Subjects: R and D
Older moms have a greater risk of giving birth to a child with autism, according to a study by scientists at UC Davis.
To reach this conclusion, Janie Shelton and colleagues reviewed all births in California during the 1990s.
They found that the risk of having a child with autism jumped 18% for each 5-year increment in maternal age. A 40-year-old woman had a 50% higher risk of having an autistic child than a 25 year-old woman.
Previous research had identified increased paternal age as a risk factor, but this one, by far the largest of its kind, showed that father’s advanced age matters only if the mom is under 30. For older moms, the risk is predicted solely by maternal age.
“This study challenges a current theory in autism epidemiology that identifies the father’s age as a key factor in increasing the risk of having a child with autism,” Janie Shelton, the study’s lead author told BurrillReport. “While maternal age consistently increases the risk of autism, father’s age only contributes an increased risk when the mother is under 30 years old.”
“We still need to figure out what it is about older parents that puts their children at greater risk for autism and other adverse outcomes, so that we can begin to design interventions,” said Irva Hertz-Picciotto the senior author on the study.
In this regard, UC Davis scientists reported in 2008 that they found antibodies to fetal brain protein in some mothers of children with autism, but not in the mothers of normal children. Others speculate that certain environmental toxins accumulate in the body with age and may play a role as well.
The write-up appears in Autism Research.