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Geier DA, Kern JK, Geier MR. A Two-Phase Case-Control Study of Autism Risk Among Children Born From the Late 1990s Through the Early 2000s in the United States. Med Sci Monit 2016; 22:5196-5202. [PMID: 28031551 PMCID: PMC5218387 DOI: 10.12659/msm.900257] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background This study evaluated the hypothesis that the 1999 recommendation by the American Academy of Pediatrics (AAP) and US Public Health Service (PHS) to reduce exposure to mercury (Hg) from Thimerosal in US vaccines would be associated with a reduction in the long-term risk of being diagnosed with autism. Material/Methods A two-phase assessment utilizing a case (n=73) -control (n=11,783) study in the Vaccine Adverse Event Reporting System (VAERS) database (for hypothesis generating) and a more rigorous, independent matched case (n=40) -control (n=40) study (hypothesis testing) was undertaken. Results Analysis of the VAERS database using logistic regression revealed that the odds ratio (OR) for being an autism case in the VAERS database significantly decreased with a more recent year of vaccination in comparison to controls (OR=0.65) from 1998 to 2003. Sex-separated analyses revealed similar significant effects for males (OR=0.62) and females (OR=0.71). Analyses of the matched case-control data revealed, using the t-test statistic, that the mean date of birth among cases diagnosed with an autism spectrum disorder (ASD) (2000.5±1.2) was significantly more in the past than in controls (2001.1±1.3). Logistic regression also revealed that the OR for being diagnosed with ASD significantly decreased with a more recent date of birth in comparison to controls (OR=0.67) from 1998–2003. Conclusions This study reveals that the risk of autism during from the late1990s to early 2000s in the US significantly decreased with reductions in Hg exposure from Thimerosal-containing childhood vaccines, but future studies should examine this phenomenon in other US populations. Vaccine programs have significantly reduced the morbidity and mortality associated with infectious disease, but Thimerosal should be removed from all vaccines.
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Affiliation(s)
- David A Geier
- Department of Research, Institute of Chronic Illnesses, Inc., Silver Spring, MD, USA.,Department of Research, CoMeD, Inc., 14 Redgate Court, Silver Spring, MD, USA
| | - Janet K Kern
- Department of Research, Institute of Chronic Illnesses, Inc., Silver Spring, MD, USA.,Department of Research, CoMeD, Inc., 14 Redgate Court, Silver Spring, MD, USA.,Department of Research, CONEM US Autism Research Group, Allen, TX, USA
| | - Mark R Geier
- Department of Research, Institute of Chronic Illnesses, Inc., Silver Spring, MD, USA.,Department of Research, CoMeD, Inc., 14 Redgate Court, Silver Spring, MD, USA
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Khaled EM, Meguid NA, Bjørklund G, Gouda A, Bahary MH, Hashish A, Sallam NM, Chirumbolo S, El-Bana MA. Altered urinary porphyrins and mercury exposure as biomarkers for autism severity in Egyptian children with autism spectrum disorder. Metab Brain Dis 2016; 31:1419-1426. [PMID: 27406246 DOI: 10.1007/s11011-016-9870-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 06/30/2016] [Indexed: 12/11/2022]
Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder that affects social, communication, and behavioral development. Recent evidence supported but also questioned the hypothetical role of compounds containing mercury (Hg) as contributors to the development of ASD. Specific alterations in the urinary excretion of porphyrin-containing ring catabolites have been associated with exposure to Hg in ASD patients. In the present study, the level of urinary porphyrins, as biomarkers of Hg toxicity in children with ASD, was evaluated, and its correlation with severity of the autistic behavior further explored. A total of 100 children was enrolled in the present study. They were classified into three groups: children with ASD (40), healthy controls (40), and healthy siblings of the ASD children (20). Children with ASD were diagnosed using DSM-IV-TR, ADI-R, and CARS tests. Urinary porphyrins were evaluated within the three groups using high-performance liquid chromatography (HPLC), after plasma evaluation of mercury (Hg) and lead (Pb) in the same groups. Results showed that children with ASD had significantly higher levels of Hg, Pb, and the porphyrins pentacarboxyporphyrin, coproporphyrin, precoproporphyrin, uroporphyrins, and hexacarboxyporphyrin compared to healthy controls and healthy siblings of the ASD children. However, there was no significant statistical difference in the level of heptacarboxyporphyrin among the three groups, while a significant positive correlation between the levels of coproporphyrin and precoproporphyrin and autism severity was observed. Mothers of ASD children showed a higher percentage of dental amalgam restorations compared to the mothers of healthy controls suggesting that high Hg levels in children with ASD may relate to the increased exposure to Hg from maternal dental amalgam during pregnancy and lactation. The results showed that the ASD children in the present study had increased blood Hg and Pb levels compared with healthy control children indicating that disordered porphyrin metabolism might interfere with the pathology associated with the autistic neurologic phenotype. The present study indicates that coproporphyrin and precoproporhyrin may be utilized as possible biomarkers for heavy metal exposure and autism severity in children with ASD.
