Summary: The authors state that although moderate alcohol intake is associated with lower risk for myocardial infarction (MI), guidelines generally suggest that adults seek other lifestyle measures to reduce cardiovascular risk. They studied whether alcohol consumption is inversely associated with risk for coronary heart disease in men who report consistently favorable lifestyle behaviors. From 51,529 male participants of the Health Professionals Follow-up Study who have reported diet and other lifestyle factors in biennial questionnaires since 1986, the authors defined a cohort of 8,867 men free of major illness to participate in a prospective study. All participants reported 4 healthy lifestyle behaviors, including a body mass index (calculated as weight in kilograms divided by height in meters squared) of less than 25, moderate to vigorous activity for 30 minutes or more per day, abstention from smoking, and a summary diet score in the top 50% for men. High dietary scores reflected a high intake of vegetables, fruits, cereal fiber, fish, chicken, nuts, soy, and polyunsaturated fat; low consumption of trans fat and red and processed meats; and multivitamin use. The authors ascertained the incidence of nonfatal MI and fatal coronary heart disease according to reported intake of beer, wine, and liquor every 4 years.
Results showed that during 16 years of follow up, the study documented 106 incident cases of MI. Compared with abstention, the hazard ratios for MI were 0.98 (95% confidence interval, 0.55-1.74) for alcohol intake of 0.1 to 4.9 g/d, 0.59 (95% confidence interval, 0.33-1.07) for alcohol intake of 5.0 to 14.9 g/d, 0.38 (95% confidence interval, 0.16-0.89) for alcohol intake of 15.0 to 29.9 g/d, and 0.86 (95% confidence interval, 0.36-2.05) for alcohol intake of 30.0 g/d or more. In men who met 3 criteria, the lower risk associated with alcohol intake of 5.0 to 29.9 g/d tended to be similar to the lower risk associated with the remaining healthy lifestyle behavior. The authors conclude that even in men already at low risk of cardiovascular disease on the basis of body mass index, physical activity, smoking, and diet, moderate alcohol intake is associated with lower risk for MI.
Comments: We earlier reported on an abstract at the AHA Epidemiology meetings last spring based on these analyses. Now, in the final paper, the authors have confirmed a rather striking reduction in the risk of MI for even very “healthy” men (i.e., lean non-smokers who exercised regularly and had a healthy diet). For men reporting an average of 15-29.9 g of alcohol per day (about 1 to 2 _ drinks), the risk of MI was 62% lower than for subjects with the same healthy lifestyles who did not consume any alcohol. These results tend to refute the hypothesis that lower coronary heart disease among moderate drinkers is due to their associated healthy lifestyle habits, and not due to their alcohol consumption.
Data from the article shows first that, regardless of alcohol intake, subjects with a greater number of healthy lifestyle factors have lower rates of MI than subjects with fewer healthy factors (e.g., much higher risk of MI for subjects with 0 or 1 of the factors than for those with more). However, going from consuming zero alcohol to 15-29.9 g of alcohol per day results in a marked decrease in the risk of MI for all groups. For example, among subjects with 4 healthy factors (lean, active, non-smokers on a healthy diet), the rates for MI appear to be about 270 for non-drinkers and just over 100 for consumers of 15-29.9 g/day. There were few subjects in some of the categories, but the overall pattern of alcohol effect was the same in all groups.
The investigators also evaluated men who met criteria for only three of the components of a healthy lifestyle and estimated the effect if they added another healthy factor. The estimated effect of stopping smoking was the single change in lifestyle that gave the greatest benefit on risk of MI. However, the estimated effect of alcohol was the same or greater than those associated with the other three lifestyle factors (consuming an optimal diet, becoming physically active, or achieving optimal weight). The investigators did not have sufficient numbers to evaluate changes in alcohol consumption over time, but other studies have shown that the risk of MI tends to increase when people stop drinking and to decrease when they begin to drink.
It is important to appreciate the marked differences in rates of MI by all of the “healthy lifestyle” factors. In the figure above, for example, going from 0-1 to 4 such factors reduced the risk of MI from almost 600 to below 300. Thus, all of the factors are important in lowering the risk of MI (and the risk of most other diseases). Still, regardless of other factors, moderate alcohol makes a large and significant contribution to a lowering of risk of MI.
Lay Summary: This paper from the Health Professionals Follow-up Study shows that there is a reduction in the risk of myocardial infarction (MI) with moderate drinking regardless of other healthy lifestyle factors. The study demonstrated that even among very “healthy” men (i.e., lean non-smokers who exercised regularly and had a healthy diet), those consuming about 1 to 2 _ drinks per day had 62% lower risk of MI than subjects with the same healthy lifestyle who did not consume any alcohol. These results tend to refute the oft-quoted hypothesis that lower coronary heart disease seen among moderate drinkers is due to their associated healthy lifestyle habits, and not to their alcohol consumption.
Article: Mukamal KJ, Chiuve SE, Rimm EB. Alcohol consumption and risk for coronary heart disease in men with healthy lifestyles. Arch Intern Med 2006;166:2145-2150.