Sunday, September 27, 2009

New government research says 1% of all U.S. children on the autism spectrum

From first part of David Kirby's story at The Huffington Post:

A pair of federally funded studies on autism rates is about to make news -- big news -- and it isn't good: It would appear that somewhere around one percent of all US children currently have an autism spectrum disorder. The rate is even higher among six to 11 year olds and among boys, according to data from at least one of the new studies.

If you are an expectant parent, or planning to have a child soon, you might want to sit down before absorbing these staggering statistics, recently released by the National Survey of Children's Health (NSCH), which is supported by the Health Resources and Services Administration (HRSA) of the US Department of Health and Human Services.

According to data from the 2007 telephone survey of parents of nearly 82,000 US children, the odds of a parent being told that their child has an ASD are one in 63. If it is a boy, the chances climb to a science fiction-like level of one in 38, or 2.6% of all male children in America.

But there was also some surprisingly good news. Enormous numbers of children who were told that they had autism went on to shed the ASD label as they got older, parents reported.

Among all children aged two to 17, according to respondents, one in 100 (100-per-10,000) currently have an ASD, which is considerably higher than the previously (CDC) estimated rate of 1-in-150, (or 66-per-10,000).

But researchers were also told by parents that 60-per-10,000 children "had autism, Asperger's Disorder etc. at some point, but not currently."

This suggests two rather remarkable things:

1. At some point in their lives, 1-in-63 US children (160-per-10,000) will be labled with an ASD and;

2. Out of every 160 children whose parents reported that they had an ASD, 60 of them (37.5%) no longer have an ASD.

Among boys, for every 260-per-10,000 male children originally identified as having an ASD, 90 of them (34.6%) reportedly do not have the diagnosis now. This still leaves a monumentally high parent-reported rate of one in 58 boys with ASD today, or 1.7 percent (170-per-10,000).

The percentage of girls who apparently lost their original label was 44.5%.

There was a big difference among age groups as well. Among those children who still have the diagnosis, the rate of ASD was 40% higher in 6-11 year olds (140-per-10,000, or 1-in-71) than the current rate of 12-17 year olds (100-per-10,000, or 1-in-100).

Interestingly, among the youngest children, two to five years old, the rate was only half that of their six- to 11-year-old siblings, (70-per-10,000 vs.140-per-10,000). Most or all of that may be due to the average age of diagnosis, which is below five years, though it does bear watching to see if these younger kids go on to double their rates and "catch up" with the older ones.

Overall, the 2007 NSCH survey revealed a 100% increase in parent-reported ASD rates compared to the 2003 NSCH survey (which showed a 50-per-10,000 reported rate).

The survey was conducted by the Data Resource Center of the Child and Adolescent Health Measurement Initiative (CAHMI) at the Oregon Health & Science University. And though the survey used what is considered to be sound methodology for estimating ASD percentages, most observers are still anxiously awaiting the release of more and even more reliable statistics -- expected soon from the CDC.

This second autism study, culled from data in the CDC's Autism and Developmental Disabilities Monitoring network (ADDM), has been eagerly anticipated for quite some time.

ADDM researchers examine the education and (when possible) medical records of all eight-year-old children in selected US cities and states. They look only at eight-year-old cohorts to allow time for all diagnoses to be made, reported and counted.

So far, ADDM has published data from just two birth cohorts: children born in 1992 (eight-year-olds in 2000) and those born in 1994 (eight-year-olds in 2002). The 1992 cohort revealed an estimated ASD rate of one in 166, or 60-per-10,000. (This has since been revised to 67-per-10,000, or one in 150).

For the 1994 cohort, the estimate was virtually unchanged, at 66-per-10,000.

CDC officials have been analyzing the 1996 birth cohort (2004 data on 8-year-olds) for years. I asked the agency a few months ago about the slow progress in releasing the numbers and was told that the data were currently "under review." No response was given to written questions about data collected from the 1998 or 2000 cohorts (in 2006 and 2008, respectively).