The old motto may be everything in moderation, but middle-aged women who enjoy a
daily glass of alcohol should try on a new mantra if they want to lower their
cancer risk, new research suggests.
In a study of nearly 1.2 million women, British researchers found that even low
to moderate alcohol consumption can boost a woman's risk of developing cancers
of the breast, liver, rectum and, in smokers, the mouth and throat, by as much
as 13 per cent combined.
These cancers have already been linked to alcohol consumption but in much higher
doses, according to the study published yesterday in the Journal of the National
Cancer Institute's online edition.
Most previous studies linking alcohol use and cancer risk have focused on men
who drank to excess, says Naomi Allen, lead study author and cancer
epidemiologist with the University of Oxford. But this discovery sheds a
disturbing light on how even a small amount of alcohol consumed on a regular
basis raises the risk of cancer, specifically in females, she says.
“What's novel about this study is even though it's low level of drinking – about
one or two alcoholic drinks regularly consumed each day – it increases a woman's
risk not just of developing breast cancer, which has been well established
already, but also cancer of the liver, cancer of the rectum and in smokers
cancer of the mouth and throat,” she says. “These are cancers that were commonly
believed to be associated with high alcohol consumption.”
Dr. Allen and her research team analyzed data from the Million Women Study,
which included more than a million middle-aged British women surveyed at breast
cancer screenings between 1996 and 2001. These women, with an average age of 55,
were routinely tracked for incidence of cancer. Of the women who reported
drinking, the average alcohol intake was 10 grams, or one drink a day. In the
study, moderate drinking for women was defined as less than 21 drinks a week or
three a day. Researchers controlled for smoking status, and whether the women
had undergone hormone replacement therapy and considered the women's ages,
socioeconomic background and place of residence among many other factors.
In all cases, the more a woman drank the higher her risk rate climbed, Dr. Allen
says.
The study also found that the type of alcohol consumed made no difference. A
glass of red wine – widely acknowledged for reducing the risk of heart disease –
and a glass of spirits increased risk the same way, Dr. Allen says.
These findings may call into question the recommended daily glass of red wine,
she acknowledges. It's a confusing mixed message, but she views her study as
just one more thing for women to discuss with their doctors.
“Only [after] you've examined heart disease in the same populations would we be
in a position to comment on the overall risks and benefits of moderate alcohol
drinking in women,” she says. It will then be the responsibility of expert
committees and governmental health organizations to create guidelines for the
public. “I think women have to be as well informed as possible and only then can
they take responsible action over how much alcohol they drink.”
Cardiologists actually don't recommend non-drinkers start sipping wine daily
says Michael Lauer, the director of the Division of Prevention and Population
Sciences at the National Heart, Lung, and Blood Institute in Bethesda, MD.
“There is this lore that a drink a day is good for you, but if you look at the
message, it's more nuanced,” he says. “The message is it may be a reduced risk,
but this is something you need to discuss with your doctor.”
In an editorial also published in the Journal of the National Cancer Institute ,
Dr. Lauer said the Oxford team's research offered “fascinating findings that
should give us pause.”
Dr. Allen says she plans to test for heart disease incidence and mortality rates
among participants in the Million Women Study so that clearer recommendations
can be made. She also wants to track what impact drinking patterns have on
increased cancer risk.
