Frequency of autism

The advent of a possible autism epidemic was first suggested in the mid-1990s by a handful of healthcare professionals who noticed sharp increases in the numbers being diagnosed and reported to public health agencies. Most authorities remain ambivalent as to whether or not the prevalence of autism is increasing [1] [2][3][4], and therefore whether the term "epidemic" is accurate.

The number of reported cases of autism has increased dramatically over the past decade.

The number of children diagnosed with autism has increased significantly in recent years, leading many scientists and health care practitioners to question whether extrinsic factors may be at least partially responsible. The cause of any increase in autism incidence is hotly debated. Researchers have speculated that genetic causes, pollution, food additives, childhood vaccinations, or more thorough diagnosis and screening may play roles. Other speculation attributes the trend of increasing diagnoses to a form of collective hysteria. Researchers have long pointed to changes in diagnostic categories in the Diagnostic and Statistical Manual of Mental Disorders as profoundly affecting the numbers diagnosed as autistic, especially changes set out in DSM-III-R [5] [6] and DSM-IV.[7].

Scope of autism prevalence

While the number of diagnoses related to autism has increased in recent decades, public health organizations and researchers have not yet been able to fully ascertain whether:

• More incidents of autism are being reported now, as a result of increased awareness of the disorder
• The diagnosis is being applied more broadly than before, as a result of the changing definition of the disorder
• The magnitude of the increase warrants urgent and/or drastic measures a full-blown epidemic would call for

Whether the real incidence of autism had been increasing was quite unclear as recently as 1999.[8] Nevertheless, an increasing prevalence of autism diagnoses has sparked concerns, especially among parents. In response to growing employee concerns among high tech workers, for instance, Microsoft became the first major US corporation to offer employees insurance coverage for the cost of behavioral training for their autistic children in 2001, due to the high prevalence among the children of employees. Elsewhere, the rising prevalence of autism spectrum children threatens to bankrupt families, school systems and government agencies around the globe.

Parent advocacy groups object to public health agencies' reservations, pointing out that if estimates of the increasing prevalence are true, several of the world's governments are confronted with a catastrophic health crisis with deep humanitarian and economic implications. They are calling for increased research into environmental factors that might cause or contribute to autism; increased research into therapies and possible cures to treat autism; and greater funding of programs to help autistic people learn to live with their disorder.

There is evidence of a large subset of children with regressive autism, where symptoms do not emerge until after one year of age, and feature a consistent set of symptoms associated with dysfunctional, elevated immune responses. "We are calling this epiphenomenon 'NIDS' (Neuro-Immune Dysfunction Syndromes)," says Dr. Michael Goldberg, a pediatrician on the clinical teaching staff at UCLA and president of the NIDS Research Institute.

In the absence of an agreed-upon explanation for the cause of autism, a vocal and growing number of parents, health professionals, politicians and others are demanding further independent study of a possible causal connection between autism and the policy of universal vaccinations. This demand reflects a highly controversial issue on the risks and benefits of vaccinations, pitting the medical community and public health agencies against a large proportion of parents (one third of parents in California, see 'vaccine theories' below) and a relatively small group of physicians. See Vaccine controversy for further discussion on vaccines.

Some members of the autism community have expressed dismay regarding the use of the term 'epidemic' to describe the increasing prevalence of autism, seeing such phrasing as inflammatory, especially when used by prestigious interests in the field of autism research.

Australia

The Australian Education Department reported a 276 percent jump in students with autism spectrum disorder between 2000 and 2005. As of 2005, a total of 23,083 Victorian students were placed in school disability and language disorder programs, rising 74 per cent from 13,257 students in 2000. An expert from the Royal Children's Hospital in Sydney, Australia said the figures were "a significant underestimate."

China

In a July, 2005, interview Robert F. Kennedy, Jr. stated that, "six years ago, autism was unknown in China. We started giving them our vaccines in 1999. Today there's 1.8 million cases of autism in China."[9] However, this seem to conflict with a 1997 study, in China, about teaching Chinese to autistic children, [10] as well as a 1991 study of a Chinese "calendar savant". [11]

Denmark

A study from Denmark was published in November 2002, attracting substantial attention. The incidence of autism reported in the Danish study appeared lower than the prevalence reported in the US and other countries. In Denmark, an incidence rate of 1 out of 727 (or 738 out of 537,303) was reported, far less than estimates of up to 1 in 86 among primary school children in the United Kingdom and around 1 out of 150 children in the US.

