Table 1. Studies that Show Brain Biomarkers Correlate with Mercury Levels in Children with ASD Biomarker Authors and Journal N Age Purpose of Study Findings Brain Tissue Autoantibodies (antineuronal antibodies) Mostafa and [26] Egypt J Pediatr Allergy Immunol ASD 40 Controls 40 3-8 y Serum antineuronal antibodies and blood mercury levels were estimated between autism and controls Higher seropositivity for antineuronal antibodies and higher blood mercury in autism vs. controls. Seropositivity of antineuronal antibodies had positive association with elevated blood mercury (found in 70% of autistic children). Both markers positively associated with behavioral abnormalities, autistic regression, EEG abnormalities Brain Tissue Autoantibodies (anti-MBP Mostafa and [27] Clin Cell Immunol ASD 50 Controls 30 5-12 y Blood mercury levels and seropositivity of anti-MBP autoantibodies in autistic children Serum levels of blood mercury were significantly higher in autistic children than healthy controls; increased levels of blood mercury were found in 48% of autistic patients, and 72% of autistic children had anti-MBP auto-antibodies. There was a significant positive association between the elevated levels of blood mercury and anti-MBP auto-antibodies in autistic children.
Brain Neuropeptides in Serum Mostafa et al. [30] Metab Brain Dis ASD 84 Controls 84 3-10 y Examined neuropeptides and mercury in serum significant and positive linear relationship between levels of serum neurokinin A and blood mercury in moderate and severe ASD, but not controls Oxidative Stress – 3-NT Sajdel-Sulkowska et al. [31] Am J Biochem Biotechnol ASD 9 Controls 10 5-37 y Oxidative stress marker 3-NT, mercury, and the antioxidant selenium in autism and controls Significant increases in the mean cerebellar levels of and in the ratio of mercury/selenium in the brains of subjects diagnosed with autism when compared to controls; there was a significant dose-dependent positive correlation between oxidative stress markers and total mercury levels ASD= autism spectrum disorders; anti-MBP= anti myelin basic protein; 3-NT =3-nitrotyrosine; EEG=electroencephalogram; y= years of age Table 2. Studies that did not Show Brain Mercury Levels were Different in Children with ASD vs. Controls Biomarker Authors and Journal N Age Purpose of Study Findings Brain Khan et al. [32] J Physiol Pharmacol ASD 10 Controls 11 4-16 y Brain mercury levels measured in extracortical regions autism vs. controls Brain mercury levels measured in extracortical regions in children with autism vs. controls were not different NT
Brain- Locus ceruleus Pamphlett and Kum Jew [33] ASD 6 Controls 11 16-48 y Levels on mercury in the locus ceruleus Higher levels of mercury were found in the controls ASD= autism spectrum disorders; y= of age 3. Studies that Show that Human Tissue Mercury Levels are Associated with ASD Symptom Severity. Body Tissue Authors and Journal N Age Purpose of Study Findings Hair Holmes et al. [34] Int J Toxicol ASD 94 Controls 45 1-2 y Relationship between autism and hair mercury levels Mercury levels inversely correlated with symptom severity Hair and nails [35] Biol Trace Elem Res ASD 45 Controls 50 4-12 y Lead and mercury in hair and nails autism vs. controls The elevation was much pronounced in LFA group subjects when compared among autistic groups MFA and HFA Hair Elsheshtawy et al. [37] Middle East Current Psychiatry ASD 32 Controls 32 Children Investigated the relationship between autism and mercury, lead, copper, zinc Positive correlation of CARS scores with mercury from hair samples Hair Geier et al. [38] Int J Environ Res Public Health ASD 18 1-6 y Hair metal concentrations and ASD severity Increasing hair mercury concentrations
