Research | Children’s Health Relationship of Thyroid Hormone Levels to Levels of Polychlorinated Biphenyls, Lead, p,p´- DDE, and Other Toxicants in Akwesasne Mohawk Youth (original) (raw)
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Environmental Research, 2008
Background: Polychlorinated biphenyls (PCBs) may interact with several thyroid functions. Severe environmental pollution by PCBs has been observed in Brescia, Italy, due to the presence of a factory that produced these compounds until 1984. Objectives: We aimed to investigate the correlation between serum levels of total PCBs and PCB 153 and thyroid hormone serum levels in adults in a cross-sectional population-based study. Methods: A total of 527 subjects were enrolled; they were face-to-face interviewed about their history of thyroid disease and provided a blood sample under fasting conditions. The serum levels of free and total triiodothyronine (FT3 and TT3), thyroxine (FT4 and TT4) and thyroid-stimulating hormone (TSH), anti-thyroperoxidase (anti-TPO) and anti-thyroglobulin (anti-TGA), and lipid-adjusted total PCBs and PCB 153 were determined. Results: There was no statistically significant difference in total PCB and PCB 153 concentrations in subjects with and without thyroid disease. Inverse, weak, statistically significant correlations were found between total PCBs and FT3 (Spearman's r ¼ À0.09) and between total PCBs and PCB 153 and TSH (Spearman's r ¼ À0.16 and À0.12, respectively). However, multiple regression analysis with FT3 and TSH serum levels as dependent variables and total PCBs and PCB 153 serum levels as predictors, including age, gender and BMI, showed a positive, rather than negative, association of PCBs and PCB 153 with FT3 and no association with TSH. Conclusions: This study does not support the hypothesis that relatively high PCB environmental exposure can determine substantial alterations in thyroid function among adult people.
Environmental …, 2008
Environmental chemicals can disrupt endocrine balance and in particular thyroid hormone (TH) homeostasis. However, studies differ with respect to thyroid profile changes and gender differences are rarely examined. This study investigated the THs, triodothyronine (T3), thyroxine (T4), and thyroid stimulating hormone (TSH), in relation to serum organochlorines (OCs), bioindicators of mercury (Hg) and blood lead (Pb) in 211 freshwater fish consumers (124 men and 87 women) from two communities in Canada. Thyroid hormones were within the normal range and the bioindicators of exposure were low compared to other reports on fish consumers. Stratified analysis showed that for women, serum T3 concentrations were negatively related to serum concentrations of PCB 138, PCB 153, the noncoplanar congeners, Arochlor 1260, and SPCB, as well as p,p 0-DDE. No relations were observed between T4 and any of the chemicals measured, but TSH was negatively related to blood Pb. For men, serum T4 was inversely related to PCB 138, non-ortho-substituted (dioxin-like) PCBs and SPCB. A significant positive relationship was observed between serum TSH and different PCB congeners (PCB 138, PCB 180, non-coplanar congeners, mono-ortho coplanar congeners, dioxin-like PCBs), as well as SPCB. Serum TSH increased with hair and blood Hg concentrations and was highest among those in the highest 50th percentile for both Hg and dioxin-like PCB congeners compared to the others. No associations were observed for T3 in men. These findings suggest that even at low concentrations, these environmental contaminants can interfere with thyroid status and effects may differ by gender.
Persistent organic pollutants and anti-thyroid peroxidase levels in Akwesasne Mohawk young adults
Environmental Research, 2009
Persistent organic pollutants, such as PCBs, HCB and DDE, have been found to elicit a broad spectrum of biologic, metabolic, and immunologic responses. The potential of these pollutants to impair immune responses and trigger autoimmune disease is of growing concern, given their structural similarity to thyroid hormones and their potential to modulate the mechanisms and interfere with the binding of these hormones. We examine the relationship of different groupings of PCBs, according to chlorination and structure, and of p,p'-DDE and HCB to anti-thyroid peroxidase antibody, a useful tool in the evaluation of thyroid dysfunction, among 115 young adults of the Akwesasne Mohawk Nation. Overall, eighteen participants (15.4%) had TPOAb levels above the normal laboratory reference range (23% of females, 9% of males). Among participants who were breast fed (n=47), those with an elevated TPOAb level had significantly higher levels of all PCB groupings, with the exception of levels of non-persistent PCBs which did not differ significantly. Levels of p,p'-DDE were also significantly elevated, while HCB and mirex were not higher among those with elevated TPOAb. Also, after stratifying by breast feeding status, participants who were breast fed showed significant, positive relationships between TPOAb levels and all PCB groupings, except groups comprised of non-persistent PCBs, and with p,p'-DDE, HCB, and mirex. No effects were evident among nonbreastfed young adults. Further studies are necessary to elucidate the site and mechanism of action of these POPs and to establish thresholds for these effects, especially among populations with background levels of toxicant exposure.
