The study showed that 9 children in every 1,000 has autism, an increase from 6 per 1,000 in theand 1 per 2,000 in the 1980s.
This represents an increase of 57% since 2002, when the government began tracking childhood autism.
Experts note that part of the increase is due to better understanding of the disorder and therefore better and more accurate diagnoses. However, there is still enough of an increase to believe that autism rates are rising, and researchers want to know why.
Because autism is primarily diagnosed before age two, many feel that the cause of autism lies during pregnancy or infancy. However, researchers do not know if the cause lies in environmental, genetic factors, or a combination of the two, and say that much more research is needed.
The CDC maintains the Autism and Developmental Disabilities Monitoring Network (ADDM), which tracks autism assessments made by health and developmental professionals. The ADDM allows tracking of autism rates over time.
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