Content uploaded by Harald Walach
Author content
All content in this area was uploaded by Harald Walach
Content may be subject to copyright.
Neuroendocrinology Letters Vol.26 No.5, October 2005
Copyright © 2005 Neuroendocrinology Letters ISSN 0172–780X ww w.nel.edu
Mercury and autism: Accelerating Evidence?
Joachim Mutter*, Johannes Naumann*, Rainer Schneider*
1
, Harald Walach*
1,2
& Boyd Haley
3
* Institute for Environmental Medicine and Hospital Epidemiology, University Hospital Freiburg,
Germany
1
Samueli Institute, European Oce, Freiburg, Germany
2
School of Social Sciences, University of Northampton, United Kingdom
3
Department of Chemistry, Lexington, University of Kentucky, USA
Correspondence to: Joachim Mutter
Institute for Environmental Medicine and Hospital Epidemiology
University Hospital Freiburg, Hugstetter Str. 55
79106 Freiburg,
GERMANY
PHONE: ++49-761-270-5489
FAX: ++49-761-270-5440
EMAIL: joachim.mutter@uniklinik-freiburg.de
Submitted: September 25, 2005 Accepted: September 27, 2005
Key words:
autism; developmental disorders; ethyl mercury; dental amalgam; mercury;
thimerosal; neurotoxicity; estrogen; testosterone; methylation; glutathion
Neuroendocrinol Lett 2005; 26(5):439–446 PMID:16264412 NEL260505A10 © Neuroendocrinology Letters www.nel.edu
Abstract
e causes of autism and neurodevelopmental disorders are unknown. Genetic
and environmental risk factors seem to be involved. Because of an observed
increase in autism in the last decades, which parallels cumulative mercury expo-
sure, it was proposed that autism may be in part caused by mercury. We review
the evidence for this proposal. Several epidemiological studies failed to nd a cor-
relation between mercury exposure through thimerosal, a preservative used in
vaccines, and the risk of autism. Recently, it was found that autistic children had a
higher mercury exposure during pregnancy due to maternal dental amalgam and
thimerosal-containing immunoglobulin shots. It was hypothesized that children
with autism have a decreased detoxication capacity due to genetic polymor-
phism. In vitro, mercury and thimerosal in levels found several days aer vaccina-
tion inhibit methionine synthetase (MS) by 50%. Normal function of MS is crucial
in biochemical steps necessary for brain development, attention and production
of glutathione, an important antioxidative and detoxifying agent. Repetitive doses
of thimerosal leads to neurobehavioral deteriorations in autoimmune susceptible
mice, increased oxidative stress and decreased intracellular levels of glutathione in
vitro. Subsequently, autistic children have signicantly decreased level of reduced
glutathione. Promising treatments of autism involve detoxication of mercury,
and supplementation of decient metabolites.
Abbreviations
MTHFR – methylene tetrahydrofolate reductase
Hg – mercury
DMSA – dimercaptosuccinic acid
DMPS – sodium 2,3-dimercapto-1-propane sulfonate
MS – methionine synthetase
ASD – autism spectrum disorders
Introduction
Autism spectrum disorders (ASD), first
described in 1943 in eleven children born in the
1930s, have increased worldwide [1,2,3,4]. All
forms of mercury are neurotoxic, especially dur-
ing brain development [5,6]. Thus, some authors
REVIEW ARTICLE
To cite this article:
Neuroendocrinol Lett 2005; 26(5):439–446
440
Neuroendocrinology Letters Vol.26, No. 5, October 2005 Copyright © Neuroendocrinology Letters ISSN 0172–780X w w w.nel.edu
assume that the increase of autism might be caused by
the worldwide increase of mercury exposure through
fish and industrial sources, amalgam [7] and addition-
ally, through increased parenteral exposure to ethyl-
mercurithiosalicate (thimerosal), first introduced by
Eli Lilly 1931 as a preservative in vaccinations [1,2,8].
Especially, in the U.S., the prevalence of autism became
endemic with an increase of about 5 in 10,000 to 60
in 10,000 after three additional thimerosal-containing
vaccines were introduced for newborns in the early
1990s, whereas in most other countries with a much
lower autism prevalence, like Germany or Denmark,
thimerosal in vaccines was reduced at the same time. In
California, the autism rate increased by 634% between
1987 and 2002, which cannot be attributed to shifts in
the interpretation of diagnostic criteria, migration or
improved diagnostic accuracies [3,4,9]. Other develop-
mental and behavioural disorders like attention deficit
disorders (ADD) or attention deficit hyperactivity
disorders (ADHD) have also increased up to 1 out of
every 6 children in the U.S. [10,11]. It should be noted
that in the 1990s, newborns until age of 6 months were
regularly exposed to a cumulative thimerosal dose of
187,5 µg [12].
This situation seems to resemble the epidemy of
Acrodynia in the last century, which affected up to
1 of 500 infants in some industrial countries. After
removing a frequently used teething powder, which
contained mercury as calomel (Hg
2
Cl
2
), acrodynia
disappeared. Interestingly, calomel is one of the less
toxic forms of mercury when given orally and mercury
chlorid (HgCl
2
), a more toxic form of inorganic mer-
cury, is about 100-fold less toxic than ethyl mercury
to neurones in vitro [13]. Beside exposure to teething
powders, it was reported in 1953 that immunisations
with thimerosal-containing vaccines preceded the
onset of acrodynia in several cases [14].
It was not until 1999 that an elimination of thi-
merosal in vaccines was recommended by the U.S.
Public Health Service and the American Academy of
Paediatrics. Despite the recommendation, the CDC
recommends thimerosal-containing flu vaccines and
tetanus boosters and even the WHO promotes the use
of thimerosal in vaccinations in border- or undeveloped
countries [15].
