Mechanism linking alcohol to reduced risk of cardiovascular disease may be related to inflammation

Older adults who consume one to seven alcoholic beverages a week may live longer and have a reduced risk for cardiac events than those who do not drink - an association that appears independent of the anti-inflammatory effects of alcohol, according to a report in the July 24 issue of Archives of Internal Medicine.

Alcohol may worsen some chronic diseases and the overall effect of drinking on survival is not clear, according to background information in the article. However, several studies have shown that alcohol may reduce the risk of coronary heart disease and heart failure and contribute to a lower death rate. Light to moderate alcohol intake has been shown to reduce levels of C-reactive protein and interleukin-6, compounds that circulate in the blood due to inflammation. Therefore, researchers have suspected that the mechanism linking alcohol to reduced risk of cardiovascular disease may be related to inflammation.

Cinzia Maraldi, M.D., of the Institute on Aging, University of Florida, Gainesville, and colleagues investigated the relationship between alcohol, death and cardiac events (such as hospitalization for heart attack, cardiac pain or heart failure) in 2,487 adults without heart disease age 70 to 79 years. Participants (average age 73.5 years, 55 percent women) were recruited between April 1997 and June 1998 and answered questions about disease diagnoses, medication use and drinking habits during an initial interview. They were classified based on how many drinks they consumed in a typical week over the past year; the categories were former; never or occasional (less than one drink per week); light to moderate (one to seven); and heavier (more than seven). During the study, each individual was contacted by telephone every six months and had a clinical assessment every year. Levels of C-reactive protein and interleukin-6 were tested in blood collected after an overnight fast at the beginning of the study.

Almost half of the participants were never or occasional drinkers. During an average 5.6 years of follow-up, 397 participants died and 383 experienced a cardiac event. Compared with never or occasional drinkers, those who drank lightly to moderately had a 26 percent lower risk of death overall and an almost 30 percent lower risk of cardiac events, even after controlling for inflammatory markers. In contrast, heavy drinkers were more likely to die or experience a cardiac event than never or occasional drinkers.

The findings indicate that the anti-inflammatory properties of alcohol alone do not explain the reduced risk of death or cardiovascular disease associated with light to moderate drinking, the authors write. Alcohol may have cellular or molecular effects that reduce the risk of cardiovascular disease, or it may interact with genetic factors to produce a protective effect.

The health effects of alcohol may not be the same for everyone, the authors caution. "The net benefit of light to moderate alcohol consumption may vary as a function of sex, race and background cardiovascular risk," they conclude. "From this point of view, recommendations on alcohol consumption should be based, as any medical advice, on a careful evaluation of an individual's risks and benefits, in the context of adequate treatment and control of established cardiovascular risk factors."