Background: Epidemiologic studies have recently related benzene hexachloride (BHC) to breast carcinoma risk. Experimental studies have also shown that beta-BHC is weakly estrogenic, hence supporting the alleged association. By directly comparing beta-BHC levels in breast adipose tissue from incident breast carcinoma cases and controls, this study examined the hypothesis that exposure to beta-BHC increases the risk of breast carcinoma in females.
Methods: A total of 490 Connecticut women (304 cases and 186 controls) were enrolled in the study during the period 1994-1997. Cases were patients ages 40-79 years with histologically confirmed incident primary breast carcinoma. Controls were patients with histologically confirmed incident benign breast disease. Breast adipose tissue was collected and analyzed for BHC isomers. A linear logistic regression model was used to adjust for potential confounders in estimating the association of exposure with disease.
Results: No significant differences in breast adipose tissue levels of beta-BHC were observed between the cases and their controls overall, nor by menopausal status or estrogen and progesterone receptor status of the breast carcinoma cases. A nonsignificant reduced risk was observed among all subjects and among pre- and postmenopausal women when the highest quartile was compared with the lowest. Parous women with higher beta-BHC levels, regardless of lactation status, had a nonsignificantly reduced breast carcinoma risk, whereas a nonsignificantly increased risk was observed among nulliparous women with higher beta-BHC levels, based on very few study subjects.
Conclusions: The results of this study do not support the hypothesis that increasing adipose tissue levels of beta-BHC are associated with an increased risk of breast carcinoma in females.