Web edition: February 25, 2009
A provocative story on the front page of today’s Washington Post reports that consuming as little as a single alcoholic beverage a day could raise a woman’s risk of cancer. The size of that increase varies by cancer type. Overall, however, it appears to be about five percent over the seven years that women were followed.
What makes these findings provocative: A host of previous studies have shown that for heart disease — the leading killer of postmenopausal women — quaffing a little alcohol regularly is better than drinking none.
So what should women do?
The answer, typical for science, is that it’s all relative.
For people worried about cancer — particularly those who have a genetic predisposition to breast malignancies — no alcohol is probably the best policy. And earlier studies have argued that line already. In this study, each seven-drinks-per-week increase in alcohol consumption upped a woman’s risk of developing breast cancer by 12 percent.
For people at low risk for heart disease, such as nearly everyone under the age of 35, there’s no health justification for drinking. And a steady diet of three or more drinks — or binging on four or more at a sitting — never ever gets a green light from the medical establishment.
But study after study has offered quantitative evidence that middle-age and older adults who take a regular nip — like that proverbial glass of sherry after dinner or at bedtime — suffer less heart disease and diabetes than teetotalers or people who consume more than two drinks a day.
Ironically, even the study referred to in today’s Post doesn’t clearly contradict that apparent license to drink a bit, even daily. The reason: The new study didn’t assess daily alcohol intake among the 1.28 million ladies in Britain studied as part of the Million Women Study. Participants were asked about weekly consumption, and then the epidemiologists analyzing those data divided the findings by seven. Among women drinking 7 to 14 servings of alcohol each week, the new study shows, risk of developing cancers at several sites beyond the breast does increase.
However . . . if someone averages seven drinks a week, those beverages might have been downed on weekends only — leading to consumption of three or more drinks at a sitting. That would be bad even for the heart. Also, in the long haul, for anyone’s liver.
Unless the servings per day can be teased out, the new study — which appears in the March 4 Journal of the National Cancer Institute — only offers fodder for speculation. And questions to be addressed in follow-up studies that home in on daily intakes.
Another interesting caveat mentioned in the new study, but omitted from today’s Post story: “Nondrinkers had an increased risk for several cancer sites compared with women who drank fewer than or equal to two drinks per week.” Naomi Allen and her colleagues at the University of Oxford note that this apparent protective effect of alcohol was statistically significant for cancers of the oral cavity and pharynx, esophagus, stomach, liver, lung, cervix and endometrium, and for renal (kidney) cell carcinoma.
Finally, there’s the impact of smoking. The new study was meant to identify cancers — beyond those in the breast — that might be associated with alcohol. It found small risk increases of one to four percent for leukemia, melanoma, and cancers of the lung, brain and colon. Far bigger increased risks — of 10 to 44 percent— were seen for cancers in the rectum, breast and a few other sites. But among those alcohol-linked spikes in cancer risk exceeding 12 percent (esophagus, liver, oral cavity and pharynx, and larynx), risks for all but liver cancer increased SOLELY among women who smoked.
Don’t get me wrong: I’m not trying to defend drinking. I’m close to a teetotaler myself. And as the mom of a teen who was injured when a drunk classmate totaled the car she was driving (at 5 p.m. on St. Patrick’s Day), I’m fairly intolerant of drinking irresponsibly.
But let’s not scare people with incomplete data. There will be plenty of time to hammer home a call for temperance if and when stronger data emerge.
Allen, N.E., et al. 2009. Moderate Alcohol Intake and Cancer Incidence in Women. Journal of the National Cancer Institute 101(March 4):296.
Lauer, M.S. and P. Sorlie. 2009. Alcohol, Cardiovascular Disease, and Cancer: Treat with Caution. Journal of the National Cancer Institute 101(March 4):282
Stein, R. 2009. A Drink a Day Raises Women's Risk of Cancer, Study Indicates. The Washington Post (Feb. 25):A1.