Danish authorities discontinued use of thimerosal in 1992 [12], but cite studies showing a continued increase in the incidence of autism as evidence that thimerosal was not a contributing factor. However, according to Robert F. Kennedy, Jr., "before banning thimerosal, Denmark registered only autistics who were hospitalized - one fifth of the afflicted populations. After the withdrawal of thimerosal, Denmark began counting out-patient autistics in its registries. The resulting spike in raw numbers therefore made it appear that autism rates actually increased after the withdrawal of thimerosal."[13]

Japan

A study released in early 2005 was the first to examine autism trends before and after the 1993 withdrawal of MMR, from the Japanese market, inclusive of children who had not had the three-in-one jab. The MMR was withdrawn in Japan in a crisis of confidence after the mumps component was linked to meningitis. The study's authors reported 48 and 86 cases per 10,000 children in two sequential years prior to withdrawal, doubling to 97 and 161 per 10,000 afterwards in two seqeuential years afterwards. [14]

Dr. Andrew Wakefield has noted the specific year to year datat shows a dip in autism diagnoses after Japanese public confidence fell in the MMR specifically, and vaccinations generally. Wakefield notes autism rates had risen to 85.9 per 10,000 for children born in 1990, but declined to 55.8 per 10,000 for children born in 1991 when MMR uptake declined before the MMR vaccine's withrdrawal. Autism rates have steadily increased since that time, after the Japanese public began to accept the notion of three separate vaccines and refinements to diagnostic criteria.[15]

Nigeria

On June 30, 2005, the Punuka Foundation, a non-governmental organization (NGO), issued a release signed by Dr. Helen Nwanze, a speech pathologist/psychologist and Mr. Okey Martins, project supervisor, which stated "there is a rising prevalence of special needs children with delayed speech, hyperative/attention deficit disorder and Austic spectrum disorder in the country." The group said nearly "54,511,850 children under age 15, of which a projected 108,000 are living with autism are living in Nigeria today."[16]

Russia

In response to a study performed in 1977, Russia banned thimerosal from children's vaccines by 1985. Despite this, the Russian autism rate did not change for at least a decade. [17]

United Kingdom

According to Vaccination News, one in eighty-six primary school children in the United Kingdom has autism, compared with one in 2,200 in 1988.[18] Another estimate of the UK incidence rate came from the National Autistic Society, which estimated autism spectrum disorders in the total population to be one in 110. A 2001 review, by the Medical Research Council, yielded an estimate of one in 166 in children under eight.

According to statistics cited by Bernard Rimland, the autism rate in the UK suddenly spiked after the first introduction of the MMR vaccine in 1989, just as it had after the MMR's introduction in the US in the late 1970s.[19]. This is consistent with evidence published in the British Medical Journal [20].

Substantial funds (over £3 million) were spent in the UK on a pro-MMR campaign. [21] Concerted efforts have been made by the British government and pharmaceutical interests to negate the widely criticised[22] 1998 study, led by Andrew Wakefield, that showed a consistent set of bowel disorders among a dozen autistic children. The authors also suggested the need for further studies into the apparent link between MMR and autism. The Danish study was among the reasons given for the interruption of Legal Aid to parents involved in UK MMR litigation.

United States

Approximately 500,000 Americans are autistic, according to a recent 'conservative' estimate, with perhaps as many as 1 in 150 US children suffering from an autism spectrum disorder. Autism is the fastest growing population of special needs students in the United States, growing at over nine hundred percent (900%) between 1992 and 2001, according to data from the US Department of Education.

The United States Centers for Disease Control (CDC) estimates one of every 250 babies is born with autism. As many as 1.5 million Americans are believed to have some form of autism, and the number is rising. Epidemiologists estimate the number of autistic children in the US alone could reach 4 million in the next decade.[23]

In 1999, the autism incidence rate in the United States was generally cited at 4.5 cases per 10,000 live births.

The 2002 Danish epidemiological study was a consideration in the 2004 US Intitutes of Medicine (IOM) Special Committee decision, which concluded an MMR-Autism connection did not exist.

