Skip directly to search Skip directly to A to Z list Skip directly to navigation Skip directly to site content Skip directly to page options
CDC Home

This page is a historical archive and is no longer maintained.

For current information, please visit

Press Briefing Transcript

CDC Press Briefing on Autism Surveillance Summary

Friday, December 18, 2009

  • Audio recording MP3 audio file (MP3, 4.62MB)

Operator: Welcome and thank you all for standing by. At this time, I would like to remind parties that your lines are in a listen only mode until the question and answer session at which time you may press star 1 to ask a question. Today's call is being recorded. If you have any objections, you may disconnect at this time. I will now turn the meeting over to Dave Daigle.

Dave Daigle: Thank you, operator. Thank you all for joining us today on the media telebriefing on CDC's MMWR Surveillance Summary on autism. We are joined today by Dr. Catherine Rice, behavioral health scientist with CDC's National Center on Birth Defects and Developmental Disabilities. She is the lead author of the MMWR surveillance summary. We'll begin with short introductory remarks by Dr. Rice and then we'll take questions right after that. Thank you.

Catherine Rice: Good afternoon. I would like to thank all of you again for joining us today. We would like to brief you on the report that CDC is releasing in today's MMWR surveillance summary on prevalence of autism spectrum disorders. The CDC considers ASDs to be a significant public health issue. Increased concern in communities, continued demand for services and increasing estimates of ASD prevalence underscore the need for a coordinated and strong response to improve the lives of people with ASDs. These results reflect data collected by the Autism and Developmental Disabilities Monitoring Network or ADDM in multiple communities throughout the U.S. through the year 2006, indicating that the prevalence of ASDs to be about 1 percent of 8-year-old children in the U.S. This study uses data based on a retrospective review of health and education records from reporting communities, which included over 300,000, or about 8 percent, of the U.S. population of 8-year-olds. All children in the included study were 8 years of age because previous research has shown that tracking this age helps us get the most complete estimate of who is affected with an ASD. The findings in this report are in line with other recently published estimates, including those released in October that were based on a telephone survey. The new report finds that between 4.2 to 12.1 per 1,000 children with an average of 9.0 per 1,000 children were identified with an ASD. This translates to about 1 in 80 and 1 in 240 children with an average of about 1 in 110 identified with an ASD.

There were ten communities who participated in an earlier 2002 surveillance year and the newer 2006 surveillance year. These communities observed an increase in identified ASD prevalence, ranging from 27 percent to 95 percent with an average increase of 57 percent. Identified ASD prevalence increased across all sex, racial, ethnic and cognitive functioning subgroups. For all sites, the most consistent pattern was the increase among boys. ASD prevalence was four to five times higher for boys than for girls with 1 in 70 boys and 1 in 315 girls identified with an ASD on average. Increases were found among boys in nine of the ten communities and among girls in four communities. With the average increase of 60 percent for boys and 48 percent for girls. Identified ASD prevalence increased on average 55 percent for white children, 41 percent for black children and 90 percent for hispanic children.

This study also helped to determine important characteristics about children with an ASD. In both 2002 and 2006, a similar proportion of children with an ASD also tested as having an intellectual disability, averaging 46 percent in 2002 and 41 percent in 2006. So intellectual disability also more commonly referred to as mental retardation. In both 2002 and 2006, a similar proportion of children with ASD were diagnosed ever with the autistic disorder subtype by a professional in the community, averaging 45 percent in 2002 and 47 percent in 2006. Between 13 percent to 30 percent of children identified with an ASD had a report of regression or loss of skills by the age of 2 years. As we know, early intervention is important for children with developmental delays. This study found that concerns regarding the development before the age of two years were noted in the evaluation records of most children identified, but the average age of first ASD diagnosis was much later at 4½ years of age.

