Moderate Wine-Drinking Benefits Extend to Type 2 Diabetes

Miriam E. Tucker

March 18, 2014

Moderate wine drinking is associated with reduced risks for cardiovascular events and all-cause mortality among patients with type 2 diabetes, according to a new analysis of data from the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified-Release Controlled Evaluation (ADVANCE) trial.

The results were published online February 27 in Diabetes Care by Juuso I. Blomster, MD, from the George Institute for Global Health, Sydney, Australia, and the University of Turku, Finland, and colleagues.

As in previous studies in the general population, the ADVANCE study of more than 11,000 patients with type 2 diabetes showed a U-shaped relationship between overall alcohol intake and cardiovascular outcomes, whereby heavy drinking appeared to negate the benefits of moderate alcohol intake.

Study coauthor Graham S. Hillis, director of the cardiovascular division at the George Institute and senior staff cardiologist at Concord Hospital Sydney, told Medscape Medical News the findings suggest that "if you drink in moderation, then no reason to stop. If you drink heavily, cut down. If you don't drink, don't worry about it. The only good reason to drink alcohol is because you enjoy it!"

One of Largest Analyses of Drinking in Type 2 Diabetes

ADVANCE was a randomized, controlled trial that enrolled 11,140 patients with type 2 diabetes from 215 sites in 20 countries. They were at least 55 years old at enrollment, had been diagnosed with type 2 diabetes at age 30 years or older and had a history of or at least 1 risk factor for vascular disease.

Patients were grouped at baseline per self-report as nondrinkers, moderate drinkers (21 or fewer drinks per week for men and 14 drinks or fewer for women), or heavy drinkers (more than 21 and 14 for men and women, respectively). Alcohol consumption was examined again at 24 months and final study visits; a drink was defined as half a pint of beer, 125 mL of wine, or 25 mL of spirits.

The analysis "is one of the largest to explore the relationship between alcohol consumption and vascular outcomes and mortality in patients with type 2 diabetes," the authors note.

Over a median 5 years of follow-up, 10% (1147) of the participants had a major cardiovascular event (death from CVD, nonfatal stroke, or nonfatal myocardial infarction), 10% (1031) experienced a microvascular complication (new or worsening renal disease or diabetic eye disease), and 9% (1031) died.

At baseline, 30% of the patients reported drinking alcohol, and 4% said they drank heavily. Of those who drank alcohol, 39% primarily drank wine, while 61% imbibed mainly beer and spirits.

Compared with nondrinkers, those who drank any alcohol had a 17% lower risk for cardiovascular events (P = .008), a 15% lower risk for microvascular complications (P = .03), and a 13% lower risk for all-cause mortality (P = .05) in a model that adjusted for a variety of potential confounders, including age, sex, body mass index, smoking, exercise, medications, and CVD history.

Heart of the Matter: Benefits Driven by Wine Intake

There was no significant relationship between number of drinks consumed and any study outcome among the moderate drinkers, whereas among the heavy drinkers, each drink appeared to raise the risk for CVD events and all-cause mortality, although the number of heavy drinkers was relatively small.

The benefits in vascular terms among moderate drinkers were seen primarily among those who drank wine: wine drinkers had a 22% lower risk for cardiovascular events (P = 0.01) and a 23% reduced risk for all-cause mortality (P = .02) compared with nondrinkers, but there was no significant reduction in microvascular complications (P = .12). In contrast, drinking beer/spirits had no significant effect on any of the study outcomes.

The researchers documented a wide variation in alcohol consumption across geographical regions, from just 9.8% of participants from Asia to 23.7% in Eastern Europe to 50.9% in established market economies. However, the variation did not appear to have an effect on the relationship with CVD outcomes, the authors note.

Dr. Hillis told Medscape Medical News that the cardiovascular benefits of moderate alcohol intake are thought to be due to factors such as increased HDL cholesterol, reduced inflammation, and an increase in insulin sensitivity, which is particularly relevant to patients with or with a tendency for type 2 diabetes.

However, he said, "The effects of alcohol are quite complex and depend a lot on the amount drunk… [Drinking alcohol] may have other benefits in moderation — but in excess, these are outweighed by other things such as caloric intake, alcohol-related cardiomyopathy, increased risk for atrial fibrillation, and noncardiac issues such as hepatic damage and social consequences."

The ADVANCE trial didn't collect data on white vs red wine, and other studies have demonstrated that certain components of red wine in particular may improve endothelial function. However, wine drinkers in general have also been reported to be less overweight, to exercise more, and to be more likely to drink with meals, all factors that might explain the overall finding for wine, the authors point out.

Dr. Hillis also cautioned against overinterpreting the findings. "It's important to recognize that all we can explore is any association between alcohol intake and outcome, and we cannot, therefore, infer causation. Unfortunately, this is not an area where it is feasible to do a [randomized controlled trial], so at the end of the day we have to weigh the available evidence and draw clinical conclusions based on this."

"Nevertheless, the current study finds no grounds to discourage mild to moderate alcohol consumption, at least in terms of its vascular effects," he and his colleagues conclude.

The ADVANCE study was funded by grants from the National Health and Medical Research Council of Australia and from Servier. Dr. Hillis and Dr. Blomster have reported no relevant financial relationships; disclosures for the authors are listed in the article.

Diabetes Care. Published online February 27, 2014. Abstract


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