Increased risk of non-Hodgkin lymphoma and serum organochlorine concentrations among neighbors of a municipal solid waste incinerator

Organochlorine chemicals may contribute to an increased risk of non-Hodgkin lymphoma (NHL) within non-occupationally exposed populations. Among these chemicals, dioxins and furans were mainly released by municipal solid waste incinerators (MSWIs) until a recent past in France, a source of exposure that is of public concern. We investigated organochlorines and the risk of NHL among neighbors of a French MSWI with high levels of dioxin emissions (Besançon, France), using serum concentrations to assess exposure. The study area consisted of three electoral wards, containing or surrounding the MSWI. Pesticides, dioxins, furans, and polychlorinated biphenyls (PCBs) were measured in the serum of 34 newly diagnosed NHL cases (2003–2005) and 34 controls. Risks of NHL associated with each lipid-corrected serum concentration were estimated using exact logistic regression. The pesticides β-hexachlorocyclohexane (odds ratio [OR] = 1.05, 95% confidence interval [CI] = 1.00–1.12, per 10 ng/g lipid) and p,p' dichloro-diphenyl-trichloroethane (DDT) (OR = 1.20, 95% CI = 1.01-1.45, per 10 ng/g lipid) were associated with NHL risk. Evidence indicated an increased NHL risk associated with cumulative WHO1998-toxic equivalency factor (TEQ) concentrations (dioxins, OR = 1.12, 95% CI = 1.03–1.26; furans, OR = 1.16, 95% CI = 1.03–1.35; dioxin-like PCBs, OR = 1.04, 95% CI = 1.00–1.07; and total TEQ, OR = 1.04, 95% CI = 1.01–1.05), as well as with non dioxin-like PCBs (OR = 1.02, 95% CI = 1.01–1.05, per 10 ng/g lipid). Most congener-specific associations were statistically significant. This study provides strong and consistent support for an association between serum cumulative WHO1998-TEQ concentrations, at levels experienced by people residing in the vicinity of a polluting MSWI, and risk of NHL.

Research Highlights
► Dioxin is classified as carcinogenic to humans.
► Few studies have examined the health effects of environmental dioxin exposure.
► Municipal solid waste incinerators are a major source of dioxins and furans.
► High serum organochlorine concentrations increase risk of non-Hodgkin lymphoma.