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Wells EM, Kopylev L, Nachman R, Radke EG, Congleton J, Segal D. Total Blood Mercury Predicts Methylmercury Exposure in Fish and Shellfish Consumers. Biol Trace Elem Res 2022; 200:3867-3875. [PMID: 34686996 PMCID: PMC9200869 DOI: 10.1007/s12011-021-02968-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 10/12/2021] [Indexed: 11/17/2022]
Abstract
Many studies evaluating methylmercury (MeHg) toxicity rely on whole blood total mercury (THg) measurements to estimate MeHg exposure. However, whole blood THg includes other forms of mercury (Hg), such as inorganic Hg, which have different exposure sources and toxicological effects than MeHg. Therefore, estimating the whole blood MeHg/THg ratio is critical to predicting MeHg exposure and, subsequently, efforts to establish an exposure-response relationship for use in risk assessment. A large, representative dataset (National Health and Nutrition Examination Survey (NHANES) 2011-2016) was used to determine the whole blood MeHg/THg ratio among (a) self-reported fish and shellfish consumers, ≥ 15 years of age (the "full adult" population (N = 5268 training dataset; N = 2336 test dataset)) and (b) female fish and shellfish consumers, 15-44 years of age (the "women of reproductive age" population (N = 1285 training dataset; N = 560 test dataset)). Unadjusted and adjusted linear and spline models with direct measurements for both THg and MeHg were evaluated. The mean whole blood MeHg/THg ratio was 0.75 (95% confidence interval (CI): 0.74, 0.75). This ratio was significantly higher among those with higher THg concentrations. All models exhibited excellent fit (adjusted R2 from 0.957 to 0.982). Performance was slightly improved in spline versus linear models. For the full adult population and women of reproductive age, the unadjusted spline model predicted whole blood MeHg concentrations of 5.65 µg/L and 5.55 µg/L, respectively, when the THg concentration was 5.80 µg/L. These results suggest that whole blood THg is a good predictor of whole blood MeHg among fish and shellfish consumers.
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Affiliation(s)
- Ellen M. Wells
- School of Health Sciences, Purdue University, West Lafayette, IN USA
- Department of Public Health, Purdue University, West Lafayette, IN USA
| | - Leonid Kopylev
- Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, 1200 Pennsylvania Ave, Washington DC, NW 20460 USA
| | - Rebecca Nachman
- Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, 1200 Pennsylvania Ave, Washington DC, NW 20460 USA
| | - Elizabeth G. Radke
- Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, 1200 Pennsylvania Ave, Washington DC, NW 20460 USA
| | - Johanna Congleton
- Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, 1200 Pennsylvania Ave, Washington DC, NW 20460 USA
| | - Deborah Segal
- Center for Public Health and Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, 1200 Pennsylvania Ave, Washington DC, NW 20460 USA
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Louis ED, Eliasen EH, Ferrer M, Iglesias Hernandez D, Gaini S, Jiang W, Zheng W, Nielsen F, Petersen MS. Blood Harmane (1-Methyl-9H-Pyrido[3,4-b]indole) and Mercury in Essential Tremor: A Population-Based, Environmental Epidemiology Study in the Faroe Islands. Neuroepidemiology 2020; 54:272-280. [PMID: 32007995 PMCID: PMC7210050 DOI: 10.1159/000505874] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 01/08/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Essential tremor (ET) is among the most prevalent neurological diseases. Its environmental determinants are poorly understood. Harmane (1-methyl-9H-pyrido[3, 4-b]indole), a dietary tremor-producing neurotoxin, has been linked to ET in a few studies in New York and Madrid. Mercury, also a tremor-producing neurotoxin, has not been studied in ET. The Faroe Islands have been the focus of epidemiological investigations of numerous neurological disorders. OBJECTIVE In this population-based, case-control study, we directly measured blood harmane concentrations (HA) and blood mercury concentrations (Hg) in ET cases and controls. METHODS In total, 1,328 Faroese adults were screened; 26 ET cases were identified whose (HA) and (Hg) were compared to 197 controls. RESULTS Although there were no statistically significant differences between diagnostic groups, median (HA) was 2.7× higher in definite ET (4.13 g-10/mL) and 1.5× higher in probable ET (2.28 g-10/mL) than controls (1.53 g-10/mL). Small sample size was a limitation. For definite ET versus controls, p = 0.126. (Hg) were similar between groups. CONCLUSIONS We demonstrated marginally elevated (HA) in definite and probable ET. These data are similar to those previously published and possibly extend etiological links between this neurotoxin and ET to a third locale. The study did not support a link between mercury and ET.
