NEW YORK, Apr 20 (Reuters) A large new study shows that black women face an increased risk of breast cancer when they take replacement hormones, and that the risk is greater for leaner women.
While previous studies have established a link between the long-term use of hormone therapy and increased breast cancer risk, most of these studies were conducted with white subjects, Dr Lynn Rosenberg of Boston University and colleagues note.
They therefore investigated the association between breast cancer and hormone therapy using data from the Black Women's Health Study, which included 32,559 women 40 years of age or older who completed questionnaires between 1995 and 2003.
In the time since then, 615 women developed breast cancer, the team reports in the Archives of Internal Medicine.
Of note, the data were collected before the results of the Women's Health Initiative were published, after which hormone use had dropped sharply.
Rosenberg's group found that 10 or more years of hormone use increased breast cancer risk by 58 percent. Women of normal weight or less who used hormones for 10 years or more had three times the risk of breast cancer, according to the report.
The greater risk seen among leaner women may have been because heavier women produce more estrogen fat tissue, so they may be less affected by taking estrogens than leaner women, Rosenberg and her team suggest.
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