Drinking coffee can protect against atrial fibrillation (A-Fib), a common heart rhythm disorder that causes rapid, irregular heartbeat and can lead to stroke and heart failure.
Doctors typically recommend that people with heart issues like A-Fib avoid caffeine out of fear that it will trigger symptoms. But a study by UC San Francisco and the University of Adelaid has concluded that drinking a cup of caffeinated coffee a day reduced A-Fib by 39%.
"Coffee increases physical activity which is known to reduce atrial fibrillation," said Gregory M. Marcus , MD, MAS, who holds the Endowed Professorship in Atrial Fibrillation Research and is an electrophysiologist at UCSF Health . Marcus is the senior author of the paper, which appears Nov. 9 in JAMA . "Caffeine is also a diuretic, which could potentially reduce blood pressure and in turn lessen A-Fib risk. Several other ingredients in coffee also have anti-inflammatory properties that could have positive effects."
A-Fib has been increasing in recent years along with obesity and the aging population. A-Fib, which has been diagnosed in more than 10 million U.S. adults, is estimated to affect up to 1 in 3 people.
Researchers named their study DECAF for Does Eliminating Coffee Avoid Fibrillation? It is the first randomized clinical trial to investigate the link between caffeinated coffee and A-Fib, and it was funded by the National Institutes of Health.
The study enrolled 200 coffee-drinking patients with persistent atrial fibrillation, or a related condition called atrial flutter along with a history of A-Fib. They were scheduled for electrical cardioversion, which gives a single electrical shock to shift the heart into a normal rhythm. They were randomly assigned either to consume at least one cup of caffeinated coffee or an espresso shot each day — or abstain from coffee and other products that contain caffeine for six months.
The group that consumed coffee had a 39% lower risk of recurrent A-Fib episodes. In addition to its anti-inflammatory effects, researchers speculated that drinking coffee might also reduce the risk of A-Fib simply by making people consume fewer unhealthy beverages.
"The results were astounding," said first author Christopher X. Wong , PhD, of UCSF and the University of Adelaide and Royal Adelaide Hospital. "Doctors have always recommended that patients with problematic A-Fib minimize their coffee intake, but this trial suggests that coffee is not only safe but likely to be protective."
Authors: From UCSF, authors are Gabrielle Montenegro; Hannah H. Oo; Isabella J. Pena; Janet J. Tang, PhD; Grace Wall; Thomas A. Dewland, MD; Joshua D. Moss, MD; Edward P. Gerstenfeld, MD; Zian H. Tseng, MD; Henry H. Hsia, MD; Randall J. Lee, MD, PhD; Jeffrey E. Olgin, MD; Vasanth Vedantham, MD; Melvin M. Scheinman, MD; and Catherine Lee, PhD.
Funding: Marcus is supported by R01 HL158825-01, R01 HL167975-01, R01 DA058069-01 and R01 HL159069-01A1 grants from the National Heart, Lung and Blood Institute, and R01 AA022222 from the National Institute on Alcohol Abuse and Alcoholism.
Disclosures: Please see the paper.
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