California

In August 1993, there were 4,911 cases of autism logged in California's Department of Developmental Services client-management system, a number excluding milder autism spectrum disorders, such as Asperger's syndrome. By April 29, 1999 the California State Department of Developmental Services reported a State-wide incidence rate of about 15 to 20 per 10,000, triggering alarms about the staggering increase. California is considered to have the best reporting system for autism in the US.

California's increase in childhood autism was not due to flawed diagnoses, according to a 2002 study led by UC Davis pediatric epidemiologist Robert Byrd. 1,685 newly diagnosed autistic children had entered the state's regional center system the previous year, marking a 273 percent increase over an 11-year period from 1988 to 1999. The data again included only children with classic autism, discounting those with PDD-NOS, Asperger's, etc. "The sheer complexity of this phenomenon prevents any clear conclusions," the report stated. "What we do know is that the number of young children coming into the system each year is significantly greater than in the past."

"It's a dramatic report, but what's shocking is that it's not clear what the cause is," said Dr. Thomas Anders, a child psychiatrist and acting director of the M.I.N.D. Institute at the University of California, Davis. Yet the report statistics were very "conservative", according to Rick Rollens, a lobbyist, former secretary of the California State Senate and father of Russell, an autistic boy, adding "It does not include people who are not part of the regional system, and it is estimated that (the regional system is) really serving only half the people with developmental disabilities," said Rollens.

According to a report by the California Department of Developmental Services, or DDS, Autistic Spectrum Disorders, Changes in the California Caseload: 1999-2002, the rate of children diagnosed with full-syndrome autism in California nearly doubled between 1999 and 2002, from 10,360 to 20,377. The report stated, "(B)etween Dec. 31, 1987, and Dec. 31, 2002, the population of persons with full-syndrome autism has increased by 634 percent."

The number of new cases of autism in California has fallen for the first time in more than 10 years in what may be a bellwether for autism rates nationwide, according to new data compiled by the state Department of Developmental Services. As of 2005, the DDS reported a total of 28,046 cases, but that the rate of increase peaked in 2002 and has dropped slightly since then. Parent activist Rick Rollens of Sacramento, who played a key role in the creation of the M.I.N.D. Institute, said the trend roughly corresponds to the removal of mercury preservatives from pediatric vaccines.[24]

Granite Bay cluster

By 1999, in Granite Bay, California, 22 of the 2,930 children enrolled in grades K-6 were autistic.

Silicon Valley cluster

A surge in autism cases in Silicon Valley may be due to genes more common in high-tech workers, according to experts cited in a 2002 BBC article, which indicated one in 150 children in the region had an autistic spectrum disorder.

Connecticut

The number of autistic children educated at public expense in Connecticut has increased 325 percent since 1996, according to the State Department of Education. Governor M. Jodi Rell included a 38 percent increase, to $25.5 million, in the State's budget, for reimbursement to local schools for special education costs.

Stratford cluster

In Stratford, Connecticut the number of children diagnosed with autism who receive special education services has increased 400 percent since 1996. Although only 20 children currently in the school system have autism, the cost for their education may exceed $750,000.

Hawaii

Rick Rollens, a co-founder of the M.I.N.D. Institute, found an autism cluster in a small, isolated area on the east shore of Oahu, Hawaii, in part consisting of a dozen native Hawaiian children with regressive autism, all suffering from gastrointestinal problems, sleep disorders, gluten and casein digestion problems, autoimmune problems, yet having no family history of autism or any other developmental disability.[25]

New Jersey

New Jersey also has a high number of autistic children. This may be because, like California, New Jersey boasts many scientific research and high technology industry enclaves, which dominate the state's economy. A significant portion of the autistic children in New Jersey, intriguingly, were either born in other States or have parents from another State; many more autistic children may have moved to New Jersey from other states specifically because of its well known special education system.

Brick Township cluster

An 'autism cluster' was identified in Brick Township, New Jersey, in 1999. Parents attributed the diagnoses to environmental pollution, but investigators could not confirm the suspicions. The town had about 40 cases among 6,000 children.

Pennsylvania

Amish anomaly

An apparent anomaly among Amish populations was reported in 2005. Although a formal study has not yet been conducted, efforts to assess the prevalence of autism in the Amish community turned up only a very few cases. About 22,000 Amish live in Lancaster County, yet only three or four Amish with autism have turned up thus far in an informal survey of Lancaster County, whereas dozens would be expected at the 1-in-166 prevalence in society at large. "You'll find all the other stuff, but we don't find the autism," according to Dr. Frank Noonan, a family doctor in Lancaster County, adding "We're right in the heart of Amish country and seeing none."