significantly correlated with increased ASD severity Whole blood and RBC Adams et al. [39] Biol Trace Elem Res ASD 51 Controls 40 3-15 y Investigated toxic metals in autism and autism severity in whole blood, RBCs, and urine Found a strong association in the degree of severity of autism for all the severity scales with mercury (whole blood and RBC) Red Blood Cells (RBC) Alabdali et al. [40] Behav Brain Func ASD 30 Controls 30 3-12 y Concentration of lead and mercury were measured in red blood cells, plus GST and vitamin E Levels of mercury GST, and vitamin E were correlated with severity of social and cognitive impairment measures GST=glutathione-s-transferase; CARS=Childhood Autism Rating Scale; ASD= autism spectrum disorders; ATEC= Autism Treatment Evaluation Checklist; LFA=low functioning autism; MFA=mid functioning autism; HFA= high functioning autism; RBC= red blood cells; y= years of age Table 4. Human Tissue Studies that Show Significantly Different Mercury Levels in ASD vs. Healthy Controls Body Tissue Authors and Journal N Age Purpose of Study Findings Hair Holmes et al. [34] Int J Toxicol ASD 94 Controls 45 Relationship between autism and The level of mercury was significantly
1-2 y first baby hair mercury levels lower in cases 0.47 ppm versus 3.63 ppm in controls Hair and nails [35] Biol Trace Elem Res ASD 45 Controls 50 4-12 y Lead and mercury in hair and nails autism vs. controls Significant elevation in the levels of mercury in both hair and nail samples in autism vs. controls Hair Majewska et al. [36] Acta Neurobiol Exp ASD 91 Controls 75 3-9 y Levels of hair mercury in autism vs. controls Autistic children significantly differed from healthy peers in the concentrations of mercury in hair Hair Elsheshtawy et al. [37] Middle East Current Psychiatry ASD 32 Controls 32 3-4 y Investigated the relationship between autism and mercury, lead, copper, zinc The level of mercury was significantly lower in cases (0.55±0.06 μg/mg) than in controls (3.2±0.2 μg/mg) Hair Mohamed et al. [41] Behav Neurol ASD 100 Controls 100 2-15 y Assess the levels and possible environmental risk factors from metals Hair mercury levels were higher in children with ASD than controls Hair Tabatadze et al. [42] Georgia Med News ASD 30 Controls 30 4-5 y Evaluation levels of essential trace elements and heavy metals in ASD vs. controls High contamination to mercury in ASD children compared to controls Hair Adams et al. [43] Toxicol Environ Chem ASD 78 Controls 31 Born between 1988-99 First baby haircuts evaluated for mercury and ASD Children with lower levels of mercury in hair were 2.5 times more likely to have ASD
Hair DeSoto & Hitlan [44] J Neurol ASD 82 Controls 55 ASD mean 7.2 y Controls mean 7.8 y Examine mercury levels in hair and blood Significant relation does between the blood levels of mercury and ASD with ASD having higher blood mercury levels Hair Blaurock-Busch et al., [45] Maedica (Buchar) ASD 44 3-9 y Assessed the levels of ten toxic metals and essential elements in hair samples of children with autism Elevated hair concentrations were noted for mercury in autism vs. controls Hair Hodgson et al. [46] Exp Biol Med (Maywood) ASD 27 Controls 27 ASD mean 5.3 y Controls mean 5.5 y Investigated hair mercury levels in autism and controls Mercury levels were markedly elevated in the hair of autistic subjects vs. control subjects Hair Obrenovich et al. [47] Biol Elem Res ASD 22 Controls 39 <6 y Hair toxic metals in autism vs. controls Significant alteration in deposition of several heavy metal species, including mercury in hair samples between the groups Hair Al-Ayadhi 2005 [48] Neurosciences (Riyadh) ASD 77 Controls 77 <14 y Hair metals in autism vs. controls Higher levels of mercury in ASD vs. controls Hair Fido & Al-Saad [49] Autism ASD 40 Controls 40 4-8 y Toxic metals in the hair of children with autism vs. controls Children with autism had significantly (p<0.001) higher concentration levels of lead,
