Authors
Sebastien Fierens, Helene Mairesse, Jean-Francois Heilier, Claire De Burbure, Jean-Francois Focant, Gauthier Eppe, Edwin De Pauw, Alfred Bernard.

Title:
Dioxin/ polychlorinated biphenyl body burden, diabetes and endometriosis: findings in a population-based study in Belgium.

Journal:
Biomarkers 8: 529-534, 2003.

Summary:
Persistent organic pollutants such as polychlorinated dibenzodioxins/ dibenzofurans (PCDD/F's or dioxins) and polychlorinated biphenyls (PCBs) accumulate in the food chain and the human body. In spite of the decreased burden of these pollutants in general population, a matter of concern is the effects of elevated levels of these chemicals in highly exposed populations. Current evidence is suggestive of a possible relationship between halogenated aromatic compounds and chronic diseases like endometriosis and diabetes.

The present study examined the risk of diabetes and endometriosis in people living near pollution sources in Belgium that are exposed to organic pollutants, dioxins and PCBs. For this study, 257 subjects (142 women and 115 men) were recruited from 2000-2001 from those living in the vicinity of an iron and steel plant (Cockerill-58 subjects), a waste dumping site (Mont-Saint-Guibert-52 subjects), a municipal solid waste incinerator in an industrial area (Pont-de-Loup-33 subjects), and in a rural area (Thumaide-51 subjects). Controls were not living near a pollution source in rural areas of southern Belgium (Daverdisse, Nassogne & Bertrix-63 subjects). All study volunteers, lived in the above mentioned areas of Belgium for a prolonged period of time and consumed locally produced food. Subjects with possible occupational exposure to these pollutants, such as workers in above mentioned plants, were excluded. Information on health status (diabetes, endometriosis), as well as a range of demographic and behavioural factors were obtained by a self-administered questionnaire. The concentrations of seventeen PCCD/F's, four dioxin-like non-ortho-PCBs (coplanar PCBs) and twelve PCB markers were assessed from a fasting blood sample and measured using gas chromatography-high resolution mass spectrometry (GC-HRMS) on the lipid fraction of the serum. Dioxin & coplanar PCB were expressed in toxic equivalents (TEQs) where as PCB markers were expressed in ng/g fat. A total of 9 cases of diabetes and 10 cases of endometriosis were observed.

In this study, the cases of diabetes and endometriosis were found to be well matched with controls for age, BMI and serum lipids. Moreover no significant differences were observed in weight loss and fat intake between cases and controls. Analysis on women did not reveal any significant association between dioxin/ PCB levels and endometriosis whereas analysis of the entire population identified diabetes as a significant determinant of serum levels of dioxin, coplanar PCB and 12 PCB markers. In addition to above findings the odds ratios (OR) and 95% confidence intervals (CI) estimated by dividing the entire population into two groups, using 90th percentile of the adjusted concentrations of dioxin, coplanar PCB and PCB markers revealed significant estimates for the relationship between diabetes and dioxins (OR=5.07, CI:1.18-21.7), coplanar PCBs (OR=13.3, CI:3.31-53.2) and 12 PCB markers (OR=7.58, CI:1.58-36.3).

Overall, this study found a significant relationship between dioxins/ PCBs concentrations in the body and diabetes but not endometriosis. But, these results should be interpreted with caution as the analysis was based on very few cases. However, the analysis of highly exposed endometriosis cases, in this study (cases living near incinerators) as well as in another study with a larger sample size, could not establish any formal relationship between dioxin/ PCB concentrations and endometriosis. For diabetes, even though the results and prior evidence were suggestive of a relationship with body burden of dioxins and PCBs, the direction of causality still has to be established. The higher levels of these pollutants in diabetics could be a consequence of diabetes induced metabolic alterations leading to slow elimination of these lipophilic compounds. However, dioxin half-life in diabetics and non-diabetics was identified to be similar, providing argument against the hypothesis of slow elimination.