Here’s another reason to start the day with a cup of joe: Scientists have found that people who drink coffee appear to live longer.
Drinking coffee was associated with a lower risk of death due to heart disease, cancer, stroke, diabetes, and respiratory and kidney disease for African-Americans, Japanese-Americans, Latinos and whites.
People who consumed a cup of coffee a day were 12 percent less likely to die during the study period compared to those who didn’t drink coffee. This association was even stronger for those who drank two to three cups a day — 18 percent reduced chance of death.
Lower mortality was present regardless of whether people drank regular or decaffeinated coffee, suggesting the association is not tied to caffeine, said V. Wendy Setiawan, senior author of the study and an associate professor of preventive medicine at the Keck School of Medicine of USC.
“We cannot say drinking coffee will prolong your life, but we see an association,” Setiawan said. “If you like to drink coffee, drink up! If you’re not a coffee drinker, then you need to consider if you should start.”
The study, which will be published in the July 11 issue of Annals of Internal Medicine, used data from the Multiethnic Cohort Study, a collaborative effort between the University of Hawaii Cancer Center and the Keck School of Medicine.
The ongoing Multiethnic Cohort Study has more than 215,000 participants and bills itself as the most ethnically diverse study examining lifestyle risk factors that may lead to cancer.
“Until now, few data have been available on the association between coffee consumption and mortality in nonwhites in the United States and elsewhere,” the study stated. “Such investigations are important because lifestyle patterns and disease risks can vary substantially across racial and ethnic backgrounds, and findings in one group may not necessarily apply to others.”
Since the association was seen in four different ethnicities, Setiawan said it is safe to say the results apply to other groups.
“This study is the largest of its kind and includes minorities who have very different lifestyles,” Setiawan said. “Seeing a similar pattern across different populations gives stronger biological backing to the argument that coffee is good for you whether you are white, African-American, Latino or Asian.”
Benefits of drinking coffee
Previous research by USC and others has indicated that drinking coffee is associated with reduced risk of several types of cancer, diabetes, liver disease, Parkinson’s disease, Type 2 diabetes and other chronic diseases.
Setiawan, who drinks one to two cups of coffee daily, said any positive effects from drinking coffee are far-reaching because of the number of people who enjoy or rely on the beverage every day.
“Coffee contains a lot of antioxidants and phenolic compounds that play an important role in cancer prevention,” Setiawan said. “Although this study does not show causation or point to what chemicals in coffee may have this ‘elixir effect,’ it is clear that coffee can be incorporated into a healthy diet and lifestyle.”
About 62 percent of Americans drink coffee daily, a 5 percent increase from 2016 numbers, reported the National Coffee Association.
As a research institution, USC has scientists from across disciplines working to find a cure for cancer and better ways for people to manage the disease.
The Keck School of Medicine and USC Norris Comprehensive Cancer Center manage a state-mandated database called the Los Angeles Cancer Surveillance Program, which provides scientists with essential statistics on cancer for a diverse population.
Researchers from the USC Norris Comprehensive Cancer Center have found that drinking coffee lowers the risk of colorectal cancer.
But drinking piping hot coffee or beverages probably causes cancer in the esophagus, according to a World Health Organization panel of scientists that included Mariana Stern from the Keck School of Medicine.
In some respects, coffee is regaining its honor for wellness benefits. After 25 years of labeling coffee a carcinogen linked to bladder cancer, the World Health Organization last year announced that drinking coffee reduces the risk for liver and uterine cancer.
“Some people worry drinking coffee can be bad for you because it might increase the risk of heart disease, stunt growth or lead to stomach ulcers and heartburn,” Setiawan said. “But research on coffee has mostly shown no harm to people’s health.”
Coffee by the numbers
Setiawan and her colleagues examined the data of 185,855 African-Americans (17 percent), Native Hawaiians (7 percent), Japanese-Americans (29 percent), Latinos (22 percent) and whites (25 percent) ages 45 to 75 at recruitment. Participants answered questionnaires about diet, lifestyle, and family and personal medical history.
They reported their coffee drinking habits when they entered the study and updated them about every five years, checking one of nine boxes that ranged from “never or hardly ever” to “4 or more cups daily.” They also reported whether they drank caffeinated or decaffeinated coffee. The average follow-up period was 16 years.
Sixteen percent of participants reported that they did not drink coffee, 31 percent drank one cup per day, 25 percent drank two to three cups per day and 7 percent drank four or more cups per day. The remaining 21 percent had irregular coffee consumption habits.
