Plasma Persistent Organic Pollutants Research Articles

Abstract MP037: Plasma Organochlorine Concentration and Risk of Diabetes: the Nurses' Health Study

Background: Animal experiments have suggested that exposure to persistent organic pollutants (POPs) may lead to increased risk of type 2 diabetes. Although recent human studies supported this hypothesis, evidence from prospective investigations is sparse. Objective: To examine the associations of plasma POP concentrations with risk of incident type 2 diabetes in a prospective setting among US women. Methods: Study population was comprised of participants from two independent nested case-control studies in the Nurses’ Health Study, in which major polychlorinated biphenyl (PCB 118, 138, 153, and 180), p-p'- dichlorodiphenyldichloroethylene (DDE), dichlorodiphenyltrichloroethane (DDT), and hexachlorobenzene (HCB) were measured. A non-parametric approach was used to derive standardized scores for plasma concentrations of lipid-adjusted POPs within each study to minimize between-study variation of the POP measurements. Risk of incident type 2 diabetes during the follow-up period (1990-2008) across the tertiles of the scores was examined. Results: Of 1,120 participants, we identified 48 incident type 2 diabetes cases. After adjusting for covariates assessed at blood draw in 1990, including smoking status, body mass index, and total fish intake, plasma HCB concentration was positively associated with type 2 diabetes risk: odds ratio (OR) (95% confidence interval [CI]) was 2.77 (1.17, 6.55, P for trend =0.022) comparing the highest vs. lowest tertile. Other POPs were not significantly associated with diabetes: the ORs (95% CI) were 1.10 (0.51, 2.34, P for trend =0.81) for p-p'-DDE, 0.93 (0.44, 1.95, P for trend =0.86) for DDT, and 0.88 (0.39, 1.97, P for trend =0.76) for sum of the 4 major PCBs, comparing the extreme tertiles. Conclusion: The significant association of plasma HCB concentration with diabetes risk supports a role of POP exposure in the etiology of type 2 diabetes. More prospective data are warranted to confirm these findings.

Associations of persistent organic pollutants with abdominal obesity in the elderly: The Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study

ObjectivesIn animal experiments, persistent organic pollutants (POPs) have induced visceral obesity. To address this possibility in humans, we evaluated associations between POPs and abdominal obesity both cross-sectionally and prospectively. MethodsTwenty-one plasma POPs (16 polychlorinated biphenyl (PCB) congeners, 3 organochlorine (OC) pesticides, 1 brominated diphenyl ether (BDE), and 1 dioxin) were measured at baseline in 970 participants aged 70years of the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS), with prospective analyses in 511 participants re-examined after 5years. Abdominal obesity was defined by an increased waist circumference. ResultsIn the cross-sectional analyses, concentrations of the less chlorinated PCBs, OC pesticides such as p,p′-DDE and dioxin had adjusted odds ratios of 2 to 3 for abdominal obesity. Many relations had inverted U-shapes rather than being linear, particularly in women. In contrast, concentrations of highly chlorinated PCBs were strongly inversely associated with abdominal obesity. In a single model including summary measures of the less chlorinated PCBs, highly chlorinated PCBs, and OC pesticides, both the positive associations and inverse associations strengthened. Similar but somewhat weaker associations were seen between POPs and risk of development of abdominal obesity in the prospective analyses. ConclusionUsing both a cross-sectional and a prospective design, low-dose exposure to less chlorinated PCBs, p,p′-DDE, and dioxin, were associated with existence or development of abdominal obesity, while highly chlorinated PCBs had an opposite association in an elderly population, despite the previous observation of higher incident diabetes associated with these same PCBs.

Determinants of AhR-mediated transcriptional activity induced by plasma extracts from Nunavik Inuit adults

The exposure of Inuit people to polychlorinated biphenyls (PCBs) and chlorinated pesticides has been well characterised but little is known regarding their exposure to dioxin-like compounds, which induce toxic effects through binding to the aryl hydrocarbon receptor (AhR). In order to obtain a global measure of persistent organic pollutants in plasma that interact with this signalling pathway, we used a luciferase reporter gene assay to assess the AhR-mediated transcriptional activity elicited by plasma sample extracts from 874 Inuit adults who were recruited in the course of a prospective epidemiological study conducted in Nunavik (Québec, Canada). Several sociodemographic, anthropometric, dietary and lifestyle variables were considered as possible modulating factors of the AhR-mediated activity in multivariate statistical analyses. The geometric mean AhR-mediated activity expressed as 2,3,7,8-tetachlorodibenzo- p-dioxin equivalents was 8.9 pg g −1 lipids (range: <5–144 pg g −1 lipids). PCB-153 concentration measured by high-resolution gas chromatography–mass spectrometry was moderately correlated to AhR-mediated activity (Pearson’s r = 0.53, p < 0.001). Multiple linear regression analyses revealed that age and omega-3 fatty acids in erythrocyte membranes (an index of marine food consumption) were positively associated with plasma AhR-mediated activity ( p < 0.001), whereas a negative association was noted with body fat mass ( p = 0.037). These results suggest that AhR-mediated transcriptional activity of Inuit plasma extracts is linked to their organochlorine body burden, most likely that of dioxin-like PCBs, polychlorinated dibenzo- p-dioxins and polychlorodibenzofurans. AhR-mediated transcriptional activity measures may prove useful in investigating possible associations between exposure to AhR agonists and adverse health effects in this indigenous population.