It is of public interest to ask, why thimerosal and
dental amalgam, which both consists of about 50% of
the most toxic nonradioactive element [16] and, in the
case of amalgam, additionally of other heavy metals
(eg. tin, copper, silver, zinc), have been used since 70
and 170 years, respectively, and, have been allowed to
bypass governmental toxicological testing. It must be
noted that until today no controlled, randomized study
regarding the safety of amalgam or thimerosal exists.
Such a future study should consider mercury exposure
through pregnancy and vaccinations, because these
exposures seem to be crucial in the pathogenesis of
autism [17,18]. Furthermore, there is no single study,
which compares the health of individuals exposed-
versus never exposed to mercury (from amalgam or
thimerosal) with the exception of the one by Mortada
Joachim Mutter, Johannes Naumann, Rainer Schneider, Harald Walach & Boyd Haley
et al. [19]. As was shown by the recent debate regarding
the as yet unrecognized profound adverse side effects
of hormone replacement therapy, the lack of a large
enough prospective controlled, randomized study may
lead to false conclusions. Against this background it
is interesting to note that several scientists from the
FDA, NIH, and CDC may have been influenced by
vaccine manufacturers or dental boards [15, 20–24].
Despite this information, the Institute of Medicine of
the U.S. concluded recently that there is no relationship
between thimerosal and autism, and that no further
studies should be conducted to evaluate the relationship
between thimerosal and autism [25]. This was done in
spite of several biological studies reporting thimerosal
to have toxic properties that made it a major suspect for
the recent autism epidemic. There were no biological
studies presented that did not show major toxic effects
of thimerosal. Thus, it is pertinent to question why the
CDC committee suggested no further research and
emphasize the importance of carefully paying attention
to published and unpublished data and note pertinent
conflicts of interest.
Search Strategy
The data base Medline was searched using Ovid
Technologies, Version rel 9.1.0 for 1966–30.8.2005
with keywords (mercur$ or thimerosal or thiomersal or
ethyl mercur$) and (autism or neurodevelopment$ or
neurotoxic$ or autoimmun$). This search was supple-
mented from the bibliography of retrieved articles. Also,
we searched the internet using google. We performed a
multidisciplinary review of the material by researchers
with different leanings and preconceptions.
Reduced mercury levels in hair of autistics
despite higher mercury exposure?
Holmes et al. [17] and Hu et al. [26] found that mer-
cury levels in the first babies’ haircut of 94 autistic chil-
dren were significantly lower (about 8-fold less) than
in 49 normal controls. This was unexpected because
the autistic children had been exposed to significantly
higher mercury levels through maternal dental amal-
gam and thimerosal containing immunoglobulins dur-
ing pregnancy [17]. Considering the mothers with 8 to
15 amalgams, the birth hair ratio was 12 times higher in
the normal versus autistic children. In contrast to iatro-
genic mercury exposure during pregnancy, no correla-
tion between maternal fish consumption and the risk
of autism for their children was reported [17]. It was
assumed that autistic children do not effectively excrete
mercury from intracellular locations into blood during
pregnancy and shortly after birth, thus showing less
mercury in first haircut [17]. Further interpretations of
the results of Holmes et al. [17] were discussed recently
[18,27,28]. In haircuts from 40 older children with
autism, other authors found elevated levels of mercury,
lead and uranium compared to 40 normal controls [29].
Other toxic metals like aluminium, arsenic, cadmium
or beryllium showed no difference [29].
441
Neuroendocrinology Letters Vol.26, No. 5, October 2005 Copyright © Neuroendocrinology Letters ISSN 0172–780X w w w.nel.edu
Mercury and autism: Accelerating Evidence?
Enhanced susceptibility, exposure and
toxicology to mercury
The process of cysteine and glutathione synthesis,
which are crucial for natural mercury detoxification,
are reduced in autistic children, possibly due to genetic
polymorphisms [13,30]. Therefore, autistics have 20%
lower plasma levels of cysteine and 54% lower levels
of glutathion, which, among others, adversely affect
their ability to detoxify and excrete metals like mercury
[13,31]. This may lead to higher Hg concentrations in
tissues like the nervous system and lead also to a longer
half-life of mercury, compared with children with nor-
mal levels of cysteine and glutathione [13,18]. As was
shown by Bradstreet and colleagues [15,32] in a study
involving 221 autistics, vaccinated autistics showed
about 6-fold increase in urinary mercury excretion
compared with normal controls after appropriate
mobilisation with DMSA. Interestingly, lead and cad-
mium levels did not differ between the groups [15,32].
Delayed detoxification of mercury severely impairs
methylation reactions (like DNA-, RNA-, cobalamin-,
protein-, phospholipids-, histones-, and neurotrans-
mitter-methylation), which further adversely affects
growth factor derived development of the brain and
attention performance. Phospholipid methylation,
which is crucial for attention, is impaired in autistic
and attention deficit hyperactivity disorders [13]. Ethyl
mercury in levels reached ten days after vaccination
in an in vivo study [33] produced an inhibition of
methylation of more than 50% in vitro [13,30]. In vitro
studies have also shown that thimerosal was more than
100-fold more potent than inorganic mercury in inhib-
iting such essential methylation reactions [30]. Also,
inorganic mercury was found to be 10-fold more potent
than lead in inhibition of neuronal micro-tubular func-
tion, which is crucial for nerve growth and transport
of neurotransmitters [34,35]. Inorganic mercury also
leads to growth inhibition and denudation of neuronal
growth cones by inducing the abnormal aggregation
of tubulin [36]. This was seen already 15 min. after
exposure to very low levels of inorganic mercury, levels
which were about 100–1000-fold lower than found in
brains of individuals with dental amalgam or Alzheim-
er’s disease [37]. This observation fits in with earlier
reports that the microtubulin protein, tubulin, was on
average 80% less viable in Alzeimer’s diseased brain
than in age-matched normal controls [79] and that this
abnormality could be induced in the brains of rats by
exposure to mercury vapor [80]. It was also shown in
vitro that low concentrations of thimerosal, which can
occur after vaccination, induce membrane- and DNA-
damage and initiate apoptosis in human neurons [38].
