Study shows that overweight seems to protect younger women from breast cancer

Reported by Susan Aldridge, PhD, medical journalist

Overweight young women are less likely to develop breast cancer before the menopause.
Although obesity is known to be a risk factor for cancer, this was not found to be so in a new study on younger women. Overweight can be linked to hormonal irregularities and maybe polycystic ovary syndrome. This means that these women might have lower levels of estrogen which, in turn, could lower breast cancer risk.

Researchers at Brigham and Women's Hospital and Harvard Medical School have studied a group of over 113,000 premenopausal women who were part of the long-running Nurses' Health Study. They were followed up from 1989 until 2003, or until they developed breast or any other cancer, died, or reached the menopause.

Those with a body mass index (BMI) of 30 or more had a 19 per cent lower risk of breast cancer than those who had a BMI between 20 and 22.4. Women whose BMI was 27.5 or more at age 18 had a 43 per cent lower risk of developing breast cancer than those whose 18-year old BMI was between 20 and 22.4. Although a failure to ovulate - and the accompanying infertility - may reduce the risk of breast cancer, this is not the whole story. For the study found that overweight young women who were not infertile also had a lower risk of breast cancer.

Source
Archives of Internal Medicine 27th November 2006

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