mercury and uranium. Blood and hair Yassa [50] Environ Toxicol Pharmacol ASD 45 Controls 45 2-10 y Blood and hair samples from 45 children from Upper Egypt with autism vs. controls High level of mercury and lead among those kids with autism, with significant decline in the blood level of lead and mercury with the use of DMSA as a chelating agent Red Blood Cells (RBC) Alabdali et al. [40] Behav Brain Func ASD 20 Controls 20 3-15 y Concentration of lead and mercury were measured in red blood cells, plus GST and vitamin E ASD had significantly higher lead and mercury levels and lower GST activity and vitamin E concentrations compared to controls RBC Geier et al. [51] ASD 83 Controls 89 ASD mean 7.3 y Controls mean 11.4 y Mercury levels in children with ASD vs. controls Mean mercury levels were 1.9-fold significantly increased in ASD (21.4 microg/L) vs. controls (11.4 microg/L). Blood (plasma) El-Ansary [52] Data in Brief ASD 20 Controls 20 3-15 y Mercury levels Blood mercury levels were higher in ASD Urine Bradstreet et al. [53] J Am Phys Surgeons ASD 221 Controls 18 3-16 Children with ASD and controls treated with multiple doses of DMSA Children with ASD excreted six-fold greater mercury than controls in urine
Blood et al. [58] Environ Health Perspect ASD 452 2-5 y Blood mercury levels in autism vs. controls After accounting for dietary and other differences in mercury exposures, total mercury in blood not statistically different Yau et al. Environ Res [59] ASD 84 Controls 159 <1 y Prenatal and exposures to mercury Total mercury in serum collected from mothers during and newborn bloodspots were not significantly associated with ASD Blood Rahbar et al. Neurotox Res [60] ASD 109 Controls 109 2-8 y Investigate the association between blood mercury concentrations in control children and ASDs Did not find a significant difference (P = 0.61) between blood mercury concentrations and ASDs Blood/toxicokinetic model McKean et al. [61] Environ Health ASD 164 DD 35 Controls 58 Mother infant pairs 274 <1 y Using concentration estimates from toxicokinetic model, exposure estimated in autism, DD, and controls Cumulative methyl-mercury exposure does not appear to detectably elevate the risk of autism or developmental delay pregnancy
Soden et al. [62] Clin Toxicol ASD 15 Controls 4 3-7 y 24-hour provoked urine excretion test for heavy metals in children with autism Excess chelatable body burden of As, Cd, Pb, or mercury is zero Urine Woods et al. [63] Environ Health Perspect ASD 64 PDD 19 Controls 114 2-12 y Mean mercury levels were evaluated between autism, PDD, and NT No differences were found between and autism in urinary mercury levels or in past mercury exposure DD=developmental delay; NT= neurotypical; PDD= pervasive developmental disorder; As= arsenic; Cd= cadmium; Pb=lead; y= years of age Table 6. Body Tissue Studies that did not Find Significantly Different Mercury Levels in ASD vs. Children with Neurological Disorders, Neuropsychiatric Disorders, or Learning Disabilities. Type of Study Authors and Journal N Age Purpose of Study Findings Blood Macedoni-Lukšič et al. [64] Biol Trace Elem Res ASD 52 neurologic disorders 22 1-16 y Levels of metals in aluminum, lead, mercury in ASD compared to children with neurological disorders No significant difference in blood levels of metals between the groups was found
