DDE and DDT in breast adipose tissue and risk of female breast cancer

A case-control study was conducted in Connecticut from 1994 to 1997 to inve stigate the relation between dichlorodiphenyldichloroethane (DDE) and dichl orodiphenyltrichloroethane (DDT) exposure and breast cancer risk. Cases and controls were women aged 40-79 years, who had breast-related surgery at th e Yale-New Haven Hospital and from whose surgical specimen the authors coul d obtain at least 0.4 g of breast adipose tissue for chemical analyses. A t otal of 304 incident breast cancer cases (including 62 in situ carcinomas) and 186 benign breast disease controls were recruited into the study. Tissu e levels of DDE and DDT were measured using gas chromatography. Statistical significance for comparisons of mean levels of DDE and DDT was calculated using analysis of variance and rank sum tests. A logistic regression model was used to estimate the association and to control confounding. The age-ad justed geometric mean tissue level of DDE for cases (736.5 pob) was similar to that for the controls (784.1 ppb), DDT levels were also similar for cas es (51.8 ppb) and controls (55.6 ppb), The adjusted odds ratio is 0.9 (95% confidence interval: 0.5, 1.5) for DDE and 0.8 (95% confidence interval: 0. 5, 1.5) for DDT when the highest quartile was compared with the lowest. The se results do not support an association between adipose tissue levels of D DE and DDT and breast cancer risk.