminuria in Chinese.

BACKGROUND AND OBJECTIVES Albuminuria is a risk factor for cardiovascular and renal disease. However, little is known about the association of 24 h urinary sodium and potassium excretion with albuminuria in China. The aim of this study was to examine this association by analyzing the data from 1,975 Chinese adults living in north China. METHODS AND STUDY DESIGN Excretion of urinary sodium, potassium and albumin was assessed in a single 24-h urine sample for each participant. Height, weight, waist circumference and blood pressure were measured and body mass index was determined as weight divided by square height. Fasting blood sample was collected and fasting glucose was measured. RESULTS The average 24-h urinary sodium and potassium excretion were 232 mmol and 40.8 mmol, resulting a mean sodium to potassium ratio of 6.7. The median (Q1-Q3) 24-h urinary albuminuria excretion was 6.1 mg (4.5-8.7 mg). Overall, urinary sodium excretion was positively associated with albumin excretion (β=0.029, p<0.001). This association was independent of major cardiovascular risk factors including age, gender, systolic blood pressure, body mass index, fasting glucose, waist circumference, hypertensive drug treatment, and smoking. Moreover, the relation of sodium and albumin was similar in the subgroups stratified by gender, adiposity and diabetic status. No significant associations of potassium excretion or sodium to potassium ratio with urinary albumin excretion were observed. CONCLUSIONS In cross-sectional analyses, high sodium intake was shown to be associated with increased urinary albuminuria in the general Chinese adult population, supporting salt restriction for renal and cardiovascular health benefit.