Moderate drinkers at no increased risk for AFib later in life

While heavy drinkers are at an established, increased risk for developing atrial fibrillation (AFib) due to their alcohol habits, light-to-moderate consumers are at virtually no increased likelihood of developing the condition, a study out of Nord-Trøndelag County in Norway has found.

The impact binge drinking has on an individual’s risk of AFib—not to mention dozens of other cardiovascular conditions—has been previously established, Imre Janszky, MD, PhD, and colleagues wrote in the study, which was published in the Journal of the American Heart Association this month. Clinicians know consuming more alcohol than the daily recommended limits (one drink for women and two drinks for men) can result in a higher long-term risk for AFib, but, prior to Janszky et al.’s study, they didn’t know how controlled drinking would affect those risks.

“Meta analyses and a recent study examining the long-term effect of the quantity of alcohol intake on AFib risk have suggested a dose-response relationship, with a slightly increased risk even among light-moderate drinkers,” the authors wrote. Janszky and colleagues designed a large-scale population study of 47,002 AFib-free Norwegian patients to take a closer look at that “slightly increased risk”—or lack thereof.

The researchers studied groups of locals who reported drinking responsibly between October 2006 and June 2008. Through questionnaires about alcohol habits, frequency of binge drinking and personal information, Janszky and co-authors were able to weed out what they labeled “problem drinkers”–those who engaged in risky alcohol-related behaviors.

The team found that, of the original cohort, 1,697 moderate drinkers developed AFib over the course of the study, which included eight years of follow-up. With an average daily alcohol intake of 3.8 grams, the adjusted hazard ratio for AFib was 1.38 when Janszky and colleagues compared patients who consumed more than seven drinks per week with those who didn’t drink at all.

The attributable risk for AFib, the authors wrote, was “negligible.” Non-risky drinkers saw less than a 1 percent increased risk for developing the condition.

AFib risk in drinkers consuming more than seven glasses of alcohol per week was comparable to risk in nondrinkers, rare drinkers and light drinkers, Janszky and co-authors found. Additional adjustments for weight, anxiety, depression and blood pressure didn’t change the results. Men who were younger were more likely to consume more than seven drinks a week.

If a patient was drinking more than 14 drinks per week, though—twice the recommended limit for optimum health—their risk for AFib increased suddenly and dramatically, according to the study, making the relationship between alcohol consumption and AFib risk a curvilinear one.

The study’s authors warned that excessive alcohol consumption continues to be incredibly risky for cardiovascular events, including cardiomyopathy, hypertension and stroke, even though light-to-moderate drinking has been previously associated with a reduced risk of ischemic heart disease and heart failure. In the case of AFib, the curved association between alcohol consumption and AFib suggests no drinking is better than anything for preventing arrhythmia.

“Overall, the quantity of alcohol consumption was associated with an increased risk of AFib, even among moderate drinkers,” Janszky et al. wrote. “However, alcohol consumption within recommended limits did not substantially increase the risk for AFib.”