In June, 2005, William F. Raub, of the Department of Health and Human Services suggested the possibility of launching studies of the Amish in response reports of a low prevalence of autism in that community.[26]

Proposed causes

When autism was first described and reported by Leo Kanner and Hans Asperger in the early 1940s, nothing was known about what was causing the previously unrecognized syndrome. The increasing numbers have led to many theories.

Better diagnostics

When the rising prevalence of autism spectrum disorders sparked research into the trend in the late 1990s, the medical establishment primarily attributed the increase to improved diagnostic screening or changes in the definition of autism. In 1994, the fourth major revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) was published [27]. It included substantially updated criteria for the diagnosis of autism and autism spectrum disorders.[28] Professional medical associations, including the American Academy of Pediatrics, say that this revision was an important factor in increasing the apparent prevalence of autism. A 2005 study by Mayo Clinic researchers found that sharp increases in autism diagnoses have followed revisions in DSM criteria and changes in funding for special education programs. [29].

Environmental pollution theories

Because autism appears to be increasing rapidly, some scientists are convinced environmental factors may be involved, arguing that genetic factors alone cannot account for the rise in autism diagnoses. University of Iowa eneticist Thomas Wassink says most researchers studying the genetics of autism now assume the disorder is caused by interplay between genes and factors from outside the body. Some scientists suspect maternal viral infections are among the primary noninherited causes of autism. Epidemiological studies have found a significantly increased risk of autism in the offspring of mothers exposed to the rubella virus early in pregnancy.[30]

Genetic predisposition

Hans Asperger noted a striking tendency for the disorder to run in families, sometimes passing directly from father to son. Clues that genes might be central to autism appeared in Leo Kanner's observations about the emotional distance among mothers of autistic children.

The odds of identical twins sharing a diagnosis of autism are about 90 percent. Parents with one autistic child face a risk of having a second autistic child are 1 in 20. After having two autistic children, the odds for the next child of the same parents rise to 1 in 3.[31]

"The current genetic research estimates that no more than 10% of all autistic cases are genetic in origin. Simply put, the remainder 90% of autistic cases is sporadic with a non-genetic etiology," according to Vijendra K. Singh, Ph.D., a professor of neuroimmunology at Utah State University.

"Geek syndrome"

High technology enclaves have been noted repeatedly for having relatively high prevalence rates of autism spectrum disorders. People with highly analytical skills and mathematical capabilities, who excel in certain industries, despite lacking basic social skills, are often labeled as 'geeks'.

The growth of technical industries, and the attendant wealth that has accrued to those with engineering skills, has significantly influenced the demographics associated with mating patterns in places like California's Silicon Valley. Bill Gates is often cited as a poster child for the geek syndrome, because his single-minded focus on detail, his rocking motions, and his flat tone of voice are suggestive of Asperger's syndrome.

According to Simon Baron-Cohen, the genetics that contribute to autism might actually result in part from assortative mating of two particular types of parents, with certain systematizing cognitive traits, both contributing genes. "My thesis with regard to sex differences is quite moderate, in that I do not discount environmental factors; I'm just saying, don't forget about biology," Baran-Cohen states.

Nutritional deficiencies

Children exhibiting behavioral and learning disorders may do so in part because of diets deficient in vital nutrients needed for their brains to function normally.

In 1998, a small study published in the Lancet found a consistent set of bowel disorders among a dozen autistic children. Although an emphasis was placed by the authors on a possible link to the MMR vaccine, the study also suggested nutritional deficits caused by bowel disorders, perhaps triggered by vaccines, may have contributed to the onset of neurological disorders.

Refrigerator mothers

Dr. Kanner's initial observation of controlled emotions among the mothers of autistic children helped give rise to the first widely accepted cause, though erroneous: the refrigerator mother syndrome. Kanner repeatedly asserted his observations were taken out of context, but the strict Freudian Bruno Bettelheim and others championed this theory that was embraced for a time by the medical establishment. The theory held sway for over 20 years, until Bernard Rimland and others managed to alter the prevailing wisdom of the medical establishment, by establishing the fact autism is an innate neurological condition.