Relationships of Thyroid Hormones with Polychlorinated Biphenyls, Dioxins, Furans, and DDE in Adults
Environmental Health Perspectives, 2007
Thyroid hormone homeostasis can be disrupted by exposure to ubiquitous and bioaccumulative organochlorines such as polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins (PCDDs). Whereas investigations of health effects have generally focused on human populations with relatively high exposures through occupation, accident, or high fish consumption, general population exposures may also carry risk. We studied associations of total thyroxine (T(4)) and thyroid-stimulating hormone (TSH) with PCBs, dioxin-like toxic equivalents (TEQs), and p,p'-diphenyldichloroethene (DDE) in adult participants without thyroid disease who participated in the 1999-2002 National Health and Nutrition Examination Survey, a cross-sectional survey examining a random sample representative of the U.S. population. We found inverse associations of total T(4) with exposure to TEQs in both sexes, with stronger associations in females. In women, mean T(4) was 8.2 microg/dL, and levels were on average 0.75 microg/dL lower (95% confidence interval, 0.04-1.46) in women in the highest quintile of TEQ exposure compared with the lowest two quintiles. Effects were stronger in people > 60 years of age, with negative associations of T(4) with PCBs and TEQs, and positive associations of TSH with PCBs and TEQs in older women, and a negative association of TSH with PCBs in older men. The data show a dose-dependent decrease in total T(4) with exposure to TEQs at levels similar to those found in the general U.S. population. The effects were stronger in women. The results suggest that older adults, who have a high risk of thyroid disease, may be more at risk for disruption of thyroid hormone homeostasis by dioxin-like organochlorines than younger adults.
Frontiers in Pediatrics, 2021
Background:Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants found in human tissues. PCBs can be transferred through the placenta and may disrupt the maternal thyroid homeostasis, and affect fetal thyroid hormone production. Several studies have shown that intrauterine exposure to PCBs might be associated with abnormal levels of thyroid hormones in mothers and their offspring.Objectives:To examine the associations between environmental exposure to PCBs and thyroid hormone levels in mothers and newborns.Methods:The EHF-Assaf-Harofeh-Ichilov cohort includes 263 mothers-newborns dyads. A total of 157 mother-newborn dyads had both PCBs and thyroid function measures. Regression models were used to estimate associations between maternal PCB exposure and maternal and newborn thyroid function, controlling for possible confounders.Results:Four PCBs congeners were analyzed: PCBs 118, 138, 153, and 180. ∑PCBs median (IQR) level was 14.65 (2.83–68.14) ng/g lipids. The m...
The Science of the total environment, 2018
Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs) are persistent organic pollutants that are universally detected. Some congeners of PCDDs, PCDFs or PCBs have dioxin-like toxicity, whereas non-dioxin-like PCBs are considered to have different toxicity. Reports of the relationships between prenatal exposure to PCDDs, PCDFs or PCBs and thyroid homeostasis in pregnant women and infants have been inconsistent. The aim of this study was to investigate the effect of maternal serum PCDD/F or PCB levels on maternal and neonatal thyroid hormone (TH) levels in a prospective cohort. Of the 514 subjects in the prospective cohort, 386 mothers and 410 infants were included for analysis. Fifteen dioxins and seventy PCBs in maternal blood collected between 23 and 41weeks of gestation were measured using high-resolution gas chromatography and high-resolution mass spectrometry. Blood samples to measure thyroid stimulating hormone (TSH) and free thyroxine (FT4) leve...
Environmental Health Perspectives, 2009
Background: An increasing number of studies have shown that several ubiquitous environmental contaminants possess thyroid hormone-disrupting capacities. Prenatal exposure to some of them, such as polychlorinated biphenyls (PCBs), has also been associated with adverse neurodevelopmental effects in infants. oBjectives: In this study we examined the relationship between exposure to potential thyroid hormone-disrupting toxicants and thyroid hormone status in pregnant Inuit women from Nunavik and their infants within the first year of life.