We know more children are identified with an ASD than in the past. These new numbers are concerning and indicate that even more individuals, families and communities are struggling to find answers. No single factor explains the changes identified in ASD prevalence over the time period studied. Some of the increases are due to better detection, particularly among children who may not have come to attention in the past, including girls, Hispanic children and children without cognitive impairment. However, a simple explanation is not apparent. And a true increase in risk cannot be ruled out. We know there are multiple and complex genetic and environmental factors which result in multiple forms of autism and we have much to learn about the causes. CDC is currently enrolling for the study to explore early development, or SEED study, to help identify risks and protective factors for ASDs and other developmental disabilities. SEED is studying potential risk factors that may be related to genes, health conditions and other factors that affected the mother's pregnancy and the child's first few years of life.

In addition, CDC is committed to help people understand developmental milestones for children through the Learn the Signs, Act Early campaign. This campaign, launched in 2004, helps inform patients, health care professionals and early educators about the importance of monitoring a child's developmental milestones and obtaining early intervention services when delays are identified. Our commitment to finding answers also includes being a member of the interagency autism coordinating committee or IACC, which was formed to address the coordination of autism research. The IACC has both federal and public members with a range of perspectives, including advocacy groups, researchers, and individuals affected with ASD. Concerted and collaborative efforts are important to address the many needs associated with ASDs. CDC considers ASDs a significant public health concern. We will continue our work in tracking trends and our research into potential risk factors so that we can understand changes in ASD rates over time. We hope that these new data might raise awareness about ASDs to help improve early identification and to provide information for policy and service planning to ultimately help meet the growing needs of individuals, families and people affected by ASDs. Thank you for your attention.

Dave Daigle: Thank you, Dr. Rice. Operator, we'll take questions now.

Operator: JoAnne Allen from Reuters. Your line is open.

JoAnne Allen: Hello. Thank you. I just wondered if you could talk a little bit about some of the possible causes or cause and effect and what is being done in the way of development or treatment.

Catherine Rice: So in terms of causes and treatment, this study in particular didn't investigate causes, but there is a very large effort going on in terms of research which is coordinated by the Interagency Autism Coordinating Committee, which has both public and private members, including the federal government and other large organizations that are doing autism research. Really, there's a multi-prong approach going on because we know there's no single cause for autism. We're not going to find the one answer that there are going to be multiple causes for multiple forms of autism. So much of the research is looking into genetics, also trying to improve the understanding of genetics as both heritable and noninheritble. In addition to trying to expand our ability to look at environmental factors and how do you look at those factors, genetic and environmental interactions, together? I would definitely refer you to the IACC strategic research plan on the NIH website to get additional information in terms of what the current sort of seeing as the best needed goals are for autism research right now.

Dave Daigle: Thank you, JoAnne. Next question please, operator.

Operator: Daniel DeNoon, WebMD, your line is open.

Dan DeNoon: So you all are saying that you can't rule out that there is a true increase. Does this – but I'm wondering if you could go further than that. It does look like none of these factors singly or together that we can think of can really account for this increase. So are we looking at a true increase or prevalence with these numbers matching so closely, those numbers recently done from the telephone survey? What can we say about this, looking like a very, very real and rather striking increase?

Catherine Rice: Well, I think it in some ways is helpful that we have multiple studies looking, using difference methods across multiple countries all kind of converging that 1 percent is the current estimate or about 1 percent the current estimate of ASD prevalence. When we looked at our particular study, one thing we're trying to do is to tease out what factors can we measure and identify over time that can help us say how much is due to identification? This is really the first effort that we've made in terms of looking at some of these factors and we'll continue to examine these data to try to get deeper. But right now, we can say some of it was due to better recordkeeping because we have a records-based methodology. So we found more evaluation per child, more information in those records, in addition to identifying particular subgroups. So we clearly know that some of this is an identification issue. But in saying how much is due to true risk is really a question of the trends and the reasons for those trends and relates so much to the causes of autism. So we have seen from research that there are a variety of items that have come up as potential causes, so, for instance, increasing risk for having an older parental age, for instance, or there has been some indications of variation in terms of exposure to – exposure to that variance hazardous air pollutants. So we need to go back and look at these data so we can try and examine additional factors. At this point, it's impossible to say how much exactly is a true increase and how much is identification. But we certainly know that this helps us know that it's important to look for the causes of autism and to take these data to help us intervene for those individuals that are here now.