Vaccine theories

The predominant theories among parents concerning the cause for the rising autism rates involve claims that childhood vaccinations contribute to autism. Bernard Rimland was among the first to attribute the cause to vaccines in the early 1990s. Parents have increasingly challenged the conventional wisdom of the medical establisment, which adamantly discounts vaccine theories. In 2002, the M.I.N.D. Institute indicated one third of parents of recently diagnosed kids blamed vaccines, in comparison to 18 percent of parents whose kids were diagnosed earlier who blamed vaccines. In the 1990s, only a very few healthcare professionals accepted the possibility that such theories might be true.

According to Bernard Rimland, "As the number of childhood vaccines has increased 700%, from 3 in the 1970s to 22 in 2000, the prevalence of autism has also showed a parallel increase of 700%...Late onset autism (starting in the 2nd year), was almost unheard of in the 1950s, 1960s, and 1970s; today such cases outnumber early onset cases 5 to 1, the increase paralleling the increase in required vaccines." [32]

Vaccines, in particular the MMR, have been accused of involvement in a number of disorders, besides autism, including neurological damage, immune system dysfunction, severe allergic reactions, seizures, Guillain-Barre Syndrome, bowel disorders, blood disorders and diabetes.[33] Among the first reports of a connection between vaccines and autistic behaviors was in the 1985 book DPT: A Shot in the Dark, by Harris Coulter, Ph.D & Barbara Loe Fisher.

Thimerosal containing vaccines

Exposure to mercury, used as a preservative in thimerosal containing vaccines (TCVs), leads to neurologic effects that may be the primary cause of the apparent autism epidemic, according to Bernard Rimland, Mark Geier, and a number of advocacy groups including Safe Minds. If true, one would expect the incidence of autism to be declining as the use of thimerosal containing vaccines declines. In the US, removal of thimerosal from children's vaccines was recommended in 1998. Childhood exposure may not have peaked until 2003 in the US, as pharmaceutical companies have moved toward compliance, according to research reported by Mark Geier.

Attenuated (weakened) live vaccines

A number of other organ systems affected by vaccines may also be involved, including gastrointestinal, respiratory, hepatic, immune, dermal, and renal. Andrew Wakefield has been at the center of controversies which escalated after the UK National Health Service's decision to withhold single-jab vaccines in favor of live virus triple-jab MMR vaccinations. However, Dr. Edward Campion, senior deputy editor of the New England Journal of Medicine, concluded from the 2002 Danish report that "This careful and convincing study shows that there is no association between autism and MMR vaccination."

Immune disorders

"An increasing number of studies in national journals are linking the regulation of the immune system with nervous system diseases such as multiple sclerosis and even Alzheimer's disease. Cognitive function, memory, and fatigue may all be controlled by small molecule immune modulators. Current treatments need to be modified if we confirm that this finding applies to children with autism," says Dr. Jeffrey Galpin, a professor at USC and an infectious disease specialist.

See also

• Andrew Wakefield
• Aspies For Freedom
• Autistic culture
• Autism rights movement
• Cure Autism Now
• Controversies in autism
• David Kirby
• Generation Rescue
• National Alliance for Autism Research
• Neurodiversity
• Perpetual child
• Vaccine controversy
• Autism

External links

Background issues on autism epidemiology

• About.com - 'The Puzzling Reality of an Autism Epidemic', Floyd Tilton
• NIDs.net - (press release) Neuro Immune Dysfunction Syndromes Medical Advisory Board and Research Institute (March 31, 2002)
• neurodiversity.com - 'Prevalence of Autism'
• neurodiversity.com - 'The "Autism Epidemic" & Real Epidemics' (and reply from the M.I.N.D. Institute Director, confirming inappropriate use of "epidemic" to describe autism prevalence'), Kathleen Seidel
• PediatricServices.com - 'The Autism Epidemic'
• ScienceDaily.com - 'The Age of Autism: What epidemic?', Dan Olmsted, Science Daily (August 1, 2005)
• ScienceDaily.com - 'The Age of Autism: The Amish anomaly', Dan Olmsted, Science Daily (April 18, 2005)
• SFGate.com - 'State autism rate confounds experts: 273% increase in 11-year span', Katherine Seligman, San Francisco Chronicle (October 18, 2002)
• TheAge.com.au - 'Number of disabled students soars' Chee Chee Leung The Age (April 26, 2005)