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Affiliation(s)
- Eman M Khaled
- Department of Pediatric, Al-Azhar University, Cairo, Egypt
| | - Nagwa A Meguid
- Department of Research on Children with Special Needs, National Research Centre, Giza, Egypt
| | - Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Toften 24, 8610, Mo i Rana, Norway.
| | - Amr Gouda
- Department of Genetic Biochemistry, National Research Centre, Giza, Egypt
| | | | - Adel Hashish
- Department of Research on Children with Special Needs, National Research Centre, Giza, Egypt
| | - Nermin M Sallam
- Department of Research on Children with Special Needs, National Research Centre, Giza, Egypt
| | - Salvatore Chirumbolo
- University Laboratory of Medical Research, Department of Medicine, University of Verona, Verona, Italy
| | - Mona A El-Bana
- Department of Medical Biochemistry, National Research Centre, Giza, Egypt
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van Wijngaarden E, Thurston SW, Myers GJ, Harrington D, Cory-Slechta DA, Strain JJ, Watson GE, Zareba G, Love T, Henderson J, Shamlaye CF, Davidson PW. Methyl mercury exposure and neurodevelopmental outcomes in the Seychelles Child Development Study Main cohort at age 22 and 24years. Neurotoxicol Teratol 2016; 59:35-42. [PMID: 27989696 DOI: 10.1016/j.ntt.2016.10.011] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 09/29/2016] [Accepted: 10/26/2016] [Indexed: 12/15/2022]
Abstract
BACKGROUND All fish contain methyl mercury (MeHg), a known neurotoxicant at adequate dosage. There is still substantial scientific uncertainty about the consequences, if any, of mothers consuming fish with naturally-acquired levels of MeHg contamination. In 1989-1990, we recruited the Main Cohort of the Seychelles Child Development Study to assess the potential developmental effects of prenatal MeHg exposure. We report here on associations with neurodevelopmental outcomes obtained at 22 and 24years of age. METHODS Neurodevelopmental tests at 22years included the Boston Naming Test, Cambridge Neuropsychological Test Automated Battery (CANTAB), and the Profile of Mood States. At 24years, we administered the Stroop Word-Color Test, the Barkley Adult ADHD Rating Scale, the Test of Variables of Attention, and the Finger Tapping test. We also administered a healthy behaviors survey at both ages. Primary analyses examined covariate-adjusted associations in multiple linear regression models with prenatal MeHg exposure. In secondary analyses we also examined associations with recent postnatal MeHg exposure. RESULTS We did not observe adverse associations between prenatal MeHg exposure and any of the measured endpoints. Some measures of attention, executive function, and delayed recall showed improved performance with increasing exposure. Secondary analysis did not show consistent patterns of association with postnatal exposure. CONCLUSIONS Our cohort has been examined at ten different ages over 24years of follow-up. Findings suggest that prenatal and recent postnatal MeHg exposure from ocean fish consumption is not adversely associated with neurobehavioral development at levels that are about ten times higher than typical U.S. exposures.
