CHOP & Lancet augment the Myth of Must be better diagnosis

Teresa Binstock
Researcher in Developmental & Behavioral Neuroanatomy
December 25, 2009


A recently published abstract from researchers at the Children's Hospital of Philadelphia (CHOP) states that the increased rate of autism-spectrum disorders "might be attributable to factors such as new administrative classifications, policy and practice changes, and increased awareness" (1). However, that the researchers selected and presented that concept and rhetoric while failing to state the other main option - environmental factors contributing substantially to the increase - is a form of bias by choice of rhetoric, especially when presented in an abstract that will be read far more widely than will the full text of the article.

In the very least, we might take heart in the fact that the CHOP authors' use of the word "might" implicitly implies "might not". And fortunately, many researchers are beginning to describe complex interactions accurately. As examples preferable to the CHOP researchers' glibness, Pessah & colleagues write, "genetic, epigenetic, and environmental factors that might act in concert to influence autism risk, severity and co-morbidities, and immunological and neurobiological targets as etiologic contributors." (12)  While Geier and colleagues offer, "Emerging evidence supports the theory that some autism spectrum disorders (ASDs) may result from a combination of genetic/biochemical susceptibility, specifically a reduced ability to excrete mercury (Hg), and exposure to Hg at critical developmental periods." (13)

In further contrast to the CHOP researchers' invocation of the establishmentarian myth that the autism epidemic "Must be better diagnosis", many of us have heard observations from long-term elementary-school teachers and from long-term special-education teachers who report that in prior decades, there weren't nearly so many affected children. Importantly, a study which evaluated how much of autism-rate increase derives from increased awareness, diagnostic changes, etc, versus an actual increase concluded that much of California's increased rate of precisely categorized autism was real (2, see also 3).

Another cleverness is noteworthy in the CHOP researchers' abstract's propagandistic rhetoric. The authors use common phraseology for DSM-IV autism - "severe deficits in socialisation, communication, and repetitive or unusual behaviour" (1). With this word usage, the authors lump a diagnostic summary for DSM-IV autism within the often confusing category "autism spectrum disorders" [sic] and have thereby slurred over important differences among DSM-IV autism, Asperger's syndrome, and DSM-IV PDD/NOS.  In contrast, more accurate phraseology is offered by Nassar et al, who offer "autism spectrum disorders (ASDs), which include autism, Asperger syndrome and pervasive developmental disorder not otherwise specified (PDD-NOS)" and also by Bryson et al, who looked within ASD subgroups, retained clarity of diagnostic categories, and wrote, "Children with autism were compared to children with other ASDs - Asperger's disorder, Rett's disorder, and PDD-NOS."

Claiming that the epidemic of autism and other ASDs is merely an artifice of better diagnosis and increased awareness is to turn attention away from the real-increase observed by long-term teachers and by astute researchers (eg, 2) and also turns attention away from increasing documentation of environmental factors associated with autism and with increased rates of autism (eg, 6-9, see also reviews in 10-11).

Blurring important differences between diagnostic categories (1) hinders the search for subgroup-specific etiologies and for subgroup-specific treatments (eg, 14-15).


References:

1. Autism
Levy SE, Mandell DS, Schultz RT.
Children's Hospital of Philadelphia
Lancet. 2009 Nov 7;374(9701):1627-38. Epub 2009 Oct 12.
$ http://linkinghub.elsevier.com/retrieve/pii/S0140-6736%2809%2961376-3

Autism spectrum disorders are characterised by severe deficits in socialisation, communication, and repetitive or unusual behaviours. Increases over time in the frequency of these disorders (to present rates of about 60 cases per 10,000 children) might be attributable to factors such as new administrative classifications, policy and practice changes, and increased awareness. Surveillance and screening strategies for early identification could enable early treatment and improved outcomes. Autism spectrum disorders are highly genetic and multifactorial, with many risk factors acting together. Genes that affect synaptic maturation are implicated, resulting in neurobiological theories focusing on connectivity and neural effects of gene expression. Several treatments might address core and comorbid symptoms. However, not all treatments have been adequately studied. Improved strategies for early identification with phenotypic characteristics and biological markers (eg, electrophysiological changes) might hopefully improve effectiveness of treatment. Further knowledge about early identification, neurobiology of autism, effective treatments, and the effect of this disorder on families is needed.


