Be It Resolved: How Alcohol Harms or Helps the Heart Remains Controversial—and Confusing
This is the first in a series of January 2017 stories looking at common New Year’s resolutions and their cardiac implications.
Few other aspects of preventive medicine have been so selectively taken to heart as the research supporting a role for mild-to-moderate drinking as “healthy” for in terms of preventing cardiovascular disease. Yet as a growing body of research suggests, the benefits of low alcohol intake extend only to certain cardiac conditions and not to others. There’s also the difficulty of separating patterns of alcohol use from other healthy behaviors, making it impossible to know for sure whether alcohol, in moderation, is itself actually doing any good.
|This is Part 1 of a 4-part series looking common New Year’s resolutions in relation to cardiovascular disease. See also our story on lifestyle changes in the setting of secondary prevention, stress and the heart, and the role of e-cigarettes in smoking cessation.|
The complex relationship between alcohol consumption and the cardiovascular system is inevitably on the minds of holiday revelers intent on curbing or cutting out alcohol for the month of January, or Dryuary as it has come to be known. Speaking with TCTMD about research published in the weeks leading up to 2017, experts said there is no reason not to push the pause button on alcohol consumption as a New Year’s resolution. Indeed, it is increasingly—if begrudgingly—accepted that alcohol is not quite as heart healthy as some may have perceived it to be in the past.
Alcohol Consumption and Atrial Fibrillation
In mid-December, researchers associated with the University of Melbourne in Australia published “a sobering review” in the Journal of the American College of Cardiology examining the link between atrial fibrillation and alcohol consumption. They note that the phenomenon of “holiday heart syndrome,” characterized by binge drinking leading to an episode of A-fib, has been well-characterized. But what they argue based on their literature review is that atrial fibrillation is not uncommon at more modest levels of alcohol intake—even those considered by some to be “healthy.”
According to senior author Peter Kistler, MBBS, PhD (Alfred Hospital, Melbourne, Australia), the positive effects of mild-to-moderate drinking on coronary disease have been widely disseminated and embraced. By contrast, he told TCTMD, the link between alcohol consumption and arrhythmias is less commonly mentioned in the lay press or raised in conversations between physicians and patients. Cardiologists themselves, he agreed, are likely somewhat confused about what advice to give their patients.
“Broadly speaking, we know that alcohol at that one to two standard drinks per day level in men and one standard drink in women has proven benefits in reducing the incidence of heart attacks, reducing the incidence of cardiovascular mortality, and even reducing total mortality and stroke,” Kistler said. “But it's a J-shaped curve, so as we go beyond four to five standard drinks per day then [alcohol] becomes dangerous. And I do think we, as physicians, kind of struggle with implementing that moderation message.”
I do think we, as physicians, kind of struggle with implementing that moderation message. Peter Kistler
In their review, Kistler along with first author Aleksandr Voskoboinik, MBBS (Alfred Hospital) and colleagues found a roughly 8% increase in the risk of atrial fibrillation with every additional standard drink. All of these data, however, are derived from observational studies not randomized trials, Kistler cautioned. Moreover, the review focused squarely on moderate alcohol consumption or higher (seven or more standard drinks per week, with one standard drink approximately equal to 12 g of alcohol).
“This review was really focusing on that one standard drink per day,” Kistler said. “Very light drinking—three to five standard drinks per week—wasn’t directly addressed.”
Alcohol Abuse and Broader Cardiac Risks
A second study, this one published earlier this week in JACC, zeroed in on the highest levels of alcohol consumption and its effect on the heart. Here, lead author Isaac Whitman, MD, senior author Gregory Marcus, MD (both University of California, San Francisco), and others used a definition of alcohol abuse derived ICD-9 and CPT codes for nearly 15 million patients. After adjusting for covariates, alcohol abuse by physician diagnosis was associated with a more than two-fold higher risk of atrial fibrillation. But perhaps more striking, alcohol abuse was also associated with a significantly increased risk of MI (HR 1.45, 95% CI: 1.40-1.51) and a more than two-fold higher risk of congestive heart failure that was also highly significant.
Even more galvanizing, the risk conveyed by alcohol abuse was stronger than that conferred by other prominent risk factors for the different cardiac diseases.
“For example,” Whitman told TCTMD, “alcohol abuse as a risk factor for A-fib is second to heart failure but stronger than valvular heart disease and stronger than hypertension. That's new. No one knew that before. Same with myocardial infarction. Alcohol abuse in our analysis was a stronger risk factor than hyperlipidemia.” In other words, he continued, “alcohol abuse is an as strong or stronger risk factor for these cardiac endpoints as other historical cardiac risk factors, and that flies in the face of previous beliefs that alcohol consumption is protective—now moderate consumption may be protective, but we've shown that high consumption is not.”
Alcohol abuse is an as strong or stronger risk factor for these cardiac endpoints as other historical cardiac risk factors, and that flies in the face of previous beliefs that alcohol consumption is protective. Isaac Whitman
In additional analyses, Whitman and colleagues demonstrated that that the cardiac risks associated with alcohol abuse appears to disproportionately impact people who do not have other cardiac risk factors.
