Children weighing less than 2,000 g (4.4 pounds) at birth may be more prone to autism spectrum disorders, a population-based study suggested.
The estimated prevalence of autism spectrum disorders reached 5% in a regional low birth weight cohort, Jennifer A. Pinto-Martin, PhD, MPH, of the University of Pennsylvania in Philadelphia, and colleagues found.
That screen-detected prevalence was five times higher than expected from the general population, the group noted in the November issue of Pediatrics
The CDC reported a 0.9% prevalence among 8-year-olds across the United States in 2006.
"This prospective study, using rigorous diagnostic procedures, confirms that the rate of autism spectrum disorders is elevated among low birth weight/preterm survivors," the researchers wrote in the paper.
That low birth weight and prematurity put children at risk of cognitive and motor disability has been well established, but their link with autism spectrum disorders was largely through retrospective studies and those that screened without diagnostic confirmation, the group noted.
Amanda Gardner writes at USA Today:
Although researchers have yet to confirm a cause-and-effect relationship between low birth weight and autism, the new findings may help explain the recent increase in the ASD rate in the U.S., Pinto-Martin says.
"The number of children with a diagnosis of autism is on the rise and [we] haven't been able to explain why," she says. "It's partly a function of awareness and better diagnosis, but we do a better job of keeping tiny babies alive and this may be one consequence of that." [emphasis added]