Spanish men who drink alcohol have a reduced incidence of coronary heart disease (CHD), according to results in the Spanish cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC) trial, published in the November 19 Online First issue of Heart.
"Spain is the world's third largest wine producer and ninth largest beer producer. In 2003, Spain was also in sixth position in the world ranking of alcohol consumption," write Larraitz Arriola, MD, from the Public Health Department of Gipuzkoa, Basque Government, San Sebastian, Spain, and colleagues.
Spain also has one of the lowest CHD mortality rates in the world, along with China, Switzerland, and France.
Although the association between alcohol consumption and CHD has been widely studied, with most studies showing a reduced risk for CHD with moderate alcohol intake, "there are numerous discussions regarding whether this association is causal or biased," the study authors write.
Inverse Association Between Alcohol Intake and CHD
The aim of this study was to describe the association between alcohol intake and CHD risk in the EPIC cohort.
The investigators assessed the alcohol intake of 15,630 men and 25,808 women for a median of 10 years from their responses to a validated dietary history questionnaire.
Participants reported how many glasses of beer, cider, wine, sweet liquor, distilled spirits, or fortified wines they consumed per day or week during the 12 months before they were recruited into EPIC. Total alcohol intake was calculated by multiplying the average ethanol content of a standard glass of whatever type of alcohol was consumed. In Spain, a "standard drink or glass" is estimated to contain approximately 10 g of alcohol.
Participants also provided information on lifestyle, including exercise and tobacco use, and other potential risk factors for heart disease, such as obesity and high cholesterol levels. All were free of CHD at baseline.
During the 10 years of follow-up, there were 609 coronary events (481 in men and 128 in women), for an incidence rate of 300.56/100,000 person-years for men and 47.93/100,000 person-years for women.
The investigators found an inverse association between alcohol consumption and CHD.
In a multivariate analysis that adjusted for smoking status, height, educational level, age, physical activity, waist-to-hip ratio, vitamin E, antithrombotic and antihemorrhagic drugs, and energy intake, the researchers found that in men, moderate, high, and very high alcohol consumption was associated with a reduced risk for CHD.
The adjusted hazard ratio (HR) was 0.90 (95% confidence interval [CI], 0.56 - 1.44) for former drinkers, 0.65 (95% CI, 0.41 - 1.04) for low consumers, 0.49 (95% CI, 0.32 - 0.75) for moderate consumers, 0.46 (95% CI, 0.30 - 0.71) for high consumers, and 0.50 (95% CI, 0.29 - 0.85) for very high consumers.
"The HR decreases in the first two categories and then remains stable for the moderate, high and very high categories," the study authors point out.
Women also benefited from alcohol intake, but the effects were not statistically significant, perhaps because of the small number of coronary events they experienced, the study authors write.
A limitation of the study could be residual or unmeasured confounding, they suggest. "Although we adjusted for several potential confounders in our different models, we could never be sure about the remaining confounders," they write. In addition, some of the participants may have changed their alcohol consumption when they became aware of their heart disease symptoms.
The study authors conclude: "Alcohol intake in men aged 29-69 years was associated with a more than 30% lower CHD incidence. This study is based on a large prospective cohort study and is free of the abstainer error."
Not an Interventional Study
William S. Harris, PhD, director of cardiovascular health research at the University of South Dakota, Sioux Falls, disagrees with this conclusion.
The assertion that alcohol lowers heart disease risk by almost a third, at least in men, misstates the findings, he told Medscape Cardiology.
"This is an epidemiological study, not an interventional study. Just because people who report drinking more have less heart disease does not mean that drinking lowers risk for heart disease. This is an extremely common logical fallacy," he said.
The study supports the idea that alcohol may have some cardioprotective effects. However, "until you take a group of people and randomly assign them to drinking alcohol or not, which is never going to happen, and then follow them for...[a certain amount of] years to see who has heart attacks, you can never say that 'alcohol lowers heart disease risk,' all you can say is that people who report drinking...[times] alcoholic beverages per day have less heart disease than people who drink...[a certain amount of] drinks per day. This is the kind of study that generates hypotheses, not conclusions."
In response to the comments by Dr. Harris, Dr. Arriola told Medscape Cardiology that, of course, she agrees her study is an epidemiologic study.
Dr. Arriola also told Medscape Cardiology: "As Dr. Harris says, there is no possible interventional study to investigate the association between alcohol consumption and CHD. So cohort studies are probably the best and the only ethical approach to study the relationship."
She added: "Of course, cohort studies have their limitations. But what we found in our study was that those men who drank alcohol had less CHD than those who did not drink. And that is what we tried to explain in the paper."
Dr. Arriola and Dr. Harris have disclosed no relevant financial relationships.
Heart. Published online November 19, 2009. Abstract.
November 20, 2009