This is the stuff of legend. So says the Simons Foundation blog in discussing a new epidemiological study out of California. A previous study reported that fathers of ASD kids are more likely to be engineers. The idea got into the mainstream media (and deep into the public psyche) when Wired Magazine even called the phenomenon the “Geek Syndrome“.
Well, someone checked. Someone being Gayle Windham, Karen Fessel and Judith Grether. If you are an autism epidemiology geek, you will recognize at least some of those names.
Here’s the abstract:
Autism spectrum disorders in relation to parental occupation in technical fields
Gayle C. Windham, Karen Fessel, Judith K. Grether
A previous study reported that fathers of children with autism spectrum disorders (ASD) were more likely to work as engineers, requiring systemizing skills, and suggesting a distinct phenotype, but alternatively this may have been related to selection biases. We conducted a population-based study to explore whether fathers, or mothers, of children with ASD are over-represented in fields requiring highly technical skills. Subjects included 284 children with ASD and 659 gender-matched controls, born in 1994 in the San Francisco Bay Area. Parental occupation and industry were abstracted verbatim from birth certificates. Engineering, computer programming, and science were examined as highly technical occupations. To limit bias by parental socio-economic status, we selected a referent group of occupations that seemed professionally similar but of a less technical nature. Odds ratios (ORs) and 95% confidence intervals (CI) were calculated by logistic regression, adjusting for parental age, education, and child race. Mothers of cases were somewhat more likely to work in hi-tech occupations (6.7%) than mothers of controls (4.0%, P=0.07), but little difference was observed among fathers, nor for engineering separately. Compared to parents in other white collar occupations, the adjusted OR for highly technical occupations among mothers was 2.5 (95% CI: 1.2-5.3) and among fathers was 1.3 (95% CI: 0.79-2.1), with no evidence of a joint effect observed. Our results regarding maternal occupation in technical fields being associated with ASD in offspring suggest further study to distinguish parental occupation as a phenotypic marker of genetic loading vs. other social or exposure factors
To summarize it even more: mothers in “highly technical” jobs had a 2.5 times higher chance of having an autistic kid. There isn’t a clear statement for fathers. Also, there isn’t evidence of a “joint effect”. I take that to mean that the “geeks marrying geeks have more autistic kids” idea didn’t pan out.
They can’t say why mothers in highly technical jobs have more autistic kids. This makes it a study that can be quoted by everyone. “It’s genetic, see mothers in technical jobs have more autistic kids”. “It’s social, mothers in technical jobs are more likely to know about autism and get their kids diagnosed”. “It’s environmental, mothers in technical jobs are exposed to more toxins”.
In the end, this is no joke. We need to understand all the factors that can affect epidemiological studies. Epidemiological data for autism are pretty muddy, in my opinion. A lot of things have happened in the last 20 years (or more) that have changed the “rate” of autism diagnoses. Anyone who wants to find one of the many causes of autism (which is, as we all know a plural: autisms), needs to understand these factors.