Oakland, CA -- One of the largest individual studies of the effects of alcohol on the risk of breast cancer shows that it makes no difference whether a woman drinks wine, beer or spirits (liquor). It is the alcohol itself (ethyl alcohol) and the quantity consumed that increases breast cancer risk, according to Kaiser Permanente researchers Yan Li, MD, PhD and Arthur Klatsky, MD.
“Population studies have consistently linked drinking alcohol to an
increased risk of female breast cancer, but until now there has been
little data, most of it conflicting, about an independent role played by
the choice of beverage type,” said Klatsky, who is presenting these
findings on September 27th at the European Cancer Conference (ECCO 14)
in Barcelona, Spain.
Li, a Kaiser Permanente oncologist, Klatsky, an investigator with the
Kaiser Permanente Division of Research in Oakland, CA and their Kaiser
Permanente colleagues studied the drinking habits of 70,033 multi-ethnic
women who had supplied information during health examinations between
1978-1985. By 2004, 2,829 of these women were diagnosed with breast
cancer. In one analysis, researchers compared the role of total alcohol
intake among women who favored one type of drink over another with women
who had no clear preference. In another analysis, researchers looked at
the possible independent role of frequency of drinking each beverage
type. Finally, they examined the role of total alcohol intake, comparing
it with women who drank less than one alcoholic drink a day.
The study found there was no difference between wine, beer or spirits in
the risk of developing breast cancer. Even when wine was divided into
red and white, there was no difference. However, when researchers looked
at the relationship between breast cancer risk and total alcohol
intake, they found that women who drank between one and two alcoholic
drinks per day increased their risk of breast cancer by 10 percent
compared with light drinkers who drank less than one drink a day. The
risk of breast cancer increased by 30 percent in women who drank more
than three drinks a day.Results were similar when researchers looked at
groups stratified by age and ethnicity.
“Statistical analyses limited to strata of wine preferrers, beer
preferrers, spirits preferrers or non-preferrers each showed that
heavier drinking – compared to light drinking – was related to breast
cancer risk in each group. This strongly confirms the relation of ethyl
alcohol to increased risk,” said Klatsky.
Although breast cancer incidence varies between populations and only a
small proportion of women are heavy drinkers, Dr Klatsky said that a 30
percent increase in the relative risk of breast cancer from heavy
drinking might translate into approximately an extra 5 percent of all
women developing breast cancer as a result of their habit.
Other studies, including research from the same authors, have shown
light-moderate alcohol drinking can protect against heart attacks, but
Klatsky said that different mechanisms were probably at work. “We think
that the heart protection benefit from alcohol is real, and is probably
derived largely from alcohol-induced higher HDL (‘good’) cholesterol,
reduced blood clotting and reduced diabetes. None of these mechanisms
are known to have anything to do with breast cancer. The possible but
unproven additional coronary benefit from drinking wine (red or white)
may be related to favorable drinking patterns common among wine drinkers
or to the favorable traits of wine drinkers, as evidenced by other
United States and Danish studies.”
Dr Klatsky said that all medical advice needed to be personalized to the
individual. “Our findings provide more evidence for why heavy drinkers
should quit or cut down.”
The Kaiser Permanente research group has been involved in studies of
alcohol drinking and health for more than three decades, including in
the area of heart disease. Kaiser Permanente is uniquely positioned to
conduct such research because investigators have access to data about a
large, multi-ethnic population with a variety of drinking habits.
The Kaiser Permanente Division of Research conducts, publishes, and
disseminates epidemiologic and health services research to improve the
health and medical care of Kaiser Permanente members and the society at
large. It seeks to understand the determinants of illness and well-being
and to improve the quality and cost-effectiveness of health care.
Currently, DOR’s 400-plus staff is working on more than 250
epidemiological and health services research projects.