Sébastien Fierens

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

Dioxins and polychlorinated biphenyls (PCBs) are persistent organic pollutants widely distributed in the food chain, which is the main source of human exposure. Their effects on human health at background exposure levels are still poorly understood. Recent epidemiological evidence suggests a possible association between these pollutants and diabetes. We report here the results of a population-based study in Belgium on 257 (142 women and 115 men) environmentally exposed subjects, including 10 cases of endometriosis and nine cases of diabetes. Seventeen 2,3,7,8-polychlorinated dibenzodioxins/dibenzofurans (PCDD/Fs or dioxins), four coplanar PCBs (International Union of Pure and Applied Chemistry [IUPAC] nos 77, 81, 126 and 169) and 12 PCB markers (IUPAC nos 3, 8, 28, 52, 101, 118, 138, 153, 180, 194, 206 and 209) were quantified in serum fat from fasting blood samples in order to estimate the body burden of these pollutants. Whilst no difference was found between women with endometriosis and their controls, diabetic patients had significantly increased serum levels of dioxins, coplanar PCBs and the 12 PCB markers. After adjustment for age and other covariates, serum total toxic equivalent activity (sum of PCDD/Fs and coplanar PCBs) and 12 PCB marker concentrations in diabetics were 62% (p=0.0005) and 39% (p=0.0067) higher, respectively, than in controls. The risk of diabetes was significantly increased in subjects in the top decile for adjusted concentrations of dioxins (odds ratio 5.1, 95% confidence interval [CI] 1.18–21.7), coplanar PCBs (odds ratio 13.3, 95% CI 3.31–53.2) or 12 PCB markers (odds ratio 7.6, 95% CI 1.58–36.3). These findings warrant further studies to assess the significance of the associations between diabetes and environmental exposure to polychlorinated pollutants.

Low Bone Density and Renal Dysfunction Following Environmental Cadmium Exposure in China

Abstract This paper presents the main findings of a study on health effects of environmental cadmium pollution in China, performed in 1998, i.e. approximately 25 years after the first warnings of such effects were published in Ambio. Forearm bone mineral density (BMD) and renal dysfunction were assessed in population groups exposed to cadmium via rice. Decreased BMD was found in postmenopausal women with elevated urinary cadmium (CdU) or cadmium in blood (CdB) and among men with elevated CdB. Also, clear and statistically significant dose-effect and dose-response relationships were found between CdB or CdU and renal dysfunction (increased excretion of retinol-binding protein). This is the first report of bone effects among Cd-exposed population groups in Asia outside Japan. The report is also of interest since it demonstrates that bone effects, a comparatively severe adverse health effect of Cd, in combination with renal dysfunction, still occurs in environmentally exposed population groups in Asia. Recent reports on bone effects in Cd-exposed population groups in Europe are discussed.

Cloning and embryonic expression pattern of the mouse Onecut transcription factor OC-2.

Onecut (OC) transcription factors are evolutionarily conserved proteins with important developmental functions. They contain a bipartite DNA-binding domain composed of a single cut domain associated with a divergent homeodomain. The human genome contains three Onecut paralogues, Hnf6 (also called Oc1), Oc2 and Oc3. We describe here the cloning of mouse (m) OC-2 and its expression pattern in the mouse embryo. The mOc2 gene was localized on chromosome 18. Analysis of the mOC-2 amino acid sequence revealed overall identities of 67% with mHNF-6 and of 56% with mOC-3, and the presence of functional domains delineated earlier in HNF-6. The sequence of the 153 residue-long cut-homeodomain was very conserved, as it was 92% identical to that of mHNF-6 and 89% identical to that of mOC-3. In situ hybridization showed expression of mOc2 in the developing nervous system and gut endoderm. Like Hnf6, Oc2 was expressed in developing liver and pancreas. As many genes that are targeted by Onecut factors are recognized by both OC-2 and HNF-6, this overlap of expression patterns may have functional implications.

Impact of Iron and Steel Industry and Waste Incinerators on Human Exposure to Dioxins, PCBs, and Heavy Metals: Results of a Cross-Sectional Study in Belgium

We evaluated the impact of two iron and steel plants and two municipal solid waste incinerators (MSWI) in Wallonia (Belgium) on the exposure of residents to dioxins, polychlorinated biphenyls (PCBs), and heavy metals. In total, 142 volunteers living around these facilities were recruited and compared with 63 referents from a rural area with no industrial source of pollution. Information about smoking habits, dietary habits, anthropometric characteristics, residential history, and health status was obtained from a self-administered questionnaire. The volunteers provided blood under fasting conditions in order to evaluate the body burden of dioxins (17 polychlorinated dibenzo-p-dioxins/dibenzofurans [PCDD/Fs] congeners) and PCBs. Samples of blood and urine were also taken for the determination of cadmium, mercury, and lead. After adjustment for covariates, concentrations of cadmium, mercury, and lead in urine or blood were not increased in subjects living in the vicinity of MSWIs or sinter plants by comparison with referents. Residents around the sinter plants and the MSWI located in the industrial area had concentrations of dioxins and PCBs in serum similar to that of referents. By contrast, subjects living in the vicinity of the MSWI in the rural area showed significantly higher serum levels of dioxins (geometric mean, 38 vs. 24 pg TEQ/g fat) and coplanar PCBs (geometric mean, 10.8 vs. 7.0 pg TEQ/g fat). Although age-adjusted dioxin levels in referents did not vary with local animal fat consumption, concentrations of dioxins in subjects living around the incinerators correlated positively with their intake of local animal fat, with almost a doubling in subjects with the highest fat intake. These results indicate that dioxins and coplanar PCBs emitted by MSWIs can indeed accumulate in the body of residents who regularly consume animal products of local origin.

Dioxin accumulation in residents around incinerators.

To evaluate the human exposure impact of municipal waste incinerators, dioxin and coplanar polychlorinated biphenyl (PCB) concentrations were determined in blood of 84 subjects who resided approximately 18 yr in the vicinity of two old incinerators, one located in a rural area (n = 51) and the other in an industrial area (n = 33). These subjects were compared with 63 controls from an unpolluted area. While no change was found in contaminant levels in residents living around the incinerator in the industrial area, subjects residing around the incinerator in the rural area possessed significantly higher serum levels of dioxins (38 vs. 24 pg TEQ/g fat) and coplanar PCBs (10 vs. 7 pg TEQ/g fat) than controls. These results were confirmed by multipleregression analysis, showing that residence around the incinerator in the rural area (partial r 2 = .18) was the major contributor to dioxin accumulation followed by age (partial r 2 = .07). A two-way analysis of variance (ANOVA) on age-adjusted dioxin levels revealed a significant interaction between residence around incinerators and the consumption of fat from local origin, especially bovine and poultry products. Although age-adjusted dioxin levels in controls did not vary with local animal fat consumption, concentrations of dioxins in subjects living around the incinerators increased proportionally to their intake of local animal fat, with almost a doubling in subjects with a fat intake higher than 150 g fat/wk. Extrapolation from these data suggests that a significant increase of dioxin body burden is likely to occur only when dioxin emissions exceed 5 ng TEQ/Nm 3 , a threshold considerably above most emissions standards currently in force.