A new study that finds the prevalence of autism spectrum disorder (ASD) among 11 surveillance sites as one in 59 among children aged eight years in 2014. Researchers at the Johns Hopkins Bloomberg School of Public Health contributed to a new U.S. Centers for Disease Control and Prevention (CDC) report that finds the prevalence of autism spectrum disorder (ASD) among 11 surveillance sites as one in 59 among children( 1.7%).

This marks a 15% increase from the most recent report two years of age, and the highest prevalence since the CDC began tracking ASD in 2000. Consistent with previous reports, boys were four times more likely to be identified with ASD than girls. The rate is one in 38 among boys (or 2.7%) and one in 152 among girls (or 0.7%). ASD is a developmental disorder characterized by social and communication impairments, combined with limited interests and repetitive behaviors.

Early diagnosis and intervention are key to improving learning and skills. Other factors may be contributing, such as increased awareness, screening, diagnostic services, treatment and intervention services. For this new report, the CDC collected data at 11 regional monitoring sites that are part of the Autism and Developmental Disabilities Monitoring (ADDM) Network in the following states: Arizona, Arkansas, Colorado, Georgia, Maryland, Minnesota, Missouri, New Jersey, North Carolina, Tennessee, and Wisconsin. 

This is the sixth report by the ADDM Network, which has used the same surveillance methods for more than a decade. Estimated prevalence rates of ASD in the U.S. reported by previous data were:

1. One in 68 children in the 2016 report that looked at 2012 data

2. One in 68 children in the 2014 report that looked at 2010 data

3. One in 88 children in the 2012 report that looked at 2008 data

4. One in 110 children in the 2009 report that looked at 2006 data

5. One in 150 children in the 2007 report that looked at 2000 and 2002 data

The estimated overall prevalence rates reported by ADDM at the monitoring sites have more than doubled since the report was first published in 2007. ASD prevalence was reported to be approximately 20 to 30% higher among white children as compared with black children in previous ADDM reports. In the current report, the difference has dropped to 7%.  Also, approximately 70% of children with ASD had borderline, average or above average intellectual ability, a proportion higher than that found in ADDM data before 2012.

Some trends in the latest CDC report remain similar, such as the greater likelihood of boys being diagnosed with ASD, the age of earliest comprehensive evaluation and presence of a previous ASD diagnosis. Specifically, non-white children with ASD are being identified and evaluated at a later age than white children. 

In Maryland, the prevalence of ASD was higher than in the network as a whole. An estimated one in 50 children (2%) was identified as having ASD one in 31 among boys and one in 139 among girls. The data were derived from health and special education records of children who were eight years old and living in Baltimore County in 2014.

The causes of autism are not completely understood; studies show that both environment and genetics may play a role. The CDC recommends that parents track their child's development and act quickly to get their child screened if they have a concern.