Is there a connection between parental age and autism risk?

Beth Greenfield writes at Yahoo that

A massive new study on autism risk has found elevations related to parental age — of both teen moms and older parents.

With an analysis of more than 5.7 million children in five countries, the study, published Wednesday in the journal Molecular Psychiatry, is the largest of its kind to ever look at the connection between parental age and autism risk.

“The size of the study speaks to the definitiveness of the findings,” says co-author Michael Rosanoff, director of public health research for Autism Speaks, the organization that funded the study. “We can now say confidently that advanced paternal and maternal age is a risk factor for autism.” Such findings are not new, he tells Yahoo Parenting, but this is by far the most sweeping of its kind.

...With an analysis of more than 5.7 million children in five countries, the study, published Wednesday in the journal Molecular Psychiatry, is the largest of its kind to ever look at the connection between parental age and autism risk.

“The size of the study speaks to the definitiveness of the findings,” says co-author Michael Rosanoff, director of public health research for Autism Speaks, the organization that funded the study. “We can now say confidently that advanced paternal and maternal age is a risk factor for autism.” Such findings are not new, he tells Yahoo Parenting, but this is by far the most sweeping of its kind.

It also turned up some new correlations: In addition to finding that autism rates were 66 percent higher among children born to dads over the age of 50 than those in their 20s (and 28 percent higher for dads in their 40s), researchers found rates were 18 percent higher with teen moms than those with moms in their 20s.

Theories regarding the rise in autism risk for kids of older parents are pretty solid, he notes, explaining that one points to evidence that “we accumulate mutations in sperm and egg cells as we age.” Another hypothesis is that people who have children at advanced ages may do so because they themselves are “on the spectrum,” and may have social difficulties that made it tough for them to couple up and become parents for much of their early adult lives; in these cases, researchers theorize, there may be a genetic link to autism.

...Looking at higher risk among teen moms, Rosanoff adds, scientists believe age itself might point to a “suboptimal pregnancy,” with less medical monitoring and higher health risks in general.

Still, there’s no reason for alarm, notes co-author Sven Sandin, a medical epidemiologist, in an Autism Speaks press release. “Although parental age is a risk factor for autism, it is important to remember that, overall, the majority of children born to older or younger parents will develop normally,” says the doctor, a medical epidemiologist with the Icahn School of Medicine at Mount Sinai, in New York, and Sweden’s Karolinska Institute.

Read more here.