“Women who walk for an hour a day can cut their chance of breast cancer by 14%,” The Guardian reports. A new study has found that even moderate regular exercise is associated with lower risk of cancer.
This US cancer prevention study involved over 73,000 postmenopausal women who were tracked for 17 years.
During this time 6% of the women developed breast cancer. The researchers then looked back to see whether reported time spent walking, sitting or in recreational physical activity was linked to risk of developing breast cancer.
The researchers found that the most physically active women had 25% reduced cancer risk compared to the least active.
Nearly half the women in the study said walking was their only form of exercise. And for these women, those who walked seven or more hours a week had reduced risk, estimated to be around 14% compared to those who walked three or less hours. The link persisted even with adjustment for other hormonal factors and body mass index (BMI) or weight gain.
The study does not prove that exercise alone is directly responsible for the decreased risk, as other lifestyle factors may be involved. For example, women who do regularly exercise may also adopt other healthy lifestyle choices such as eating a healthy diet.
Nevertheless, walking as a form of exercise is accessible, free and good for the heart and for weight control. So the finding that it may also protect against breast cancer is welcome news.
Read more about the benefits of walking.
Where did the story come from?
The study was carried out by researchers from the American Cancer Society and was also funded by the Society. The study was published in the peer-reviewed medical journal Cancer Epidemiology, Biomarkers & Prevention.
The findings of the study were reported accurately by the UK, with several papers including useful comments from breast cancer experts.
What kind of research was this?
This was a prospective cohort study that aimed to examine the association between all kinds of physical activity and leisure time sitting (for example time spent watching TV) and the risk of breast cancer. The cohort consisted of postmenopausal women aged 50 to 74.
Researchers also looked at whether this association differed according to whether the breast cancer was oestrogen receptor positive or negative (OR status). Oestrogen receptor positive cancers are where the cancer cells have receptors for the oestrogen, and therefore the hormone is stimulating the cancer to grow. These women may be candidates for the hormone therapies for breast cancer such as Tamoxifen.
Other factors that were taken into account were the women’s body mass index, weight gain and use of hormone replacement therapy (HRT).
The researchers point out that there is evidence for a lower risk of breast cancer in women who do vigorous physical activity such as swimming or aerobics.
However, it is said to be unclear whether moderate exercise such as walking has the same association. And if there is an association does it differ according to the factors described above?
Prolonged periods of sitting have been associated with some cancers but any link between sitting time and breast cancer is not well understood, they say.
Source: Read More at NHS