June 4, 2012

Coffee Drinkers Have Lower Risk of Death

Group of people drinking coffee in a cafe.

Older adults who drink coffee—either caffeinated or decaffeinated—may have a lower risk of death than those who don't drink coffee, according to a new analysis. The finding adds to growing evidence that coffee drinking may have health benefits.

Coffee is one of the most popular drinks in the world, but its health effects are unclear. The brew contains a diverse mix of biologically active compounds, so its effects in the human body can be difficult to tease out. Past studies have found mixed results when examining coffee's potential effects on the major causes of death, such as cancer and heart disease.

In the new study, a research team led by Dr. Neal Freedman of NIH's National Cancer Institute (NCI) explored the association between coffee drinking and the risk of death. They examined data on more than 400,000 U.S. men and women, ages 50 to 71, who participated in the NIH-AARP Diet and Health Study. Information about coffee intake was collected once by questionnaire at study entry in 1995-1996. Participants were followed through the end of 2008. In the analysis, the researchers adjusted for the effects of other risk factors on mortality, such as smoking and alcohol consumption.

The team reported in the May 17, 2012, edition of the New England Journal of Medicine that coffee drinking appeared to decrease the risk of death. Compared to men and women who didn't drink coffee, those who drank 3 or more cups per day had approximately a 10% lower risk of death. Coffee drinkers were less likely to die from heart disease, respiratory disease, stroke, injuries and accidents, diabetes and infections.

The researchers didn't find any association between coffee consumption and deaths from cancer in women. Coffee drinking was linked to a slightly higher risk of cancer death in men, but the association was of marginal statistical significance.

The most-studied compound in coffee is caffeine, but the findings were similar among those who drank their coffee caffeinated or decaffeinated. “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,” says Freedman.

The researchers stress that the associations they found don't prove that drinking coffee makes people live longer. Coffee intake was assessed by questionnaire at a single time point and so might not reflect consumption over the course of the study. The participants also didn't report how their coffee was prepared (espresso, boiled, filtered, etc.). Preparation methods can affect the levels of many compounds in coffee.

“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,” Freedman says.

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References: N Engl J Med. 2012 May 17;366(20):1891-904. PMID: 22591295