Blood, urine and hair Albizzati et al. [65] Przegl Epidemiol ASD 17 Neuropsychiatric disorders 17 6-16 y Metals in blood, urine and hair samples from children with autism and children with neuropsychiatric disorders, unspecified No difference was between children with autism and children with neuropsychiatric disorders, unspecified Urine Wright et al. [66] PloS One ASD 56 Siblings 42 Controls 121 Delayed 34 5-16 y Urinary mercury levels between children with ASD and controls- normal and with learning disabilities No statistically significant differences were found between children with ASD and controls ASD= autism spectrum disorders; y= years of age Table 7. Studies that Show that Mercury Body Burden Biomarkers Correlate with ASD Severity Biomarker Authors and Journal N Age Purpose of Study Findings Heme Synthesis Pathway Metabolite (precoproporphyrin) Nataf et al. [71] Toxicol Applied Pharmacol ASD 106 Controls 163 2-15 y Examined urinary porphyrin levels in children with disorders The atypical molecule precoproporphyrin, a specific indicator of heavy metal toxicity, was also elevated in autistic disorder but not significantly in Asperger's Heme Synthesis Pathway Metabolite (coproporphyrins) Geier & Geier [72] Neurotox Res ASD 37 7-22 y Examined urinary porphyrin pattern indicative of mercury toxicity An apparent effect was observed between autism response
severity and increased urinary coproporphyrins Heme Synthesis Pathway Metabolites (pentacarboxyporphyrin, precoproporphyrin, and coproporphyrin) Geier et al. [73] J Neurol Sci ASD 26 2-13 y Urinary porphyrins and transsulfuration metabolites in ASD were examined Mercury urinary porphyrins were significantly correlated with increasing CARS scores and GSSG levels. Heme Synthesis Pathway Metabolites (coproporphyrins) Geier et al. [74] J Toxicol Environ Health A ASD 71 Controls 14 ASD 3-22 y Controls 3-59 y Evaluated relationship between ASD severity and urinary porphyrins Participants with severe ASD had significantly increased cP I, cP III, and total cP levels in comparison to participants with mild ASD. A significant correlation was observed between increasing cP levels and CARS scores. Heme Synthesis Pathway Metabolites (pentacarboxyporphyrin, precoproporphyrin, and coproporphyrin) Kern et al. [75] Biometals ASD 24 2-13 y Urinary porphyrins and specific domains of the ATEC The results of the study indicated that the overalll ATEC scores and each of the ATEC subscales (Speech/Language, Sociability, Sensory/Cognitive Awareness, Health/Physical/Behavior) were linearly related to urinary porphyrins associated with mercury toxicity. Heme Synthesis Pathway Metabolite (pentacarboxyl (penta) and coproporphyrins) et al. [76] Autism Res ASD 30 PDD 14 Controls 32 Evaluated penta and coproporphyrins as biological ASD and PDD childrenhad higher mean urinary penta and concentrations copro-
to that of the control group. Plasma Frye et al. [85] Transl Psychiatry ASD 18 Controls 18 ASD mean 8.5 y Controls mean 8.8 y Plasma markers of oxidative stress and measures of cognitive and language development and ASD behavior ASD groups demonstrated lower fGSH and fGSH/GSSG Plasma Geier et al. [86] J Neurol Sci ASD 28 2-16 y Examined plasma transsulfuration metabolites Decreased plasma levels of reduced glutathione (GSH), cysteine, and sulfate were observed among study participants relative to controls Plasma James et al. [87] Am J Clin Nutr ASD 40 Controls 42 2-7 y Plasma concentrations of metabolites and glutathione status in autistic children pathway concentrations in autistic children were significantly different from values in the control; and decreased glutathione redox status in autism vs. controls Plasma et al. [88] ASD 80 Controls 73 3-14 y Plasma concentrations of metabolites and glutathione redox status in autistic children Plasma levels of cysteine, glutathione, and the ratio of reduced to oxidized glutathione, an
