Jack, Jim and Jose may be doing more than hurting heads; they may be breaking hearts. According to a study published July 22 in the Journal of the American College of Cardiology, what people drink is as important as how much and how often they drink in developing atrial fibrillation (AF).

The data suggest that not only is binge drinking and regular heavy drinking bad for the heart, but moderate frequency drinking of stronger alcoholic beverages may be as well.

A research team from Stockholm led by Susanna C. Larsson, PhD, of the Karolinska Institutet, enrolled 79,019 Swedish participants from the Cohort of Swedish Men and the Swedish Mammography Cohort who in 1998 were between the ages of 45 and 83 years of age. They were followed until 2009, death or diagnosis of AF. In addition to noting traditional risk factors for AF, Larsson and colleagues asked participants to self-report the number of drinks consumed per day and per week, the amount consumed on a single occasion and the type of alcohol consumed.

Type of alcohol was defined as liquor, strong wine, wine and three classifications of beer based on alcohol content (less than 2.25 percent, 2.8 percent to 3.5 percent and more than 3.5 percent by volume).

Larsson et al discovered that overall binge drinking, which was defined as the consumption of five or more drinks on a single occasion, was associated with an increased risk ratio of 1.13. Notably, when looking at this behavior with the type of beverage consumed, wine and then liquor were associated with increased risks for AF. While wine consumption had a risk ratio of 1.24, beer drinking at a risk ratio of 1.02 was not considered to have an increased risk for AF.

Removing binge drinking from the equation, risks were comparable to those noted in other studies: Moderate-to-heavy drink frequency per week (15 to 12 drinks or more than 21 drinks) had an increased risk for AF (1.11 and 1.34, respectively) compared to those who drank less than one drink per week.

Responding to these findings, David Conen, MD, MPH, and Christine M. Albert, MD, MPH, of Brigham and Women’s Hospital in Boston, wrote that while “the question of how much is too much is not definitely answered by this study,” risks for AF should not discourage people from enjoying alcohol, particularly beer -- in moderation.