(RxWiki News) Drinking in moderation isn't usually frowned upon, and may even have some health benefits. However, in older individuals with heart disease or advanced diabetes, it could increase the risk of developing atrial fibrillation, a common heart arrhythmia.
The World Health Organization defines moderate drinking as two daily alcoholic beverages for women and three a day for men.
"Reducing alcohol intake is beneficial."
Koon Teo, PhD, LRCP, a professor in the Department of Medicine for McMaster University in Canada, noted that both moderate and heavy drinking over the age of 55 had increased incidence of atrial fibrillation.
Dr. Teo said that moderate drinkers who binge drink also have an elevated risk similar to habitual heavy drinkers.
During the large study researchers followed more than 30,000 participants over the age of 55 with a history of heart disease or advanced diabetes that had resulted in organ damage. Patients, who hailed from 40 different countries, had participated in the ONTARGET or TRANSCEND trials, which began in late 2001 and followed patients for an average of 56 months.
About 70 percent of participants were men, and the average age was 66. Of the participants, 62 percent were considered low alcohol consumers, drinking up to one alcoholic beverage a week, while 37 percent were moderate drinkers.
Just over 1 percent were heavy drinkers. Most binge drinkers -- those who on occasion drank five or more drinks in a day regardless of their usual consumption -- fell into the moderate consumption group.
Investigators identified 2,093 new cases of atrial fibrillation during the follow-up period. After adjustments for age and gender, researchers found that the incidence of atrial fibrillation was 15 per 1,000 person years in the low-intake group, 17 in the moderate group and 21 among heavy drinkers.
"Because drinking moderate quantities of alcohol was common in our study, our findings suggest that the effect of increased alcohol consumption, even in moderate amounts, on the risk of atrial fibrillation among patients with existing cardiovascular disease may be considerable," Dr. Teo wrote in his study.
Previous research suggested that binge drinking could increase the risk of atrial fibrillation, but has not linked moderate drinking to increased risk.
Researchers said that the findings indicate recommendations about the protective effects of moderate alcohol consumption may need to be updated.
The research was recently published in the Canadian Medical Association Journal.