Alcohol consumption and incidence of proteinuria: a retrospective cohort study

Previous studies report conflicting results of a dose-dependent association between alcohol consumption and incidence of chronic kidney disease. Only a few studies have assessed the clinical impact of > 45-65 g/day of critically high alcohol consumption.

This retrospective cohort study included 88,647 males and 88,925 females with dipstick urinary protein ≤ ± and estimated glomerular filtration rate ≥ 60 mL/min/1.73 m² at their first annual health examinations between April 2008 and March 2010 in Japan. The exposure was the self-reported alcohol consumption. The outcome was proteinuria defined as dipstick urinary protein ≥ 1 + or ≥ 2 +.

During median 1.8 years (interquartile range 1.0-2.1) of the observational period, 5416 (6.1%) males and 3262 (3.7%) females developed proteinuria defined as dipstick urinary protein ≥ 1 +. In males, a U-shape association between alcohol consumption and proteinuria was observed in a multivariable-adjusted Poisson regression model [incidence rate ratio (95% confidence interval) of rare, occasional, and daily drinkers with ≤ 19, 20-39, 40-59, and ≥ 60 g/day: 1.00 (reference), 0.86 (0.79-0.94), 0.70 (0.64-0.78), 0.82 (0.75-0.90), 1.00 (0.90-1.11), and 1.00 (0.85-1.17), respectively], whereas a J-shape association was observed in females [1.00 (reference), 0.81 (0.75-0.87), 0.74 (0.64-0.85), 0.93 (0.78-1.11), 1.09 (0.83-1.44), and 1.45 (1.02-2.08), respectively]. Similar associations with dipstick urinary protein ≥ 2 + were shown in males and females.

Moderate alcohol consumption was associated with lower risk of proteinuria in both males and females. Females with ≥ 60 g/day of high alcohol consumption were at higher risk of proteinuria, whereas males were not. Females were more vulnerable to high alcohol consumption, than males.