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Affiliation(s)
- Edwin van Wijngaarden
- University of Rochester School of Medicine and Dentistry, Rochester, NY, United States.
| | - Sally W Thurston
- University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Gary J Myers
- University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Donald Harrington
- University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | | | - J J Strain
- Ulster University, Coleraine, Northern Ireland, United Kingdom
| | - Gene E Watson
- University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Grazyna Zareba
- University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Tanzy Love
- University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | | | | | - Philip W Davidson
- University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
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Carter CJ, Blizard RA. Autism genes are selectively targeted by environmental pollutants including pesticides, heavy metals, bisphenol A, phthalates and many others in food, cosmetics or household products. Neurochem Int 2016; 101:S0197-0186(16)30197-8. [PMID: 27984170 DOI: 10.1016/j.neuint.2016.10.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 10/18/2016] [Accepted: 10/26/2016] [Indexed: 11/21/2022]
Abstract
The increasing incidence of autism suggests a major environmental influence. Epidemiology has implicated many candidates and genetics many susceptibility genes. Gene/environment interactions in autism were analysed using 206 autism susceptibility genes (ASG's) from the Autworks database to interrogate ∼1 million chemical/gene interactions in the comparative toxicogenomics database. Any bias towards ASG's was statistically determined for each chemical. Many suspect compounds identified in epidemiology, including tetrachlorodibenzodioxin, pesticides, particulate matter, benzo(a)pyrene, heavy metals, valproate, acetaminophen, SSRI's, cocaine, bisphenol A, phthalates, polyhalogenated biphenyls, flame retardants, diesel constituents, terbutaline and oxytocin, inter alia showed a significant degree of bias towards ASG's, as did relevant endogenous agents (retinoids, sex steroids, thyroxine, melatonin, folate, dopamine, serotonin). Numerous other suspected endocrine disruptors (over 100) selectively targeted ASG's including paraquat, atrazine and other pesticides not yet studied in autism and many compounds used in food, cosmetics or household products, including tretinoin, soy phytoestrogens, aspartame, titanium dioxide and sodium fluoride. Autism polymorphisms influence the sensitivity to some of these chemicals and these same genes play an important role in barrier function and control of respiratory cilia sweeping particulate matter from the airways. Pesticides, heavy metals and pollutants also disrupt barrier and/or ciliary function, which is regulated by sex steroids and by bitter/sweet taste receptors. Further epidemiological studies and neurodevelopmental and behavioural research is warranted to determine the relevance of large number of suspect candidates whose addition to the environment, household, food and cosmetics might be fuelling the autism epidemic in a gene-dependent manner.
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Affiliation(s)
- C J Carter
- PolygenicPathways, Flat 2, 40 Baldslow Road, Hastings, East Sussex, TN34 2EY, UK.
| | - R A Blizard
- Molecular Psychiatry Laboratory, Mental Health Sciences Unit, University College, London, UK
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Kern JK, Geier DA, Sykes LK, Haley BE, Geier MR. The relationship between mercury and autism: A comprehensive review and discussion. J Trace Elem Med Biol 2016; 37:8-24. [PMID: 27473827 DOI: 10.1016/j.jtemb.2016.06.002] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 05/17/2016] [Accepted: 06/01/2016] [Indexed: 12/28/2022]
Abstract
The brain pathology in autism spectrum disorders (ASD) indicates marked and ongoing inflammatory reactivity with concomitant neuronal damage. These findings are suggestive of neuronal insult as a result of external factors, rather than some type of developmental mishap. Various xenobiotics have been suggested as possible causes of this pathology. In a recent review, the top ten environmental compounds suspected of causing autism and learning disabilities were listed and they included: lead, methyl-mercury, polychorinated biphenyls, organophosphate pesticides, organochlorine pesticides, endocrine disruptors, automotive exhaust, polycyclic aromatic hydrocarbons, polybrominated diphenyl ethers, and perfluorinated compounds. This current review, however, will focus specifically on mercury exposure and ASD by conducting a comprehensive literature search of original studies in humans that examine the potential relationship between mercury and ASD, categorizing, summarizing, and discussing the published research that addresses this topic. This review found 91 studies that examine the potential relationship between mercury and ASD from 1999 to February 2016. Of these studies, the vast majority (74%) suggest that mercury is a risk factor for ASD, revealing both direct and indirect effects. The preponderance of the evidence indicates that mercury exposure is causal and/or contributory in ASD.
