Tuesday, July 11, 2017

Summary for Patients - Is Coffee Consumption Associated With Lower Risk for Death? 

In The Media
Richard Lehman’s journal review—17 July 2017
Ann Intern Med  11 July 2017
Coffee: wake up and smell the confounding
Two big observational studies suggest that coffee drinking is associated with longevity. You drink coffee, and would like to believe good things about coffee. So your first instinct, as you sip the aromatic liquid and feel the caffeine buzz, is to rejoice. But you are a scientist: look closer. The first study is of the EPIC cohort, where E stands for European. Over half a million Europeans recorded their coffee consumption on one occasion. Those who claimed to drink the most had a slightly higher rate of survival at 16.4 years than those who said they did not drink coffee. There was a markedly lower rate of death from gastrointestinal causes. Epidemiologically, it’s quite intriguing, but I defy anyone to conduct a randomised trial for a sufficient length of time. So at best we can say that coffee drinking is unlikely to be harmful. The same message emerges from a study of 185 855 Americans of mixed ethnicity, after adjustment for confounders. The coffee drinkers were a bit less likely to die over a period of 16 years, compared with non-coffee-drinkers. Don’t let your coffee get cold while you muse on these matters. Observational evidence is observational evidence and will never be anything more.
The Lancet 15 July 2017  Vol 390

Coffee Drinkers Really Do Live Longer
In two new studies published in the Annals of Internal Medicine, researchers delved into the coffee-drinking habits of more than 700,000 people in the U.S. and in 10 European countries. The scientists were particularly interested in looking at death rates among people of non-white populations. In both studies, people in these groups who drank more coffee tended to have a lower risk of dying during the study period than those who drank less coffee, or no coffee.
Source - Time

Annals of Internal Medicine: Summaries for Patients
Is Coffee Consumption Associated With Lower Risk for Death?                     
11 July 2017
Published: Ann Intern Med. 2017.
DOI: 10.7326/P17-9041

What is the problem and what is known about it so far?

Coffee is one of the most commonly consumed beverages in the world. Some studies have found that drinking more coffee is associated with a lower risk for death. These studies have included mostly white populations, and it is not clear whether this association is found in other groups. In addition, the relationship between coffee drinking and risk for death might differ according to the way coffee is prepared.

Why did the researchers do these 2 studies?
To determine whether the association between coffee consumption and risk for death differs according to ethnicity and cultural differences in how coffee is prepared.

Who was studied?
One of the studies included more than 185,000 adults from a range of ethnicities (African American, Latino, Native Hawaiian, Japanese American, and white). The other included more than 520,000 adults from 10 European countries, where people prepare coffee in different ways.

How were the studies done?
In both studies, the authors asked participants whether they drank coffee and how much, together with questions about other factors that influence a person's risk for health problems and death (for example, cigarette smoking, exercise, diabetes, and heart disease). They then followed the participants for years to see how many died and whether the death rate differed for those who had reported drinking more coffee.

What did the researchers find?
In both studies, people who reported drinking more coffee tended to live longer than those who reported drinking less. This was true in African Americans, Japanese Americans, Latinos, and whites. This finding did not differ among the 10 European countries. Rates of death from certain diseases seemed to be lower in those who reported drinking more coffee than in those who did not drink coffee, although the rate of death from ovarian cancer may have been higher.

What were the limitations of the studies?
These studies were based on a single report of how often the participants drank coffee, which may have changed over the years they were followed and might not have been accurate. In addition, although the researchers tried to account for this, people who say they drink a lot of coffee may differ from those who do not in other ways that may affect their health.

What are the implications of the studies?
Although drinking coffee cannot be recommended as being good for your health on the basis of these kinds of studies, the studies do suggest that for many people, no long-term harm will result from drinking coffee.
Source - Annals of Internal Medicine


NEJM Journal Watch
Coffee Studies Imply More Is Better, but...
By Joe Elia
Edited by David G. Fairchild, MD, MPH, and Jaye Elizabeth Hefner, MD

Two large studies find an inverse association between coffee consumption and mortality, but recommending more of the stuff "would be premature," according to an editorial in the Annals of Internal Medicine.

The EPIC study followed over a half-million subjects in 10 European countries for an average of 16 years. It found that those in the highest quartile of consumption had significantly lower all-cause mortality than nonconsumers after adjustment for smoking and other covariates.

The Multiethnic Cohort study followed some 200,000 Hawaiians and Californians, also for an average of 16 years. As with EPIC, higher consumption was associated with lower all-cause mortality after adjustment. The effect was seen across all ethnic groups, Native Hawaiians excepted.

However, two editorials weaken the brew, pointing out that unmeasured confounders, such as higher income leading to higher coffee consumption, may be at play. Coffee-lovers may rejoice that at least no adverse effects were found.

Annals of Internal Medicine article on EPIC study (Free abstract)
Annals of Internal Medicine article on Multiethnic Cohort (Free abstract)
Annals of Internal Medicine editorial #1 (Subscription required)
Annals of Internal Medicine editorial #2 (Subscription required)
Background: Recent NEJM Journal Watch Cardiology coverage of coffee, tea, and the heart (Your NEJM Journal Watch subscription required)
Source - NEJM Journal Watch

Healio - In the Journals

Drinking coffee reduces risk for death
July 10, 2017
Among people of various ethnicities and cultures, higher coffee consumption — whether caffeinated or decaffeinated — was associated with all-cause and cause-specific mortality benefits, according to two new studies published in Annals of Internal Medicine.

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