Exercise cuts breast cancer risk31st October 2008
Researchers in the United States say that vigorous activity like scrubbing floors or windows, or running, is linked to a lower risk of breast cancer in post-menopausal women.
In a study of more than 32,000 women, scientists concluded that doing heavy household chores can slash the chance of breast cancer by a third.
Such activities were just as effective as running, cycling uphill and playing competitive tennis, in research which looked at cancers which developed after the menopause.
The more active women who appeared more protected in the 11-year study also tended to be slimmer, and to be non-smokers.
The results confirm existing advice that participating in vigorous physical activity for at least 30 minutes a day has benefits.
However, while less vigorous activity is recommended as part of an overall healthy lifestyle, it had no apparent effect on cancer risk.
Washing clothes, mowing the lawn, or going for a walk were considered "moderate" by researchers, and not associated with any benefits.
A team led by Michael Leitzmann from the Division of Cancer Epidemiology and Genetics at the National Cancer Institute set out to shed more light on the link between breast cancer and physical activity after two recent meta-analyses suggested it.
They wanted to shed more light on the type, frequency, duration and intensity of activity involved.
The report, published in the journal Breast Cancer Research, analysed data from a prospective cohort (group) study in which the researchers studied the relationship of total, vigorous and non-vigorous physical activity to the risk of developing postmenopausal breast cancer.
Using data from a previous study called the Breast Cancer Detection Demonstration Project (BCDDP) Follow-up study, it looked at 32,269 women who had been followed-up between 1987 and 1998.
These women answered questionnaires about their "usual physical activity", including household, occupational and leisure activities in the previous year.
Participants were asked the number of hours during the week and weekend that they typically spent in moderate activities like light housework and walking, and in vigorous physical activities like chopping wood, scrubbing floors or strenuous sports. The answers to the questionnaire were then converted to a weekly average.
The relationship between activity and risk of breast cancer was limited to women with a body mass index (BMI) of less than 25. Their risk was cut by almost a third.
There was no reduction in risk for women with a higher BMI, or for those who engaged in more moderate activities.
But the authors said the questionnaire format may mean that people over-estimated their time spent in physical activity, a common phenomenon compared with face-to-face interviews.
Most of the women in the study were white, and their activity levels might have changed during the course of the follow-up study, they added.
Share this page
There are no comments for this article, be the first to comment!
Post your comment
Only registered users can comment. Fill in your e-mail address for quick registration.
Title: Exercise cuts breast cancer risk
Author: Luisetta Mudie
Article Id: 8993
Date Added: 31st Oct 2008