What’s Behind the Rise in Autism Cases?

In a new study, Danish researchers suggest that the dramatic increase in children diagnosed with an autism spectrum disorder is mainly the result of how the condition is now reported– not a case of more children developing the disorder. Background information for this study indicates that many people had been concerned that environmental factors were solely behind the rising number of autism diagnoses, according to a CBS News report.

Lead researcher Stefan Hansen says that he hopes that the results of this study this will be helpful as parents make health decisions for their children. Hansen, from the biostatistics section in the department of public health at Aarhus University, says it wasn’t until 1995 that Denmark’s national health registries begin making diagnosis outside of a hospital environment. And the situation was similar in the United States. With today’s more thorough diagnostics, the U.S. Centers for Disease Control and Prevention now estimate that one in 68 children has an autism spectrum disorder. The reported prevalence of the condition has greatly increased over 30 years.

While scientists aren’t sure about what causes autism, it’s likely that both genetics and environment play a role. Amy Daniels, the assistant director for public health research at Autism Speaks, a New York City-based advocacy group, says she agrees that a significant cause in the reported increases result from changes in diagnostic methods. Daniels adds that the findings in this new study are “consistent with past research documenting non-causal factors such as increased autism awareness.”


To conduct the study, researchers collected data on nearly 700,000 children born between 1980 to 1991 and followed them until they were either diagnosed with autism, died or emigrated, or the end of 2011, whichever came first. Almost 4,000 from that research group were diagnosed with autism, with most after 1995 when diagnostic criteria changed. The study was published online November 3 in JAMA Pediatrics.

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