Regional Differences in Levels of Persistent Organic Pollutants in Plasma of South African Delivering Women: Impact of the Reintroduction of DDT Use in Malaria Areas

Regional Differences in Levels of Persistent Organic Pollutants in Plasma of South African Delivering Women: Impact of the Reintroduction of DDT Use in Malaria Areas

Concentrations of persistent organic pollutants in plasma from two species of turtle from the Tennessee River Gorge

Persistent organic pollutants (POPs) are characterized by their resistance to degradation, biomagnification, global transport, and adverse toxicological effects. The goal of this study was to determine baseline concentrations of several classes of POPs, including polychlorinated biphenyls (PCBs), organochlorine pesticides, and polybrominated diphenyl ethers (PBDEs) in two turtle species, the Cumberland slider ( Trachemys scripta troosti) and the common musk turtle ( Sternotherus odoratus) from the Tennessee River Gorge. Plasma samples from five male and five female adults of each species were analyzed for concentrations of 83 PCB congeners, six DDT compounds, four toxaphene congeners, 18 additional pesticides, pentachlorobenzene, octachlorostyrene, and 28 PBDE congeners using gas chromatography/mass spectrometry. In both species, total PCBs were the predominant contaminant class, at approximately 10-fold higher concentration than p,p′-DDE, total PBDEs, and total chlordanes. Mirex, dieldrin and one toxaphene congener (Parlar 50) were also detected at even lower concentrations. The female turtles had lower concentrations of some contaminants (PCB 153 + 132, oxychlordane, mirex, PBDE 153, PBDE 154, ΣPBDEs) than males, suggesting maternal transfer to eggs. Cumberland sliders had lower concentrations of PCB 138, p,p′-DDE, ΣDDTs, oxychlordane, PBDE 47, and PBDE 99 than musk turtles. The turtles had a unique PBDE pattern with PBDE 100 predominating. The POP concentrations were lower than those measured previously in other reptiles from contaminated sites where endocrine disruption has been observed. One exception was a female musk turtle with 29.9 ng g −1 p,p′-DDE (wet mass basis), which is greater than the concentrations measured in reptiles with evidence of endocrine disruption. Additional monitoring and research is necessary to determine if other species or age classes in this turtle assemblage might be at higher risk of POP accumulation, as well as to assess the potential risk of these concentrations on their health and reproduction.

Global DNA Hypomethylation Is Associated with High Serum-Persistent Organic Pollutants in Greenlandic Inuit

BackgroundPersistent organic pollutants (POPs) may influence epigenetic mechanisms; therefore, they could affect chromosomal stability and gene expression. DNA methylation, an epigenetic mechanism, has been associated with cancer initiation and progression. Greenlandic Inuit have some of the highest reported POP levels worldwide.ObjectiveOur aim in this study was to evaluate the relationship between plasma POPs concentrations and global DNA methylation (percent 5-methylcytosine) in DNA extracted from blood samples from 70 Greenlandic Inuit. Blood samples were collected under the Arctic Monitoring and Assessment Program and previously analyzed for a battery of POPs.MethodsWe used pyrosequencing to estimate global DNA methylation via Alu and LINE-1 assays of bisulfite-treated DNA. We investigated correlations between plasma POP concentrations and global DNA methylation via correlation coefficients and linear regression analyses.ResultsWe found inverse correlations between percents methylcytosine and many of the POP concentrations measured. Linear regressions, adjusting for age and cigarette smoking, showed statistically significant inverse linear relationships mainly for the Alu assay for p,p′-DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane; β = −0.26), p,p′-DDE [1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene; β = −0.38], β-hexachlorocyclohexane (β = −0.48), oxychlordane (β = −0.32), α-chlordane (β = −0.75), mirex (β = −0.27), sum of polychlorinated biphenyls (β = −0.56), and sum of all POPs (β = −0.48). Linear regressions for the LINE-1 assay showed β estimates of similar magnitudes to those using the Alu assay, however, none was statistically significant.ConclusionsThis is the first study to investigate environmental exposure to POPs and DNA methylation levels in a human population. Global methylation levels were inversely associated with blood plasma levels for several POPs and merit further investigation.

Persistent organic pollutants in plasma of delivering women from Arkhangelsk

The high levels of persistent organic pollutants have caused concern about human health, especially the health of the foetus and newborn child. This has especially been the case for Greenlandic and Canadian Inuits, where elevated levels of PCB and p,p′-DDE have been reported. In recent studies from arctic Russia the levels of β-HCH and the DDT-group have been reported to be high, whereas the levels of PCB are low. However, the information from Northern Russia is, so far, incomplete. In this study, 27 delivering women from the city of Arkhangelsk, Russia, participated. They completed a questionnaire before delivery and plasma samples were collected after delivery. The analytical method developed to support this study involved gel permeation chromatography and silica gel purification, in addition to a traditional GC-MS method, and thus include acid labile compounds. The arithmetic mean levels of p,p′-DDE, β-HCH and p,p′-DDT were 5.42, 3.59 and 1.17 μg/l, respectively. Toxaphene 26 and 50 were the only toxaphenes above the limit of detection, with arithmetic mean levels of 0.05 and 0.09 μg/l, respectively. Among the PCB congeners, PCB 138/163 was the most abundant with an arithmetic mean of 0.53 μg/l. The elevated levels of β-HCH and p,p′-DDT as well as a low DDE/DDT ratio is a strong indication of fresh and maybe local sources in this area.