Autism More Common in IT-Rich Regions

Fran Lowry

June 24, 2011

June 24, 2011 — Autism diagnoses appear to be more common in geographic areas that have a high proportion of jobs in the information technology (IT), computer, and engineering sectors, new research shows.

Conducted in the Netherlands with senior author Simon Baron-Cohen, PhD, director of the Autism Research Centre, University of Cambridge, the study shows these regions have twice the expected rate of autism diagnoses.

"We hypothesized that there might be a link between having a talent for IT, engineering, math, and computers — or what Professor Baron-Cohen calls 'systemizing' — and having a child with autism," coauthor Rosa Hoekstra, PhD, from the Open University, Milton, Keynes, and a visiting scientist at the Autism Research Center, told Medscape Medical News.

Dr. Rosa Hoekstra

But other autism experts disagree. Irva-Hertz-Picciotto, PhD, MPH, a professor at the University of California Davis Medical School, told Medscape Medical News she believes there is no evidence to support a uniquely elevated risk in children whose parents are employed in those specified occupations.

"It is also not clear whether the higher rate seen both at the ‘ecologic’ and ‘individual’ level in children with more highly educated parents is due to a truly higher incidence of autism spectrum disorder [ASD] vs a greater likelihood of it being recognized and correctly diagnosed," she said.

The study was published online June 20 in the Journal of Autism and Developmental Disorders.

As Dr. Cohen has written previously, systemizing is the drive to analyze how systems work and to predict, control and build systems — skills that are required in disciplines such as engineering, physics, computing, and mathematics.

He and his team have also found evidence for a familial association between a talent for systemizing and autism. For instance, in earlier work, they showed that fathers and grandfathers of children with autism are over-represented in the field of engineering, and another study showed that mathematical talent is linked to autism.

Information Technology Hub

In the current study, the researchers contacted all the schools in 3 different regions of the Netherlands — Eindhoven, Haarlem, and Utrecht — and asked how many children had a diagnosis of autism, attention-deficit/hyperactivity disorder (ADHD), or dyspraxia.

"Eindhoven is known as the technology hub of the Netherlands," said Dr. Hoekstra. "The Eindhoven University of Technology is located there, as well as the High Tech Campus Eindhoven, where IT and other technology companies such as Philips, ASML, IBM, and ATOS Origin are based. In that region, 30% of the jobs are in technology or IT."

Haarlem and Utrecht are similar in population and socioeconomic status but have far fewer jobs in IT and technology.

The study showed that the school reported rates of ADHD and dyspraxia were similar for all 3 areas, but the school-reported rates of autism were markedly higher in the Eindhoven region than in the other 2 regions.

In Eindhoven, the prevalence rate of autism was 2.3% (229 kids per 100,000), whereas in Haarlem it was 0.8% (84 per 100,000) and in Utrecht, 0.6% (57 per 10,000).

Important Contribution to Autism Epidemiology

"These results are in line with the idea that in regions where parents gravitate towards jobs that involve strong 'systemizing,' such as the IT sector, there will be a higher rate of autism among their children, because the genes for autism may be expressed in first degree relatives as a talent in systemizing," Dr. Baron-Cohen said in a statement.

"The results also have implications for explaining how genes for autism may have persisted in the population gene pool, as some of these genes appear linked to adaptive, advantageous traits."

For her part, Dr. Hoekstra stressed that the results were based on school reports.

"They do not include kids who might have an autism diagnosis and the school just doesn’t know that, and also do not include kids who may warrant a diagnosis but who haven’t been detected yet."

"Or it could be that the incident rates in the regions of Haarlem and Utrecht represent an underdiagnosis of autism. But the rates in Eindhoven were about 2 to 2.5 times more than what you would expect," she said.

The next step is to study these results more systematically, she added.

"We need to validate the diagnoses and also see if there are alternative explanations for the elevated rate of autism in Eindhoven. These findings are important in the field of autism epidemiology since they seem to suggest that there is a regional variation in the prevalence of autism. We hope to study the causes of such variation more closely so we can really come to grips with what is driving the differences," said Dr. Hoekstra.

No Evaluation of Parents

"The main drawback of this study is that it does not evaluate the parents of children with autism spectrum disorder directly to find out their occupations but instead uses rates in 3 areas, each of about a quarter of a million people. The rates are then compared, and it is found that the area having a higher proportion of persons employed in the systematizing professions has a much higher rate of ASD," Dr. Hertz-Picciotto noted.

This type of design, which is termed by epidemiologists as an "ecologic" study, is subject to a variety of biases that may not have been controlled, she said.

"It is impossible to tell, for instance, whether the difference might simply reflect a difference according to level of education. Many studies have seen differences in diagnosis rates for ASD according to parental education. This could also explain the lack of difference across regions in other mental health conditions, such as ADHD, which are not more prevalent in families with higher education."

Dr. Hertz-Picciotto added that the authors' hypothesis is closely tied to a sizable body of literature by Dr. Simon Baron-Cohen, suggesting that the trait of 'systematizing' is overdeveloped in persons with autism.

"In essence, I see Baron-Cohen’s work as an exquisite refinement of our understanding of 1 aspect of the existing definition of ASD, namely the presence of repetitive behaviors and restricted interests, sometimes described as ritualistic behaviors.

"Baron-Cohen, however, focuses on how persons with ASD see the world rather than how they behave. It’s useful for descriptive purposes, but it would be wrong to think that this provides insight into 'causation.' Having parents who have pursued a specific occupation does not cause autism in the children. Moreover, because of the weak study design (using rates in areas rather than linking individuals with ASD to their parents’ occupations, this paper does not add much," she said.

Better to Focus Research Elsewhere

The authors mention that further study is needed, but Dr. Hertz-Picciotto countered that she and her colleagues have already done such a study.

"Unlike Baron-Cohen’s team, we did not select a small number of communities. Instead, we examined the entire state of California and assessed variation in rates of ASD to identify clusters.

"We also used exact locations of residences of the cases, allowed the ‘borders’ of the clusters to be determined by the individual cases, rather than being set a priori by the investigator, and used multiple methods for cluster investigation to guard against chance findings. With this robust methodology, we identified 10 clusters across the state. One fell within the area of Silicon Valley…while 9 were elsewhere in the state," she said.

What distinguished these clusters from the surrounding areas was the high percentage of parents with at least a college education. "Of course, many professions other than those included in Baron-Cohen’s selected group would be found in these clusters, including professions such as law, architecture, city planning, journalism, etc," she noted.

Finally, Dr. Hertz-Picciotto believes that, even if the topic were to be pursued and the hypothesis corroborated, the information may not be particularly useful.

"What would be the translation into practice? Would it lead to better treatments, prevention? We would do far better to pursue the broad array of environmental exposures coming from the chemical, physical, and microbiological factors that surround pregnant women and young infants with many of these known to affect brain development."

Dr. Baron-Cohen, Dr. Hoekstra, and and Dr. Hertz-Picciotto have disclosed no relevant financial relationships.

J Autism Dev Disord. Published online June 20, 2011.

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