Higher Coffee Consumption Is Associated With Lower Mortality Risks Among Nonwhite Populations
abstract
This abstract is available on the publisher's site.
Access this abstract nowBackground
Coffee consumption has been associated with reduced risk for death in prospective cohort studies; however, data in nonwhites are sparse.
Objective
To examine the association of coffee consumption with risk for total and cause-specific death.
Design
The MEC (Multiethnic Cohort), a prospective population-based cohort study established between 1993 and 1996.
Setting
Hawaii and Los Angeles, California.
Participants
185 855 African Americans, Native Hawaiians, Japanese Americans, Latinos, and whites aged 45 to 75 years at recruitment.
Measurements
Outcomes were total and cause-specific mortality between 1993 and 2012. Coffee intake was assessed at baseline by means of a validated food-frequency questionnaire.
Results
58 397 participants died during 3 195 484 person-years of follow-up (average follow-up, 16.2 years). Compared with drinking no coffee, coffee consumption was associated with lower total mortality after adjustment for smoking and other potential confounders (1 cup per day: hazard ratio [HR], 0.88 [95% CI, 0.85 to 0.91]; 2 to 3 cups per day: HR, 0.82 [CI, 0.79 to 0.86]; ≥4 cups per day: HR, 0.82 [CI, 0.78 to 0.87]; P for trend < 0.001). Trends were similar between caffeinated and decaffeinated coffee. Significant inverse associations were observed in 4 ethnic groups; the association in Native Hawaiians did not reach statistical significance. Inverse associations were also seen in never-smokers, younger participants (<55 years), and those who had not previously reported a chronic disease. Among examined end points, inverse associations were observed for deaths due to heart disease, cancer, respiratory disease, stroke, diabetes, and kidney disease.
Limitation
Unmeasured confounding and measurement error, although sensitivity analysis suggested that neither was likely to affect results.
Conclusion
Higher consumption of coffee was associated with lower risk for death in African Americans, Japanese Americans, Latinos, and whites.
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Additional Info
Disclosure statements are available on the authors' profiles:
Association of Coffee Consumption With Total and Cause-Specific Mortality Among Nonwhite Populations
Ann. Intern. Med 2017 Jul 11;[EPub Ahead of Print], SY Park, ND Freedman, CA Haiman, L Le Marchand, LR Wilkens, VW SetiawanFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
Coffee and reduction in death
Coffee is good. Coffee is bad. The studies bounce back and forth, but it is an important issue because 2.25 billion cups are drunk worldwide per day. So, benefit or harm has a huge impact on society. Some studies have shown a link between coffee consumption and lower levels of inflammation, insulin resistance, and risk for diabetes.
In this study, the researchers looked at coffee consumption and mortality—the ultimate endpoint.1 First of all, the study was not funded by the coffee manufacturers. The data came from the EPIC (European Prospective Investigation into Cancer and Nutrition) study, which was tracking 521,330 people from 10 different European countries. The researchers compared mortality risk between non-coffee drinkers and coffee drinkers who consumed the highest amounts among the 41,693 people in the study who died over the course of 16.4 years.
All-cause mortality was reduced by 12% in men (HR, 0.88 [95% CI, 0.82–0.95]) and 7% in women (HR, 0.93 [CI, 0.87–0.98]). Mortality rates associated with digestive disease and cardiovascular disease represented the largest reductions. There was one bad signal for women, which was an increase in ovarian cancer–related death (HR, 1.31 [CI, 1.07-1.61]), but there was no obvious mechanism to explain this finding. For that matter, there are no definitive mechanisms to explain any of the death benefits. A subgroup of patients did have biomarker tests that evaluated liver enzymes, inflammatory markers, and A1c. All of them were reduced in the coffee vs non-coffee drinkers.
In the United States, using the data from the MEC Study (Multiethnic Cohort Study of Diet and Cancer), which was funded by the National Cancer Institute, the researchers found the same death reduction with coffee consumption.2 Their database was over 185,000 people from different ethnic backgrounds who were followed for over 16 years. They found that one cup of coffee per day reduced death by 12% (HR, 0.88 [95% CI, 0.85–0.91]) and two to three cups per day reduced death by 18% (HR, 0.82 [CI, 0.79–0.86]). No benefit was gained with more than four cups per day versus two to three cups (HR, 0.82 [CI, 0.78–0.87]).
Interestingly, the trends were similar between drinkers of caffeinated and decaffeinated coffee, which means caffeine may not be the beneficial ingredient. This makes sense because there have been reports that very high caffeine consumption in the form of energy drinks is associated with harm. One suggested mechanism for coffee’s benefits is the polyphenol content in coffee. Polyphenols are very powerful antioxidants and perhaps they reduce vascular and DNA damage, and thereby reduce death.
Now, these studies are always thought-provoking but are never definitive because there are variables that we cannot control. For example, was it a black coffee or a double-double? The calorie content would be significantly different. Was the coffee consumed with friends sitting leisurely at a café or was it a cup of coffee between your knees that you sucked up with a straw as you weaved through rush hour traffic? The point is that these studies do have some flaws because you can’t get all the information from self-administered questionnaires.
However, it would be impossible to do a proper randomized trial with 20,000 people who drink two cups of coffee per day and 20,000 people who don’t drink any, and then follow them for 5 years and see which group suffered more deaths. That study is not going to happen. So, in the vacuum of no data, these studies are useful in giving us some direction.
For now, we can tell our patients that coffee consumption is not harmful (except for the small increase in ovarian cancer death). People need not feel guilty for having a coffee or two—they may live longer. But I would say limit the double-doubles and I would say sit back, relax, and enjoy the coffee. Maybe the important part in the “coffee break” is the “break” part. Enjoy your coffee.
References
Could My Coffee Be a Good Addiction?
What a relief! I cannot function in the morning without a cup of coffee, and two large observational trials, the Multiethnic Cohort (MEC) study and the European Prospective Investigation into Cancer and Nutrition (EPIC) study, found that coffee consumption is associated with reduced total mortality.1,2
MEC enrolled 185,855 individuals of African American, native Hawaiian, Japanese American, and Latino descent. Coffee intake was assessed at baseline, and mortality was determined after an average of 16.2 years. EPIC enrolled 521,330 individuals from 10 European countries and determined mortality after an average of 16.4 years.
MEC found that, compared with no coffee, 1, 2 to 3, and 4 or more cups per day reduced the risk of death by 12%, 16%, and 18%, respectively. Heart, cancer, respiratory, stroke, diabetes, and kidney deaths were all reduced. EPIC found that men and women in the highest quartile of coffee consumption had 12% and 7% reductions in all-cause mortality. Coffee was associated with reduced digestive disease deaths in both men and women. Circulatory and cerebrovascular disease mortality was reduced in women, but ovarian cancer mortality was increased.
Most clinicians think of coffee as a source of caffeine and as a potential cause of palpitations, but coffee contains other compounds with potentially beneficial health effects. Indeed, in MEC, both caffeinated and decaffeinated coffee consumption was associated with reductions in death. A subset of 14,800 EPIC participants had biomarkers measured, and coffee use was associated with lower liver enzyme, hsCRP, lipoprotein(a), and hemoglobin A1c levels.
These are observational studies and so cannot prove causation, but the enormous sample sizes and control for confounders provides credibility to the results. For those patients in whom caffeinated coffee worsens palpitations, decaffeinated coffee may be just as beneficial. These results can be used to reassure patients that their coffee addiction may be more beneficial than harmful, and to even suggest that an increase from no to some coffee may be beneficial.
References