Habitual Alcohol Intake Modifies Relationship of Uric Acid to Incident Chronic Kidney Disease

Abstract

Background: Previous studies showed that higher serum uric acid levels increased the risk of chronic kidney disease (CKD), but moderate alcohol consumption decreased it. The comparative importance of serum uric acid levels and habitual alcohol consumption as risk factors for CKD remain undefined. We therefore evaluated the relationship of baseline serum uric acid level in combination with daily alcohol consumption to the incidence of CKD. Methods: A prospective cohort study of 9,116 middle-aged nondiabetic ­Japanese men without CKD nor proteinuria who were not taking antihypertensive medications nor urate-lowering medications at entry. CKD was defined as estimated glomerular filtration rate <60 mL/min/1.73 m2. We investigated the relationship of baseline serum uric acid level in combination with daily alcohol consumption to the incidence of CKD during an 11-year observation period. Daily alcohol consumption was classified into 4 groups: nondrinkers, light drinkers (0.1–23.0 g ethanol/day), moderate drinkers (23.1–46.0 g ethanol/day), and heavy drinkers (≥46.1 g ethanol/day). Cox proportional hazards models were used in multivariate analysis. Results: During the 79,361 person-years follow-up period, a total of 1,230 subjects developed CKD. In multivariate models, higher serum uric acid levels increased risk of CKD; and moderate daily alcohol consumption decreased the risk. Multiple-adjusted hazard ratios of CKD were 1.38 (95% CI 1.11–1.70), 1.58 (95% CI 1.28–1.95), 2.27 (95% CI 1.86–2.77), and 3.12 (95% CI 2.56–3.81) for quintile 2, quintile 3, quintile 4, and quintile 5 of serum uric acid levels, respectively, compared with quintile 1, and that for moderate drinkers was 0.55 (95% CI 0.46–0.66) compared with nondrinkers. In the joint analysis of alcohol consumption and serum uric acid, moderate drinkers with the lowest tertile of serum uric acid levels had the lowest risk of CKD, but nondrinkers with the highest tertile of serum uric acid levels had the highest risk of CKD. Conclusions: Serum uric acid level and daily alcohol consumption were independently associated with the risk of CKD. Nondrinkers with the highest serum uric acid level had the highest risk of CKD.