Estrogen therapy article

[CLTann]

The following was found today:

BMI and Estrogen Metabolism Linked to Breast Cancer Risk



NEW YORK (Reuters Health) Feb 23 - Among women not using hormone therapy (HT), obesity and estrogen metabolism are associated with an increased risk of postmenopausal breast cancer, according to findings published in the March issue of the International Journal of Cancer.

"Hormone therapy and body mass index (BMI) have been associated with postmenopausal breast cancer," Dr. Francesmary Modugno, of the University of Pittsburgh, Pennsylvania, and colleagues write. "Because estrogen metabolism may affect breast cancer risk and can be altered by weight and HT, it might play a role in the HT-BMI-breast cancer associations."

The researchers conducted a nested case-control study within the Observational Study of the Women's Health Initiative to examine the association between obesity, HT, estrogen metabolism, and the risk of breast cancer. They compared baseline levels of 2- and 16-alpha-hydroxy estrone (2-OHE1 and 16-alpha-OHE1) in 200 women who developed breast cancer during follow-up and 200 healthy, matched controls.

In women who used HT, there was a modest but significant increase in 16-alpha-OHE1 and significantly higher 2-OHE1 levels in both cases and controls. For these HT users, there were no associations observed between BMI, estrogen metabolism, and breast cancer risk.

For non-HT users, however, "greater BMI and higher 16-alpha-OHE1 were individually and jointly associated with increased cancer risk," the investigators found. Compared with women with low BMI and low estrogen metabolite levels, those with a high BMI and high 16-alpha-OHE1 had an odds ratio for breast cancer of 3.51.

Estrogen metabolism is affected by both BMI and HT, the team concludes, "potentially explaining the interaction between BMI and HT in relation to breast cancer risk."

Int J Cancer 2006;118:1292-1301.