Humphrey and co-workers [39] have shown recently
that this apoptosis is mediated by mitochondria in an
in vitro study. Genotoxic effects were also observed
in another in vitro study [49]. Furthermore, autistics
seem to be genetically more susceptible for toxin
derived inhibition of methylation processes [13]. As an
example, polymorphism of methylen tetrahydrofolate
reductase (MTHFR) gene was more frequent in chil-
dren with autism [41]. It was assumed consequently
that about 15% of the population may show enhanced
susceptibility to mercury exposure [15].
Studies on monkeys have shown that ethyl mercury,
like mercury vapour, crosses the cell membrane and
is then converted intracellularly to inorganic mercury
(Hg
2+
), which accumulates preferentially in the brain
and the kidneys [42]. Intracellular accumulation of
mercury was shown to be higher for ethyl- compared
to methyl mercury but clearance rate was higher for
ethyl mercury [42]. There were no differences in the
toxico-kinetics of methyl mercury as compared with
i.m. thimerosal in animals [43]. In contrast, another
study in immature mice found higher mercury levels
in blood, brain and kidneys after methyl mercury
exposure compared to ethyl mercury exposure [44]. In
this study a form of methyl mercury that may be 20
times more toxic that the one found in fish was used
[37]. However, it seems to be likely that toxico-kinetic
studies in mice and monkeys are not comparable due
to metabolic differences. Mice, in contrast to primates,
for instance, are able to produce grams of vitamin C, a
potent antioxidant, especially when under stress.
Picchichero et al. [33] argue that ethyl mercury
administered through vaccines is eliminated rapidly
from the blood and rapidly excreted in stool. In this
study, only 33 children at age of 2 and 6 month were
used for blood mercury assessment, thus potentially
overlooking individuals with impaired mercury excre-
tion. Blood levels were obtained days to weeks after
vaccination, thus peak levels could not have been mea-
sured. The mercury dose was much lower than through
vaccination in the 1990s. Nonetheless and somewhat
weakly founded, the authors concluded from this data,
“This study gives comforting reassurance about the
safety of ethyl mercury as a preservative in childhood
vaccines” [33]. Others have already criticised this study
[45] or mention points of possible conflicts of interests
[46].
Despite of that, as described above, levels of ethyl
mercury found 8 days after vaccination [33] leads to
50% inhibition of methionine synthetase (MS) in vitro
[13,30]. An earlier study using rabbits injected with
thimerosal containing radioactive mercury showed
that from hour 1 post injection to hour 6 the level of
radioactive mercury in the blood dropped over 75%
while from hour 2 post injection to hour 6 there were
singnificantly increased radioactivity levels in the fetal
brain, liver and kidney [81]. This latter study strongly
implies that a rapid drop in blood mercury levels from
thimerosal injection is due to uptake by other organs of
the body and not due to excretion.
Therefore, the implications by others of thimerosal
safety based on shorter blood levels half-lives [33] suf-
fers from a lack of logic. Additionally, in a recent study,
thimerosal was a potent inhibitor of phagocytosis by
mononuclear phagocytes inhibiting the process at
low nanomolar levels [82]. Phogocytosis is the first
step of the innate immune system and it seems likely
that injection of thimerosal would therefore inhibit an
442
Neuroendocrinology Letters Vol.26, No. 5, October 2005 Copyright © Neuroendocrinology Letters ISSN 0172–780X w w w.nel.edu
infants immune system as they only have the innate
system until the aquired system is built up by aging.
In contrast to astrocytes or hepatocytes, neurons are
unable to synthesize cysteine, the rate limiting amino
acid for glutathione synthesis [47]. Thus, neurons are
most sensitive to mercury toxicity since, as mentioned
above, glutathione is the major intracellular agent in
mercury- and heavy metal detoxification [18]. It is well
known that thimerosal and inorganic mercury deplete
intracellular glutathione levels, which subsequently
leads to increased oxidative stress, neuronal cytotoxicity
and death [47–50]. The toxic effects of ethyl mercury
seem to be similar to those of methyl mercury as indi-
cated by James et al. [47]. Of 13 children treated with
a thimerosal containing topological “antiseptic” for
umbilical cord infection, 10 died [83]. This antiseptic
was used world-wide on adolescents and adults with
very little reported negative effects. This strongly
implied that infants were much more susceptible to
thimerosal toxicity than older humans and question
any decision to inject this material into infants.
Autoimmunity and inammation
An autoimmune pathogenesis of autism, triggered
by bacterial antigens, dietary peptides and mercury
was proposed by Vojdani et al. [51]. Autopsied brains
of autistics demonstrated chronic activation of microg-
lia and astrocytes, thus indicating an autoimmune
processes [52]. Note that mercury is a potent inducer
of haptene mediated autoimmune reactions [7,16], in
particular when given repetitively, which is the case in
children exposed early to iatrogenic mercury during
pregnancy (through maternal amalgam and thimero-
sal) and then, again after birth through vaccinations.
In autoimmune sensitive mouse strains, vaccinations
with thimerosal in doses and timing equivalent to the
paediatric immunisation schedule of the U.S. in 2001
lead to profound behavioural and neuropathologic
disturbances, which are comparable to autism [53]. In
a preliminary report, the autoimmune reaction persists
long after mercury can no longer be detected [54]. It
is important to note that thimerosal doses applied in
this study were lower than the ones given to newborns
in the 1990s in the U.S. It was also shown, that the risk
of thimerosal sensitation is increased in individuals
with gene deletions of the glutathione S-transferases
M1 and T1 [55]. Recently, it was shown on genetically
metal-susceptible mice that, in contrast to methyl
mercury, thimerosal leads to strong autoimmunity
[56,57]. Mercury also increases neurotoxicity of glu-
tamate [37]. Interestingly, microglial activation and
enhanced glutamate cytotoxicity has been described in
many neurodegenerative diseases. As a side note, the
risk of multiple sclerosis, another autoimmune disease,
may be enhanced through additional vaccinations with
thimerosal containing Hepatitis B vaccines [58].