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Affiliation(s)
- Janet K Kern
- Institute of Chronic Illnesses, Inc., 14 Redgate Court, Silver Spring, MD, 20905 USA; Council for Nutritional and Environmental Medicine, Mo i Rana, Norway; CoMeD, Inc., 14 Redgate Court, Silver Spring, MD, 20905 USA.
| | - David A Geier
- Institute of Chronic Illnesses, Inc., 14 Redgate Court, Silver Spring, MD, 20905 USA; CoMeD, Inc., 14 Redgate Court, Silver Spring, MD, 20905 USA
| | - Lisa K Sykes
- CoMeD, Inc., 14 Redgate Court, Silver Spring, MD, 20905 USA
| | - Boyd E Haley
- University of Kentucky, 410 Administration Drive, Lexington, KY, 40506 USA
| | - Mark R Geier
- Institute of Chronic Illnesses, Inc., 14 Redgate Court, Silver Spring, MD, 20905 USA; CoMeD, Inc., 14 Redgate Court, Silver Spring, MD, 20905 USA
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Environmental pollutants and child health-A review of recent concerns. Int J Hyg Environ Health 2016; 219:331-42. [PMID: 27216159 DOI: 10.1016/j.ijheh.2016.05.001] [Citation(s) in RCA: 214] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 05/02/2016] [Accepted: 05/03/2016] [Indexed: 01/09/2023]
Abstract
In recent years, many new studies have evaluated associations between environmental pollutants and child health. This review aims to provide a broad summary of this literature, comparing the state of epidemiological evidence for the effects of a wide range of environmental contaminants (air pollutants, heavy metals, organochlorine compounds, perfluoroalkyl substances, polybrominated diphenyl ethers, pesticides, phthalates and bisphenol A) on child health outcomes. The review addresses effects on foetal growth and prematurity, neurodevelopment, respiratory and immune health, and childhood growth and obesity. Findings of recent prospective studies and meta-analyses have corroborated previous good evidence, often at lower exposure levels, for effects on foetal growth of air pollution and polychlorinated biphenyls (PCBs), for neurotoxic effects of lead, methylmercury, PCBs and organophosphate pesticides, and for respiratory health effects of air pollution. Moderate evidence has emerged for a potential role of environmental pollutants in attention deficit hyperactivity disorder and autism (lead, PCBs, air pollution), respiratory and immune health (dichlorodiphenyldichloroethylene - DDE - and PCBs), and obesity (DDE). In addition, there is now moderate evidence that certain chemicals of relatively recent concern may be associated with adverse child health outcomes, specifically perfluorooctanoate and foetal growth, and polybrominated diphenyl ethers and neurodevelopment. For other chemicals of recent concern, such as phthalates and bisphenol A, the literature is characterised by large inconsistencies preventing strong conclusions. In conclusion, since most of the recent literature evaluates common exposures in the general population, and not particularly high exposure situations, this accumulating body of evidence suggests that the unborn and young child require more protection than is currently provided. Large, coordinated research efforts are needed to improve understanding of long-term effects of complex chemical mixtures.
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Thimerosal-Preserved Hepatitis B Vaccine and Hyperkinetic Syndrome of Childhood. Brain Sci 2016; 6:brainsci6010009. [PMID: 26999226 PMCID: PMC4810179 DOI: 10.3390/brainsci6010009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Revised: 03/06/2016] [Accepted: 03/08/2016] [Indexed: 11/16/2022] Open
Abstract
(1) BACKGROUND: Hyperkinetic syndrome of childhood (HKSoC) is an International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9) category in which the majority of the children are also diagnosed under the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR), where the umbrella term is "Attention-Deficit and Disruptive Behavior Disorders". The diagnostic criteria for HKSoC are developmentally inappropriate inattention, hyperactivity, and impulsivity. Some studies have implicated mercury (Hg) exposure as a risk factor. (2) METHODS: This hypothesis testing study; using the Vaccine Safety Datalink; assessed the toxicological effects of bolus exposure to organic-Hg from Thimerosal-containing vaccines (TCVs) by examining the relationship between Thimerosal-preserved hepatitis B vaccines (TM-HepB) given at varying levels and at specific intervals in the first six months after birth and the risk of a child being diagnosed with HKSoC. (3) RESULTS: Children diagnosed with HKSoC were significantly more likely to be exposed to increased organic-Hg from TM-HepB doses given within the first month (odds ratio = 1.45; 95% confidence interval (CI) = 1.30-1.62); within the first two months (odds ratio = 1.43; 95% CI = 1.28-1.59); and within the first six months (odds ratio = 4.51; 95% CI = 3.04-6.71) than controls. (4) CONCLUSION: The results indicate that increasing organic-Hg exposure from TCVs heightens the risk of a HKSoC diagnosis.
