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(BETHESDA, MD) – Drinking up to two alcoholic beverages a day on average does not appear to damage the heart muscle of older adults, and these light-to-moderate drinkers tend to develop heart failure at a lower rate than older people who drink no alcohol, according to a new study in the July 18, 2006, issue of the Journal of the American College of Cardiology.
“Light and moderate drinking – which we defined as one to six, or seven to 13 drinks per week – were associated with a lower risk of developing heart failure over time, even accounting for the link between heart attacks and heart failure,” said Kenneth J. Mukamal, M.D., M.P.H., M.A., from Beth Israel Deaconess Medical Center in Boston, Mass. “This was similar in all different subgroups we studied and accounting for as many differences between drinkers and non-drinkers as we could.”
The researchers, including first author Chris L. Bryson, M.D., M.S., from the University of Washington and the VA Puget Sound Health Services Research and Development Service (HSR&D) in Seattle, analyzed data collected on 5,595 Medicare recipients who participated in the Cardiovascular Health Study. This study recruited generally healthy participants during the late 1980s and early 1990s and tracked their heart health for up to nine years. The average age of the participants was 72 at the time they enrolled.
Compared with abstainers*, the adjusted risk of heart failure was lower among subjects who reported consuming one to six drinks per week (hazard ratio [HR] 0.82, 95 percent confidence interval [CI] 0.67 to 1.00, p = 0.05) and seven to 13 drinks per week (HR 0.66, 95 percent CI 0.47 to 0.91, p = 0.01).
Heart attacks are a leading cause of heart failure. The Cardiovascular Health Study and other studies previously have reported that people who drink some alcohol tend to have fewer heart attacks, but adjusting the study results to take the heart attack rates into account made only a slight difference in the association between alcohol and reduced heart failure rates (for one to six drinks per week, HR 0.84, 95 percent CI 0.65 to 1.04; for seven to 13 drinks per week, HR 0.69, 95 percent CI 0.49 to 0.99).
Dr. Mukamal cautioned that people should not make decisions about drinking alcohol based on this study or on a desire to influence heart failure risk. He pointed out that this type of observational study cannot prove that alcohol actually protects against heart failure, nor does it explain the biological basis for any link between alcohol and the health of the heart.
“We can only speculate at this point about the mechanism. One possibility, which interventional studies have already shown, is that in people with known heart failure, alcohol can lower blood pressure in the pulmonary artery. This is a key part of developing heart failure. It is also possible that alcohol prevents more subtle forms of heart blockage, other than full-blown heart attacks, that themselves contribute to heart failure,” Dr. Mukamal said.
The Cardiovascular Health Study did not include enough participants who reported heavy drinking to allow the researchers to look for any potentially detrimental effects of drinking more than 13 alcoholic beverages per week. Dr. Mukamal noted the researchers did draw a distinction between abstainers and former drinkers or those who quit during the study. People who stop drinking may have an illness or alcohol-related issues that could affect their heart failure risk. He said the Cardiovascular Health Study collected extensive demographic and clinical information, which allowed the researchers to minimize the chances that some personal characteristic or lifestyle factor other than alcohol use affected their results.
* For these analyses, subjects were classified as “abstainers” if they did not report any alcohol use during the entire follow-up period, as “quitting during the study” if they reported alcohol use in a prior exam year but no use in the current year, and as “quitting before the study” if they were a former drinker at baseline.
An alcoholic beverage was defined as a 12-oz. beer, a 6-oz. glass of wine, or a shot (about 1-oz.) of liquor.
Sources quoted in this news release do not report any potential conflicts of interest regarding this topic.
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