indication of antioxidant capacity and redox homeostasis, were significantly decreased B-lymphocytes Sharpe et al. [89] J Toxicol. ASD 4 Controls 4 5-13 y TM exposure in from individuals with autism, their nonautistic twins, and their nontwin siblings Exposure to TM resulted in four of the families showed thimerosal hypersensitivity, whereas none of the control individuals displayed this Peripheral blood mononuclear cells Rose et al. [90] Autism Res Treat ASD 43 Controls 41 3-10 y Quantified the intracellular glutathione redox couple (GSH/GSSG) in resting peripheral blood mononuclear cells Both glutathione and cysteine redox ratios were decreased in autistic compared to control children serum albumin Vojdani et al. [91] ASD 50 Controls 50 3-14 y Measured IgG, IgM and IgA antibodies against CD26, CD69, streptokinase, gliadin and casein peptides and against mercury bound to human serum albumin in autism TM binds to lymphocyte receptors and/or tissue enzymes, resulting in autoimmune reaction in children with autism Blood RNA, Gene Expression Stamova et al. [92] Neurotox Res ASD 33 Controls 51 2-5 y Correlations between gene expression and mercury levels in blood of boys with and without autism Findings suggest different genetic transcriptional programs
associated with mercury levels in autism compared to controls Blood (plasma) El-Ansary [52] Data in Brief ASD 20 Controls 20 3-15 y Levels of GSH/GSSG Blood GSH levels were lower in ASD LCL= lymphoblastoid cell TM= Thimerosal; GSH = reduced glutathione; fGSH = reduced free glutathione; GSSG=oxidized glutathione; GPx=glutathione peroxidase; GST=glutathione-S-transferase; GR=glutathione reductase; GCL=glutamate cysteine ligase; y= years of age Table 10. Epidemiological Studies that Show Thimerosal in Vaccines is a Risk Factor for ASD Type of Study/ Source of Exposure Authors and Journal Database Age or Time Frame Purpose of Study Findings Epidemiology TCVs Gallagher & Goodman [93] J Toxicol Environ Health A NHIS database 3-17 y Examine NHIS 1997-2002, boys years old, born before 1999 and exposure to TM U.S. male neonates vaccinated with the hepatitis B vaccine prior to 1999 (from vaccination record) had a threefold higher risk for parental report of autism diagnosis compared to boys not vaccinated as neonates during that same time period
Epidemiology TCVs Gallagher & Goodman [94] Toxicol & Environ Chemistry NHANES database 1-9 y Examine National Health and Nutrition Examination Survey 1999–2000, children aged 1–9 years Boys given Thimerosal (Hep B) more susceptible to developmental disability than unvaccinated boys Epidemiology TCVs Young et al. [95] J Neuro Sci VSD database to 13 months Ecological study of TM containing vaccines and risk of NDs Increased risk of an ASD diagnosis with TCVs Epidemiology TCVs Geier & Geier [96] VAERS database 1994-1998 Dose (50 vs. 25 micrograms) of mercury from TM in VAERS Increased odds ratios for autism with higher doses of TM Epidemiology TCVs Geier & Geier [97] Med Sci VAERS database 1997-2001 VSD database 1992-1997 Association between TCVs DTaP comparison to DTaP and autism in VAERS and VSD Exposure to mercury from TCVs administered in the US was a consistent significant risk factor for autism Epidemiology TCVs Geier & Geier [98] Pediatr Rehabil VAERS database USDE 2001 Dose of TCVs and autism in VAERS and USDE data Dose-response curves showed increases in odds ratios of NDs (autism) from both VAERS and USDE closely linearly correlated with increasing doses of TM-containing childhood vaccines Epidemiology TCVs Geier & Geier [99] Exp Biol Med database 1992-2000 TM-DTaP and NDs in VAERS An association was between and autism
Epidemiology TCVs Geier and Geier [100] Med Sci Monitor BSS-CDC database USDE CDC yearly live birth estimates Mercury doses from TCVs on population prevalence of autism Evidence showing a direct relationship between increasing doses of mercury from TCVs and autism Epidemiology TCVs et al. [101] Biol Elem Res VSD database PDD 534 PDD mean 4.1 y Relationship between Hib and the risk for PDD Evidence supporting TCVs as a risk factor for PDD Epidemiology TCVs Geier et al. [102] IJERPH VSD database 1991-2000 NDs/PDD and Thimerosal dose Evidence supporting TCVs as a risk factor for NDs/PDD that is dose dependent Epidemiology TCVs et al. [104] Transl Neurodegener VAERS database 1998-2000 VSD