COMMENTARY

Alcohol and AF: More Data, More Questions, and Some Philosophy

John Mandrola

Disclosures

July 14, 2014

Medical experts have long debated the matter of drinking alcohol and achieving health. Lately, detailed analyses of hordes of data, some old and some new, have split the field into believers and skeptics. Questions remain: Is alcohol beneficial? Detrimental? Or is drinking alcohol like most everything else in life: if taken in moderation, and, as part of a balanced healthy lifestyle, just fine?

This brief commentary will surely not be able to answer such lofty questions. Instead, an easier task is to consider new data on the relationship of alcohol intake and the risk of developing atrial fibrillation. Then, for fun, we can let the data lead us into the temptation . . . to think.

The Most Recent Alcohol and AF Study

A study released this week in the Journal of the American College of Cardiology adds to and strengthens the current observational data on alcohol intake and AF[1].

Researchers in Sweden took advantage of the fact that two large databases (n=79 019 total subjects) of health studies included self-reported alcohol intake. They then used medical-record linkage in the Swedish inpatient register to identify cases of symptomatic AF episodes (n=7245 cases) over a 12-year period. After the research team correlated alcohol intake with AF incidence, they then added their own meta-analysis. (It's important to note that the research team could identify only symptomatic AF cases, which underestimates the true incidence of AF.)

Three of the four major results of this study will not surprise any AF caregiver. The fourth, which stems from subgroup analysis, provokes an interesting possibility, especially for beer lovers.

  1. Compared with people who drank less than one drink per week, those who drank one to two drinks daily or greater than three drinks daily had a 14% and 39% greater relative risk of having AF. This relationship persisted after adjustment for binge drinking.

  2. Binge drinking, defined as drinking more than five drinks at one time, was especially proarrhythmic. Even after adjustment for total alcohol intake and other confounding illness, binge drinking increased the risk of AF by over 10%.

  3. There was a clear dose-response relationship. Using data from the meta-analysis, the researchers observed a linear relationship between alcohol intake and AF risk. They reported an 8% increase in AF risk per one-drink/day increment in alcohol. These findings are quite similar to previous observational trials.

  4. Perhaps the most surprising finding of the study was that the type of beverage might have mattered. Liquor conferred the greatest risk, followed by wine, but beer consumption had no association.

My Take and My Philosophy

I'm quite conflicted about the potential health aspects of alcohol. Of the many issues, four jump to mind when I think about alcohol and AF.

The first, and easiest, thing to say about alcohol and AF is that there is a relationship. This study, taken in aggregate with previous studies and applied to clinical experience, suggests a strong and linear association. And though association does not equal causation, there is biologic plausibility here.

Alcohol can have electrophysiologic effects. It can disrupt sleep, deliver calories, and promote obesity and high blood pressure. There is also compelling evidence to suggest alcohol is cardiomyopathic—a sure way to promote an AF substrate. The cardiomyopathy link is bolstered by a (decidedly softer) cycling observation: namely, any bike racer who wishes to improve muscular function abstains from alcohol. I have observed this in my training and have yet to interview a bike racer who thinks drinking makes him faster.

The second thing to say about alcohol and AF is that a person is not a population. It's not controversial to say people differ in their susceptibility to both alcohol and AF. The most recent study on alcohol and cardiovascular disease, for instance, showed that people who harbor a single nucleotide polymorphism (SNP) that predisposes to alcohol sensitivity (and presumably causes them to drink less or not at all) had better CV-risk-factor profiles[2]. Any AF doctor has seen this spectrum—from the young person who gets AF with a sip of wine to the 90-year-old who boasts an enviable sinus rhythm despite taking a daily shot of whiskey. Someday we will better understand these personal genomic risks. For now, it suffices to know they exist.

The third thing to say about alcohol and AF treatment is that it makes electrophysiologists think hard about our important role as stewards. Is it right or just to expose patients to risky and expensive AF treatments, say drugs or catheter ablation, if their problem could be resolved by abstaining from (heavy or any) drinking? I ask this as a question, but I'm pretty sure I know the answer. You do, too.

Perhaps the least clear area of the alcohol-AF issue delves into the philosophy of life. That is, the notion of finding balance and happiness in our very short lives. If, and this is a big if, alcohol consumption could be part of a balanced happy life, one that even includes eating sugary desserts (shh), it becomes possible to think alcohol might just be neutral or even beneficial. Consider . . . the cold beer after a spirited mountain bike ride; the glass of rosé (from Provence) on a hot summer evening; the shared half-carafe of red wine with friends or a loved one.

It is indeed hard to unilaterally proclaim such human pleasures unhealthy. For if we do that, we surely do a lot.

But then there are the trade-offs, those damn trade-offs.

JMM

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