Study ties older dads to autistic children

Men over 40 are nearly six times as likely to father an autistic child as those under 30, according to a new study that provides support for the role of genetics in the developmental disorder.

At least two previous small studies have hinted at such a link, said epidemiologist Abraham Reichenberg of the Mount Sinai School of Medicine in New York, who led the new study.

His team examined records of more than 318,000 Israelis born in the 1980s and provides "the first convincing evidence" that advancing paternal age is an important risk factor for development of the disorder, he said.

Like earlier studies, the new one, reported Monday in the Archives of General Psychiatry, found no significant effect associated with increasing maternal age.

Autism is a severe developmental disorder in which children seem isolated from the world around them. There is a broad spectrum of symptoms, marked by poor language skills and an inability to handle social relations. No cure exists, but many problems can be alleviated with intensive behavioral therapy.

Many researchers now believe that genetics plays a role in the onset of autism, said Dr. Fred Volkmar of Yale University, who was not involved in the study.

Other studies have shown that sperm mutate more often in older men, potentially leading to an increased risk for abnormalities in their children.

Most studies have failed to find evidence to support a persistent belief among some parents that mercury-containing childhood vaccines are to blame.

The team studied all children born in Israel during six consecutive years in the 1980s. They linked birth records to those of the Israeli draft board, which assesses mental and physical health of most Israelis at age 17.

The data contained the ages of both the mother and father at the time of conception for 132,271 teens and data on only the father's age for an additional 186,235. Similar results were found with both groups.

Children of fathers who were between 15 and 29 years of age had a risk of about 6 in 10,000 of developing autism. Children of fathers in their thirties had a risk of 9 in 10,000. Children of fathers in their forties had a risk of 32 in 10,000, and children of fathers who were older than 50 had a risk of 52 in 10,000.

In a paper published Monday in the Archives of General Psychiatry, the researchers said the number of cases of autism among families with the oldest dads was too small to lead to definitive conclusions about that group, but there was little doubt about the overall trend.

Scientists in the United States are increasingly thinking about autism in terms of a spectrum of problems, which is why they have coined the term autism spectrum disorders. The federal government estimates the risk for autism spectrum disorders in the United States is around 3.4 for every 1,000 children between the ages of 3 and 10.

Whether that number is on the rise or not has been hotly contested; better outreach and diagnostic efforts may be finding children who would previously have gone undetected. Disparities in access to health care complicates the picture.

Material from The Washington Post and The Associated Press is included in this report