Even as studies have consistently found an association between moderate alcohol consumption and reduced heart attack risk in men, an important question has persisted: What if the men who drank in moderation were the same individuals who maintained good eating habits, didn't smoke, exercised and watched their weight - How would you know that their reduced risk of myocardial infarction wasn't the result of one or more of these other healthy habits?
A new study led by researchers at Beth Israel Deaconess Medical Center (BIDMC) and the Harvard School of Public Health (HSPH) helps answer this question. Reported in the October 23, 2006 issue of the Archives of Internal Medicine, the findings show for the first time that among men with healthy lifestyles, those who consumed moderate amounts of alcohol - defined as between one-half and two drinks daily - had a 40 to 60 percent reduced risk of heart attack compared with healthy men who didn't drink at all.
"This latest research speaks to how robust the link is between moderate drinking and heart attack risk," explains lead author Kenneth Mukamal, MD, MPH, an internist at Beth Israel Deaconess Medical Center (BIDMC) and Associate Professor of Medicine at Harvard Medical School. "The fact that we found the association [between alcohol consumption and heart attack] to be just as strong in this tightly controlled group of men as we've found it to be in more general studies suggests that physicians should not avoid alcohol consumption as a topic for discussion when talking with patients about ways to reduce their risk of myocardial infarction."
Using data from the Health Professionals Follow-up Study (a large HSPH-based cohort of more than 50,000 male health professionals between the ages of 40 and 75 who have been answering health-based questionnaires at regular intervals over the past 20 years), Mukamal and HSPH researchers Eric Rimm, ScD, and Stephanie Chiuve, ScD, identified 8,867 men. Members of this group reported four healthy lifestyle behaviors: body mass index (BMI) of less than 25; moderate to vigorous physical activity for at least 30 minutes per day; abstention from smoking; and a diet consistently high in intake of fruits, vegetables, cereal fiber, fish, chicken, nuts, soy and polyunsaturated fat, and low in trans fats, processed meats and red meats, along with regular use of a multi-vitamin supplement.
Over a follow-up period of 16 years, the authors assessed the participants' daily alcohol intake (beer, white wine, red wine, or spirits) using a standardized and validated questionnaire.
Between 1986 and 2002, 106 men had heart attacks. This included eight of the 1,282 who drank between 15 and 29.9 grams of alcohol per day (the equivalent of two drinks), nine of the 714 who drank 30 grams or more per day (more than two drinks), 34 of the 2,252 who drank .1 to 4.9 grams per day and 28 of the 1,889 who did not drink at all.
Their final analysis showed that among the subjects who were able to maintain all four healthy behaviors for at least a portion of the follow-up time (the authors updated data over the course of the study to account for changes in lifestyle habits, such as weight gain), those who consumed alcohol in moderation had a 40 to 60 percent lower risk of heart attack than either the non-drinkers or the very light drinkers (less than 5 grams of alcohol per day).
"Based on these numbers, we estimate that approximately 25 percent of the heart attacks that occurred among these healthy individuals might be attributed to abstention [or extremely light drinking]," explains Mukamal.
Because there are other safe ways to lower heart attack risk, such as exercising, staying trim, and eating properly, moderate alcohol consumption is not typically discussed with patients as another healthy lifestyle option, the authors note.
"There's no question that all of these other behaviors are important, and can help prevent other chronic diseases besides heart disease," says Mukamal. "But there's no reason to consider the recommendations as mutually exclusive." These latest results, he says, suggest that moderate drinking could be viewed as a complement to these other lifestyle interventions in reducing a man's risk of heart attack.
"The medical community has often dismissed moderate drinking out of hand without really considering the evidence on its merits alone," he adds. "One of the goals [of this research] was to focus conversation on the actual risks and benefits of moderate drinking itself. We hope this is one step in initiating that discussion."