COLORADO SPRINGS — Former nondrinkers who initiated moderate alcohol consumption in middle age experienced a 38% reduction in cardiovascular events over 4 years, compared with continued nondrinkers, in the Atherosclerosis Risk in Communities study.
“The current American Heart Association guidelines state that moderate alcohol consumption at this level can be part of a healthy lifestyle, but caution that if you don't already drink, don't start. This research challenges that policy. A 38% lower chance of having an acute MI or stroke is extremely significant. That's a bigger effect than you'd expect with initiation of statin therapy,” said Dr. Dana E. King, professor of family medicine at the Medical University of South Carolina, Charleston.
Results were presented at a conference on cardiovascular disease epidemiology and prevention sponsored by the American Heart Association.
Atherosclerosis Risk in Communities (ARIC) is an ongoing National Heart, Lung, and Blood Institute-sponsored prospective epidemiologic study of 15,792 middle-aged black and white men and women free of known cardiovascular disease and diabetes in four communities across the United States. During the first 6 years, 7,697 enrollees who were nondrinkers at baseline began moderate consumption of alcohol, defined in accord with the AHA and American Diabetes Association as not more than two drinks per day for men and one for women. An additional 0.4% of former nondrinkers began heavier drinking, Dr. King said.
During the next 4 years of follow-up, the combined rate of fatal and nonfatal cardiovascular events was 6.9% among new moderate drinkers and 10.7% in the continued teetotalers. After adjustment for age, race, sex, diabetes, hypertension, hyperlipidemia, and physical activity, adoption of moderate alcohol intake remained an independent protective factor against cardiovascular events, with an associated 38% relative risk reduction.
All-cause mortality didn't differ significantly between the two groups, perhaps because of the limited number of fatalities, but there was a trend in favor of the new moderate drinkers, who showed a 29% relative risk reduction.
The new heavy drinkers displayed a nonsignificant trend for more cardiovascular events than did continued nondrinkers over the 4-year period.
The reasons why former nondrinkers in ARIC began consuming alcohol in middle age weren't assessed as part of the study. “We would presume that it was for the health benefits, but we don't know,” Dr. King said in an interview.
He added that he wouldn't anticipate a formal change in AHA policy on the basis of a single study.
Yet these ARIC findings “certainly tilt the scale” in favor of physician counseling on a case-by-case basis that patients consider making alcohol part of a heart-healthy diet, provided they don't use certain medications or have a strong family or personal history of problem drinking, liver disease, or selected other health problems.
“It's a small minority of the population that gets in trouble with drinking, and perhaps we should not restrict the benefit of this healthy lifestyle choice in people who don't have a problem with alcohol,” he said.
Follow-up in ARIC will continue. That's important because some possible adverse consequences of new drinking—for example, a potential increase in certain types of cancer—might take longer than 4 years to become apparent.
The ARIC alcohol adoption findings were published simultaneously with Dr. King's presentation at the annual conference (Am. J. Med. 2008;121:201–6).
'A 38% lower chance of having an acute MI or stroke is extremely significant.' DR. KING
New moderate drinkers showed a 29% relative risk reduction in mortality. ©James Cox/Fotolia.com