Older parents more likely to have an autistic child

NEW YORK (Reuters Health) - Advanced maternal age and paternal age are both risk factors for having a child with an autism spectrum disorder (ASD), a large study indicates. However, the researchers emphasize that risk of having a child with an ASD is very small, even for the oldest parents.

"A number of studies have looked at the impact of maternal age on autism, but the results have been inconsistent. Paternal age has been much less studied," lead author Dr. Lisa A. Croen told Reuters Health. "Our findings support a link between advanced (parental) age and autism, although the effect on risk is small."

According to Croen, from Kaiser Permanente in Oakland, California, the new findings do not make a strong argument for or against having children at a younger age.

The study, which is reported in Archives of Pediatrics and Adolescent Medicine, involved all singleton children who were born at Kaiser Permanente between 1995 and 1999. Of the children studied, 593 were later diagnosed with an ASD and 132,251 were not.

With each 10-year increase in the mothers' age the ASD risk rose by 31 percent, while for 10-year increments in the fathers' age it went up by 28 percent.

Compared with parents between 25 and 29 years of age, mothers and fathers who were 40 years of age or older were 27 percent and 52 percent more likely, respectively, to have a child with an ASD.

The link between advanced parental age and ASD risk was stronger for girls than for boys, but the association was not statistically significant.

Croen said that she was not surprised by the findings given previous reports supporting a link and the fact that a number of childhood diseases are associated with advanced parental age. She added that her group has now explored this topic further using data from the entire state of California and plans to submit these findings shortly for publication.

SOURCE: Archives of Pediatrics and Adolescent Medicine, April 2007.