2. The rise in autism and the role of age at diagnosis
Hertz-Picciotto I, Delwiche L.
Epidemiology. 2009 Jan;20(1):84-90.
http://www.pinniped.net/hertz2009.pdf

BACKGROUND: Autism prevalence in California, based on individuals eligible for state-funded services, rose throughout the 1990s. The extent to which this trend is explained by changes in age at diagnosis or inclusion of milder cases has not been previously evaluated. METHODS: Autism cases were identified from 1990 through 2006 in databases of the California Department of Developmental Services, which coordinates services for individuals with specific developmental disorders. The main outcomes were population incident cases younger than age 10 years for each quarter, cumulative incidence by age and birth year, age-specific incidence rates stratified by birth year, and proportions of diagnoses by age across birth years. RESULTS: Autism incidence in children rose throughout the period. Cumulative incidence to 5 years of age per 10,000 births rose consistently from 6.2 for 1990 births to 42.5 for 2001 births. Age-specific incidence rates increased most steeply for 2- and 3-year olds. The proportion diagnosed by age 5 years increased only slightly, from 54% for 1990 births to 61% for 1996 births. Changing age at diagnosis can explain a 12% increase, and inclusion of milder cases, a 56% increase. CONCLUSIONS: Autism incidence in California shows no sign yet of plateauing. Younger ages at diagnosis, differential migration, changes in diagnostic criteria, and inclusion of milder cases do not fully explain the observed increases. Other artifacts have yet to be quantified, and as a result, the extent to which the continued rise represents a true increase in the occurrence of autism remains unclear.


3. Prevalence of autism spectrum disorders --- autism and developmental disabilities monitoring network, United States, 2006
Autism and Developmental Disabilities Monitoring Network Surveillance Year 2006 Principal Investigators.
MMWR Surveill Summ. 2009 Dec 18;58(10):1-20.
http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5810a1.htm

