Plasma organochlorine levels and risk of non-Hodgkin lymphoma in the Nurses' Health Study.

Numerous studies have reported positive associations of environmental exposure to polychlorinated biphenyls (PCB) and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) with the risk of non-Hodgkin lymphoma (NHL). In a case-control study nested within the Nurses' Health Study, a prospective cohort of U.S. women, we measured concentrations of PCBs and p,p'-DDE in blood samples from 145 women diagnosed with NHL at least 6 months after blood draw and 290 age- and race-matched controls. We used conditional logistic regression to estimate the odds ratios and 95% confidence intervals for each quartile of exposure relative to the lowest quartile. We also evaluated these associations for major histologic subtypes of NHL. There was no consistent evidence of an association of p,p'-DDE, total PCBs, immunotoxic, or individual PCB congeners with risk of NHL. These results do not support the hypothesis of a positive association between PCB exposure and development of NHL.