Bassig BA, et al. - In a case-control study nested within three prospective cohorts in Shanghai and Singapore, researchers assessed the risk of non-Hodgkin lymphoma (NHL) and pre-diagnostic blood levels of organochlorine pesticides/metabolites and polychlorinated biphenyl congeners among 167 NHL cases and 167 controls. A link between β-HCH (hexachlorocyclohexane) blood levels and NHL risk was supported, which raised concern as the environment worldwide contains substantial quantities of persistent, toxic residues of HCH. Although a link between DDT (dichlorodiphenyltrichloroethane) and NHL was shown by some evidence, the results for p,p’-DDE (p,p’-dichlorodiphenyldichloroethylene) did not support a link. In samples from the Asian cohorts vs various cohorts in the United States and Norway, up to 12 and 65 times higher median levels of p,p’-dichlorodiphenyldichloroethylene (p,p’-DDE, the primary DDT metabolite) and β-HCH were detected, respectively.