Thyroid hormones are associated with exposure to persistent organic pollutants in aging residents of upper Hudson River communities

The aim of this study was to evaluate the association between persistent organic pollutants (POPs) and thyroid hormones in an aging population. Forty-eight women and 66 men, aged 55–74 years and living in upper Hudson River communities completed a questionnaire and provided blood specimens. Serum was analyzed for thyrotropin (thyroid stimulating hormone, TSH), free (fT₄) and total thyroxine (T₄), total triiodothyronine (T₃), and for POPs. POPs included 39 polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and dichlorodiphenyldichloroethylene (DDE) determined by gas chromatography with electron capture detection (GC–ECD), and nine polybrominated diphenyl ethers (PBDEs) determined by high-resolution gas chromatography with high-resolution mass spectrometry detection (HRGC–HRMS). Multivariable linear regression analysis was used to evaluate associations between thyroid hormones and sums of POPs, adjusted for covariates and stratified by sex. Effects were expressed as differences in thyroid hormone levels associated with a doubling in the level of exposure. Among women, DDT + DDE increased T₄ by 0.34 μg/dL (P = 0.04) and T₃ by 2.78 ng/dL (P = 0.05). Also in women, sums of PCBs in conjunction with PBDEs elicited increases of 24.39–80.85 ng/dL T₃ (P < 0.05), and sums of PCBs in conjunction with DDT + DDE elicited increases of 0.18–0.31 μg/dL T₄ (P < 0.05). For men estrogenic PCBs were associated with a 19.82 ng/dL T₃ decrease (P = 0.003), and the sum of estrogenic PCBs in conjunction with DDT + DDE elicited an 18.02 ng/dL T₃ decrease (P = 0.04). Given age-related declines in physiologic reserve, the influence of POPs on thyroid hormones in aging populations may have clinical implications and merits further investigation.     

Exposure to persistent organic pollutants and hypertensive disease

Previous research suggests that exposure to persistent organic pollutants (POPs) increases the risk of chronic diseases such as hypertension. We identified the zip codes of more than 800 waste sites contaminated with POPs and other pollutants, based on which we classified zip codes of upstate New York into three groups: "POPs sites", zip codes containing hazardous waste sites with POPs; "other waste sites", zip codes containing hazardous waste sites but not with POPs; and "clean sites", zip codes without any known hazardous waste sites. Age, gender, race, and zip code of residence of patients diagnosed with hypertension (ICD-9 codes 401-404) were identified using the New York Statewide Planning and Research Cooperative System (SPARCS) for the years 1993-2000. A generalized linear model, the negative binomial model, was used to assess the effect of living in a zip code with a hazardous waste site on the discharge rate of hypertension. After control for the aforementioned covariates, we found a statistically significant elevation of 19.2% (95% CI = 8.5%, 31%) in hypertension discharge rate for "POPs sites" and a 10% elevation in discharge rates for "other waste sites" as compared to "clean sites". In a subset of "POPs sites" where people have higher income, smoke less, exercise more and have healthier diets, there was still a 13.9% elevation of hypertension discharge rate as compared to "clean sites". The results support the hypothesis that living near hazardous waste sites, particularly sites containing POPs, may constitute a risk of exposure and of developing hypertension.     

Overview of toxicological aspects of polybrominated diphenyl ethers: a flame-retardant additive in several consumer products

Polybrominated diphenyl ethers (PBDEs) are ubiquitous environmental contaminants due to their long half-life and widespread use as flame retardants in several consumer products, including plastics. In addition to other actions, these compounds are characterized as thyroid hormone disruptors. Thyroid hormones affect the function of nearly all tissues via their effects on cellular metabolism and the essential roles they play in differentiation and growth. Interference with thyroid hormone homeostasis by these environmental compounds, therefore, has the potential to impact development and every system in the body. Their presence in human breast milk is particularly troubling due to exposure of nursing children. The last trimester of pregnancy up to 2 years of age corresponds to a time of rapid neurodevelopment and represents a period of vulnerability to environmental insults. Rodent studies indicate that PBDEs may act as developmental neurotoxicants and effects on the reproductive system have been reported as well. Concerns exist regarding possible impacts of exposure, in particular ones which occur during development, on human health. This paper is part of a series of articles regarding contaminants in plastic and provides an overview regarding PBDEs, a class of flame-retardant additives to plastic. PBDEs possess a similar structure to the polychlorinated biphenyls (PCBs) previously used as lubricants in electrical generators and transformers until production was prohibited approximately 25 years ago. Parallels between the two compounds will be briefly made and in particular, as more epidemiological studies on PCBs are available than on PBDEs, a few examples concerning thyroid homeostasis, cognitive function and sexually dimorphic behavior in humans will be mentioned.     

