Alcohol Boosts the Risk of Breast Cancer. Many Women Have No Idea.

A group of friends drinking alcohol
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Drinking alcohol is known to raise women's risk of developing breast cancer, but many women aren't aware of this link, a new study from the United Kingdom suggests.

The study researchers analyzed information from 205 women who were undergoing breast cancer screening or seeking treatment for breast cancer symptoms at a U.K. hospital. The women were surveyed about their knowledge of risk factors for breast cancer.

About half the women surveyed knew that smoking was a risk factor for breast cancer, and 30% recognized obesity as a risk factor. But only about 20% knew that consuming alcohol was a risk factor, the study found.

Even among health care staff, knowledge of the connection between alcohol and breast cancer was still lacking — of 33 health care staff surveyed, 49% identified alcohol as a risk factor for breast cancer. [7 Odd Things That Raise Your Risk of Cancer (and 1 That Doesn't)]

The new study was conducted at a single health center in the U.K., and so the findings don't necessarily apply to the general population. But the findings do agree with previous research conducted in the United States: A 2017 survey by the American Society of Clinical Oncology found that 70% of Americans didn't know that drinking alcohol is a risk factor for cancer.

It's estimated that alcohol consumption is responsible for around 5% to 11% of all breast cancer cases, with higher risks seen among heavy drinkers. A recent study also estimated that drinking a bottle of wine a week is the equivalent of smoking 10 cigarettes per week for women, in terms of their overall cancer risk.

The new study also suggests that it may be difficult for people to estimate exactly how much alcohol they consume. The study showed that more than half of participants couldn't correctly estimate the alcohol content in any of four commonly consumed alcoholic drinks — a glass of wine, a pint of beer, a liter of cider and a bottle of liquor.

"This suggests that many women may be unaware that their level of alcohol consumption may be increasing their risk of breast cancer," the authors wrote in the June 18 issue of the journal BMJ Open.

It's possible that breast cancer screenings and visits for breast cancer symptoms might serve as "teachable moments" to inform women about ways to decrease their breast cancer risk, such as by reducing alcohol consumption, the authors said.

Indeed, when women in the study were asked how they would feel about having a 5-minute session in which they were provided with cancer prevention information at their breast cancer screenings or appointments for breast symptoms, about 30% percent said this would make them more likely to attend those appointments, and 70% said it would make no difference.

This suggests that "women would not be put off attending breast [cancer] screening or clinic appointments if they were aware they would receive some cancer prevention education," and may in fact be more likely to attend, the authors said.

However, more research would be needed about how to best deliver such information. Both patients and health care providers expressed concern that such sessions might come across as placing stigma on women who drink or blaming women for drinking.

Originally published on Live Science.

Rachael Rettner

Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.