The researchers identified the half a million participants through the United Kingdom biobank, an initiative to enroll approximately 9.2 million people, with long-term follow-up, and create a large database of individual, genetic sequencing to further understand the role of DNA on disease and treatment. But overall, relative to non-drinkers, those who drank one cup of coffee per day had an 8% lower risk of premature death - a rate that rose slightly as consumption increased, peaking at 16% for those drinking six to seven daily cups, before dipping slightly, to 14%, for those having eight or more cups each day.
As with any observational study like this though, where people are quizzed on their past and existing habits, we can't definitively say that coffee causes a longer life. For instance, a 2015 review of 12 studies showed coffee had a protective effect against depression - more than most teas.
"These findings suggest the importance of non caffeine constituents in the coffee-mortality association and provide further reassurance that coffee drinking can be a part of a healthy diet".
This adds to a significant body of research indicating that coffee is connected to a long list of health benefits. The benefit was seen with instant, ground, decaf, and in people with genetic glitches affecting how their bodies use caffeine.
Coffee contains more than 1,000 compounds that might explain the results, including cell-protecting antioxidants.
Coffee lovers around the world are enjoying their cup of brew a little bit more today.
Drinking coffee could be beneficial, regardless of whether a person metabolizes the drink quickly or slowly.
Drink an unsettling amount of coffee a day?
This study also looked at another question scientists have been asking: how genetics affects coffee consumption. One cup of coffee lowers the risk of death by eight percent.
No doubt more coffee studies will be along in the very near future.
Of the study cohort, about 78 percent were coffee drinkers and researchers followed up with this group over 10 years with the end result being mortality.
When all causes of death were combined, even slow caffeine metabolisers had a longevity boost. An editorial by Eliseo Guallar from the Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland, said there is no way to know if coffee prevents chronic disease and reduces mortality because there are too many factors to weigh like why people start drinking coffee.