Synergistic toxicity and the role of steorids
In vitro studies point to the possibility that neuro-
toxicity of mercury or thimerosal is enhanced through
mercurials but also through neomycin and aluminum-
hydroxid (also used in vaccines) and testosterone, while
estrogen decreases the toxic effects [59]. In another
study, estrogen is shown to decrease the toxicity of
inorganic mercury on neurones [50]. These observa-
tions may explain the 4 to 1 ratio of boys to girls in
autism [60] and leads to possible therapies. It was also
proposed that lead might play a pathogenetic role in
neurodevelopment disorders and autism. Combination
of lead and mercury resulted in a synergistic increase of
toxicity in vitro, respectively [61].
Epidemiological studies
It should be noted that epidemiological studies
and studies using mercury levels in blood and urine,
which do not consider genetic susceptibility factors,
autoimmunity reactions and mercury exposure during
pregnancy (amalgam, thimerosal), are not able to detect
a statistically significant effect, even if there is one.
Nevertheless, some studies have shown a correla-
tion between mercury exposure and the risk of autism.
Using data from the Vaccine Adverse Events Reporting
System (VAERS), Vaccine Safety Data (VSD), Biologi-
cal Surveillance Summaries of the Centers for Disease
Control and Prevention (CDC) and the U.S. Depart-
ment of Education datasets, a significant correlation
was found between the risk of neurodevelopmental
disorders and the cumulative thimerosal dose given
parenterally, which exceeds (11–150 fold) the EPA and
FDA established maximum permitted levels for the
daily oral ingestion of methyl mercury [11,21,62–65].
In a first analysis (“Generation Zero analysis”) of the
Vaccine Safety Datalink datasets (VSD), Verstraeten et
al. had described a significant increase of autism risk
in children at one month, with the highest mercury
exposure levels compared with children with no expo-
sure [22]. In four subsequent separate generations of
the analysis, which involve the exclusion of children
with no thimerosal exposure and less than two polio
vaccines, the statistical significance disappeared
[21,22,66]. The prevalence of autism in Amish People,
a population which deny vaccination to their children
and with low incidence of caries, seem to be very low
in comparison to the general prevalence in the U.S. in
a preliminary report [67]. However, also other cultural,
environmental or behavioural factors might explain
this fact.
Other epidemiological studies did not find an
association between thimerosal containing vaccines
and autism in United Kingdom [68] and in Denmark
[69–71]. Most of these studies did not use controls,
which were never exposed to mercury [72]. Addition-
ally, maternal mercury exposure during pregnancy
was not measured. We analyse a prominent example
below.
Joachim Mutter, Johannes Naumann, Rainer Schneider, Harald Walach & Boyd Haley
443
Neuroendocrinology Letters Vol.26, No. 5, October 2005 Copyright © Neuroendocrinology Letters ISSN 0172–780X w w w.nel.edu
Madsen et al. [69] compare the number of newly
recorded autism cases prior to 1992, when thimero-
sal-containing vaccines were used, with those after
1992, when such vaccines were no longer produced in
Denmark. The authors observe a rise in autism rates
after removal of thimerosal, and thus conclude that
thimerosal plays no role in the aetiology of autism
[69]. Some important methodical flaws must be noted
in this context:
1. Autism counts were based on hospitalized, inpatient
records in the first cohort and then changed in the
middle of the study period (1995) to include out-
patient records. Therefore, the purported increases
after 1994 may be explained by the additional re-
cruitment of an existing autism population that did
not require hospitalisation.
2. After 1992, the registry added in patients from a
large Copenhagen clinic, which accounted for 20%
of the caseload in Denmark. The patients from this
clinic were excluded prior to 1992.
3. The diagnostic category changed after 1993 from
“psychosis proto-infantilis” of ICD-8 (code 299) to
“childhood autism” of ICD-10. Another paper using
the same inpatient registry reports that the psychosis
proto-infantilis category includes inpatient cases that
do not fulfil the criteria for autism [73].
4. Many of the children were between 7–9 years old,
and most were over 4 years old, when recorded.
But the onset of autism must occur, by definition
in the diagnostic criteria, before three years of age.
The most widely used approach to assessing autism
trends is to use year of birth as the “incidence time”
5. Another recent study performed by Madsen et al.
[74] reported Danish autism rates of 6 per 10,000
for children born in the 1990s. These Danish rates
are very low in the 1990s compared to the U.S. [12].
Madsen et al. [69] report also inpatient rates for the
pre-1993 “psychosis proto-infantilis” at well below 1
per 10,000. This low rate would contradict the single
published survey of autism rates from Denmark,
which indicated an autism rate of over 4 per 10,000
as far back as the 1950s [75].
6. Additional confounders were present in the U.S.
with high prevalence of autism that were not present
in Denmark: Between 1970–92, the only childhood
vaccine given in Denmark until 5 months of age
was the monovalent pertussis vaccine. In the United
States, children were exposed to multiple doses of
diphtheria, pertussis, tetanus, polio, hepatitis B and
haemophilus influenza B (Hib) vaccines before five
months of age in the 1990s. Additionally, Denmark
did not administer thimerosal-containing Rho-D
immunoglobulin during pregnancy, which may
increase the risk for the development of autism [17].