Problem/Condition: Autism spectrum disorders (ASDs) are a group of developmental disabilities characterized by atypical development in socialization, communication, and behavior. ASDs typically are apparent before age 3 years, with associated impairments affecting multiple areas of a person's life. Because no biologic marker exists for ASDs, identification is made by professionals who evaluate a child's developmental progress to identify the presence of developmental disorders. Reporting Period: 2006. Methods: Earlier surveillance efforts indicated that age 8 years is a reasonable index age at which to monitor peak prevalence. The identified prevalence of ASDs in U.S. children aged 8 years was estimated through a systematic retrospective review of evaluation records in multiple sites participating in the Autism and Developmental Disabilities Monitoring (ADDM) Network. Data were collected from existing records in 11 ADDM Network sites (areas of Alabama, Arizona, Colorado, Florida, Georgia, Maryland, Missouri, North Carolina, Pennsylvania, South Carolina, and Wisconsin) for 2006. To analyze changes in identified ASD prevalence, CDC compared the 2006 data with data collected from 10 sites (all sites noted above except Florida) in 2002. Children aged 8 years with a notation of an ASD or descriptions consistent with an ASD were identified through screening and abstraction of existing health and education records containing professional assessments of the child's developmental progress at health-care or education facilities. Children aged 8 years whose parent(s) or legal guardian(s) resided in the respective areas in 2006 met the case definition for an ASD if their records documented behaviors consistent with the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, text revision (DSM-IV-TR) criteria for autistic disorder, pervasive developmental disorder--not otherwise specified (PDD NOS), or Asperger disorder. Presence of an identified ASD was determined through a review of data abstracted from developmental evaluation records by trained clinician reviewers. Results: For the 2006 surveillance year, 2,757 (0.9%) of 307,790 children aged 8 years residing in the 11 ADDM sites were identified as having an ASD, indicating an overall average prevalence of 9.0 per 1,000 population (95% confidence interval [CI] = 8.6--9.3). ASD prevalence per 1,000 children aged 8 years ranged from 4.2 in Florida to 12.1 in Arizona and Missouri, with prevalence for the majority of sites ranging between 7.6 and 10.4. For 2006, ASD prevalence was significantly lower in Florida (p<0.001) and Alabama (p<0.05) and higher in Arizona and Missouri (p<0.05) than in all other sites. The ratio of males to females ranged from 3.2:1 in Alabama to 7.6:1 in Florida. ASD prevalence varied by type of ascertainment source, with higher average prevalence in sites with access to health and education records (10.0) compared with sites with health records only (7.5). Although parental or professional concerns regarding development before age 36 months were noted in the evaluation records of the majority of children who were identified as having an ASD, the median age of earliest documented ASD diagnosis was much later (range: 41 months [Florida]--60 months [Colorado]). Of 10 sites that collected data for both the 2002 and 2006 surveillance years, nine observed an increase in ASD prevalence (range: 27%--95% increase; p<0.01), with increases among males in all sites and among females in four of 11 sites, and variation among other subgroups. Interpretation: In 2006, on average, approximately 1% or one child in every 110 in the 11 ADDM sites was classified as having an ASD (approximate range: 1:80--1:240 children [males: 1:70; females: 1:315]). The average prevalence of ASDs identified among children aged 8 years increased 57% in 10 sites from the 2002 to the 2006 ADDM surveillance year. Although improved ascertainment accounts for some of the prevalence increases documented in the ADDM sites, a true increase in the risk for children to develop ASD symptoms cannot be ruled out. On average, although delays in identification persisted, ASDs were being diagnosed by community professionals at earlier ages in 2006 than in 2002. Public Health Actions: These results indicate an increased prevalence of identified ASDs among U.S. children aged 8 years and underscore the need to regard ASDs as an urgent public health concern. Continued monitoring is needed to document and understand changes over time, including the multiple ascertainment and potential risk factors likely to be contributing. Research is needed to ascertain the factors that put certain persons at risk, and concerted efforts are essential to provide support for persons with ASDs, their families, and communities to improve long-term outcome.


4. Autism spectrum disorders in young children: effect of changes in diagnostic practices.
Nassar N et al.
Int J Epidemiol. 2009 Oct;38(5):1245-54. Epub 2009 Sep 7.

BACKGROUND: It is unclear whether the increase in autism over the past two decades is a real increase or due to changes in diagnosis and ascertainment of autism spectrum disorders (ASDs), which include autism, Asperger syndrome and pervasive developmental disorder not otherwise specified (PDD-NOS)... CONCLUSIONS: The rise in incidence of all types of ASDs by year of diagnosis appears to be related to changes in diagnostic and service provision practices in WA. In children aged


5. Characteristics of children with autism spectrum disorders who received services through community mental health centers
Bryson SA, Corrigan SK, McDonald TP, Holmes C.
Autism. 2008 Jan;12(1):65-82.
$ http://aut.sagepub.com/cgi/reprint/12/1/65

Despite the presence of significant psychiatric comorbidity among children with autism spectrum disorders (ASDs), little research exists on those who receive community-based mental health services. This project examined one year (2004) of data from the database maintained by 26 community mental health centers (CMHCs) in the Midwestern US state of Kansas. Children with autism were compared to children with other ASDs - Asperger's disorder, Rett's disorder, and PDD-NOS. Children with autism predictably received more special education services than children with other ASDs, while the latter were more likely to have experienced prior psychiatric hospitalization. Children with ASDs other than autism were also significantly more likely to be diagnosed with attention deficit hyperactivity disorder, oppositional defiant disorder, depressive disorders, and bipolar disorder. In 2004, Kansas CMHCs served less than 15 percent of the children estimated to have an ASD. Implications of these findings are discussed.


