Modest Drinking can Heighten your Risk for Cancer

Source: MedScape.org

 

April 14, 2011 — “A considerable proportion of the most common and most lethal cancers is attributable to former and current alcohol consumption,” concludes a large European study published online April 8 in BMJ.

The researchers attribute about 10% of all cancers in men and about 3% of all cancers in women to previous and current alcohol consumption.

The estimates come from an analysis of data from the huge ongoing European Prospective Investigation Into Cancer (EPIC) and from representative data on alcohol consumption compiled by the World Health Organization (WHO).

The risk increases even with drinking moderate amounts.

“This research supports existing evidence that alcohol causes cancer and that the risk increases even with drinking moderate amounts,” coauthor Naomi Allen, DPhil, an epidemiologist at Oxford University, United Kingdom, said in a statement.

The original data in the EPIC study were collected from 1992 to 2000, so “the results from this study reflect the impact of people’s drinking habits about 10 years ago,” Dr. Allen noted.

“People are drinking even more now than they were then, and this could lead to more people developing cancer because of alcohol in the future,” she added.

Data From 8 Countries

The EPIC study, which is still ongoing, is one of the largest studies of diet and cancer ever conducted. It involved more than half a million people in Europe.

For this analysis of alcohol and cancer, the researchers used EPIC data from 363,988 participants from 8 European countries — France, Italy, Spain, the Netherlands, United Kingdom, Greece, Germany, and Denmark. Two of these centers (France and the Netherlands) recruited only women, so the total cohort was about two thirds female (254,870 women; 109,118 men).

Data on the incidence of cancer was obtained through record linkage with national cancer centers and from sources such as death certificates, health insurance records, and pathology reports.

Information on alcohol consumption was collected using a detailed questionnaire about the frequency and amount of drinking and the type of beverages consumed during the previous year. The researchers also computed data on alcohol exposure in the general population using data from a WHO survey.

Cancer Attributable to Alcohol

The researchers assumed a causal association between alcohol and cancer of the upper aerodigestive tract (which includes the oral cavity, pharynx, larynx, and esophagus), liver cancer, female breast cancer, and colorectal cancer (as decreed by the WHO’s International Agency for Research on Cancer).

The team then calculated the proportion of these specific cancers that could be attributable to previous and current alcohol consumption. They estimated that, in 2008, alcohol was responsible for 44% of the upper aerodigestive tract cancers in men and 25% in women, 33% of liver cancer in men and 18% in women, 17% of colorectal cancer in men and 4% in women, and 5% of breast cancer in women.

A substantial portion of these cancers attributable to alcohol consumption was linked to drinking more than the currently recommended upper limit, the researchers note.

The World Cancer Research Fund and the American Institute for Cancer Research recommend a maximum of 2 drinks per day (about 24 g of alcohol) for men and 1 drink (about 12 g) for women.

The team calculated that drinking more than this was responsible for 57% to 87% of the cancers attributable to alcohol (i.e., upper aerodigestive tract, liver, colorectal, and female breast cancer) in men and from 40% to 98% in women.

“Our data show that many cancer cases could have been avoided if alcohol consumption is limited to 2 alcoholic drinks per day in men and 1 alcoholic drink per day in women, which are the recommendations of many health organizations,” said lead author Madlen Schütze, PhD student and epidemiologist at the German Institute of Human Nutrition in Potsdam-Rehbrücke, Nuthetal, Germany.

“Even more cancer cases could be prevented if people reduced their alcohol intake to below recommended guidelines or stopped drinking alcohol altogether,” she said in a statement.

Although a substantial portion of the cancers were attributable to high alcohol intake, the remaining cancers were attributable to drinking alcohol at or under the currently recommended levels.

Risk Increases With Every Drink

“The cancer risk increases with every drink, so even moderate amounts of alcohol — such as a small drink each day — increases the risk of these cancers,” according to a press release from Cancer Research UK, which cosponsors the ongoing EPIC study, along with several European agencies.

“Many people just don’t know that drinking alcohol can increase their cancer risk,” said Sara Hiom, director of health information at Cancer Research UK.