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Keil KP, Lein PJ. DNA methylation: a mechanism linking environmental chemical exposures to risk of autism spectrum disorders? ENVIRONMENTAL EPIGENETICS 2016; 2:dvv012. [PMID: 27158529 PMCID: PMC4856164 DOI: 10.1093/eep/dvv012] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
There is now compelling evidence that gene by environment interactions are important in the etiology of autism spectrum disorders (ASDs). However, the mechanisms by which environmental factors interact with genetic susceptibilities to confer individual risk for ASD remain a significant knowledge gap in the field. The epigenome, and in particular DNA methylation, is a critical gene expression regulatory mechanism in normal and pathogenic brain development. DNA methylation can be influenced by environmental factors such as diet, hormones, stress, drugs, or exposure to environmental chemicals, suggesting that environmental factors may contribute to adverse neurodevelopmental outcomes of relevance to ASD via effects on DNA methylation in the developing brain. In this review, we describe epidemiological and experimental evidence implicating altered DNA methylation as a potential mechanism by which environmental chemicals confer risk for ASD, using polychlorinated biphenyls (PCBs), lead, and bisphenol A (BPA) as examples. Understanding how environmental chemical exposures influence DNA methylation and how these epigenetic changes modulate the risk and/or severity of ASD will not only provide mechanistic insight regarding gene-environment interactions of relevance to ASD but may also suggest potential intervention strategies for these and potentially other neurodevelopmental disorders.
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Affiliation(s)
- Kimberly P. Keil
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Pamela J. Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
- *Correspondence address. Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, 1089 Veterinary Medicine Drive, Davis, CA 95616, USA. Tel:
(530) 752-1970
; Fax:
(530) 752-7690
; E-mail:
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Al-Saleh I, Nester M, Abduljabbar M, Al-Rouqi R, Eltabache C, Al-Rajudi T, Elkhatib R. Mercury (Hg) exposure and its effects on Saudi breastfed infant's neurodevelopment. Int J Hyg Environ Health 2016; 219:129-41. [DOI: 10.1016/j.ijheh.2015.10.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 10/18/2015] [Accepted: 10/19/2015] [Indexed: 10/22/2022]
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Andra SS, Austin C, Arora M. Tooth matrix analysis for biomonitoring of organic chemical exposure: Current status, challenges, and opportunities. ENVIRONMENTAL RESEARCH 2015; 142:387-406. [PMID: 26219084 PMCID: PMC4609267 DOI: 10.1016/j.envres.2015.06.032] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 06/21/2015] [Accepted: 06/25/2015] [Indexed: 05/18/2023]
Abstract
Epidemiological evidence supports associations between prenatal exposure to environmental organic chemicals and childhood health impairments. Unlike the common choice of biological matrices such as urine and blood that can be limited by short half-lives for some chemicals, teeth provide a stable repository for chemicals with half-life in the order of decades. Given the potential of the tooth bio-matrix to study long-term exposures to environmental organic chemicals in human biomonitoring programs, it is important to be aware of possible pitfalls and potential opportunities to improve on the current analytical method for tooth organics analysis. We critically review previous results of studies of this topic. The major drawbacks and challenges in currently practiced concepts and analytical methods in utilizing tooth bio-matrix are (i) no consideration of external (from outer surface) or internal contamination (from micro-odontoblast processes), (ii) the misleading assumption that whole ground teeth represent prenatal exposures (latest formed dentine is lipid rich and therefore would absorb and accumulate more organic chemicals), (iii) reverse causality in exposure assessment due to whole ground teeth, and (iv) teeth are a precious bio-matrix and grinding them raises ethical concerns about appropriate use of a very limited resource in exposure biology and epidemiology studies. These can be overcome by addressing the important limitations and possible improvements with the analytical approach associated at each of the following steps: (i) tooth sample preparation to retain exposure timing, (ii) organics extraction and pre-concentration to detect ultra-trace levels of analytes, (iii) chromatography separation, (iv) mass spectrometric detection to detect multi-class organics simultaneously, and (v) method validation, especially to exclude chance findings. To highlight the proposed improvements we present findings from a pilot study that utilizes tooth matrix biomarkers to obtain trimester-specific exposure information for a range of organic chemicals.