6. Environmental mercury release, special education rates, and autism disorder: an ecological study of Texas
Palmer RF et al. Health Place. 2006 Jun;12(2):203-9.
{free online}
http://www.generationrescue.org/pdf/seed.pdf

The association between environmentally released mercury, special education and autism rates in Texas was investigated using data from the Texas Education Department and the United States Environmental Protection Agency. A Poisson regression analysis adjusted for school district population size, economic and demographic factors was used. There was a significant increase in the rates of special education students and autism rates associated with increases in environmentally released mercury. On average, for each 1,000 lb of environmentally released mercury, there was a 43% increase in the rate of special education services and a 61% increase in the rate of autism. The association between environmentally released mercury and special education rates were fully mediated by increased autism rates. This ecological study suggests the need for further research regarding the association between environmentally released mercury and developmental disorders such as autism. These results have implications for policy planning and cost analysis.


7. Proximity to point sources of environmental mercury release as a predictor of autism prevalence
Palmer RF et al. Health Place. 2009 Mar;15(1):18-24.
{free online}
http://images.huffingtonpost.com/2009-01-29-Palmer2008.pdf

The objective of this study was to determine if proximity to sources of mercury pollution in 1998 were related to autism prevalence in 2002. Autism count data from the Texas Educational Agency and environmental mercury release data from the Environmental Protection Agency were used. We found that for every 1000 pounds of industrial release, there was a corresponding 2.6% increase in autism rates (p<.05) and a 3.7% increase associated with power plant emissions(P<.05). Distances to these sources were independent predictors after adjustment for relevant covariates. For every 10 miles from industrial or power plant sources, there was an associated decreased autism Incident Risk of 2.0% and 1.4%, respectively (p<.05). While design limitations preclude interpretation of individual risk, further investigations of environmental risks to child development issues are warranted.


8. Autism spectrum disorders in relation to distribution of hazardous air pollutants in the san francisco bay area
Windham GC et al. Environ Health Perspect. 2006 Sep;114(9):1438-44.
{free online}
http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1570060&blobtype=pdf

OBJECTIVE: To explore possible associations between autism spectrum disorders (ASD) and environmental exposures, we linked the California autism surveillance system to estimated hazardous air pollutant (HAP) concentrations compiled by the U.S. Environmental Protection Agency. METHODS: Subjects included 284 children with ASD and 657 controls, born in 1994 in the San Francisco Bay area. We assigned exposure level by census tract of birth residence for 19 chemicals we identified as potential neurotoxicants, developmental toxicants, and/or endocrine disruptors from the 1996 HAPs database. Because concentrations of many of these were highly correlated, we combined the chemicals into mechanistic and structural groups, calculating summary index scores. We calculated ASD risk in the upper quartiles of these group scores or individual chemical concentrations compared with below the median, adjusting for demographic factors. RESULTS: The adjusted odds ratios (AORs) were elevated by 50% in the top quartile of chlorinated solvents and heavy metals [95% confidence intervals (CIs) , 1.1-2.1], but not for aromatic solvents. Adjusting for these three groups simultaneously led to decreased risks for the solvents and increased risk for metals (AORs for metals: fourth quartile = 1.7 ; 95% CI, 1.0-3.0 ; third quartile = 1.95 ; 95% CI, 1.2-3.1) . The individual compounds that contributed most to these associations included mercury, cadmium, nickel, trichloroethylene, and vinyl chloride. CONCLUSIONS: Our results suggest a potential association between autism and estimated metal concentrations, and possibly solvents, in ambient air around the birth residence, requiring confirmation and more refined exposure assessment in future studies.


9. Hepatitis B triple series vaccine and developmental disability in US children aged 1-9 years
 Gallagher C, Goodman M. Toxicol Environ Chem 2008 90(5):997-1008.
{free online}
http://fourteenstudies.org/pdf/hep_b.pdf

This study investigated the association between vaccination with the Hepatitis B triple series vaccine prior to 2000 and developmental disability in children aged 1-9 years (n = 1824), proxied by parental report that their child receives early intervention or special education services (EIS). National Health and Nutrition Examination Survey 1999-2000 data were analyzed and adjusted for survey design by Taylor Linearization using SAS version 9.1 software, with SAS callable SUDAAN version 9.0.1. The odds of receiving EIS were approximately nine times as great for vaccinated boys (n = 46) as for unvaccinated boys (n = 7), after adjustment for confounders. This study found statistically significant evidence to suggest that boys in United States who were vaccinated with the triple series Hepatitis B vaccine, during the time period in which vaccines were manufactured with thimerosal, were more susceptible to developmental disability than were unvaccinated boys.


