Light Alcohol Use May Protect Against Sudden Cardiac Death

"This is the largest prospective study to look at alcohol consumption and sudden cardiac death in men and the first prospective study to find a reduction in sudden cardiac death from light drinking," says Christine M. Albert, M.D., associate physician in the division of preventive medicine at Brigham and Women's Hospital and instructor of medicine at Harvard Medical School in Boston. Albert is also a cardiac electrophysiologist at Massachusetts General Hospital.

Researchers looked at 21,537 men involved in the Physicians Health Study, a long-term study of male physicians and risk factors for heart disease. All of them were free of cardiovascular disease and provided information on their consumption of alcoholic beverages. During 12 years of follow up, there were 141 cases of sudden cardiac death.

The risk of sudden cardiac death was reduced by 60 percent in men who drank two to four drinks per week, and 79 percent in men who consumed five to six drinks a week, less than one drink per day on average.

About half of all deaths from coronary heart disease are sudden and unexpected. Sudden cardiac death usually occurs when the heart begins beating too rapidly or chaotically to pump blood efficiently. It claims the lives of about 250,000 Americans each year. Although these findings are considered significant, Albert says they should alone not be used to generate guidelines on drinking and heart disease. Light drinkers in this study may have had other health behaviors that lessened their risk of sudden cardiac death. Researchers did not compare the effects of drinking patterns, such as consuming small amounts of alcohol daily versus drinking all of the alcohol in one sitting, which could have harmful effects. Scientists know that binge drinking -- consuming large quantities of alcohol in a brief period -- causes abnormal heart rhythms that can lead to sudden cardiac death.

"Based on the data, I wouldn't recommend that non-drinkers start drinking. One has to consider all the risks and benefits of drinking alcohol," Albert says. "You don't know how likely a person is to become addicted to alcohol, and there is also the risk of cancer to consider." Previous studies have found evidence that heavy alcohol consumption may increase an individual's risk of certain types of cancer.

"Consuming more two or more drinks per day has been associated with an increased breast cancer risk in women," Albert says, adding "this study was done only in men, so we can't be sure if our results would apply to women as well.

"Other studies have shown that the risk of sudden cardiac death increases with heavy alcohol consumption," she says. "Our study found the risk began to increase at more than two drinks per day."

"For now, it appears that drinking a small amount of alcohol doesn't increase a man's risk of sudden cardiac death and may actually decrease it. So if someone drinks in small amounts it's probably fine to continue," she says.

As for how alcohol might reduce the risk of sudden cardiac death in men, Albert says one explanation might be that it reduces the formation of blood clots in arteries, which can cut off the flow of oxygen-rich blood to the heart. Small amounts of alcohol also may reduce fatal disturbances in the heart's rhythm.

Co-authors include JoAnn E. Manson, M.D., Dr. P.H.; Nancy R. Cook, Sc.D.; Umed A. Ajani, M.B.B.S.; J. Michael Gaziano, M.D., M.P.H.; and Charles H. Hennekens, M.D.