The epidemiological studies that seem to support
the missing of a causal link between thimerosal and
autism, are thus inconclusive, and some of them are
fraught with methodological flaws or inconsistencies.
They cannot be used to lay the topic at rest. The situ-
ation rather calls for a joint effort to clarify the points
in question. Meanwhile, given the lack of effective
treatment options in autism, one might want to use
the evidence reviewed here for an experimental form
of treatment.
Promising treatments of autistics
According to preliminary results, chelation of
heavy metals is now the preferred treatment therapy
developed by the Autism Think Tank of the Defeat
Autism Now Foundation, which now considers autism
as a curable disease based on the observed reversal of
diagnosis of numerous children after such treatment
[76]. Enhanced detoxification through hyperbaric
oxygen therapy and transdermal usage of Dimercap-
topropansulfonate (DMPS) seem to be effective treat-
ment options for autistics according to Buttar [77] and
Harch [78]. Furthermore, preliminary results suggests
that substitution of metabolites important for intracel-
lular glutathione synthesis and methylation, which
lacks in autistic children due to mercury exposure
and genetic sensitivity [31], like methylcobalamin,
s-adenyl-methionine and tetrahydrofolic acid, leads to
improvement of symptoms in a about 80% of autistic
children [13,31]. Subsequently, these agents were able
to normalise the blood levels of glutathione and cyste-
ine in autistic children [31].
Conclusion
Taken together, all the above mentioned data from
experimental, clinical and partly from epidemiological
studies appear to show that repetitive mercury expo-
sure during pregnancy (through thimerosal and dental
amalgam), and after birth, through thimerosal contain-
ing vaccinations in genetically susceptible individuals
is one potential pathogenetic factor in autism. Other
metals and toxicants, partly present in vaccines, and the
hormonal situation might have synergistic effects with
mercury. This has not been officially acknowledged.
Therefore it is mandatory to perform further studies
that address this issue with sound methodology and
through research uninfluenced by commercial, profes-
sional or political interests. Given the widespread use of
mercury in medical products, even a small frequency
of pathological side effects have a significant impact to
public health. Therefore, for preventive purposes, it is
mandatory to avoid further use of mercury in medical
products in industrial and undeveloped countries.
Acknowledgement
HW and RS are supported by the Samueli Institute.
JM received support from Foundation Landesbank
Baden-Württemberg, Natur und Umwelt, Stuttgart,
and Foundation Viamedica, Freiburg.
Mercury and autism: Accelerating Evidence?
444
Neuroendocrinology Letters Vol.26, No. 5, October 2005 Copyright © Neuroendocrinology Letters ISSN 0172–780X w w w.nel.edu
REFERENCES
1 Bernard S, Enayati A, Redwood L, Roger H, Binstock T. Autism:
a novel form of mercury poisoning. Med Hypotheses 2001; 56:
462–71.
2 Bernard S, Enayati A, Roger H, Binstock T, Redwood L. The role
of mercury in the pathogenesis of autism. Mol Psychiatry 2002;
7:S42–S43.
3 Blaxill MF. Study fails to establish diagnostic substitution as a
factor in increased rate of autism. Pharmacotherapy 2004; 24:
12–13.
4 Blaxill MF. What‘s going on? The question of time trends in au-
tism. Public Health Rep 2004; 119:536–51.
5 Costa LG, Aschner M, Vitalone A, Syversen T, Soldin OP. Devel-
opmental neuropathology of environmental agents. Annu Rev
Pharmacol Toxicol 2004; 44:87–110.
6 Davidson PW, Myers GJ, Weiss B. Mercury exposure and child
development outcomes. Pediatrics 2004; 113(4 Suppl):1023–
29.
7 Mutter J, Naumann J, Sadaghiani C, Walach H, Drasch G. Amal-
gam studies: disregarding basic principles of mercury toxicity.
Int J Hyg Environ Health 2004; 207:391–7.
8 Blaxill MF, Redwood L, Bernard S. Thimerosal and autism? A
plausible hypothesis that should not be dismissed. Med Hy-
potheses 2004; 62:788–94.
9 California Department of Developmental Services: Autism spec-
trum disorders: Changes in the California caseload and update:
1999 through 2002. Sacramento, CA. California Health and Hu-
man Services Agency, (2003).
10 Burton D. Truth revealed: New scientific discoveries regarding
mercury in medicine an autism. Opening statement before the
U.S. House of Representatives. Subcommittee on human rights
and wellness, Sept. 8 (2004). Available from: URL: http://reform.
house.gov/WHR/Hearings/EventSingle.aspx?EventID=18156
[cited 2005, September 20].
11 Geier DA, Geier MR. A two-phased population epidemiological
study of the safety of thimerosal-containing vaccines: a follow-
up analysis. Med Sci Monit. 2005; 11:CR160–70.
12 Ball LK, Ball R, Pratt RD. An assessment of thimerosal use in
childhood vaccines. Pediatrics 2001; 107:1147–54.
13 Deth RC. Truth revealed: New scientific discoveries regarding
mercury in medicine and autism. Congressional Testimony be-
fore the U.S. House of Representatives. Subcommittee on hu-
man rights and wellness, Sept. 8. (2004). Available from: URL:
http://reform.house.gov/WHR/Hearings/EventSingle.aspx?
EventID=18156 [cited 2005, September 20].
14 Warkany, J., Hubbard, D.M.: Acrodynia and mercury. J Pediatr
1953; 42:365–86.
15 Bradstreet J. A case-control study of mercury burden in chil-
dren with autistic Disorders and measles virus genomic RNA in
cerebrospinal fluid in children with regressive autism. Immuni-
zation safety review: Vaccines and autism. Institute of Medicine,
Febr. 9 (2004). Available from: URL: http://www.iom.edu/sub-
page.asp?id=18065 [cited 2005, September 20].
