Coffee and Irregular Heartbeat Study Not All Cream
Coffee lovers may have a new reason to embrace that morning cup of java. According to new research appearing in BMC Medicine, there’s no evidence that high coffee consumption increases the risk of atrial fibrillation, the most common type of irregular heartbeat. But that’s not the end of the story.
Coffee consumption has been linked to a variety of health benefits, including reducing the risk of major diseases such as type 2 diabetes, Alzheimer’s disease, liver cancer, breast cancer, and multiple sclerosis, to helping with weight loss and more. According to the authors of the new analysis, however, it “remains unclear” whether drinking coffee affects a person’s risk of developing atrial fibrillation (afib), a condition that can lead to an increased risk of heart failure, stroke, and death.
Coffee consumption and atrial fibrillation
Thus, a team from Karolinska Institutet conducted the largest study to date of its kind to determine whether high coffee consumption may increase the risk of atrial fibrillation. The study had two parts:
- The first part included analyzing data from 76,475 adults who reported on their daily coffee consumption. The study, which included two cohorts, began in 1997 and was followed up for 12 years
- The second part was a follow-up meta-analysis that involved 248,910 individuals from four prospective studies.
After the team evaluated all the data from the two main sources of information, they reported that:
- Coffee consumption was not associated with an increased risk of afib, even among those who drank 5 or more cups of coffee daily
- In the follow-up study, afib occurred in 4,311 men during 449,744 person-years and in 2,730 women during 382,000 person-years. Overall, while coffee consumption was not associated with a risk of this type of irregular heartbeat, the reviewers did see a nonsignificant positive association between drinking coffee and afib among men and a nonsignificant inverse association in women, suggesting that men might be more sensitive to drinking lots of coffee
- In the meta-analysis, the reviewers noted 10,406 cases of afib among 248,910 individuals in the six studies. One of those studies showed a statistically significant reduced risk of developing afib when compared the highest (5 or more) with the lowest (less than 2) amount of coffee consumption
Based on the findings of this review, the authors found “no overall association between coffee consumption and AF [atrial fibrillation] risk.” However, they also pointed out that these findings do not suggest that drinking lots of coffee is not linked to other types of irregular heartbeat.
Coffee and other irregular heartbeats
More specifically, the authors explained that despite their findings, “coffee (or caffeine) may trigger arrhythmia.” In an earlier study published in BMC Cardiovascular Disorders involving 100 patients with idiopathic paroxysmal afib (sudden, severe episodes of afib, cause unknown), 25 percent of them said that drinking coffee was a trigger for arrhythmia.
In the current study, the authors pointed out that in the two cohorts, participants who had afib when they entered the study, on average, drank less coffee than those who did not have atrial fibrillation. This suggests that some people with afib may have stopped consuming coffee or reduced their consumption because coffee had an arrhythmic-triggering effect. (Question: Do you know anyone who experiences irregular heartbeat after drinking coffee? I do.) Therefore, while downing cups of joe may not cause afib in the majority of drinkers, coffee could still play a role in arrhythmia in some cases.
American Heart Association
Hansson A et al. Arrhythmia-provoking factors and symptoms at the onset of paroxysmal atrial fibrillation: a study based on interviews with 100 patients seeking hospital assistance. BMC Cardiovascular Disorders 2004; 4:13.
Larsson SC et al. Coffee consumption is not associated with increased risk of atrial fibrillation: results from two prospective cohorts and a meta-analysis. BMC Medicine 2015 Sept 21. DOI:10.1185/s12916-015-0447-8