The prevalence of autism spectrum disorder among American children is much higher than what earlier data showed, a new federal report says.
Autism spectrum disorder (ASD), which starts normally by age three, is a developmental disorder that leads to significant social, communication and behavioral changes. Till date, no medical or blood test is available for an early diagnosis of this condition. The behavior and development of the child are some factors used by health practitioners to determine the disorder.
According to the latest report from Centers for Disease Control and Prevention (CDC), one in every 50 school children in the U.S. has autism. The new estimate that found a sharp increase in the number of autistic children within one year clearly shows the 2012 report from CDC, based on medical and school records, under-estimated the rate as one in 88 children.
The new results, based on parental interviews, do not mean that more children are getting the disorder, but that health practitioners are better able to diagnose the condition even in children with milder symptoms, compared to earlier.
For the current study, researchers did phone interviews of nearly 95,000 families having children, in 2007 and between 2011 and 2012. Researchers found the prevalence of autism among children, aged between six and 17, going up from 1.16 percent in 2007 to 2 percent between 2011 and 2012. Boys aged between 14 and 17 were found more affected by the disorder than girls.
"The results of the cohort analyses increase confidence that differential survey measurement error over time was not a major contributor to observed changes in the prevalence of parent-reported ASD. Rather, much of the prevalence increase from 2007 to 2011-2012 for school-aged children was the result of diagnoses of children with previously unrecognized ASD," the authors wrote.
Previous studies have shown various factors, including maternal fever, use of anti-epileptic drug Valproate in pregnancy, exposure to preservative propionic acid (PA) and maternal deficiency of vitamin D increases the risks of autism. Apart from that, countless studies have also shown a strong link between autism and early exposure to heavy metals like lead and mercury.