16 Mutter J, Naumann J, Walach H, Daschner FD. Amalgam: Eine
Risikobewertung unter Berücksichtigung der neuen Literatur
bis 2005. [Amalgam risk assessment with coverage of refer-
ences up to 2005]. Gesundheitswesen 2005; 67:204–216.
17 Holmes AS, Blaxill MF, Haley BE. Reduced levels of mercury
in first baby haircuts of autistic children. Int J Toxicol 2003;
22:277–85.
18 Mutter J, Naumann J, Sadaghiani C, Walach H, Drasch G: Mer-
cury and autism: Response to the letter of K. E. v. Mühlendahl
[Int. J. Hyg. Environ. Health 208 (2005) 435]. Int J Hyg Environ
Health 2005; 208:437–8.
19 Mortada WI, Sobh MA, El-Defrawy MM, Farahat EF. Mercury in
dental restoration: Is there a risk of nephrotoxicity? J Nephrol
2002; 15:171–6.
20 Fischer RD. Truth revealed: New scientific discoveries regard-
ing mercury in medicine and autism. Congressional Testimony
before the U.S. House of Representatives. Subcommittee on
human rights and wellness, Sept. 8. (2004) Available from:
URL: http://reform.house.gov/WHR/Hearings/EventSingle.aspx?
EventID=18156 [cited 2005, September 20].
21 Geier DA, Geier MR. Autism and thimerosal-containing vac-
cines: Analysis of the vaccine adverse events reporting system
(VAERS). Immunization safety review: Vaccines and autism. In-
stitute of Medicine, Febr. 9, (2004). Available from: URL: http://
www.iom.edu/subpage.asp?id=18065 [cited 2005, September
20].
22 Redwood, L. Truth revealed: New scientific discoveries regard-
ing mercury in medicine and autism. Congressional Testimony
before the U.S. House of Representatives. Subcommittee on
human rights and wellness, Sept. 8, (2004). Available from:
URL: http://reform.house.gov/WHR/Hearings/EventSingle.aspx?
EventID=18156 [cited 2005, September 20].
23 Weldon D. Congressional speakers. Immunization safety review:
Vaccines and autism. Institute of Medicine, Febr. 9. (2004). Avail-
able from: URL: http://www.iom.edu/subpage.asp?id=18065
[cited 2005, September 20].
24 Willman D. The National Institutes of Health: Public Servant or
Private Marketer? Los Angeles Times 2004; Dec. 22.
25 Institute of Medicine (US). Immunization Safety Review: Vac-
cines and Autism. Washington, DC: National Acedemy Press,
2004.
26 Hu LW, Bernard J, Che. Neutron Activation analysis of Hair sam-
ples for the Identification of Autism. Transactions of the Ameri-
can Nuclear Society 2003; v89:681–2.
27 Grether J, Croen L, Theis C, Blaxill M, Haley B, Holmes A. Baby
hair, mercury toxicity and autism. Int J Toxicol 2004; 23:275–6.
28 Muhlendahl KE. Commentary regarding the article by Mutter et
al. “Amalgam studies: Disregarding basic principles of mercury
toxicity” [Int. J. Hyg. Environ. Health 207 (2004) 391–397]. Int J
Hyg Environ Health 2005; 208:435.
29 Fido A, Al-Saad S. Toxic trace elements in the hair of children
with autism. Autism 2005; 9:290–8.
30 Waly M, Olteanu H, Banerjee R, Choi SW, Mason JB, Parker BS,
Sukumar S, Shim S, Sharma A, Benzecry JM, Power-Charnitsky
VA, Deth RC: Activation of methionine synthase by insulin-like
growth factor-1 and dopamine: a target for neurodevelopmen-
tal toxins and thimerosal. Mol Psychiatry 2004; 9:358–70.
31 James SJ, Cutler P, Melnyk S et al. Metabolic biomarkers of in-
creased oxidative stress and impaired methylation capacity in
children with autism. Am J Clin Nutr 2004; 80:1611–17.
32 Bradstreet J, Geier DA, Kartzinel JJ, Adams J, Geier M. A case-
control study of mercury burden in children with autistic spec-
trum disorders. J Am Phys Surg 2003; 8:76–9.
33 Pichichero ME, Cernichiari E, Lopreiato J, Treanor J: Mercury
concentrations and metabolism in infants receiving vac-
cines containing thiomersal: a descriptive study. Lancet 2002;
360:1737–41.
34 Stoiber T, Bonacker D, Bohm KJ, Bolt HM, Thier R, Degen GH,
Unger E. Disturbed microtubule function and induction of mi-
cronuclei by chelate complexes of mercury(II). Mutat Res 2004;
563:97–106.
35 Thier R, Bonacker D, Stoiber T, Bohm KJ, Wang M, Unger E, Bolt,
HM, Degen G. Interaction of metal salts with cytoskeletal motor
protein systems. Toxicol Lett 2003; 140–141:75–81.
36 Leong CC, Syed NI, Lorscheider FL. Retrograde degeneration of
neurite membrane structural integrity of nerve growth cones
following in vitro exposure to mercury. Neuroreport 2001;
12:733–7.
37 Mutter J, Naumann J, Sadaghiani C, Schneider R, Walach H.
Alzheimer Disease: Mercury as pathogenetic factor and apoli-
poprotein E as a moderator. Neuro Endocrin Lett 2004; 25:275–
83.
38 Baskin DS, Ngo H, Didenko VV. Thimerosal induces DNA breaks,
caspase-3 activation, membrane damage, and cell death in cul-
tured human neurons and fibroblasts. Toxicol. Sci 2003; 74:361–
68..
39 Humphrey ML, Cole MP, Pendergrass JC, Kiningham KK. Mito-
chondrial mediated thimerosal-induced apoptosis in a hu-
man neuroblastoma cell line (SK-N-SH). Neurotoxicology 2005;
26:407–16.
