By Shaun Heasley
June 9, 2015
The odds of having a child with autism appear to go up and down as moms and dads move through life, according to the largest study of its kind.
|For the first time, a new study finds that the difference|
in age between a child’s mother and father
can impact the risk for autism. (Thinkstock)
In an analysis looking at more than 5.7 million children in five countries around the world, researchers found an increased likelihood of autism in kids with older parents, those born to teenage mothers and in circumstances where there is a large age gap between a child’s mother and father.
“Though we’ve seen research on autism and parental age before, this study is like no other,” said Michael Rosanoff, director of public health research at Autism Speaks and a co-author of the study published online Tuesday in the journal Molecular Psychiatry.
“By linking national health registries across five countries, we created the world’s largest data set for research into autism’s risk factors. The size allowed us to look at the relationship between parents’ age and autism at a much higher resolution — under a microscope, if you will,” he said.
For the study, researchers used national health records in Denmark, Israel, Norway, Sweden and Western Australia to assess autism rates for 5,766,794 children born between 1985 and 2004. More than 30,000 of the children were diagnosed with the developmental disorder.
Among children born to dads over age 50, autism rates were 66 percent higher than kids born to men in their 20s, the study found. Meanwhile, for fathers in their 40s, the rate was 28% higher.
For moms, autism rates were 15 percent greater for those in their 40s and 18 percent higher in teenage mothers as compared to women who gave birth in their 20s.
Increased rates of autism were also found in cases where there were large age gaps between a child’s parents. The highest risk was observed in children born to dads who were ages 35 to 44 and moms who were at least 10 years younger.
“These results suggest that multiple mechanisms are contributing to the association between parental age and ASD risk,” the authors said in their findings.
Despite the significance of parental age as an autism risk factor, however, researchers said it is important to note that most children are typically developing regardless of the ages of their parents.