Even Moderate Drinking Increases the Risk for Cancer

April 8, 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 28 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."

BMJ. Published online April 8, 2011