In a recent study published in the European Journal of Preventive Cardiology, researchers evaluated the impact of coffee consumption on the incidence of cardiovascular disease (CVD), arrhythmias, and mortality.
Coffee is consumed ubiquitously across most societies. Historically, health practitioners have recommended that CVD patients avoid coffee. However, recent evidence from observational studies points to the safety and beneficial effects of coffee consumption on CVD prevention and arrhythmia incidence. Notwithstanding the evidence, there is a general lack of dedicated research regarding the impact of coffee intake on important clinical outcomes like CVD and mortality.
About the study
The present study evaluated the associations between coffee subtypes and incident outcomes using the United Kingdom (UK) Biobank. Participants aged 40 to 69 years were recruited from 2006 to 2010. Surveys and questionnaires on lifestyle risk factors were administered at baseline. The health outcomes of participants were evaluated over a long-term follow-up.
The UK Biobank dataset comprised over half a million participants. Subjects were excluded if ethnicity information was unavailable or if they pulled out of the UK Biobank. Further, individuals were excluded if they had CVD at enrolment or failed to provide information on coffee consumption, type, body mass index (BMI), tea consumption, and alcohol/smoking status.
The associations between incident cardiovascular outcomes and coffee subtypes were assessed among participants who had a cardiovascular diagnosis during follow-up and those who did not. The study’s primary outcome was the relationship of coffee subtypes with the incidence of CVD, arrhythmias, and mortality.
Coffee subtypes included caffeinated (ground/instant) and decaffeinated coffee. CVDs included congestive cardiac failure (CCF), coronary heart disease (CHD), and ischemic stroke. Arrhythmias included ventricular tachycardia (VT), supra-VT (SVT), ventricular fibrillation (VF), and atrial fibrillation (AF)/atrial flutter.
Mortality outcomes were all-cause deaths, sudden cardiac death, and cardiovascular mortality. Cox proportional hazards regression models, adjusted for potential confounders, assessed the effects of coffee on the incident outcomes. A reference coffee intake of zero cups per day was used to compare with other consumption levels.
The final analytic sample comprised 449,563 participants, predominantly male (55.3%), with a median age of 58. The median follow-up time was 12.5 years. More than 100,000 (22.4%) participants were non-coffee drinkers (controls). Arrhythmias were diagnosed in 30,100 (6.7%) participants during follow-up. After adjustment, the lowest risk of developing arrhythmias was noted in those consuming two-three cups of coffee daily.
More than 43,100 (9.6%) participants developed CVDs during follow-up. Of these, 34,677 developed CHD, 12,966 had CCF, and 6767 developed ischemic stroke. The authors observed significant reductions in the incidence of CVDs with a coffee intake of up to five cups/day. The lowest risk of incident CHD was associated with an intake of two-three cups of coffee daily.
The lowest risk of CCF and ischemic stroke was noted in people who consumed two-three cups of coffee daily. More than 27,800 participants died during follow-up, which included 4402 deaths due to cardiovascular causes. A significant decrease in all-cause deaths was associated with a coffee intake of up to five cups per day.
There was no association between coffee consumption and the risk of sudden cardiac death. The coffee type of the participants was predominantly instant (44.1%), followed by ground (18.4%) and decaffeinated (15.2%). Instant coffee intake of two/three cups daily was associated with the lowest risk for any arrhythmia, CHD, stroke, and all-cause mortality.
Ground coffee intake at all consumption levels was associated with a significant decrease in the incidence of any arrhythmia and risk of cardiovascular and all-cause mortality. Consumption of two/three cups of decaffeinated coffee significantly reduced the risk of CVD, CCF, and CHD. Cardiovascular and all-cause mortality risk was also significantly lower with two-three cups/day intake of decaffeinated coffee.
The study found that the intake of instant, ground, and decaffeinated coffee was associated with equivalent decreases in the incidence of CVDs and cardiovascular/all-cause mortality. Coffee intake of two-to-three cups/day was consistently associated with the highest reductions in the risk for CVD, CCF, CHD, and all-cause mortality.
Intake of instant and ground coffee, but not decaffeinated coffee, was associated with a lower risk of incident arrhythmias. Taken together, consumption of caffeinated and decaffeinated coffee at two-three cups/day was associated with a significant decrease in the incidence of CVDs and mortality. The findings suggest that mild/moderate consumption of coffee should be considered part of a healthy lifestyle.