10. Environmental risk factors for autism: Do they help cause de novo genetic mutations that contribute to the disorder?
Dennis K. Kinney et al.
Med Hypotheses. 2010 Jan;74(1):102-6.
http://tinyurl.com/ye4q5xo

Recent research has discovered that a number of genetic risk factors for autism are de novo mutations. Advanced parental age at the time of conception is associated with increased risk for both autism and de novo mutations. We investigated the hypothesis that other environmental factors associated with increased risk for autism might also be mutagenic and contribute to autism by causing de novo mutations. A survey of the research literature identified 9 environmental factors for which increased pre-conceptual exposure appears to be associated with increased risk for autism. Five of these factors--mercury, cadmium, nickel, trichloroethylene, and vinyl chloride--are established mutagens. Another four--including residence in regions that are urbanized, located at higher latitudes, or experience high levels of precipitation--are associated with decreased sun exposure and increased risk for vitamin D deficiency. Vitamin D plays important roles in repairing DNA damage and protecting against oxidative stress--a key cause of DNA damage. Factors associated with vitamin D deficiency will thus contribute to higher mutation rates and impaired repair of DNA. We note how de novo mutations may also help explain why the concordance rate for autism is so markedly higher in monozygotic than dizygotic twins. De novo mutations may also explain in part why the prevalence of autism is so remarkably high, given the evidence for a strong role of genetic factors and the low fertility of individuals with autism--and resultant selection pressure against autism susceptibility genes. These several lines of evidence provide support for the hypothesis, and warrant new research approaches--which we suggest--to address limitations in existing studies. The hypothesis has implications for understanding possible etiologic roles of de novo mutations in autism, and it suggests possible approaches to primary prevention of the disorder, such as addressing widespread vitamin D deficiency and exposure to known mutagens.


11. Similarities in features of autism and asthma and a possible link to acetaminophen use
Kevin G. Becker, Stephen T. Schultz
Medical Hypotheses 74 (2010) 7–11
http://tinyurl.com/y8fsbte

Autism and autism spectrum disorders are enigmatic conditions that have their origins in the interaction of genes and environmental factors. In this hypothesis, genes statistically associated with autism are emphasized to be important in inflammation and in innate immune pathways, including pathways for susceptibility to asthma. The role of acetaminophen (paracetamol) in an increased risk for asthma is described and a possible similar link to an increased risk for autism is suggested.


12. Immunologic and neurodevelopmental susceptibilities of autism.
Pessah IN et al.
Neurotoxicology. 2008 May;29(3):532-45.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2475601/pdf/nihms55471.pdf

Symposium 5 focused on research approaches that are aimed at understanding common patterns of immunological and neurological dysfunction contributing to neurodevelopmental disorders such as autism and ADHD. The session focused on genetic, epigenetic, and environmental factors that might act in concert to influence autism risk, severity and co-morbidities, and immunological and neurobiological targets as etiologic contributors. The immune system of children at risk of autism may be therefore especially susceptible to psychological stressors, exposure to chemical triggers, and infectious agents. Identifying early biomarkers of risk provides tangible approaches toward designing studies in animals and humans that yield a better understanding of environmental risk factors, and can help identify rational intervention strategies to mitigate these risks.


