Thyroid function in lead smelter workers: absence of subacute or cumulative effects with moderate lead burdens

Schumacher, Cynthia; Brodkin, Carl A.; Alexander, Bruce H.; Cullen, Mark R.; Rainey, Petrie M.; Netten, Chris van; Faustman, Elaine M.; Checkoway, Harvey

doi:10.1007/s004200050305

Cited by 29 publications

(20 citation statements)

References 15 publications

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“…Pb exposure [mean 15 µg/dL blood Pb (BPb) level] was negatively correlated with transthyretin levels in cerebrospinal fluid samples from human patients (Zheng et al 2001). Previous studies of populations with high exposure to Pb (indicated by BPb levels of > 20 µg/dL) suggested negative associations with circulating T 4 , FT 4 , or T 3 (López et al 2000; Robins et al 1983; Singh et al 2000; Tuppurainen et al 1988); however, associations were not evident in other similar study populations (Erfurth et al 2001; Schumacher et al 1998; Siegel et al 1989). Fewer studies have investigated associations of BPb levels of < 10 µg/dL with THs.…”

mentioning

confidence: 70%

Thyroid Hormones in Relation to Lead, Mercury, and Cadmium Exposure in the National Health and Nutrition Examination Survey, 2007–2008

Chen

Kim

Chung

et al. 2013

Environ Health Perspect

124

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Background: Heavy metals, such as lead (Pb), mercury (Hg), and cadmium (Cd), are known toxicants, but their associations with the thyroid axis have not been well quantified at U.S. background levels.Objectives: We investigated the relationships between thyroid hormones (total and free thyroxine [TT4 and FT4], total and free triiodothyronine [TT3 and FT3], thyroid-stimulating hormone [TSH], and thyroglobulin [Tg]) and levels of Pb, Hg, and Cd in blood and Cd in urine.Methods: We separately analyzed a sample of 1,109 adolescents (12–19 years of age) and a sample of 4,409 adults from the U.S. National Health and Nutrition Examination Survey (NHANES) 2007–2008. We estimated associations after adjusting for age, sex, race, urinary iodine, body mass index, and serum cotinine.Results: The geometric mean (GM) levels of blood Pb (BPb), total Hg, and Cd were 0.81 µg/dL, 0.47 µg/L, and 0.21 µg/L in adolescents and 1.43 µg/dL, 0.96 µg/L, and 0.38 µg/L in adults, respectively. The GMs of urinary Cd were 0.07 and 0.25 µg/g creatinine in adolescents and adults, respectively. No consistent pattern of metal and thyroid hormone associations was observed in adolescents. In adults, blood Hg was inversely related to TT4, TT3, and FT3 and urinary Cd was positively associated with TT4, TT3, FT3, and Tg, but there were no associations with Pb. Associations were relatively weak at an individual level, with about 1–4% change in thyroid hormones per interquartile range increase in Hg or Cd.Conclusions: Our analysis suggests an inverse association between Hg exposure and thyroid hormones, and a positive association between Cd exposure and thyroid hormones in adults.

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mentioning

confidence: 70%

Thyroid Hormones in Relation to Lead, Mercury, and Cadmium Exposure in the National Health and Nutrition Examination Survey, 2007–2008

Chen

Kim

Chung

et al. 2013

Environ Health Perspect

124

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“…Some report no relationship (Erfurth et al 2001; Gennart et al 1992; Schumacher et al 1998), whereas others report depressed thyroid hormone levels and/or function (Liang et al 2003; Robins et al 1983; Sandstead et al 1969). It is also possible that lead may have different effects on thyroid hormones at different levels of exposure.…”

Section: Discussionmentioning

confidence: 99%

Relationship of Thyroid Hormone Levels to Levels of Polychlorinated Biphenyls, Lead, p,p ′ - DDE, and Other Toxicants in Akwesasne Mohawk Youth

