(RxWiki News) The search for possible causes of autism has gone in a lot of different directions. But finding a link does not mean finding a cause.
A recent study found a link between obesity in fathers and risk for autism in children, but it doesn't mean fathers' obesity causes autism.
The researchers compared the obesity of mothers and fathers in a large group of children to the children's risk of autistic spectrum disorders.
The results showed a link between fathers' weight and autistic disorder and Asperger disorder, but not pervasive developmental disorder.
"Ask your doctor about maintaining a healthy weight."
This study, led by Pal Suren, MD, MPH, of the Norwegian Institute of Public Health in Oslo, Norway, looked for possible links between obesity in parents and a child's risk of having autism.
The researchers studied 92,909 Norwegian children, aged 4 through 13, and their parents' body mass index (BMI).
BMI is a ratio of a person's height to weight and is used to determine if they have a healthy weight. A BMI of 30 or greater is considered obese.
Among the children included in the study, 419 had been diagnosed with an autism spectrum disorder at the conclusion of the study.
This number included 162 with autistic disorder, 103 with Asperger disorder and 154 with pervasive developmental disorder not otherwise specified.
In looking at the BMI of mothers, the researchers did not find a strong link between obesity and autism risk. A link existed, but it was very weak.
In looking at the BMI of fathers, however, the researchers found a stronger link.
Among obese fathers, 0.27 percent of their children had autism, compared to 0.14 percent of the children among fathers with normal weight (a BMI less than 25).
These numbers put the odds of autistic disorder at 1.7 times greater for children of obese fathers than for children of normal-weight fathers.
Meanwhile, 0.38 percent of children born to obese fathers had Asperger disorder, compared to 0.18 percent of children born to fathers with a normal weight.
These figures meant that the odds of Asperger disorder were twice as high in children of obese fathers than in fathers with a normal weight.
The researchers did not find any links between obesity in parents and pervasive developmental disorder in children.
It's not clear why this link exists, but these findings do not mean that obesity in fathers causes autism, as Glen Elliott, MD, PhD, a clinical professor at the Stanford University Department of Psychiatry and Behavioral Sciences, noted.
“Studies showing associations between two conditions, in this case, obesity in the father and autism in the child, often suggest intriguing links that might not otherwise emerge," Dr. Elliott said.
"However, they are, at most, a first step towards looking for possible causes of a disorder such as autism," he said. "It is highly unlikely that a parent’s obesity is the reasons his or her child has autism.”
This study was published April 7 in the journal Pediatrics. The authors reported no conflicts of interest.
The research was funded by the Norwegian Ministry of Health and Care Services, the Norwegian Ministry of Education and Research, the Research Council of Norway/FUGE, the National Institute of Neurologic Disorders and Stroke and the National Institute of Environmental Health Sciences.