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BLOG: December 2009
Autism epidemic worsening: CDC report
Is the incidence of autism among U.S. children so high to justify calling it autism epidemic? If one looks at the percentage number, it appears to be rather low; even if it keeps increasing - especially with respect to what it was, or thought to be, just a 2-3 decades ago - it is at present estimated to be "only" about 1%. But one in hundred means that the total number of children affected by autism runs into hundreds of thousands. So, yes, it does have epidemic proportions.
The U.S. Centers for Disease Control (CDC) reported its analysis of data collected by the Autism and Developmental Disabilities Monitoring (ADDM) Network, covering areas in 11 U.S. states - Alabama, Arizona, Colorado, Florida, Georgia, Maryland, Missouri, North Carolina, Pennsylvania, South Carolina, and Wisconsin - with a total of 307,790 children aged 8 (7.9% of all children of this age in the U.S.).
While the Network is not designed to be nationally representative sample, the proportion of children is large enough to give good indication of the overall autism trend in the U.S.
Children were classified as ASD (Autism Spectrum Disorder, including autistic disorder, pervasive developmental disorder not otherwise specified or PDD NOS, and Asperger disorder) cases based on professional assessment of their developmental progress in their records at health-care and/or educational facilities. The results are as follows:
□ total of 2,757 children (0.9%) were identified as having ASD
□ incidence per 1,000 ranged from 4.2 in Florida to 12.1 in Arizona and Missouri
□ ratio of males to females ranged from 3.2:1 in Alabama to 7.6:1 in Florida
□ median age of earliest documented ASD diagnosis ranged from 41 months in Florida to 60 months in Colorado; on average, ASD is diagnosed at an earlier age than in 2002
□ ASD prevalence increased among males in all 11 state areas, and among females in only 4 states
□ compared to 2002 (for 10 states that collected data for both 2006 and 2002), ASD prevalence increased 57% (9 vs. 6.6 children in 1,000, respectively)
Actual incidence is likely to be higher, since not all areas had both health and educational records available, with the average ASD prevalence in areas with both data sources available 33% higher (10 vs. 7.5 in 1,000). The report cites other studies (Japan, Sweden, U.K. and U.S.) estimating ASD prevalence at over 1%, as well as study from Norway identifying ASD symptoms in as many as 2.7% of children.
After laying all the numbers down, the report concludes that ASD is an "urgent public health concern", requiring research to determine potential risk factors, as well as expanding support network for affected children and families. More so considering that only 10-20% of affected children are expected to recover.
If "determining potential risk factors" implies finding out what is causing ASD, there is certainly a lot of work to be done. With ASD symptoms ranging from relatively mild to debilitating cognitive/behavioral handicaps, much is at stake, and it should speed these efforts up.
For some reason, however, little has been done. A spotty evidence linking autism to some exogenous (alcohol or antiseizure medications during pregnancy, diseases like measles, measles - and possibly other - early childhood vaccines, alone or combined, other chemical exposures) and endogenous (various genetic predispositions) factors is all that's been gathered so far.
By contrast, the list of medications commonly used to treat ASD symptoms, all the way from 2y to 18y olds, is over three dozen long. At least someone is doing well off of this epidemic...