40 Westphal GA, Asgari S, Schulz TG, Bunger J, Muller M, Hallier
E. Thimerosal induces micronuclei in the cytochalasin B block
micronucleus test with human lymphocytes. Arch Toxicol 2003;
77:50–5.
41 Boris M, Goldblatt A, Galenko J, James SJ. Association of MTHFR
Gene variants wit autism. Journal of American Physicans and
Surgeons 2004; 9:106–8.
42 Magos L, Brown AW, Sparrow S et al. The comparative toxicol-
ogy of ethyl- and methylmercury. Arch Toxicol 1985; 57:260–7.
Joachim Mutter, Johannes Naumann, Rainer Schneider, Harald Walach & Boyd Haley
445
Neuroendocrinology Letters Vol.26, No. 5, October 2005 Copyright © Neuroendocrinology Letters ISSN 0172–780X w w w.nel.edu
43 Oskarsson A, Palminger Hallen I, Sundberg J, Petersson Grawe
K. Risk assessment in relation to neonatal metal exposure. Ana-
lyst 1998; 123:19–23.
44 Harry GJ, Harris MW, Burka LT. Mercury concentrations in
brain and kidney following ethylmercury, methylmercury and
Thimerosal administration to neonatal mice. Toxicol Lett 2004;
154:183–9.
45 Colmann E, Halsey NA, Golman LR, Westphal G, Hallier E. Mer-
cury in infants given vaccines containing thiomersal. Lancet
2003; 361:698–99.
46 Geier MR, Geier DA. Mercury in vaccines and potential conflicts
of interest. Lancet 2004; 364:1217.
47 James SJ, Slikker W 3rd, Melnyk S, New E, Pogribna M, Jernigan
S. Thimerosal neurotoxicity is associated with glutathione de-
pletion: protection with glutathione precursors. Neurotoxicol-
ogy 2005; 26:1–8.
48 Muller M, Westphal G, Vesper A, Bunger J, Hallier E. Inhibition
of the human erythrocytic glutathione-S-transferase T1 (GST
T1) by thimerosal. Int J Hyg Environ Health 2001; 203:479–81.
49 Olivieri G, Brack C, Muller-Spahn F, Stahelin HB, Herrmann M,
Renard P, Brockhaus M, Hock C. Mercury induces cell cytotox-
icity and oxidative stress and increases beta-amyloid secretion
and tau phosphorylation in SHSY5Y neuroblastoma cells. J.
Neurochem 2000; 74:231–6.
50 Olivieri G, Novakovic M, Savaskan E, Meier F, Baysang G, Brock-
haus M, Muller-Spahn F. The effects of beta-estradiol on SHSY5Y
neuroblastoma cells during heavy metal induced oxidative
stress, neurotoxicity and beta-amyloid secretion. Neuroscience
2002; 113:849–55.
51 Vojdani A, Pangborn JB, Vojdani E, Cooper EL. Infections, toxic
chemicals and dietary peptides binding to lymphocyte recep-
tors and tissue enzymes are major instigators of autoimmunity
in autism. Int J Immunopathol Pharmacol 2003; 16:189–99.
52 Vargas DL, Nascimbene C, Krishnan C, Zimmerman AW, Pardo
CA. Neuroglial activation and neuroinflammation in the brain
of patients with autism. Ann Neurol 2005; 57:67–81.
53 Hornig M, Chian D, Lipkin WI. Neurotoxic effects of postnatal
thimerosal are mouse strain dependent. Mol Psychiatry 2004;
9:833–45.
54 Hornig M. Truth revealed: New scientific discoveries regarding
mercury in medicine an autism. Congressional Testimony be-
fore the U.S. House of Representatives. Subcommittee on hu-
man rights and wellness, Sept. 8, (2004). Available from: URL:
http://reform.house.gov/WHR/Hearings/EventSingle.aspx?
EventID=18156 [cited 2005, September 20].
55 Westphal GA, Schnuch A, Schulz TG, Reich K, Aberer W, Brasch J,
Koch P, Wessbecher R, Szliska C, Bauer A, Hallier E. Homozygous
gene deletions of the glutathione S-transferases M1 and T1 are
associated with thimerosal sensitization. Int Arch Occup Envi-
ron Health 2000; 73:384–8.
56 Havarinasab S, Hultman P. Organic mercury compounds and
autoimmunity. Autoimmun Rev. 2005; 4:270–5.
57 Havarinasab S, Haggqvist B, Bjorn E, Pollard KM, Hultman P.
Immunosuppressive and autoimmune effects of thimerosal in
mice. Toxicol Appl Pharmacol. 2005; 204:109–21.
58 Hernan MA, Jick SS, Olek MJ, Jick H. Recombinant hepatitis B
vaccine and the risk of multiple sclerosis: a prospective study.
Neurology 2004; 63:838–42.
59 Haley B. Reduced levels of mercury in first baby haircuts of
Autistic children. Immunization safety review: Vaccines and au-
tism. Institute of Medicine, Febr. 9, (2004). Available from: URL:
http://www.iom.edu/subpage.asp?id=18065 [cited 2005, Sep-
tember 20].
60 Geier MR, Geier DA. The potential importance of steroids in the
treatment of autistic spectrum disorders and other disorders
involving mercury toxicity. Med Hypotheses 2005; 64:946–54.
61 Schubert J, Riley EJ, Tyler SA. Combined effects in toxicology
– a rapid systematic testing procedure: cadmium, mercury, and
lead. J Toxicol Environ Health 1978; 4:763–76.
62 Geier MR, Geier DA. Neurodevelopmental disorders after thime-
rosal-containing vaccines: a brief communication. Exp Biol Med
2003; 228:660–64.
63 Geier DA, Geier MR. An assessment of the impact of thimerosal
on childhood neurodevelopmental disorders. Pediatr Rehabil
2003; 6:97–102.