The impacts of emission trends of POPs on human concentration dynamics: Lessons learned from a longitudinal study in Norway (1979–2007)

Background

In this short communication, our focus is on the relationship between human concentrations of select persistent organic pollutants (POPs) and environmental emissions. It is based on a longitudinal study (1979–2007) conducted in Norway.

Circulating levels of persistent organic pollutants (POPs) and carotid atherosclerosis in the elderly

Background and objective: Increased circulating levels of persistent organic pollutants (POPs) have been associated with myocardial infarction. Because myocardial infarction is an atherosclerotic disease, we investigated, in a cross-sectional study, whether POP levels are related to atherosclerosis.Methods: In the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study (n = 1,016 participants 70 years of age), the prevalence of carotid artery plaques was determined by ultrasound. The number of carotid arteries with plaques (0, 1, or 2) was recorded. Also, the intima-media thickness (IMT) and gray scale median of the intima-media complex (IM-GSM) were measured. Twenty-three POPs, comprising 16 polychlorinated biphenyls (PCBs), 5 pesticides, 1 dioxin, and 1 brominated compound (brominated diphenyl ether congener BDE-47), were analyzed by high-resolution chromatography coupled to high-resolution mass spectrometry.Results: Seven of the POPs (PCB congeners 153, 156, 157, 170, 180, 206, and 209) were significantly associated with the number of carotid arteries with plaques even after adjusting for multiple risk factors (sex, waist circumference, body mass index, fasting blood glucose, systolic and diastolic blood pressure, high-density lipoprotein and low-density lipoprotein cholesterol, serum triglycerides, smoking, antihypertensive treatment, and statin use; p = 0.002–0.0001). Highly chlorinated PCBs (congeners 194, 206, and 209) were associated with an echolucent IM-GSM (p < 0.0001 after adjustment), whereas associations between POPs and IMT were modest.Conclusions: Circulating levels of PCBs were associated with atherosclerotic plaques and echogenicity of the intima-media complex independent of cardiovascular risk factors, including lipids. This suggests that POPs may be a risk factor for myocardial infarction, but associations need to be confirmed in prospective studies.     

Biomonitoring of mercury and persistent organic pollutants in Michigan urban anglers and association with fish consumption

The 32-mile Detroit River and surrounding tributaries have been designated as a Great Lakes Area of Concern due to pollution from decades of municipal and industrial discharges, sewer overflows and urban development. Key pollutants in fish samples from the Detroit River include mercury, polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (DDE), dioxins and furans. A biomonitoring study was conducted to assess exposures to these persistent toxic substances in Detroit urban shoreline anglers who may be at high exposure risk due to consumption of locally caught fish. Using a modified venue-based sampling approach, 287 adult shoreline anglers along the Detroit River were recruited and participated in the program. Study participants provided blood and urine specimens and completed a questionnaire following informed consent. We examined percentile estimates for total blood mercury, PCBs, DDE, and dioxin-like total toxic equivalency (TEQ) concentrations among study participants. Multiple linear regression was used to identify important predictors of contaminant concentrations. Participants consumed a median of 64 Detroit River caught fish meals in the past year. The Detroit urban anglers’ median total blood mercury concentrations was 3.2 times higher than that for the general adult U.S. population. PCB concentrations among the Detroit anglers aged 18–39 years were higher than the U.S. population of the same race/ethnicity. Elevated levels of DDE and total TEQ concentrations were not observed in the cohort. Eating more locally caught fish was associated with higher total blood mercury and serum PCB concentrations. The biomonitoring data served to inform public health officials and help guide environmental public health actions to reduce harmful exposures.     

