Science

David Chieng, Rodrigo Canovas, Louise Segan,
Hariharan Sugumar, Aleksandr Voskoboinik, Sandeep Prabhu, Liang-Han Ling, Geoffrey Lee, Joseph B. Morton, David M. Kaye, Jonathan M. Kalman, and Peter M. Kistler

Aims:
Epidemiological studies report the beneficial effects of habitual coffee consumption on incident arrhythmia, cardiovascular disease (CVD), and mortality. However, the impact of different coffee preparations on cardiovascular outcomes and survival is largely unknown. The aim of this study was to evaluate associations between coffee subtypes on incident outcomes, utilizing the UK Biobank.

Methods and results:
Coffee subtypes were defined as decaffeinated, ground, and instant, then divided into 0, 5 cups/day, and compared with non-drinkers. Cardiovascular disease included coronary heart disease, cardiac failure, and ischaemic stroke. Cox regression modelling with hazard ratios (HRs) assessed associations with incident arrhythmia, CVD, and mortality. Outcomes were determined through ICD codes and death records. A total of 449 563 participants (median 58 years, 55.3% females) were followed over 12.5 ± 0.7 years. Ground and instant coffee consumption was associated with a significant reduction in arrhythmia at 1–5 cups/day but not for decaffeinated coffee. The lowest risk was 4–5 cups/day for ground coffee [HR 0.83, confidence interval (CI) 0.76–0.91, P less than 0.0001] and 2–3 cups/day for instant coffee (HR 0.88, CI 0.85–0.92, P less than 0.0001). All coffee subtypes were associated with a reduction in incident CVD (the lowest risk was 2–3 cups/day for decaffeinated, P = 0.0093; ground, P less than 0.0001; and instant coffee, P less than 0.0001) vs. non-drinkers. All-cause mortality was significantly reduced for all coffee subtypes, with the greatest risk reduction seen with 2–3 cups/day for decaffeinated (HR 0.86, CI 0.81–0.91, P less than 0.0001); ground (HR 0.73, CI 0.69–0.78, P less than 0.0001); and instant coffee (HR 0.89, CI 0.86–0.93, P less than 0.0001).

Conclusion:
Decaffeinated, ground, and instant coffee, particularly at 2–3 cups/day, were associated with significant reductions in in-
cident CVD and mortality. Ground and instant but not decaffeinated coffee was associated with reduced arrhythmia.