64 Geier MR, Geier DA. Thiomersal in childhood vaccines, neurode-
velopment disorders, and heart disease in the United States. J
Am Phys Surg 2003; 8:6–11.
65 Geier DA, Geier MR. A comparative evaluation of the effects of
MMR immunization and mercury doses from thimerosal-con-
taining childhood vaccines on the population prevalence of
autism. Med Sci Monit 2004; 10, PI33–9.
66 Verstraeten T, Davis RL, DeStefano F, Lieu TA, Rhodes PH, Black
SB, Shinefield H, Chen RT, Vaccine Safety Datalink Team. Safety
of thimerosal-containing vaccines: a two-phased study of com-
puterized health maintenance organization databases. Pediat-
rics 2003; 112:1039–48.
67 Olmsted D. The Age of Autism: Witness. The Washington Times;
May 10, 2005. Available from URL: http://washingtontimes.
com/upi-breaking/20050508-112601-3643r.htm [cited 2005;
Sep tember 20].
68 Andrews N, Miller E, Grant A, Stowe J, Osborne V, Taylor B.
Thimerosal exposure in infants and developmental disorders:
a retrospective cohort study in the United Kingdom does not
support a causal association. Pediatrics 2004; 114:584–91.
69 Madsen KM, Lauritsen MB, Pedersen CB et al. Thimerosal and
the Occurrence of Autism: Negative Ecological Evidence From
Danish Population-Based Data. Pediatrics 2003; 112:604–6.
70 Hviid A, Stellfeld M, Wohlfahrt J, Melbye M. Association be-
tween thimerosal-containing vaccine and autism. JAMA 2003;
290:1763–66.
71 Stehr-Green P, Tull P, Stellfeld M, Mortenson PB, Simpson D.
Autism and thimerosal-containing vaccines: lack of consistent
evidence for an association. Am J Prev Med 2003; 25:101–6.
72 Bernard S. Analysis of the Danish Autism Registry Database
in Response to the Hviid et al Paper on Thimerosal in JAMA.
(2003). Available from: URL: http://www.safeminds.org/re-
search/docs/Hviid_et_alJAMA-SafeMindsAnalysis.pdf [cited
2005, September 20].
73 Bertrand J, Mars A, Boyle C, Bove F, Yeargin-Allsopp M, Decou-
fle P. Prevalence of autism in a United States population: the
Brick Township, New Jersey, investigation. Pediatrics 2001;
108:1155–61.
74 Madsen KM, Hviid A, Vestergaard M et al. A population-based
study of measles, mumps, and rubella vaccination and autism.
N Engl J Med 2002; 347:1477–82.
75 Carbone KM, Rubin SA, Pletnikov M. Borna disease virus (BDV)-
induced model of autism: application to vaccine safety test de-
sign. Mol Psychiatry 2001; 7 (Suppl 2):S36–7.
76 Autism Research Institute: Treatment options for mercury/
metal toxicity in autism and related developmental disabilities:
Consensus paper. (2005). Available from URL: http://www.au-
tismwebsite.com/ari/dan/mercurymetaldetox.htm [cited 2005;
September 20].
77 Buttar RA. Autism Spectrum Disorders: An Update of Federal
Government Initiatives and Revolutionary New Treatments of
Neurodevelopmental Diseases. Congressional Testimony before
the U.S. House of Representatives. Subcommittee on human
rights and wellness, May 6 (2004). Available from: URL: http://
reform.house.gov/WHR/Hearings/EventSingle.aspx?EventID=
13567 [cited 2005, September 20].
78 Harch P. Autism Spectrum Disorders: An Update of Federal Gov-
ernment Initiatives and Revolutionary New Treatments of Neu-
rodevelopmental Diseases. Congressional Testimony before the
U.S. House of Representatives. Subcommittee on human rights
and wellness, May, 6, (2004). Available from: URL: http://reform.
house.gov/WHR/Hearings/EventSingle.aspx?EventID=13567
[cited 2005, September 20].
79 Pendergrass JC, Haley BE. Mercury-EDTA Complex Specifically
Blocks brain-tubulin-GTP Interactions: Similarity to Observa-
tions in Alzheimer’s Disease. In: Status Quo and Perspective (In-
ternational Symposium Proceedings ed. Friberg LT and Schrau-
zer GN). Stuttgart-New York: Gerog Thieme Verlag; 1995. pp.
98–105.
80 Pendergrass JC, Haley BE, Vimy MJ, Winfield SA, Lorscheider FL.
Mercury vapor inhalation inhibits Binding of GTP to tubulin in
rat brain: Similarity to a molecular lesion in Alzehimer’s Disease
brain. Neurotoxicology 1997; 18:315–24.
81 Gasset AR, Itoi M, Ischii Y, Ramer RM. Teratogenicities of oph-
thalmic drugs. II/Teratogenicities and tissue accumulation of
thimerosal. Arch Ophthalmol 1975; 93:52–5.
Mercury and autism: Accelerating Evidence?
446
Neuroendocrinology Letters Vol.26, No. 5, October 2005 Copyright © Neuroendocrinology Letters ISSN 0172–780X w w w.nel.edu
82 Rampersad GC, Suck G, Sakac D, Fahim S, Fop A, Denomme GA
et al. Chemical compounds that target thioldisulfide groups on
mononuclear phagocytes inhibit immune mediated phgocyto-
sis of red blood cells. Transfusion 2005; 45:384–93.
83 Fagan DG, Pritchard JS, Clarkson TW, Greenwood MR. Organ
mercury levels in infants with omphaloceles treated with or-
ganic mercurial antiseptic. Arch Dis Child 1977; 52:962-4.
Joachim Mutter, Johannes Naumann, Rainer Schneider, Harald Walach & Boyd Haley
