Circumcision and the development of autism and ADHD
A study of a large sample of boys that reported an association between circumcision during childhood and the development of autism spectrum disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD) has not surprisingly received attention in the media and on social networking sites and blogs. The author, Professor Morten Frisch, has speculated about links between painful injuries and stress responses which has no doubt added to the controversy.
What did the research involve?
The study, published in the Journal of the Royal Society of Medicine, examined more than 340,000 boys born in Denmark between 1994 and 2003. They examined the health outcomes of the boys at the age of 9 and reported that almost 5,000 cases of autism had been diagnosed. The study reported that circumcision raised the overall chances of an autism diagnosis by 46%. Basically the study involved comparing two different datasets and reporting correlations/associations between variables. As we have noted previously within our How to ‘Research the Headlines’ series, correlation does not equal causation and a whole range of other (known as confounding) variables could explain the link (rendering the link effectively meaningless potentially).
What did the researchers say?
In a press release on the study findings, the lead author Morten Frisch, outlined that the study was partially motivated by animal findings that linked a single painful injury to lifelong deficits in stress response. He went on to state that “painful experiences in neonates have been shown in animal and human studies to be associated with long-term alterations in pain perception, a characteristic often encountered among children with ASD”. The inference then is that the act of circumcision leads to the development of these developmental disorders.
What did the media say?
Clearly the study is very much an exploratory/speculative study and caution is needed in making any direct inference from the findings. So did the media take this cautious approach? Well actually they did and they followed this path very carefully calling on experts in the field, for example, in evaluating the study. The Daily Mail reported the opinions of Professor Jeremy Turk, a Consultant Child and Adolescent Psychiatrist, as well as reporting comments from Dr. Rosa Hoekstra, a Lecturer in Psychology at the Open University. Both raised caution about the speculative nature of the study and noted that confounding variables were highly likely to account for the findings. They additionally sought the opinion of a representative of Milah UK, a body that speaks for the Jewish community on issures related to circumcision. Their representative, Prof. David Katz also commented on the correlational nature of the study within the Daily Mail coverage. The Daily Mail also included a subheading ‘experts have urged caution over the extremely speculative findings’ and so if the reader does not go beyond the initial headlines and read the story they should still get the gist that the link is likely to be speculative.
Speculation by researchers
We have on many occasions, here at Research the Headlines, commented when journalists have been over speculative. There are frequently examples where researchers are overly speculative in press releases and when communicating with the media. Caution is essential, especially when the topic concerns such sensitive issues as the cause of a lifelong psychological disorder, which has serious consequences for the development of the child and has significant effects on the family. Fortunately on this occasion the media were careful in their reporting on these speculative findings.
Frisch, M. & Simonsen, J. (2015). Ritual circumcision and risk of autism spectrum disorder in 0- to 9-year-old boys: national cohort study in Denmark. Journal of the Royal Society of Medicine. DOI:10.1177/0141076814565942