Coffee is one of the most widely consumed stimulants worldwide and is generally considered to be safe or even beneficial for health. However, increased risk of myocardial infarction and hypertension has been suggested for individuals who carry a functional variant at cytochrome P450 1A2 (CYP1A2), which makes them less effective at metabolizing caffeine.
The aim of this study was to examine if the CYP1A2 genotype or a genetic score for caffeine metabolism (caffeine-GS) modifies the association between habitual coffee consumption and the risk of cardiovascular disease (CVD).
Genetic data and information on habitual coffee intake and relevant covariates were available for 347,077 individuals in the UK Biobank, including 8368 incident CVD cases. We used logistic regression to test for the association between coffee intake and CVD risk, and whether the association varies with CYP1A2 genotype or caffeine-GS.
The association between habitual coffee intake and CVD risk was nonlinear, and, compared with participants drinking 1-2 cups/day, the risk of CVD was elevated for non-drinkers, drinkers of decaffeinated coffee, and those who reported drinking >6 cups/day (increase in odds by 11%, 7%, and 22%, respectively, P-curvature = 0.013). CYP1A2 genotype and caffeine-GS were not associated with CVD (P ≥ 0.22 for all comparisons). There was no evidence for an interaction between the CYP1A2 genotype or caffeine-GS and coffee intake with respect to risk of CVD (P ≥ 0.53).
Heavy coffee consumption was associated with a modest increase in CVD risk, but this association was unaffected by genetic variants influencing caffeine metabolism.