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Affiliation(s)
- Elan D Louis
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA,
- Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, Connecticut, USA,
- Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, Connecticut, USA,
| | - Eina H Eliasen
- Department of Occupational Medicine and Public Health, The Faroese Hospital System, Tórshavn, Faeroe Islands
| | - Monica Ferrer
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | | | - Shahin Gaini
- Centre for Health Science, Faculty of Health Sciences, University of the Faroe Islands, Tórshavn, Faeroe Islands
- Infectious Diseases Division, National Hospital Faroe Islands, Tórshavn, Faeroe Islands
- Department of Infectious Diseases, Odense University Hospital/University of Southern Denmark, Odense, Denmark
| | - Wendy Jiang
- Purdue University School of Health Sciences, West Lafayette, Indiana, USA
| | - Wei Zheng
- Purdue University School of Health Sciences, West Lafayette, Indiana, USA
| | - Flemming Nielsen
- Department of Environmental Medicine, University of Southern Denmark, Odense, Denmark
| | - Maria Skaalum Petersen
- Department of Occupational Medicine and Public Health, The Faroese Hospital System, Tórshavn, Faeroe Islands
- Centre for Health Science, Faculty of Health Sciences, University of the Faroe Islands, Tórshavn, Faeroe Islands
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Louis ED, Ferrer M, Eliasen EH, Gaini S, Petersen MS. Tremor in normal adults: A population-based study of 1158 adults in the Faroe Islands. J Neurol Sci 2019; 400:169-174. [PMID: 30954661 DOI: 10.1016/j.jns.2019.03.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 02/25/2019] [Accepted: 03/20/2019] [Indexed: 12/27/2022]
Abstract
There are virtually no population-based data on tremor in normal individuals. Using a population-based sample of 1158 normal adults ages 40-98 years in the Faroe Islands, we characterized the extent of normal action tremor across age and gender strata. Participants drew two Archimedes spirals with each hand, and tremor was systematically quantified by a senior movement disorder neurologist using a reliable and valid ordinal rating scale (ratings = 0-3). Tremor was nearly universal - 1145 (98.9%) participants had a total mean spiral score > 0. Older age was associated with more tremor (p < .001) and spiral scores were higher in males than females (p < .001). The proportion of individuals with a spiral rating ≥ 1.5 (i.e., more than mild tremor) was low (1.8% - 8.5%); however, this value reached 19.6% in left-hand spirals of males ≥70 years old. In this population-based study of more than one thousand normal adults, the vast bulk (i.e., 98.9%) had tremor on spiral drawing. In general, the tremor was mild. The proportion of individuals with tremor above the mild range varied across age and gender strata. These extensive data may be used as a gold standard for defining normal levels of tremor within adult populations.
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Affiliation(s)
- Elan D Louis
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA; Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA; Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, USA.
| | - Monica Ferrer
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Eina H Eliasen
- Department of Occupational Medicine and Public Health, The Faroese Hospital System, Tórshavn, Faroe Islands
| | - Shahin Gaini
- Infectious Diseases Division, National Hospital Faroe Islands, Tórshavn, Faroe Islands; Department of Infectious Diseases, Odense University Hospital/University of Southern Denmark, Odense, Denmark; Centre for Health Science, Faculty of Health Sciences, University of the Faroe Islands, Tórshavn, Faroe Islands
| | - Maria Skaalum Petersen
- Department of Occupational Medicine and Public Health, The Faroese Hospital System, Tórshavn, Faroe Islands; Centre for Health Science, Faculty of Health Sciences, University of the Faroe Islands, Tórshavn, Faroe Islands
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Calabrese EJ, Iavicoli I, Calabrese V, Cory-Slechta DA, Giordano J. Elemental mercury neurotoxicity and clinical recovery of function: A review of findings, and implications for occupational health. ENVIRONMENTAL RESEARCH 2018; 163:134-148. [PMID: 29438899 DOI: 10.1016/j.envres.2018.01.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 01/16/2018] [Accepted: 01/17/2018] [Indexed: 06/08/2023]
Abstract
This paper assessed approximately 30 studies, mostly involving occupationally exposed subjects, concerning the extent to which those who developed elemental mercury (Hg)-induced central and/or peripheral neurotoxicities from chronic or acute exposures recover functionality and/or performance. While some recovery occurred in the vast majority of cases, the extent of such recoveries varied considerably by individual and endpoint. Factors accounting for the extensive inter-individual variation in toxicity and recovery were not specifically assessed such as age, gender, diet, environmental enrichment, chelation strategies and dose-rate. While the data indicate that psychomotor endpoints often show substantial and relatively rapid (i.e., 2-6 months) recovery and that neuropsychological endpoints display slower and less complete recovery, generalizations are difficult due to highly variable study designs, use of different endpoints measured between studies, different Hg exposures based on blood/urine concentrations and Hg dose-rates, the poor capacity for replicating findings due to the unpredictable/episodic nature of harmful exposures to elemental Hg, and the inconsistency of the initiation of studies after induced toxicities and the differing periods of follow up during recovery periods. Finally, there is strikingly limited animal model literature on the topic of recovery/reversibility of elemental Hg toxicity, a factor which significantly contributes to the overall marked uncertainties for predicting the rate and magnitude of recovery and the factors that affect it.
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Affiliation(s)
- Edward J Calabrese
- Department of Environmental Health Sciences, University of Massachusetts, Morrill I, N344, Amherst, MA 01003, USA.
| | - Ivo Iavicoli
- Department of Public Health, University of Naples Federico II, Via S. Pansini 5, Naples 80131, Italy.
| | - Vittorio Calabrese
- Department of Biomed & Biotech Sciences, School of Medicine, University of Catania, Via Santa Sofia 97, Catania 95125, Italy.
| | - Deborah A Cory-Slechta
- Environmental Medicine, Pediatrics & Public Health Sciences, University of Rochester School of Medicine, Rochester, NY 14642, USA.
| | - James Giordano
- Department of Neurology and Biochemistry, and Neuroethics Studies Program-Pellegrino Center for Clinical Bioethics, Georgetown University Medical Center, Washington, D.C. 20057, USA.
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