Alcohol and increased risk of breast cancer

Alcohol, diet, exercise and breast cancer – it’s complicated

New research widely reported in the media from the World Cancer Research Fund (WCRF) this week has provided further evidence of the link between alcohol consumption and an increased risk of breast cancer in women. Emeritus Professor of Applied Statistics at The Open University, Kevin McConway, breaks the figures down for us.

There are numerous factors that can impact on your likelihood of developing breast cancer, including age, height and genes. This recent research suggests that women can lower their risk of breast cancer by focusing on factors within their control such as diet, exercise, and maintaining a healthy weight. It analysed more than 100 studies studying the medical history of 12 million women and found that drinking an extra small glass of wine every day can increase breast cancer risk by 9% after the menopause.

Should I give up alcohol?

Emeritus Professor of Applied Statistics, Kevin McConway

Emeritus Professor of Applied Statistics, Kevin McConway

“Evidence that drinking alcohol increases breast cancer risk has been around for a long time,” said Professor McConway, “and though the WCRF does take into account some new evidence, fundamentally not much has changed. Considering the data at face value, the effect on breast cancer, while it looks real to me, isn’t huge.

“Breast cancer is one of the commonest cancers, and according to Cancer Research UK (CRUK), of 100 UK women, about 12 or 13 will develop a breast cancer at some point in their lives. Imagine that these 100 women all drank an extra small glass of wine or half a pint of beer every day, compared to what they drink now. The WCRF figures suggest that this would lead to one more of them developing a breast cancer during their lifetime.

Any increase in risk is a bad thing, but it’s only one more out of 100 women, and that has to be set against whatever pleasure the women might obtain from their drinking.

Should I be doing more exercise?

“The association between body fat and breast cancer depends on when you’re carrying the extra weight and when in your life the cancer might occur. How do you balance this out? It’s certainly true that most breast cancers occur after the menopause, so in one sense things that affect cancer risk after the menopause might be considered more important.

“It is equally important to emphasise that breast cancer is not the only disease that has evidence of links to being overweight or to aspects of diet and exercise. Decisions on whether and how to change one’s lifestyle shouldn’t be made on the basis of breast cancer risk alone, but evidence of other risks might well point in the same direction.”

How can I reduce the risk of breast cancer?

“The research itself is reasonably measured and mentions various limitations. For example, in reference to the possible causes or mechanisms, it states these: ‘remain uncertain and are likely complex.’ The conclusions of the research are complicated, and it’s not straightforward to pick out clear implications from it on how you might reduce your risk of breast cancer.

Like many cancers, breast cancer isn’t generally caused by something simple like getting an infection or having an injury – different factors have to act together.

“Most of the factors that were studied in this report are themselves linked in complicated ways. For example, the researchers concluded that being overweight or obese throughout adult life increases the risk of breast cancer after the menopause.

“But if you were overweight and wanted to change that, you’d have to do it by changing your diet, cutting out or reducing alcohol, and increasing your exercise, or some combination of all of them. So sorting out the separate effects of alcohol, being overweight, diet, and exercise, and deciding what is cause and effect, is not easy.”