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A recently updated page on GPnotebook put me in great form and secured my financial contributions to my local coffee shop for the foreseeable future. The updated page looks at various studies on the association between coffee and mortality.

The studies reviewed include a slightly older paper that still offers important evidence. The authors performed a cohort study with a sample of participants in the National Institutes of Health–American Association of Retired Persons Diet and Health Study. A cohort study, as we know, is an observational study that follows a group of people and looks at certain outcomes, very often ones relating to their health.

The study involved more than 400,000 participants of retirement age who were followed for a median of 13.6 years. Notably, 52,000 people in the group passed away over the study period.

The cohort’s coffee consumption was assessed once at baseline. Information gained on coffee intake put participants into 10 possible categories, ranging from zero to six or more cups per day. There was an additional baseline question about the type of coffee (caffeinated versus decaffeinated).

Interestingly, and to my personal delight, I was reminded by reading this page of a key finding from the study: an inverse dose–response relationship between coffee consumption and mortality.

Among men, those who drank between two and three cups per day had a 10% decreased risk of mortality. Those men who drank between four and five cups per day had a 12% decreased risk of mortality and those who drank six or more cups per day had, again, a 10% decreased risk of mortality compared with non-coffee drinkers.

Among women, those who drank between two and three cups per day had a 13% decreased risk mortality, those who drank between four and five cups per day had a 16% reduced risk, and those who drank six or more cups of coffee per day had a 15% decreased risk of mortality compared with non-coffee drinkers.

The authors adjusted results for various confounding factors that could affect their validity – including age, BMI, race, level of education, lifestyle factors (e.g. current and prior smoking) and comorbidities.

Coffee consumption was associated with reduced mortality across several disease categories (including heart disease, stroke, injuries and accidents, and diabetes).

However, the authors of this study did caution that this was only an observational study, with further research needed into the area for more conclusive information on the subject. They also specifically pointed out that people with a prior cardiovascular event were excluded from their study.

The GPnotebook page in question also summarises other data relating to coffee, including from some more recent papers. The evidence examined includes a further study supporting the inverse relationship between coffee intake and mortality, one that looks at cardiometabolic conditions, mortality and coffee intake, and one that links drinking more than four cups of coffee per day with increased stroke risk. It really is worth a look.

Additionally of interest are a page on coffee intake and risk of hypertension and one on prostate cancer risk. And not to leave out the tea drinkers, this page looks at long-term tea drinking and mortality.

For me, reading the updated page provided great food for thought and made me feel less guilty about my own frequent coffee intake. I can’t say, though, that I will be actively promoting sky-high coffee intake for my patients in everyday practice without more conclusive evidence emerging. But it is useful to have this information to hand if people ask specific questions about coffee intake and mortality as this has been in the media in some countries lately.

I hope you enjoyed this latest email, and I look forward to writing for you again next month.