With diagnoses of autism rising at staggering rates, the hunt for its causes continues, often with frustratingly inconclusive results. A study published Monday in the journal Pediatrics adds yet another potential culprit to an already long list: the obesity of the father.
Researchers tracked more than 90,000 Norwegian children to determine whether maternal prepregnancy body mass index (BMI) or paternal BMI were associated with diagnosis of autism spectrum disorders. While the mothers' weight did not have any correlation with whether children were diagnosed with autism spectrum disorders, paternal obesity did — children of obese fathers were nearly twice as likely to be diagnosed with autism compared with those whose fathers were a normal weight.
If that sounds surprising to you, it was to the researchers as well, who noted in their report:
Our finding came as a surprise because we had expected maternal obesity to be the most prominent risk factor. Maternal obesity was also associated with an increased risk of both autistic disorder and Asperger disorder in unadjusted analyses, but the increase was substantially attenuated by adjustment for paternal BMI.
In other words, while maternal obesity studied alone may appear to increase the risk of autism spectrum disorders in their children, that association goes away when you account for the father's weight.
While this was a large observational study that provides some intriguing new pieces for the currently unsolvable puzzle of autism, it's worth noting that it's only one piece. The authors themselves refer to an earlier California study that seemed to point the finger at obese mothers, but that study didn't account for paternal weight. Then there's the research that suggests autism starts well before birth, but doesn't indicate exactly how or why that might be the case.
In short, we have a long way to go before we figure out what causes autism spectrum disorders. Until that time comes, it's probably a good idea no matter what to try to maintain a healthy weight!