WEDNESDAY, May 19, 2010 (HealthDay News) -- A major French study links moderate drinking to a lower risk for cardiovascular disease, but challenges the notion that moderate drinking gets the credit.
Instead, the researchers say, people who drink moderately tend to have a higher social status, exercise more, suffer less depression and enjoy superior health overall compared to heavy drinkers and lifetime abstainers.
"A causal relationship between cardiovascular risk and moderate drinking is not at all established" by the study, which looked at the health status and drinking habits of 149,773 French adults, said Dr. Boris Hansel, an endocrinologist at the Hopital de la Pitie in Paris who specializes in cardiovascular prevention. He is the lead author of a report on the study in the European Journal of Clinical Nutrition.
Men and women who reported their alcohol intake as low or moderate did have a more favorable health status than those who said they never drank and those who reported high alcohol intake. Men who drank moderately were more likely to have a lower body-mass index, lower fasting triglycerides and blood glucose, lower blood pressure, and other factors associated with a lower risk of heart disease, while their female counterparts had smaller waists, lower blood pressure, lower fasting triglycerides, and lower "bad" LDL cholesterol levels.
And the study found a "strong and constant" link between moderate drinking in both sexes and high levels of HDL cholesterol, the "good" kind that helps keep arteries clear of fat.
But data on the overall lifestyle of people in the study indicate that "there is no link between the increased level of HDL cholesterol and reduced cardiovascular risk," Hansel noted.
"The relationship between moderate drinking and lower cardiovascular risk is due to confounding factors," he said. "That is because moderate drinking is in large part a matter of higher social status. Social status, a lower level of depression and a higher level of physical activity probably explains the relationship between alcohol and lower cardiovascular risk."
The study is the most recent in a long series that have found lower rates of heart disease, stroke and other cardiovascular problems in moderate drinkers, as compared to teetotalers and heavy drinkers. Hansel's analysis of the newly reported study, however, challenges the conventional interpretation that moderate drinking is good for the heart.
The American Heart Association's cautious recommendation is that "if you drink, do so in moderation." That means no more than two drinks a day for a man, one drink a day for a women, with a drink defined as 12 ounces of beer, 4 ounces of wine or 1 ounce of 100-proof spirits.
Two U.S. experts disagreed on the interpretations of the French study.
The study does not prove that alcohol itself provides no benefit, said Dr. Arthur Klatsky, a senior consultant in cardiology at the Kaiser Permanente Health program in Oakland, Calif.
"This is yet another study which shows that moderate drinkers have a better health profile," Klatsky said. "We don't have randomized controlled trials, so that always leaves open the possibility that cofounders might be responsible for the cardiovascular benefits."
The health benefits of high HDL cholesterol levels are clearly established, and explain about half the benefits seen in other studies, Klatsky said. Those studies have consistently shown a cardiovascular benefit for moderate drinking in a number of different population groups, he said.
"That is a fairly compelling case that I don't think is destroyed by this kind of evidence," Klatsky said.
Indeed, the French researchers only note that a causal link has not been proven. "Our results cannot eliminate the cardioprotective effects of alcohol," they wrote in their conclusion.
But Carla A. Green, a senior investigator at the Kaiser Permanente Center for Health Research in Portland, Ore., said, "There is increasing evidence that a lot of the health benefits that have been attributed to alcohol consumption are due to healthy habits that also include moderate alcohol consumption."
There might be some beneficial effect of alcohol itself, but "based on research to date, it has a much smaller effect than has been thought in the past," Green said.
She cited a recent study she led on alcohol consumption, health status and use of health services. "Heavy drinkers appear to avoid going to doctors," Green said. "The reasons include shame and not wanting to be lectured. So heavy drinkers are not going to get the health care they need and will get sicker."
But neither Green and Klatsky saw a need to change existing recommendations on moderate alcohol consumption. "I see no reason to change the general recommendations about what is sensible drinking," Klatsky said.
Advice on alcohol and health is available from the American Heart Association.