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Affiliation(s)
- Syam S Andra
- Exposure Biology, Lautenberg Environmental Health Sciences Laboratory, Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Christine Austin
- Exposure Biology, Lautenberg Environmental Health Sciences Laboratory, Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Faculty of Dentistry, University of Sydney, Sydney, NSW, Australia
| | - Manish Arora
- Exposure Biology, Lautenberg Environmental Health Sciences Laboratory, Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Faculty of Dentistry, University of Sydney, Sydney, NSW, Australia.
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Prenatal and childhood polybrominated diphenyl ether (PBDE) exposure and attention and executive function at 9-12 years of age. Neurotoxicol Teratol 2015; 52:151-61. [PMID: 26271888 DOI: 10.1016/j.ntt.2015.08.001] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 08/03/2015] [Accepted: 08/05/2015] [Indexed: 01/01/2023]
Abstract
OBJECTIVE California children's exposures to polybrominated diphenyl ether flame retardants (PBDEs) are among the highest measured worldwide. We previously reported associations for prenatal and childhood PBDE exposures with decrements in attention, processing speed, fine motor coordination, and cognition in children at ages 5 and 7 years. Here, we investigate associations of PBDEs with attention and executive function at ages 9 to 12 years in the expanded CHAMACOS cohort. METHODS We measured PBDEs in prenatal and child age 9 year serum samples for families enrolled in the study since pregnancy ("CHAM1", N=321). In a subsequent cohort for which families were enrolled at child age 9 ("CHAM2", N=301), we measured PBDEs in maternal and child samples collected at child age 9, and used predictive modeling to estimate prenatal exposure levels. We examined associations of measured and estimated PBDE concentrations on children's attention and executive functioning at ages 9, 10½, and 12 years. RESULTS Geometric means for prenatal and childhood ΣPBDE levels (sum of PBDE-47, -99, -100, -153) for the expanded CHAMACOS cohort were 26.3 and 63.2 ng/g lipid, respectively, and did not differ significantly between CHAM1 and CHAM2 families. We found consistent associations of prenatal exposure to PBDEs with poorer attention and executive function, measured with parent report and direct neuropsychological testing of the child. For example, using GEE models of repeated outcome measures at ages 9 and 12, a 10-fold increase in prenatal ΣPBDE was associated with poorer response consistency on the Conners' Continuous Performance Test II (β=2.9; 95% CI: 0.9, 4.8) and poorer working memory on the Behavioral Rating Inventory of Executive Function (β=2.5; 95% CI: 0.5, 4.4). Child age 9 ΣPBDE levels were associated with poorer parent-reported attention and executive function for girls but not boys. CONCLUSIONS Our results suggest that the prefrontal cortex may be a potential target for PBDE exposure and add to a growing literature showing that these ubiquitous toxicants may adversely affect neurodevelopment.
