Men who drank four to five cups of coffee daily reduce their risk of death over a 13-year period by 12%, while women's risk drops by 16%, according to a new study.

Researchers at the US National Cancer Institute (NCI; Bethesda, MD, USA) conducted a study to examine the association of coffee drinking with subsequent total and cause-specific mortality among 229,119 men and 173,141 women participating in the in the National Institutes of Health–AARP Diet and Health Study, who were 50-71 years of age at baseline. Information about coffee intake was collected once by questionnaire at study entry in 1995-1996. Participants were followed until they died or December 31, 2008, whichever came first.

The results showed that coffee drinkers were less likely to die from heart disease, respiratory disease, stroke, injuries and accidents, diabetes, and infections, although the association was not seen for cancer. Adjusted hazard ratios for death among men who drank coffee as compared with those who did not were 0.99 for drinking less than one cup per day, 0.94 for one cup, 0.90 for 2 or 3 cups, 0.88 for 4 or 5 cups, and 0.90 for 6 or more cups of coffee per day. The respective hazard ratios among women were 1.01, 0.87, 0.84, and 0.85.

The results were similar in subgroups, including persons who had never smoked and persons who reported very good to excellent health at baseline. The researchers stressed that coffee drinkers were also more likely to smoke, and that therefore, after adjustment for tobacco-smoking status and other potential confounders, there was a significant inverse association between coffee consumption and mortality. The study was published in the May 17, 2012, issue of the New England Journal of Medicine (NEJM).

“We found coffee consumption to be associated with lower risk of death overall, and of death from a number of different causes,’’ said lead author Neal Freedman, PhD, of the division of cancer epidemiology and genetics. “Although we cannot infer a causal relationship between coffee drinking and lower risk of death, we believe these results do provide some reassurance that coffee drinking does not adversely affect health.”

“The mechanism by which coffee protects against risk of death, if indeed the finding reflects a causal relationship, is not clear, because coffee contains more than 1,000 compounds that might potentially affect health,’’ added Dr.Freedman. “The most studied compound is caffeine, although our findings were similar in those who reported the majority of their coffee intake to be caffeinated or decaffeinated.”

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