ENVIRONMENTAL RISK-FACTORS AND FEMALE BREAST-CANCER

The increasing incidence of breast cancer in the United States and the international variation in risk have led to speculation that environm ental risk factors are an important cause of breast cancer. We review the epidemiologic evidence on the breast cancer risk associated with a mbient environmental exposures experienced passively by the US populat ion, and discuss the difficulties associated with measurement of speci fic exposures in environmental studies. We review geographic variation of breast cancer rates in the United States, and exposure to organoch lorines, ionizing and electromagnetic radiation, and passive smoking. Results are inconclusive but do not support a major role of environmen tal risk factors in the etiology of breast cancer.