Scientists have known for some time that physical activity can reduce the risk of cancer, especially bowel and breast cancer. In December 2006, researchers working on the EPIC study published results showing that physical activity can cut the risk of breast cancer. Specifically, the team found that activity in the home – namely housework – was the most beneficial form of exercise.
This research was partly funded by Cancer Research UK, and was widely covered in the media in articles such as this story on BBC News Online. It is important to stress that these results came out of a large, wide-ranging study into the links between lifestyle and many different types of cancer.
But the results of this research raise certain issues. Women who have had breast cancer may feel upset that a link is being made between housework and the disease. And some people may think that the presentation of these results was sexist. So what’s the real story?
EPIC is an international study involving more than 500,000 men and women from ten European countries. The researchers are investigating many aspects of cancer and lifestyle, including diet and exercise. They regularly publish results from EPIC in international scientific journals, in order to share their findings with the rest of the world.
For this particular study, the EPIC team looked at information from more than 200,000 pre- and postmenopausal women across Europe over 6 years. On average, the premenopausal women in the study were 42 years old, while the postmenopausal women were 59.
Most of the women either did not work outside the home, or had sedentary jobs with little or no opportunity for physical activity. Overall, fewer than one in ten of the women was classed as “active” by the researchers. The scientists divided up types of physical activity into recreational activity (walking, cycling and sports), occupational activity (activities carried out at work) and household activity (housework, DIY, childcare and gardening). Then the researchers investigated how the amounts of different types of physical activity the women did correlated with whether or not they developed breast cancer.
When the team looked at the effects of different types of activity, they discovered that postmenopausal women who did more overall activity were less likely to get breast cancer than those who were relatively inactive. This difference was seen after researchers took into account other factors that are important in cancer risk, including bodyweight and the amount of alcohol drunk. In fact, the women who were most active were nearly a fifth less likely to develop the disease than the least active women.
When they studied the data in greater depth, the researchers found that women who did the most household activity were less likely to develop breast cancer than those who did the least. For postmenopausal women, a 20 per cent reduction in risk was found for those who did the most activity. For the most active premenopausal women, the risk dropped by 30 per cent.
But how much housework do you need to do to make a difference to your risk of breast cancer? In this study, the women were doing an average of 16 to 17 hours of housework every week. This sounds quite high, but the figure covers a wide range of household chores.
The researchers concluded that their results showed the benefit of moderate physical activity in reducing breast cancer risk in middle-aged and older women. So exercise in the form of housework – and other household activities – can count towards this.
When considering this kind of research, it is important to understand the concept of cancer risk. Of course, there are no guarantees in life. Even people who lead very healthy lifestyles can get cancer, although they are statistically less likely to develop the disease. So this research doesn’t mean that women with untidy homes will definitely develop breast cancer; neither does it mean that having a spotless house will guarantee you won’t get the disease.
However, being regularly physically active – including doing the housework – can reduce your risk of breast cancer. There are several things that all of us, women and men, can do to reduce our risk of cancer, and you can find out more from Cancer Research UK’s Healthy Living pages.
Is it sexist?
Were the scientists being sexist by linking housework to a predominantly female cancer? It is important to point out that housework and household activities such as gardening and childcare were the main forms of activity for the majority of women in the study. Women in older age groups are less likely to play sports, or have a very active job. So it is not surprising that those who were most active were the ones doing most housework.
The EPIC team is looking at a wide range of other risk factors and cancer types. But in order to make sense of the huge amounts of data from the 500,000 study participants, the researchers can only investigate one aspect at a time. This work was a specific piece of research, looking in particular at breast cancer and activity, rather than a range of cancers that affect both men and women.
Finally, in another paper published in December 2006, the team also showed that physical activity in the form of housework can significantly cut the risk of bowel cancer in both men and women. So there’s absolutely no excuse for men to dodge the dusting!
This article was first published in 2007 on the Behind the Headlines section of our website. We have now moved this content to the blog.
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P. H. Lahmann et al (2007). Physical Activity and Breast Cancer Risk: The European Prospective Investigation into Cancer and Nutrition Cancer Epidemiology Biomarkers & Prevention, 16 (1), 36-42 DOI: 10.1158/1055-9965.EPI-06-0582
Christine Friedenreich et al (2006). Physical Activity and Breast Cancer Risk: The European Prospective Investigation into Cancer and Nutrition Cancer Epidemiology Biomarkers & Prevention, 15, 2398-2407