The finding is based on 11,000 U.S. children in kindergarten through eighth grade. The group included 131 children diagnosed with an autism spectrum disorder, according to their parents.
The kids' parents reported their earnings -- including salaries and interest on investments -- along with their education level, age, and other factors.
The survey results suggest that "families with a child with autism attain lower income than expected based on their educational and demographic characteristics," write the researchers, who included Guillermo Montes, PhD, of the Children's Institute in Rochester, N.Y.
"The average loss of annual income associated with having a child with autism spectrum disorder was $6,200," Montes and colleagues calculate.
That figure is only about income. It doesn't include expenses related to autism, such as out-of-pocket costs for therapies and schooling.
Why the income gap? The researchers speculate that parents of children with autism spectrum disorders may "make different working choices than other parents," perhaps because their communities don't provide enough services and resources for autism.
The researchers advise health care providers to ask families of children with autism about financial difficulties and to help them access the services and resources they need.