database 1991-1999 Risk of ASD following TCVs Evidence supporting TCVs as a risk factor for ASD Epidemiology TCVs Geier et al. [104] J Biochem Pharmacol Res VAERS database 1997-1999 2004-2006 Risk of NDs following DTaP Evidence supporting TCVs as a risk factor for NDs/PDD HepB=Hepatitis B vaccine; TCVs = Thimerosal containing vaccines; ASD= autism spectrum disorders; PDD=pervasive developmental disorders; ND= neurodevelopmental disorder; TM=Thimerosal; DTaP= Diphtheria, Tetanus, acellular Pertussis; HepB= Hepatitis B vaccine; Hib=Haemophilus influenzae Type b; RhoGAM=Rho (D) Immune Globulin; VAERS=Vaccine Adverse Events Reporting System; VSD=Vaccine Safety Datalink; USDE= US Department of Education; TCVs=Thimerosal-containing vaccines; EPA= Environmental Protection Agency; RBC=red blood cells; DD= developmental disability; NHANES= National Health and Nutrition Examination; NHIS=National Health Interview Survey; BSS- CDC= Biological Surveillance Summaries of the Centers for Disease Control; y= years of age Table 11. Epidemiology Studies that did not Find a Relationship between Thimerosal in Vaccines is a Risk Factor for ASD
Epidemiology TCVs Price et al. [110] Pediatrics VSD 1994-1999 ASD 256 Controls 752 6-13 y TCVs and autism No findings of increased risk for any of the three ASD outcomes Epidemiology TCVs Schechter and [111] Arch Gen Psychiatry California Department of Developmental Services 1995-2007 Autism prevalence in California removal of TM from most childhood vaccines Data do not support the hypothesis that exposure to TCVs during childhood is a primary cause of autism Epidemiology TCVs Mrozek-Budzyn et al. [112] Przegl Epidemiol. Medical Records ASD 96 Controls 193 Children To determine an association of TCVs exposure with the risk of autism No evidence of an association between TCVs and autism TCVs = Thimerosal containing vaccines; ASD= autism spectrum disorders; ND= neurodevelopmental disorder; TM=Thimerosal; DTaP= Diphtheria, Tetanus, acellular Pertussis; VSD= Vaccine Safety Datalink; y= years of age Table 12. Epidemiological Studies that Show Thimerosal in RhoGam is a Risk Factor for ASD Type of Study Source of Exposure Authors and Journal N Age or Time Frame Purpose of Study Findings Epidemiology RhoGAM Geier et al. [116] Neuro Endocrin Lett NDs 298 Controls 124 Controls 2,021 Maternal RhoGAM Increases in maternal among children with NDs, autism spectrum disorders, and
1980-2001 Controls 2002+ Epidemiology RhoGAM Geier & Geier [117] J Matern Fetal Neonatal Med ASD 53 Controls 926 ASD 1987-2001 Controls Maternal RhoGAM Significant dose-response relationship between the severity of the regressive ASDs and total mercury dose children received from RhoGAM RhoGAM=Rho (D) Immune Globulin; NDs= neurodevelopmental disorders Table 13. Epidemiological Studies that did not Show Thimerosal in RhoGam is a Risk Factor for ASD Type of Study Source of Exposure Authors and Journal N Age or Time Purpose of Study Findings Epidemiology RhoGam Miles and Takahashi [118] Am J Med Genet A ASD 214 Children diagnosed Association between Rh status, RhoGam use in and autism No association was found between maternal RhoGam use and autism RhoGAM=Rho (D) Immune Globulin;
Table 14. Epidemiological Studies that Show Mercury in Air Pollution is a Risk Factor for ASD Type of Study Source of Exposure Authors and Journal N Age or Time Frame Purpose of Study Findings Epidemiology Prenatal Mercury Exposure Zhang and Wong [119] Environ Int mercury emission based on the data of 1999 in China Examined mercury exposure increases in China Evidence suggests an increase in autism related to increasing mercury exposure Epidemiology Coal-burning plants Palmer et al. [120] Health Place Texas Education Department 2000-2001 EPA- Toxic Release Inventory 2004 4 million children enrolled in grades K through 12 Mercury release, special