Over the course of the study, 58,397 participants — about 31 percent — died. Cardiovascular disease (36 percent) and cancer (31 percent) were the leading killers.
The data was adjusted for age, sex, ethnicity, smoking habits, education, preexisting disease, vigorous physical exercise and alcohol consumption.
Setiawan’s previous research found that coffee reduces the risk of liver cancer and chronic liver disease. She is currently examining how coffee is associated with the risk of developing specific cancers.
Researchers from the University of Hawaii Cancer Center and the National Cancer Institute contributed to this study. The study used data from the Multiethnic Cohort Study, which is supported by a $19,008,359 grant from the National Cancer Institute of the National Institutes of Health.
More stories about:Cancer, Diabetes, Diet, Research
"Drinking three cups of coffee a day could add years to your life, suggest studies," reports the Metro.
It follows the results of European and US studies that looked at the relationship between how much coffee people drink and death.
The European study included more than 450,000 people. Researchers found men who drank the highest amounts of coffee had a 12% overall reduced risk of death at follow-up from causes including cancer and cardiovascular, digestive and respiratory conditions.
Women had a 7% reduced risk overall, but a greater risk of dying of cancer the more coffee they drank.
These findings need to be interpreted with caution – the research doesn't prove coffee reduces the risk of death. Many other factors that might have played a role weren't taken into account.
Drinking coffee can be part of a healthy, balanced diet. Current guidelines recommend drinking no more than around four cups a day.
Pregnant women are advised to consume no more than 200mg of caffeine a day, the equivalent of two mugs of instant coffee.
There are no magic shortcuts (or magic coffee beans) for achieving good health and living a longer life.
Leading a healthy lifestyle by having a varied, healthy diet and getting regular exercise is the best way to achieve this.
Where did the story come from?
The study was carried out by researchers from a range of more than 20 academic and health institutions across Europe, including Imperial College London and the International Agency for Research on Cancer in France.
The European research was funded by a number of institutions, including the European Commission Directorate General for Health and the Consumers and International Agency for Research on Cancer.
Two authors declared potential conflicts of interest, naming grants from the pharmaceutical companies Biogen, Merck and Pfizer, although the companies weren't involved in this study.
Another author declared receiving grants from Unilever and FrieslandCampina, two consumer goods companies also not involved in the research.
The study was published in the peer-reviewed journal Annals of Internal Medicine.
A second study from the US looking at the same topic was published in the journal at the same time, and reported similar positive results.
The UK media's coverage of this research was generally accurate, with The Guardian rightly highlighting the fact "scientists say that the link might just be down to coffee drinkers having healthier behaviours".
What kind of research was this?
This cohort study looked at data from people enrolled in the European Prospective Investigation into Cancer and Nutrition (EPIC) to see if there were links between coffee consumption and overall deaths, as well as deaths from specific diseases.
This type of study is good for looking at this kind of issue, as it involves people already participating in other research and allows data on a large number of people to be examined.
But cohort studies can't show cause and effect, so aren't able to prove that drinking coffee decreases or increases likelihood of death.
A randomised controlled trial where people are put into groups to either drink coffee or not drink coffee until they died would be needed to prove this, something that wouldn't be feasible.
What did the research involve?
The researchers took data from 451,743 participants, mostly over the age of 35, from the EPIC study and looked at their coffee consumption and death from all causes and specific causes.
Participants were recruited between 1992 and 2000, mostly from the general population of 10 European countries: Denmark, France, Germany, Greece, Italy, the Netherlands, Norway, Spain, Sweden, and the UK.
People who reported having cancer, heart disease, diabetes or a history of stroke at the start weren't included in the study.
Similarly, people who reported an extremely high or extremely low calorie consumption weren't included, as these people would not be representative of the population at large.
People were also excluded when follow-up information and information on coffee consumption was missing.
Participants recorded the number of cups of coffee they drank each month, week or day through self-reported questionnaires or interviews.
Coffee consumption (in ml a day) was calculated using the typical cup sizes for each institution involved per country.
The amount consumed was split into four quartiles:
- quartile 1 (low consumption) – up to 83ml a day for UK data
- quartile 2 (low to medium consumption) – up to 380ml for UK data
- quartile 3 (medium to high consumption) – up to 488ml for UK data
- quartile 4 (high consumption) – above 488ml
The quartiles were country specific, with the average daily amount ranging from 93ml a day in Italy to 900ml a day in Denmark.
