Moderate alcohol consumption increases the risk of atrial fibrillation in older people with heart disease or advanced diabetes, says a study by McMaster researchers.
"Moderate alcohol intake, with or without episodic binge drinking, is associated with an increased incidence of atrial fibrillation in older and high risk cardiovascular disease or diabetes patients," said Dr. Koon Teo, an author of the study and a professor of medicine at the Michael G. DeGroote School of Medicine at McMaster University. "Among moderate drinkers, the effect of binge drinking on atrial fibrillation risk is similar to that of habitual heavy drinking."
The study was published October 1 by the Canadian Medical Association Journal (CMAJ). Atrial fibrillation, or an irregular heartbeat, is a concern because it increases the risk of stroke.
The findings come from a large study involving more than 30,000 individuals 55 years or older from 40 countries who had a history of cardiovascular disease or advanced diabetes with organ damage. Data came from the clinical trials which followed participants for four and half years.
Moderate alcohol consumption was measured as one to 14 drinks a week for women and one to 21 drinks a week for men. Binge drinking was classified as five or more drinks a day.
The incidence rate of atrial fibrillation rose to 6.3% of the low intake group, 7.8% in the moderate and 8.3% in the high intake groups. The increase in atrial fibrillation cases linked to higher alcohol consumption was found in each age group.
The report said that since moderate drinking is common for more than a third of the population, these findings suggest the effect of increased alcohol consumption, even in moderate amounts, on atrial fibrillation risk in patients with pre-existing cardiovascular disease may be considerable.
Limited data from other studies indicates that binge drinking in healthy people may increase the risk of atrial fibrillation, although moderate drinking in healthy individuals does not appear to be linked to increased risk.
"Recommendations made about the protective effects of moderate alcohol intake in patients at high risk of cardiovascular disease may need to be tempered with these findings," the report said.