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Uno Y, Uchiyama T, Kurosawa M, Aleksic B, Ozaki N. Early exposure to the combined measles-mumps-rubella vaccine and thimerosal-containing vaccines and risk of autism spectrum disorder. Vaccine 2015; 33:2511-6. [PMID: 25562790 DOI: 10.1016/j.vaccine.2014.12.036] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 12/12/2014] [Accepted: 12/16/2014] [Indexed: 12/21/2022]
Abstract
OBJECTIVE This case-control study investigated the relationship between the risk of Autism Spectrum Disorder (ASD) onset, and early exposure to the combined Measles-Mumps-Rubella (MMR) vaccine and thimerosal consumption measured from vaccinations in the highly genetically homogenous Japanese population. METHODS Vaccination histories at 1, 3, 6, 12, 18, 24, and 36 months from birth were investigated in ASD cases (189 samples), and controls (224 samples) matching age and sex in each case. Crude odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated to determine relationship between MMR vaccination and ASD. The differences in mean values of the thimerosal dosage between cases and controls were analyzed using an unpaired t-test. MMR vaccination and thimerosal dosage were also investigated using a conditional multiple-regression model. RESULTS There were no significant differences in MMR vaccination and thimerosal dosage between cases and controls at any age. Furthermore, the ORs (95% CIs) of MMR vaccination and thimerosal dosage associated with ASD in the conditional multiple regression model were, respectively, 0.875 (0.345-2.222) and 1.205 (0.862-1.683) at age 18 months, 0.724 (0.421-1.243) and 1.343 (0.997-1.808) at 24 months, and 1.040 (0.648-1.668) and 0.844 (0.632-1.128) at 36 months. Thus, there were no significant differences. CONCLUSIONS No convincing evidence was found in this study that MMR vaccination and increasing thimerosal dose were associated with an increased risk of ASD onset.
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Affiliation(s)
- Yota Uno
- Department of Child and Adolescent Psychiatry, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya, Aichi 466-8550, Japan; Department of Psychiatry, Yokohama Psycho-Developmental Clinic, Chigasaki chuo 7-7-2F, Tsuzuki-ku, Yokohama, Kanagawa 224-0032, Japan.
| | - Tokio Uchiyama
- Department of Psychiatry, Yokohama Psycho-Developmental Clinic, Chigasaki chuo 7-7-2F, Tsuzuki-ku, Yokohama, Kanagawa 224-0032, Japan; Department of Faculty of Human Development, Fukushima University Graduate School, Kanayagawa 1, Fukushima, Fukushima 960-1248, Japan.
| | - Michiko Kurosawa
- Department of Epidemiology and Environmental Health, Juntendo University Graduate School of Medicine, Hongo 2-1-1, Bunkyo-ku, Tokyo 113-8421, Japan.
| | - Branko Aleksic
- Department of Psychiatry, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya, Aichi 466-8550, Japan.
| | - Norio Ozaki
- Department of Child and Adolescent Psychiatry, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya, Aichi 466-8550, Japan; Department of Psychiatry, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, Showa-ku, Nagoya, Aichi 466-8550, Japan.
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A dose-response relationship between organic mercury exposure from thimerosal-containing vaccines and neurodevelopmental disorders. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2014; 11:9156-70. [PMID: 25198681 PMCID: PMC4199012 DOI: 10.3390/ijerph110909156] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Revised: 08/07/2014] [Accepted: 08/26/2014] [Indexed: 11/25/2022]
Abstract
A hypothesis testing case-control study evaluated concerns about the toxic effects of organic-mercury (Hg) exposure from thimerosal-containing (49.55% Hg by weight) vaccines on the risk of neurodevelopmental disorders (NDs). Automated medical records were examined to identify cases and controls enrolled from their date-of-birth (1991–2000) in the Vaccine Safety Datalink (VSD) project. ND cases were diagnosed with pervasive developmental disorder (PDD), specific developmental delay, tic disorder or hyperkinetic syndrome of childhood. In addition, putative non-thimerosal-related outcomes of febrile seizure, failure to thrive and cerebral degenerations were examined. The cumulative total dose of Hg exposure from thimerosal-containing hepatitis B vaccine (T-HBV) administered within the first six months of life was calculated. On a per microgram of organic-Hg basis, PDD (odds ratio (OR) = 1.054), specific developmental delay (OR = 1.035), tic disorder (OR = 1.034) and hyperkinetic syndrome of childhood (OR = 1.05) cases were significantly more likely than controls to receive increased organic-Hg exposure. By contrast, none of the non-thimerosal related outcomes were significantly more likely than the controls to have received increased organic-Hg exposure. Routine childhood vaccination may be an important public health tool to reduce infectious disease-associated morbidity/mortality, but the present study significantly associates organic-Hg exposure from T-HBV with an increased risk of an ND diagnosis.
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