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NEW YORK (Reuters Health) - One or two alcoholic drinks a day can help healthy people-and heart patients-live longer, new research confirms.
But the two new studies-one of nearly 250,000 US adults, the other an analysis of eight previous studies of more than 16,000 people with heart disease and other problems related to clogged arteries-also show that drinkers who exceeded recommended limits for alcohol consumption saw no heart health benefits.
"No question, heavy or binge drinking can have adverse health outcomes," Dr. Simona Costanzo and colleagues from Catholic University in Campobasso, Italy, warn in their report.
However, they add, doctors should tell their patients with heart disease and other clogged artery-related problems, together known as cardiovascular disease, that moderate alcohol consumption-a drink a day for women, two for men-"should not be harmful to their health."
There is considerable evidence that moderate drinking helps reduce the risk of heart disease and death from heart-related causes, likely due to the fact that drinking alcohol is linked to higher levels of "good" cholesterol.
However, questions have been raised about how research on alcohol and health is done, Dr. Kenneth J. Mukamal of Beth Israel Deaconess Medical Center in Boston and his team, the authors of the other study, write.
To address these issues, Mukamal and his colleagues looked at nine years' worth of data from the National Health Interview Survey from 1987 to 2000, including 245,207 people in all. Census bureau employees perform the survey in person every year, sampling a representative group of around 20,000 to 40,000 US citizens.
The researchers correlated the information on alcohol consumption with data from the National Death Index up until 2002, identifying 10,670 deaths from cardiovascular causes among survey participants.
The risk of dying due to heart disease or stroke was about the same for people who had never drank, meaning they had less than 12 drinks in their lifetime; people who drank infrequently, meaning they had more than 12 drinks in their life, but never drank more than 12 drinks in a given year; and ex-drinkers, who had more than 12 drinks in their lives and had consumed more than 12 drinks per year in the past, the researchers found.
But for light drinkers, defined as men or women who had three drinks a week or less, risk was 31 percent lower than for non-drinkers.
Among moderate drinkers (women who had three to seven drinks each week and men who had three to 14 drinks a week), risk was 38 percent lower than it was for abstainers.
Heavy drinkers, meaning women who had more than seven drinks a week and men who downed more than 14 drinks weekly, had the same cardiovascular death risk as non-drinkers.
Mukamal and his team also found that people who had two drinks on days when they consumed alcohol were "consistently" at lower risk than people who had three or more drinks per drinking day.
The study's strengths include its size, the fact that it included a broad sample of the US population, and its ability to separate people who had never drank or only rarely drank from those who had drank previously but quit, Mukamal noted in an E-mail interview.
"Our results suggest that even in this well-designed study, the lower risk linked to moderate drinking remains," he told Reuters Health. "However, it also clearly confirms that the benefit is lost for excessive drinking."
People with cardiovascular disease get mixed messages on whether moderate drinking is OK. The US Food and Drug Administration advises people with heart disease who drink alcohol to quit, but guidelines from the American Heart Association say they can drink in moderation, Costanzo and her colleagues point out in their report.
To better understand the risks and potential benefits of alcohol for cardiovascular patients, the researchers identified eight studies including 16,351 patients with cardiovascular disease. They analyzed the relationship between alcohol consumption and death due to cardiovascular disease among study participants, as well as the association between drinking and overall mortality.
The Italian team found a similar benefit pattern to the one Mukamal and his colleagues identified: heart patients who drank were less likely to die than abstainers, and the maximum benefit was seen for those who consumed between 5 to 10 grams of alcohol a day. A standard drink-12 ounces of beer or 5 ounces of wine, for example-contains about 14 grams of alcohol, according to the Centers for Disease Control and Prevention.
But people who drank more than about 25 grams of alcohol daily had overall mortality and cardiovascular death risks exceeding those of abstainers, and the more they drank, the higher the risk.
"Cardiovascular patients should be informed that low-to-moderate alcohol consumption (1 drink/day for women or up to 2 drinks/day for men) should not be harmful to their health," Costanzo and her team say. However, patients who don't drink regularly shouldn't be encouraged to start, they add, and those who drink heavily should be encouraged to quit or at least sharply reduce their alcohol intake.
"The risks of moderate drinking differ by sex, age, personal history, and family history," Dr. Arthur L. Klatsky of Kaiser Permanente Medical Center in Oakland, California, notes in an editorial accompanying the studies. While the case for alcohol's heart benefits is "compelling," he adds, "as is often the case in medical practice, advice about lifestyle must be based on something less than certainty."
He concludes: "What is required is a synthesis of common sense and the best available facts."
SOURCE: Journal of the American College of Cardiology, March 30, 2010.