Moderate to heavy alcohol consumption may increase the risk for albuminuria, according to Australian researchers.

Compared with individuals who consumed less than 10 grams of ethanol per day, those who drank 30 grams or more of ethanol per day (or approximately three standard alcoholic drinks) were at significantly increased risk of developing new-onset albuminuria over five years of follow-up, investigators reported in Nephrology Dialysis Transplantation (2009; published online ahead of print).

Sarah L. White, a PhD candidate at The George Institute, University of Sydney, together with colleagues from Royal Prince Alfred Hospital Sydney, the Baker IDI Heart and Diabetes Institute and Monash Medical Centre in Melbourne, Australia, studied 6,259 adults aged 25 years and older who did not have a history of alcohol dependence participating in the Australian Diabetes, Obesity and Lifestyle study (AusDiab), a prospective, population-based cohort study coordinated by the Baker IDI Heart and Diabetes Institute.

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The researchers determined alcohol consumption status and volume and frequency using standardized interviewer administered questionnaires and self-administered food frequency questionnaires.

Overall, risk of developing albuminuria over five years was increased 59% among individuals who consumed 30 grams or more of ethanol per day, compared with those who consumed less than 10 grams per day. As illness-related abstinence is more common with advancing age, the investigators also examined this relationship in people younger than 65 years.

In the younger population, consumption of 30 grams or more of ethanol per day was associated with a doubling in risk of new onset albuminuria over five years after adjusting for age, gender, blood pressure, diabetes, and other lifestyle-related risk factors.

“Alcohol consumption, particularly heavy drinking, is likely to be a significant modifiable risk factor for the development of albuminuria,” the authors concluded.

What remains unclear, they noted, is the biological mechanism by which alcohol induces kidney damage and the natural history of this process and its relationship with markers of kidney function in the general population.

In addition, the researchers found that consumption of 30 grams or more of ethanol per day versus less than 10 grams was associated with a 40% reduction in risk of CKD, defined as an estimated glomerular filtration rate (GFR) below 60 mL/min/1.73 m2. The finding is consistent with previous studies. They noted that the Physicians Health Study found that men who consumed at least seven drinks per week had a 30% decreased risk of developing CKD compared with those who consumed no more than one drink per week.

As to how moderate to heavy drinking could be associated with a reduced risk of developing CKD, authors suggest a possible explanation relates to the serum creatinine-based method of estimating GFR.

Several factors related to alcohol consumption but unrelated to renal function such as diet, inflammatory disease, muscle metabolism, total muscle mass, and decreased creatinine production resulting from liver damage may influence serum creatinine concentration and introduce inaccuracy into the estimation of GFR. Reported observations of a reduced risk of CKD associated with higher levels of alcohol consumption potentially therefore do not represent a true biological effect.