Drinking coffee is associated with lower mortality rates, and a new study suggests that caffeine is not responsible for the effect.
Researchers had demographic and health data on 498,134 British people, average age 57, including information on coffee consumption and on the genetic variants that affect caffeine metabolism. More than three-quarters were coffee drinkers.
Over 10 years of follow-up, there were 14,255 deaths. They found that the risk of death from any cause, and particularly from cancer and cardiovascular disease, declined steadily as coffee consumption increased. Those who drank a cup a day had a 6 percent lower risk than those who drank less than that, and people who drank eight or more cups a day had a 14 percent lower risk.
The study, in JAMA Internal Medicine, adjusted for age, race, smoking, sex, body mass index, alcohol consumption and other health and behavioral factors.
The associations were similar for ground and instant coffee, and for caffeinated and decaffeinated. Moreover, it made no difference whether people had the genetic variants for slower or faster caffeine metabolism.