“Cutting back on alcohol is one of the most important ways of lowering your cancer risk,” along with not smoking and maintaining a healthy bodyweight, she said.

The researchers touch on this point in their discussion. They refer back to studies that have shown a beneficial effect of alcohol on death from cardiovascular disease, especially coronary heart disease and ischemic stroke, which have in the past led to recommendations to enjoy a drink to benefit the heart.

But they point out that “even though light to moderate alcohol consumption might decrease the risk for cardiovascular disease, and mortality, the net effect is harmful.”

“Thus, alcohol consumption should not be recommended to prevent cardiovascular disease or all-cause mortality,” they write.

No Sensible Limit

The researchers also emphasize that this latest study, in addition to several others, shows that “there is no sensible limit below which the risk of cancer is decreased.”

This point was also made recently in an editorial in the Journal of the National Cancer Institute (2009;101:282-283), which accompanied findings from the British Million Women Study showing that even 1 drink a day significantly increased the risk for cancer (J Natl Cancer Inst. 2009;101:296-305).

There is no level of alcohol than can be considered safe.

At that time, editorialists Michael Lauer, MD, and Paul Sorlie, PhD, from the division of prevention and population sciences at the National Heart, Lung and Blood Institute in Bethesda, Maryland, wrote: “From a standpoint of cancer risk, the message of this report could not be clearer. There is no level of alcohol that can be considered safe.”

Clinical Context

 

Study Highlights

 

• The EPIC is a multicenter prospective cohort study from 1992 to 2000 that recruited more than 500,000 men and women aged 37 to 70 years from 10 European countries.
• Participants were selected from the general population, except in France and the Netherlands. This analysis included participants without cancer at recruitment who were not in the top or bottom 1% of the ratio of energy requirement to energy expenditure.
• The investigators determined alcohol consumption using a validated dietary questionnaire assessing frequency and portion size of beer/cider, wine, spirits, and fortified wine covering the 12 months before recruitment.
• Past alcohol consumption was assessed as self-reported consumption at the ages of 20, 30, 40, and 50 years.
• Participants were differentiated by never-consumption, former consumption (past consumption but no current consumption), and lifetime consumption (current and past consumption).
• The incidence of cancer was determined with use of regional cancer registries, self-report, next-of-kin report, pathology registers, health records, or death certificates.
• Loss to follow-up was less than 2% in all countries.
• Analysis was stratified by sex, age, education, body mass index, physical activity, menopause status in women, and other factors.
• Alcohol-attributable fractions for cancer risk were calculated.
• The recommended level of alcohol consumption was defined as 2 drinks a day (24 g) for men and 1 drink a day (12 g) for women.
• Consumption over that level was considered higher than recommended.
• Across the countries, there was a north-to-south gradient in alcohol consumption.
• Consumption was highest in Germany and Denmark and lowest in Greece and Spain, with a similar pattern seen for consumption above the recommended level.
• Among male and female lifetime alcohol consumers, the risk for all cancers increased with each additional drink a day.
• Former alcohol consumption in men was also associated with an increased risk for all alcohol-related cancers.
• 10% and 3% of the risk for total cancer were attributable to lifetime alcohol consumption in men and women, respectively.
• The number of attributable cases varied by country because of different population sizes.
• For selected cancers, the respective risks for men and women were 44% and 25% for upper aerodigestive tract cancers, 33% and 18% for liver cancer, 17% and 4% for colorectal cancer, and 5% for breast cancer in women.
• The highest absolute number of alcohol-related cases in men was found for aerodigestive tract cancers and in women for breast cancer.
• A substantial portion of attributable risk was due to consumption above the recommended level of alcohol for men and women.
• The authors concluded that lifetime alcohol consumption in men and women, especially above recommended levels, was associated with increased cancer risk and that restricting consumption to recommended levels would reduce cancer risk.

Clinical Implications

 

• Lifetime alcohol consumption, especially above recommended levels, in men and women is associated with an increased cancer risk.
• The highest cancer risk with alcohol consumption is for aerodigestive tract cancers in men and breast cancer in women.