Data on cause and date of death was collected from cancer registries, local health organisations and death records, as well as through active follow-up from other sources.
Specific causes of death included digestive, respiratory, circulatory and cerebrovascular causes, as well as ischaemic heart disease, cancer, suicide, and external causes.
Information on the following potential confounding factors was recorded and taken into account during the analysis:
- alcohol consumption
- physical activity
- body mass index
- use of oral contraceptives and menopausal hormone therapy, as well as menopausal status
What were the basic results?
After an average follow-up of 16.4 years, there were 41,693 deaths. Among these, 18,003 were from cancer, 9,106 from circulatory diseases, 2,380 from cerebrovascular diseases, and 3,536 from ischaemic heart diseases.
For all causes of death:
- Men who drank the highest amount of coffee had a 12% lower risk of death than non-consumers (adjusted hazard ratio [aHR] 0.88, 95% confidence interval [CI] 0.82 to 0.95).
- Women who drank the highest amount of coffee also had a 7% lower risk of death than non-consumers (aHR 0.93, 95% CI 0.87 to 0.98).
For specific causes of death:
- Men who drank the highest amount of coffee versus non-consumers and low consumers had a 59% lower risk of death from digestive disease (aHR 0.41, 95% CI 0.32 to 0.54).
- Women who drank the highest amount of coffee versus non-consumers and low consumers had a 40% lower risk of death from digestive disease (aHR 0.60, 95% CI 0.46 to 0.78).
- Women who drank the highest amount of coffee versus non-consumers had a 22% lower risk of death from circulatory disease (aHR 0.78, 95% CI 0.68 to 0.90).
- Women who drank the highest amount of coffee versus non-consumers had a 30% lower risk of death from cerebrovascular disease (aHR 0.70, 95% CI 0.55 to 0.90).
One negative finding was that women who drank the highest amount of coffee had a 12% higher risk of death from cancer (aHR 1.12, 95% CI 1.02 to 1.23). No other associations were seen between coffee consumption and the other causes of death studied.
The US study showed similar findings in that higher coffee consumption was linked to a lower risk of death.
How did the researchers interpret the results?
The researchers concluded that, "Our results suggest that higher levels of coffee drinking are associated with lower risk for death from various causes, specifically digestive and circulatory diseases."
They added: "Because coffee consumption is so widespread and intakes are modifiable, its potentially beneficial clinical implications should be carefully considered."
This study, conducted on a large number of people across Europe, was backed up by similar findings in the US. It appears to show some association between people who drink higher amounts of coffee and a reduced risk of death.
But the "potentially beneficial clinical implications" need to be considered carefully for a number of reasons:
- Although the analyses were adjusted for some confounding variables, there may be a number of other factors that differ between the groups that account for the differences in death, such as socioeconomic status, family history, other medical conditions, and use of medication to name a few.
- Participants with a range of illnesses, including cancer, heart disease, stroke or diabetes, were excluded from the study. These people may have different coffee habits from those included in the study, biasing the results.
- Coffee consumption was self-reported and might have been over or underestimated, leading to inaccuracies in the results.
- Coffee consumption was only assessed at one point in time – people's habits might vary greatly over days, months and years, so one snapshot might not give an accurate picture of lifelong coffee drinking habits.
- Combining different cut-off levels of coffee per country may lead to inaccurate results.
- Lots of analyses were carried out on a range of diseases, most of which weren't significant, and the likelihood of finding some significant results by chance would be fairly likely. Those significant results reported therefore need to be treated with caution.
- Not all outcomes were positive: women had a greater risk of death from cancer if they drank higher amounts of coffee.
The media like to run stories on one single drink or "superfood" that will "guarantee" good health. This, of course, is nonsense: the only way to increase your chances of leading a longer, healthier life is to have a healthy, balanced diet and exercise regularly.
Links To The Headlines
Drinking three cups of coffee a day could add years to your life, suggest studies. Metro, July 11 2017
Coffee cuts risk of dying from stroke and heart disease, study suggests. The Guardian, July 10 2017
Coffee drinkers live longer – perhaps. BBC News, July 11 2017
Drinking coffee could reduce your chance of death, scientists say. The Independent, July 10 2017
Links To Science
Gunter MJ, Murphy N, Cross AJ, et al. Coffee Drinking and Mortality in 10 European Countries: A Multinational Cohort Study. Annals of Internal Medicine. Published online July 11 2017