“I think that everyone already knew that alcohol abuse is bad: it increases the risk of some cancers, suicide, domestic abuse, car accidents—all these things,” he said. “So ‘alcohol abuse is bad,’ that’s not new. What’s new is that it’s bad for more reasons than we realized, [reasons] that fly in the face of what a lot of people may have thought.”
Higher Alcohol Consumption: A Growing Problem?
Whitman and Kistler—both electrophysiologists—acknowledged that the greatest cardiac harms from alcohol are seen at the highest levels of alcohol intake, although Kistler’s review also documented A-fib at much more moderate levels of consumption. But there’s mounting evidence that higher levels of alcohol intake, even habitual drinking, are becoming less rare.
New data from the National Survey on Drug Use and Health published last month show that alcohol “binging” and other alcohol use disorders among adults age 50 years and older skyrocketed between 2005 and 2014. Worryingly, while men tended to abuse alcohol more frequently than did women, some of the largest increases in these behaviors were actually seen among older women.
To TCTMD, Kistler noted that alcohol is believed to be responsible for 30-60% of people who report to the emergency room with atrial fibrillation and that 25% of these have subsequent episodes of A-fib related to alcohol and binge drinking over the next 12 months, underscoring the scope of what appears to be an entrenched problem.
“No one can justify that extra drink anymore by saying 'it’s good for my heart,’" Whitman observed. “No, it's not.”
Indeed, an editorial accompanying Whitman et al’s study this week took a tougher stand on the long-standing “heart healthy” status of mild-to-moderate alcohol consumption. In it, Michael Criqui, MD, and Isaac Thomas, MD (University of California, San Diego), take aim at the reliability of the observational studies on which the widespread acceptability of alcohol is based. These studies are particularly problematic, they note, since light-to-moderate drinkers also tend to practice healthier lifestyles than do both abstainers and heavy drinkers.
“The recent infatuation with the potential benefits of light-to-moderate drinking for CVD protection,” they write, “appears to be based on observational and subtly confounded data, rather than on randomized clinical trial evidence, and perhaps on more than a little wishful thinking.”
A Glass Half Full
To TCTMD, both Kistler and Whitman spoke of the need to rethink how cardiologists should share advice about alcohol with their patients. “It’s a somewhat confused message, isn't it?” Kistler acknowledged. “We've said okay, it's positive on some of the bigger issues—mortality, cardiovascular mortality, and coronary disease—but then how do we interpret that in light of the increase in atrial fibrillation risk? I think we just have to tailor it to the patients we're treating. I don't think this finding leads us to broadly change our approach to recommendations around moderate alcohol intake.”
But Whitman, like Criqui and Thomas, was less confident that the advice on mild-to-moderate alcohol intake still stands. “Our message should be: we don't know,” he said. “There are different types of heart disease, and mild to moderate consumption may reduce the risk of heart attack, but it's also been shown to increase the risk of some other things like atrial fibrillation.”
The lay press, he added, “never latched onto the fact that mild consumption of alcohol increases your risk of atrial fibrillation, which is the number one cause of embolic stroke in this country.”
JACC editor Valentin Fuster, MD (Mount Sinai Medical Hospital, New York, NY), offered his views on the Whitman paper via the JACC podcast, released during the festive season. Fuster, crediting the editorialists, observed in it that anyone who believes that mild-to-moderate alcohol consumption is healthy for the heart is now “on shaky ground.”
“On behalf of JACC, for 2 or 3 days you may have a glass of wine,” he concluded, adding with a droll note in his voice: “And since we want to be generous, perhaps a maximum of two in this holiday season.”
That was back in the jolly old days of December. For Dryuary, neither Kistler nor Whitman see any harm in all of a sudden calling it quits on alcohol after imbibing more heavily over the holiday period, or at any other time of year (although cold turkey would be inappropriate for people with alcohol addiction). “We do that frequently in people who really notice a relationship between alcohol and atrial fibrillation. We do get them to stop abruptly,” Kistler said. “And it is reasonably common to see their atrial fibrillation stop.”
Whitman had an even more philosophical answer: “This is a personal opinion, not anything to do with our research, but I think exercising one's control over one's alcohol consumption is always a good idea, because it demonstrates to that person that they have control. And if they can't do that, then maybe they don't have control.”
Voskoboinik A, Prabhu S, Ling L, et al. Alcohol and atrial fibrillation. A sobering review. J Am Coll Cardiol. 2016;68:2567-2767.
Whitman IR, Agarwal V, Nah G, et al. Alcohol abuse and cardiac disease. J Am Coll Cardiol. 2017;69:13-24.
Criqui MH, Thomas IC. Alcohol consumption and cardiac disease. Where are we now? J Am Coll Cardiol. 2017;69:25-27.
- Criqui reports having no relevant conflicts.
- Kistler reports support via a practitioner fellowship from the National Health and Medical Research Council.
- Whitman and Marcus report receiving grant support from the National Institute on Alcohol Abuse and Alcoholism.