Schell

Gallo

Denham

et al. 2008

Environ Health Perspect

107

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BackgroundIt is well documented that acute exposure to high levels of persistent organic pollutants, such as polychlorinated biphenyls (PCBs), p,p′-dichlorophenyldichloroethylene (p,p′-DDE), and hexachlorobenzene (HCB), can affect human health including thyroid function. Chronic exposure to multiple toxicants is common but difficult to analyze, and most prior studies have focused on adults or newborns, creating a gap in our understanding of multitoxicant effects among adolescents.ObjectiveWe investigated whether levels of PCBs, p,p′-DDE, HCB, mirex, lead, and mercury reflecting past chronic exposure are associated with alterations in levels of thyroid-stimulating hormone (TSH), triiodothyronine (T3), total thyroxine (TT4), and free thyroxine (FT4) among older children and adolescents.MethodsThe sample consists of youth from the Akwesasne Mohawk Nation (n = 232) who reside in proximity to several industries that have contaminated the local environment. We used multiple regression analysis to examine the effect of PCB groupings, p,p′-DDE, HCB, lead, and mercury on thyroid hormones after adjusting for sociodemographic covariates and controlling for all other toxicants.ResultsExposure to PCBs affects the thyroid hormone profile in adolescents. The group of persistent PCBs was positively associated with TSH but inversely related to FT4. Nonpersistent PCBs were significantly and negatively related to FT4 only. HCB was negatively associated with T4, and lead was positively associated with T3. Breast-fed adolescents had higher levels of persistent PCBs and p,p′-DDE but not of nonpersistent PCBs or any other toxicant when compared with non-breast-fed adolescents. Though having lower levels of persistent PCBs and p,p′-DDE, non-breast-fed adolescents exhibited significant relationships between persistent PCBs and TSH and FT4, but breast-fed adolescents did not. It appears that PCBs from breast milk obscure the relationship between prenatal PCB exposure and thyroid function by adding random variation in PCB levels.ConclusionOur results demonstrate a reduction in thyroid function in adolescents in relation to their current serum levels of PCBs. These observations are consistent with the hypothesis that pre-natal exposure to PCBs alters thyroid function in a long-lasting manner but does not exclude the possibility that postnatal exposure is influential also.

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“…Workers with PbBs of approximately 20-30 μg/dL showed no clear indications of thyroid dysfunction (Dursun and Tutus 1999;Erfurth et al 2001;Refowitz 1984;Schumacher et al 1998). Serum T 4 , EFT 4 , and TSH were assessed in a cross-sectional study of 151 male lead smelter workers that examined doseresponse relationships across specifically defined levels of lead exposure (Schumacher et al 1998).…”

Section: Crossmentioning

confidence: 99%

“…Serum T 4 , EFT 4 , and TSH were assessed in a cross-sectional study of 151 male lead smelter workers that examined doseresponse relationships across specifically defined levels of lead exposure (Schumacher et al 1998). The mean duration of employment in lead-exposed areas was 4.3 years, the mean current PbB was 24 μg/dL (15% exceeded 40 μg/dL), and the mean PbB for the preceding 10 years was 31 μg/dL (26% exceeded 40 μg/dL).…”

Section: Crossmentioning

confidence: 99%

Characterizing Golden Eagle Risk to Lead and Anticoagulant Rodenticide Exposure: A Review

Herring

Eagles‐Smith

Buck

2017

Journal of Raptor Research

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Thyroid function in lead smelter workers: absence of subacute or cumulative effects with moderate lead burdens

Abstract: In contrast to studies observing thyroid dysfunction in the setting of high lead exposure and related clinical poisoning, our findings weigh against a significant physiologic effect on thyroid function at lower levels (< 60 microg/dl) of occupational lead exposure.

Cited by 29 publications

References 15 publications

Thyroid Hormones in Relation to Lead, Mercury, and Cadmium Exposure in the National Health and Nutrition Examination Survey, 2007–2008

Thyroid Hormones in Relation to Lead, Mercury, and Cadmium Exposure in the National Health and Nutrition Examination Survey, 2007–2008

Relationship of Thyroid Hormone Levels to Levels of Polychlorinated Biphenyls, Lead, p,p ′ - DDE, and Other Toxicants in Akwesasne Mohawk Youth

Characterizing Golden Eagle Risk to Lead and Anticoagulant Rodenticide Exposure: A Review

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