电子垃圾拆解地区多氯联苯经口暴露健康风险评价

目的 研究电子垃圾拆解地区经口暴露多氯联苯(PCBs)对人群健康产生的潜在健康危害。方法 运用美国环保署人群健康风险评估模型, 评估电子垃圾拆解地区经口暴露多氯联苯对人群的致癌和非致癌风险。结果 电子垃圾拆解地区水、稻米、包心菜、鸡蛋和鲫鱼中PCBs含量均高于对照区(均P<0.05);人群健康风险评估结果表明拆解区成年男性、成年女性和儿童经口暴露PCBs的非致癌风险分别为2.53×10^-6、3.04×10^-6、2.14×10^-6, 均高于美国环保局定义的人群风险水平值(1×10^-6);拆解区成年男性、成年女性和儿童人群经口暴露PCBs的致癌风险分别为4.34×10^-5、5.20×10^-5、9.72×10^-6, 对照区人群经口暴露PCBs的致癌风险分别为4.45×10^-6、4.61×10^-6、1.37×10^-6。结论 电子垃圾拆解产生的PCBs已对当地环境造成一定程度的污染, 并对当地人群存在潜在的健康风险。     

Revised and new reference values for some persistent organic pollutants (POPs) in blood for human biomonitoring in environmental medicine

Reference values for environmental pollutants related to the German population are established continuously by the Human Biomonitoring Commission of the German Federal Environmental Agency. The revised and new reference values for organochlorine compounds in whole blood are derived from the German Environmental Survey 1998 (adults aged 18-69 years) and from a survey performed with children (age 9-11 years) in south-west Germany 1998/99. The levels of organochlorine compounds in blood of adults increased with increasing age. Therefore the reference values are revised for different age groups (age groups: 18-19, 20-29, 30-39, 40-49, 50-59, 60-69). The reference values for PCB 138 in whole blood range from 0.4 to 2.2 micrograms/l, for PCB 153 from 0.6 to 3.3 micrograms/l, for PCB 180 from 0.3 to 2.4 micrograms/l, for beta-HCH from 0.3 to 0.9 microgram/l and for HCB from 0.4 to 5.8 micrograms/l. The reference values for DDE among adults in East Germany are higher compared to those in West Germany. The reference values of DDE in blood for adults in West Germany increase from 1.5 micrograms/l to 11 micrograms/l for the different age groups. The corresponding results for East Germany are 3 and 31 micrograms/l. The following reference values in blood of children (age 9-11 years) are recommended: 0.3 microgram/l for PCB 138, 0.4 microgram/l for PCB 153, 0.3 microgram/l for PCB 180, 0.9 microgram/l for sum of PCB (138 + 153 + 180), 0.3 microgram/l for beta-HCH, 0.3 microgram/l for HCB and 0.7 microgram/l for DDE. In comparison with the former evaluation the revised reference values for PCB, beta-HCH and HCB levels in blood were reduced especially for younger adults.     

Differences in serum concentrations of organochlorine compounds by occupational social class in pancreatic cancer

Background

The relationships between social factors and body concentrations of environmental chemical agents are unknown in many human populations. Some chemical compounds may play an etiopathogenic role in pancreatic cancer.

Objective

To analyze the relationships between occupational social class and serum concentrations of seven selected organochlorine compounds (OCs) in exocrine pancreatic cancer: dichlorodiphenyltrichloroethane (p,p′-DDT), dichlorodiphenyldichloroethene (p,p′-DDE), 3 polychlorinated biphenyls (PCBs), hexachlorobenzene, and β-hexachlorocyclohexane.

Methods

Incident cases of exocrine pancreatic cancer were prospectively identified, and interviewed face-to-face during hospital admission (n=135). Serum concentrations of OCs were analyzed by high-resolution gas chromatography with electron-capture detection. Social class was classified according to occupation.