education rates, and autism disorder Association between environmentally released mercury and special education rates were fully mediated by increased autism rates. Epidemiology Coal-burning power plants Palmer et al. [121] Health Place EPA- Toxic Release Inventory 1998 Proximity to mercury release and autism prevalence Association between proximaty of released mercury and autism Epidemiology Coal burning power plants Blanchard et al. [122] Rev Environ Health US EPA National Scale Air Toxins Assessment 2002 Texas Education Association Occurrence of autism related to distribution of mercury in ambient air Risk of autism is greater in the geographic areas of higher levels of ambient mercury Epidemiology Industrial facilities Dickerson et al. [123] US EPA- Toxics Release ASD prevalence and proximity to industrial facilities Association between urban residential proximity to industrial
releasing arsenic, lead or mercury into air ADDM releasing arsenic, lead or mercury facilities emitting air pollutants and higher ASD prevalence Epidemiology Air Pollution Windham et al. [124] Environ Health Perspect HAP concentrations 1996 ASD 284 Controls 657 Born in 1994 ASD and environmental exposures, ambient air, San Francisco Bay Increased risk of ASD associations included mercury, cadmium, nickel, trichloroethylene, and vinyl chloride Epidemiology Air Pollution Roberts et al. [125] Environ Health Perspect US EPA Nurse’s Health Study II ASD 325 Controls 22,101 Associations between U.S. EPA levels of hazardous air pollutants at time and place of birth and ASD Overall measure of metals were significantly associated with ASD, with odds ratios ranging from 1.5 (for overall metals measure) to 2.0 (for diesel and mercury) EPA= Environmental Protection Agency; ASD= autism spectrum disorders; ADDM = Autism and Developmental Disabilities Monitoring; HAP= hazardous air pollutant Table 15. Epidemiological Studies that did not Show Mercury in Air Pollution is a Risk Factor for ASD Type of Study Source of Exposure Authors and Journal N Age or Time Frame Purpose of Study Findings
Epidemiology Coal Lewandowski et al. [126] Texas Toxic Release Inventory School District Autism Prevalence 2001-2007 Mercury exposure from coal-fired power plants and autism in Texas Analysis suggests mercury emissions not consistently associated with autism prevalence in Texas school districts Table 16. Epidemiological Studies that Show Mercury from Other Sources is a Risk Factor for ASD Type of Study Source of Exposure Authors and Journal N Age or Time Purpose of Study Findings Epidemiology mercury dental amalgams Geier et al. [128] ASD 100 7-13 y Maternal dental amalgams during pregnancy and risk of autism Subjects with > or =6 amalgams were 3.2-fold significantly more likely to be diagnosed with autism (severe) in comparison to ASD (mild) than subjects with < or =5 amalgams. Epidemiology General/Pink Disease Shandley & Austin [129] J Tox Environ Health Australian Pink Disease Support Group 2009 Tested the hypothesis that individuals with a hypersensitivity Prevalence rate of ASD among the grandchildren of pink disease survivors (1 in 22) to be
to mercury (pink disease survivors) may be more likely to have descendants with an ASD significantly higher than the comparable general population prevalence rate (1 in 160). ASD= autism spectrum disorders; y= of age Table 17. Epidemiological Studies that did not Show Mercury from Other Sources is a Risk Factor for ASD Type of Study Source of Exposure Authors and Journal N Age or Time Purpose of Study Findings Epidemiology Maternal van Wijngaarden et al. [130] Epidemiology Seychelles Child Development Study 1986-1990 Evaluated the association between prenatal methylmercury exposure and ASD phenotype Prenatal exposure to methylmercury was not associated with ASD phenotypic behaviors ASD = autism spectrum disorders