13. A comprehensive review of mercury provoked autism
Geier DA et al.
Indian J Med Res. 2008 Oct;128(4):383-411.
http://www.icmr.nic.in/ijmr/2008/october/1004.pdf

Emerging evidence supports the theory that some autism spectrum disorders (ASDs) may result from a combination of genetic/biochemical susceptibility, specifically a reduced ability to excrete mercury (Hg), and exposure to Hg at critical developmental periods. Elemental/inorganic Hg is released into the air/water where it becomes methylated and accumulates in animal tissues. The US population is primarily exposed to methyl-Hg by fish consumption. In addition, many pharmaceuticals have been, and some continue to be, a ubiquitous source of danger because they contain mercurials. Mercurials may be found in drugs for the eye, ear, nose, throat, and skin; in bleaching creams; as preservatives in cosmetics, tooth pastes, lens solutions, vaccines, allergy test and immunotherapy solutions; in antiseptics, disinfectants, and contraceptives; in fungicides and herbicides; in dental fillings and thermometers; and many other products. Hg has been found to cause immune, sensory, neurological, motor, and behavioural dysfunctions similar to traits defining/associated with ASDs, and that these similarities extend to neuroanatomy, neurotransmitters, and biochemistry. Furthermore, a review of molecular mechanisms indicates that Hg exposure can induce death, disorganization and/or damage to selected neurons in the brain similar to that seen in recent ASD brain pathology studies, and this alteration may likely produce the symptoms by which ASDs are diagnosed. Finally, a review of treatments suggests that ASD patients who undergo protocols to reduce Hg and/or its effects show significant clinical improvements in some cases. In conclusion, the overwhelming preponderance of the evidence favours acceptance that Hg exposure is capable of causing some ASDs.


14. Novel clustering of items from the Autism Diagnostic Interview-Revised to define phenotypes within autism spectrum disorders
Hu VW, Steinberg ME.
Autism Res. 2009 Apr;2(2):67-77.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2737479/pdf/nihms-118849.pdf

Heterogeneity in phenotypic presentation of Autism spectrum disorders has been cited as one explanation for the difficulty in pinpointing specific genes involved in autism. Recent studies have attempted to reduce the "noise" in genetic and other biological data by reducing the phenotypic heterogeneity of the sample population. The current study employs multiple clustering algorithms on 123 item scores from the Autism Diagnostic Interview-Revised (ADI-R) diagnostic instrument of nearly 2,000 autistic individuals to identify subgroups of autistic probands with clinically relevant behavioral phenotypes in order to isolate more homogeneous groups of subjects for gene expression analyses. Our combined cluster analyses suggest optimal division of the autistic probands into four phenotypic clusters based on similarity of symptom severity across the 123 selected item scores. One cluster is characterized by severe language deficits, while another exhibits milder symptoms across the domains. A third group possesses a higher frequency of savant skills while the fourth group exhibited intermediate severity across all domains. Grouping autistic individuals by multivariate cluster analysis of ADI-R scores reveals meaningful phenotypes of subgroups within the autistic spectrum, which we show, in a related (accompanying) study, to be associated with distinct gene expression profiles.


15. Gene expression profiling differentiates autism case-controls and phenotypic variants of autism spectrum disorders: evidence for circadian rhythm dysfunction in severe autism.
Hu VW et al.
The George Washington University Medical Center
Autism Res. 2009 Apr;2(2):78-97.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2737477/pdf/nihms-126147.pdf

Autism spectrum disorders (ASD) are neurodevelopmental disorders characterized by delayed/abnormal language development, deficits in social interaction, repetitive behaviors and restricted interests. The heterogeneity in clinical presentation of ASD, likely due to different etiologies, complicates genetic/biological analyses of these disorders. DNA microarray analyses were conducted on 116 lymphoblastoid cell lines (LCL) from individuals with idiopathic autism who are divided into three phenotypic subgroups according to severity scores from the commonly used Autism Diagnostic Interview-Revised questionnaire and age-matched, nonautistic controls. Statistical analyses of gene expression data from control LCL against that of LCL from ASD probands identify genes for which expression levels are either quantitatively or qualitatively associated with phenotypic severity. Comparison of the significant differentially expressed genes from each subgroup relative to the control group reveals differentially expressed genes unique to each subgroup as well as genes in common across subgroups. Among the findings unique to the most severely affected ASD group are 15 genes that regulate circadian rhythm, which has been shown to have multiple effects on neurological as well as metabolic functions commonly dysregulated in autism. Among the genes common to all three subgroups of ASD are 20 novel genes mostly in putative noncoding regions, which appear to associate with androgen sensitivity and which may underlie the strong 4:1 bias toward affected males.


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