Early Chemical Exposure May Raise Later Breast Cancer Risk

Women with occupational exposure before age 36 appear to have highest risk
By Jane Parry
HealthDay Reporter

FRIDAY, April 2 (HealthDay News) -- Women who have occupational exposure to acrylic and nylon fibers or to polycyclic aromatic hydrocarbons, particularly those exposed at a younger age, may be at increased risk of postmenopausal breast cancer, according to a study in the April 1 issue of Occupational and Environmental Medicine.

France Labrèche, Ph.D., of the Quebec National Institute of Public Health in Montreal, and colleagues conducted a study of 556 women aged 50 to 75 with incident malignant breast cancer, as well as 613 women with other cancers who acted as matched controls. Chemical and industrial hygiene experts used the women's job histories to ascertain their exposure to approximately 300 agents.

Once odds ratios were adjusted to take account of the usual breast cancer risk factors, the researchers found that women with occupational exposure to several agents had increased risks, and the risks were highest in women exposed before the age of 36 years. There was an increased odds ratio for each 10-year increment in duration of exposure before age 36 to acrylic fibers (7.69) and to nylon fibers (1.99). For progesterone-negative and estrogen-positive tumors, the odds ratio at least doubled for each 10-year increase in exposure to monoaromatic hydrocarbons and to rayon and acrylic fibers. In addition, the odds ratio before age 36 doubled for exposure to organic solvents that metabolize into reactive oxygen species, and to acrylic fibers. The authors further noted a three-fold increase for estrogen- and progesterone-positive tumors, with exposure to polycyclic aromatic hydrocarbons from petroleum sources.

"Our findings are consistent with the hypothesis that breast tissue is more sensitive to adverse effects if exposure occurs when breast cells are still proliferating," the authors write. "More refined analyses, adjusting for hormonal receptor subtypes and studies focusing on certain chemical exposures are required to further our understanding of the role of chemicals in the development of breast cancer."

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