Results

Multivariate-adjusted concentrations of all seven compounds were higher in occupational social classes IV-V (the less affluent) than in classes I-II; they were higher as well in class III than in classes I-II for four compounds. Concentrations of six OCs were higher in manual workers than in non-manual workers (p<0.05 for PCBs). Social class explained statistically between 3.7% and 5.7% of the variability in concentrations of PCBs, and 2% or less variability in the other OCs.

Conclusions

Concentrations of most OCs were higher in the less affluent occupational social classes. In pancreatic cancer the putative causal role of these persistent organic pollutants may not be independent of social class. There is a need to integrate evidence on the contribution of different social processes and environmental chemical exposures to the etiology of pancreatic and other cancers.     

Greenland sledge dogs (Canis familiaris) develop liver lesions when exposed to a chronic and dietary low dose of an environmental organohalogen cocktail

We assessed the relationship between exposure to organohalogen polluted minke whale (Balaenoptera acutorostrata) blubber and liver morphology and function in a generational controlled study of 28 Greenland sledge dogs (Canis familiaris). The prevalence of portal fibrosis, mild bile duct hyperplasia, and vascular leukocyte infiltrations was significantly higher in the exposed group (all Chi-square: p<0.05). In case of granulomas, the frequency was significantly highest in the bitches (P generation) while the prevalence of portal fibrosis was highest in the F generation (pups) (both Chi-square: p<0.05). No significant difference between exposed and controls was found for bile acid, ALAT, and ALKP, while ASAT and LDH were significantly highest in the control group (both ANOVA: p<0.05). We therefore suggest that a daily intake of 50-200g environmentally organohalogen polluted minke whale blubber can cause liver lesions in Greenland sledge dogs. It is reasonable to infer that other apex predators such as polar bears (Ursus maritimus) and humans may suffer from similar impacts.     

Childhood polybrominated diphenyl ether (PBDE) exposure and executive function in children in the HOME Study

Prenatal exposure to polybrominated diphenyl ethers (PBDEs) have been reported to impair executive function in children, but little is known whether childhood PBDE exposures play a role. Using the Health Outcomes and Measures of the Environment (HOME) Study, a prospective birth cohort in the greater Cincinnati area, we investigated the association between repeated measures of PBDEs during childhood and executive function at 8 years in 208 children and whether effect modification by child sex was present. We used child serum collected at 1, 2, 3, 5, and 8 years to measure PBDEs. The Behavior Rating Inventory of Executive Function was completed by parents to assess executive function at 8 years. We used multiple informant models to examine childhood PBDEs during several exposure windows. Null associations were observed between early childhood PBDEs and executive function. However, we observed significant adverse associations between a 10-fold increase in concurrent concentrations of BDE-28 (β = 4.6, 95% CI 0.5, 8.7) and BDE-153 (β = 4.8, 95% CI 0.8, 8.8) with behavioral regulation. In addition, PBDEs at 8 years were significantly associated with poorer emotional and impulse control. No associations were noted between childhood PBDEs and metacognition or global executive function. However, child sex significantly modified the associations, with significantly poorer executive function among males with higher concurrent BDE-153, and null associations in females. Our study findings suggest that concurrent PBDE exposures during childhood may be associated with poorer executive function, specifically behavior regulation. Males may also be more sensitive to adverse associations of concurrent PBDEs on executive function.     

The INMA—INfancia y Medio Ambiente—(Environment and Childhood) project: More than 10 years contributing to environmental and neuropsychological research

Background

In 2003 the INMA—INfancia y Medio Ambiente (Environment and Childhood) project, a Spanish national network of birth cohorts including more than 3500 participants, was set up with the aim to assess the health impacts of pre- and postnatal environmental exposures on children. The project has published more than 60 papers on maternal and environmental factors related to neuropsychological development in children, one of the main research interests within the project. With the present review, we evaluate the evidence provided by the INMA project on this topic and discuss how the data can contribute to cover the challenges that children’s environmental health research will face in the coming years.