HEALTH NEWS

Study Title:

Association of Coffee Drinking with Total and Cause-Specific Mortality

Study Abstract

Background
Coffee is one of the most widely consumed beverages, but the association between coffee consumption and the risk of death remains unclear.

Methods
We examined the association of coffee drinking with subsequent total and cause-specific mortality among 229,119 men and 173,141 women in the National Institutes of Health–AARP Diet and Health Study who were 50 to 71 years of age at baseline. Participants with cancer, heart disease, and stroke were excluded. Coffee consumption was assessed once at baseline.

Results
During 5,148,760 person-years of follow-up between 1995 and 2008, a total of 33,731 men and 18,784 women died. In age-adjusted models, the risk of death was increased among coffee drinkers. However, coffee drinkers were also more likely to smoke, and, after adjustment for tobacco-smoking status and other potential confounders, there was a significant inverse association between coffee consumption and mortality. Adjusted hazard ratios for death among men who drank coffee as compared with those who did not were as follows: 0.99 (95% confidence interval [CI], 0.95 to 1.04) for drinking less than 1 cup per day, 0.94 (95% CI, 0.90 to 0.99) for 1 cup, 0.90 (95% CI, 0.86 to 0.93) for 2 or 3 cups, 0.88 (95% CI, 0.84 to 0.93) for 4 or 5 cups, and 0.90 (95% CI, 0.85 to 0.96) for 6 or more cups of coffee per day (P<0.001 for trend), the respective hazard ratios among women were 1.01 (95% CI, 0.96 to 1.07), 0.95 (95% CI, 0.90 to 1.01), 0.87 (95% CI, 0.83 to 0.92), 0.84 (95% CI, 0.79 to 0.90), and 0.85 (95% CI, 0.78 to 0.93) (P<0.001 for trend). Inverse associations were observed for deaths due to heart disease, respiratory disease, stroke, injuries and accidents, diabetes, and infections, but not for deaths due to cancer. Results were similar in subgroups, including persons who had never smoked and persons who reported very good to excellent health at baseline.

Conclusions
In this large prospective study, coffee consumption was inversely associated with total and cause-specific mortality. Whether this was a causal or associational finding cannot be determined from our data.

From press release:

Older adults who drank coffee -- caffeinated or decaffeinated -- had a lower risk of death overall than others who did not drink coffee, according a study by researchers from the National Cancer Institute (NCI), part of the National Institutes of Health, and AARP.


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. These results from a large study of older adults were observed after adjustment for the effects of other risk factors on mortality, such as smoking and alcohol consumption. Researchers caution, however, that they can't be sure whether these associations mean that drinking coffee actually makes people live longer. The results of the study were published in the May 17, 2012 edition of the New England Journal of Medicine.

Neal Freedman, Ph.D., Division of Cancer Epidemiology and Genetics, NCI, and his colleagues examined the association between coffee drinking and risk of death in 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. The participants were followed until the date they died or Dec. 31, 2008, whichever came first.

The researchers found that the association between coffee and reduction in risk of death increased with the amount of coffee consumed. Relative to men and women who did not drink coffee, those who consumed three or more cups of coffee per day had approximately a 10 percent lower risk of death. Coffee drinking was not associated with cancer mortality among women, but there was a slight and only marginally statistically significant association of heavier coffee intake with increased risk of cancer death among men.

"Coffee is one of the most widely consumed beverages in America, but the association between coffee consumption and risk of death has been unclear. We found coffee consumption to be associated with lower risk of death overall, and of death from a number of different causes," said Freedman. "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 investigators caution that coffee intake was assessed by self-report at a single time point and therefore might not reflect long-term patterns of intake. Also, information was not available on how the coffee was prepared (espresso, boiled, filtered, etc.), the researchers consider it possible that preparation methods may affect the levels of any protective components in coffee.

"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," said 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."

Study Information

Neal D. Freedman, Ph.D., Yikyung Park, Sc.D., Christian C. Abnet, Ph.D., Albert R. Hollenbeck, Ph.D., and Rashmi Sinha, Ph.D.
Association of Coffee Drinking with Total and Cause-Specific Mortality
New England Journal of Medicine
2012 May
Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Rockville, MD.