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Breast Cancer and Exogenous Estrogens.

NIOSH 1985 May:19 pages
Epidemiological studies on the development of breast cancer in women who took estrogens after menopause were reviewed. The first of these studies appeared in 1974, and during the next 5 years several follow up and case control studies were published. The relative risk estimates were not considered convincing. Two follow up studies were not conclusive; one of them found an excessive risk, but the other only detected the expected incidence rates. Three of eight studies published since 1980 reported an increased risk under certain conditions: use of high estrogen doses (1.25 milligrams or more of conjugated estrogens per day for 3 years or more), use in women who had undergone bilateral oophorectomy, or use of parenteral estrogen administration. The results of the other five studies were essentially negative. According to the author, the best estimates of the magnitude of the risk are between 0.9 and 1.5; these results were derived from large well designed case control studies. Several theories, which were discussed, have attempted to explain the role of estrogens in breast cancer occurrence. It is pointed out that laboratory experiments have demonstrated estrogen effects on breast tissue. The author concludes that this effect alone is a justification for placing estrogens on a list of suspected carcinogenic agents.
Epidemiology; Risk-analysis; Biostatistics; Humans; Breast-cancer; Cancer-rates; Carcinogenicity; Estrogenic-hormones;
Publication Date
Document Type
Conference/Symposia Proceedings;
Fiscal Year
Source Name
Proceedings of a Symposium on Epidemiology and Health Risk Assessment, Columbia, Maryland, May 14-16, 1985, Centers for Disease Control/NIOSH, 19 pages, 29 references
Page last reviewed: May 5, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division