1. Greater amount of moderate, habitual coffee consumption was associated with lower risk of arrhythmias.
2. Genetic differences in caffeine metabolism did not modulate effect of coffee consumption on risk of arrhythmia.
Evidence Rating Level: 2 (Good)
Coffee is widely consumed and has been thought to increase risk of arrhythmia. However, whether moderate, habitual coffee intake is associated with risk of arrhythmia has not been clearly documented.
This prospective cohort study assessed association between daily coffee intake and rate of cardiac arrhythmias in adults aged 40-69 years using UK Biobank data. 386,258 adults were followed from 2006 to 2018, with coffee intake measured through participant questionnaires. Participants who were pregnant, with pre-existing arrhythmias, or self-withdrew from the study were excluded. The primary outcome was rate of arrhythmia in general (atrial fibrillation, atrial flutter, supraventricular tachycardia, premature atrial complexes, and premature ventricular complexes). Secondary outcomes assessed the rate of each type of these arrythmias alone. Lastly, DNA was collected from participants at initial assessment to determine whether genetic differences in caffeine metabolism modulated association between coffee intake and arrhythmias (assessed via mendelian randomization studies).
During the study period, 16,979 participants developed arrhythmias. Each additional cup of habitual coffee (up to 8 cups) consumed was associated with a 3% lower risk of incident arrhythmias (hazard ratio 0.97, 95% CI, 0.96-0.98; p<0.01). Moreover, there was no evidence for genetic variants on caffeine metabolism modulating this effect. However, there were limitations noted in this study. Since this study was based on self-reporting, the accuracy in capturing amount and changes in pattern of coffee consumption might be limited. Nonetheless, this study was significant as it offered evidence towards debunking the prior held assumption that coffee intake is associated with arrhythmias.
Click to read the study in JAMA Internal Medicine
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