Attribution to vaccines suggested or alleged

• Autisme.net - 'The Autism Explosion', Bernard Rimland, Ph.D.
• AutismCanada.org - 'The Autism Epidemic is Real, and Excessive Vaccinations are the cause' Bernard Rimland, PhD (July 14, 2003)
• Independent-Media.tv - 'UK Psychologist Says Definite Link Between Vaccines & Autism', Evelyn Pringle (March 7, 2005)
• InformedChoice.info - 'MMR vaccine and the autism epidemic: In a compulsory inoculation program, it is the responsibility of the developers, promoters and enforcers to prove safety and efficacy'
• MSNBC.com - 'A coverup for a cause of Autism? RFK Jr. explans how ingredient in vaccines may have contributed to spread' (interview transcript), MSNBC (June 22, 2005)
• WorldNetDaily.com - 'Vaccines fueling autism epidemic? Report: U.S. infants exposed to mercury beyond EPA, FDA limits' Kelly Patricia O'Meara (June 9, 2003)
• VaccinationNews.com - 'Autism Prevalence'

Attribution to vaccines uncertain or refuted

• AAP.org - 'Study Fails to Show a Connection Between Thimerosal and Autism', American Academy of Pediatrics (May 16, 2003)
• Autism-RxGuideBook.net - 'A Population-Based Study of Measles, Mumps, and Rubella Vaccination and Autism', Kreesten Meldgaard Madsen, MD, Anders Hviid, MSc, Mogens Vestergaard, MD, Diana Schendel, PhD, Jan Wohlfahrt, MSc, Poul Thorsen, MD, Jørn Olsen, MD, and Mads Melbye, MD
• NationalAcademies.org - 'MMR Vaccine and Thimerosal-Containing Vaccines Are Not Associated With Autism, IOM Report Says'
• MMRtheFacts.nhs.uk - MMR News and Research from the British National Health Service

Genetic vulnerability and the 'geek syndrome'

• BBC.co.uk - 'Autism link to "geek genes"' (August 14, 2002)
• Edge.org - 'The Assortative Mating Theory: A Talk with Simon Baron-Cohen' (April 6, 2005)
• Wired.com - 'The Geek Syndrome: Autism - and its milder cousin Asperger's syndrome - is surging among the children of Silicon Valley. Are math-and-tech genes to blame?' Steve Silberman Wired (December, 2001)
• WUStL.edu - 'Autism's genetic structure offers insights' Jim Dryden Washinghton University Record (May 13, 2005)

References

• CPA-APC.org - Diagnosis and Epidemiology of Autism Spectrum Disorders Lee Tidmarsh, MD, Fred R Volkmar, MD, The Canadian Journal of Psychiatry, Vol 48 pp 517–525, 2003

• NIH.gov - 'The changing prevalence of autism in California', L.A. Croen, J.K. Grether, J Hoogstrate, S Selvin, Journal of Autism Developmental Disorders Vol 32, No 3, pp 207-15, June, 2002
• NIH.gov -'The epidemiology of autistic spectrum disorders: is the prevalence rising?', Lorna Wing, D. Potter, Ment Retard Dev Disabil Res Rev, Vol 8, No 3, pp 151-61, 2002
• NIH.gov - 'Prevalence of autistic spectrum disorders in Lothian, Scotland: An estimate using the 'capture-recapture' technique', M.J. Harrison, A O'Hare, H. Campbell, A. Adamson, J McNeillage, Arch Dis Child. May 10, 2005
• NIH.gov - 'The incidence of autism in Olmsted County, Minnesota, 1976-1997: results from a population-based study', W.J. Barbaresi, S.K Katusic, R.C. Colligan, A.L. Weaver, S.J. Jacobsen, Arch Pediatr Adolesc Med, Vol 159, No 1, pp 37-44, January, 2005
• NEJM.org - 'A Population-Based Study of Measles, Mumps, and Rubella Vaccination and Autism' Kreesten Meldgaard Madsen, MD, Anders Hviid, MSc, Mogens Vestergaard, MD, Diana Schendel, PhD, Jan Wohlfahrt, MSc, Poul Thorsen, MD, Jørn Olsen, MD, and Mads Melbye, MD, New England Journal of Medicine, Vol 347, No 19, pp1477-1482, November 7, 2002
• ParentAdvocates.org - 'MMR – Autism Epidemiological Studies: Just a distraction', F. Edward Yazbak, MD, FAAP