Dave Daigle: Thanks, Daniel. Next question please, operator.

Operator: Again, if you would like to ask a question, please press star 1 and record your name. Next, Stephen Smith from the Boston Globe, your line is open.

Stephen Smith: Hi. Good afternoon, Dr. Rice, and thanks for taking the question. I have two, if I may, please. Could you discuss the fairly broad incidence rate that you found, the broad differences among sites, roughly to go from 4 per 1,000 to 12 per 1,000. That's a fairly broad range. What does that say to you? And secondly, I was hoping that you might address the whole issue of this study in the context of vaccination. One of the punitive causes that some groups have put out there for autism is thimerosal in vaccine. Clearly if we're talking about 8-year-olds in 2006, this is a cohort that would have been vaccinated at a time after the thimerosal had been removed from those childhood vaccines. So if this is an increase, what does this say about laying to rest the concerns that had existed around thimerosal?

Catherine Rice: Okay. So going back to the first question about the range in terms of prevalence rate. So, we did find a range of 4.2 to 12.1. Surprisingly was seven of the sites were in a consistent range where they were closer being between 95 to 130 per every one child having an ASD. So in the sites that had a lower prevalence, in those particular sites, they had – part of it has to do with in terms of the methodology and having less information available in the types of records that they were able to review. Where some sites were able to look at both health and education records and some sites we're not. So we think that the sites on the lower end are an underestimate. On the higher end, it's a challenge to say why some of those sites have identified higher prevalence, but they are in range with the overall average as well as some studies in Europe and Asia showing over about 1 percent. So that gives us some indication of the variation over time. And also given that autism is a behaviorally defined disorder, we would always expect to have some variation in terms of the prevalence estimate, although we try to boil things down to a single number, there is always going to be somewhat of a range. So we would expect that.

Stephen Smith: In the context of vaccination?

Catherine Rice: So the second question, in the context of vaccination, this study in particular wasn't designed to look at risk factors or causes in and of itself. So it doesn't specifically say anything about vaccinations. So one thing that you had mentioned in terms of timing, these children were born in 1998 and were eight years of age in 2006. So at this point, thimerosal was still – was being removed, I believe phasing out in 200. So we need to continue to track prevalence of autism in future cohorts to see how variation would change based on that timing.

Dave Daigle: Thanks very much, Stephen. Next question, operator.

Operator: Ben Kerry, New York Times, your line is open.

Ben Kerry: Hello. Thanks for taken the question. I would like to know about the range of – two questions. One is about the range of the spectrum, so it clearly includes severe autism. But on the other side of that range, what did it include, social difficulty, pervasive developmental disorder, Asperger's, what's the universe there?

Catherine Rice: When we say children are identified with ASD or autism spectrum disorder, we include what's typically the three primary Autism Spectrum Disorders: autistic disorder, Asperger's disorder and atypical autism or pervasive developmental disorder not otherwise specified. As I mentioned, in 2002 and 2006, we saw pretty similar proportion of children who were identified with autistic disorder ever. So 45 percent in 2002 and 47 percent in 2006.

Dave Daigle: Ben, did you have another question?

Ben Kerry: So the – the estimate is based on a review, it sound like a review of health and school records. Does that mean the researchers didn't – did they not meet the kids?

Catherine Rice: Yeah. This was based on a review of existing records. But rather than only taking the diagnosis as it was documented in the record, we had a team of clinicians who went through and evaluated the descriptions in the record to confirm the presence of the DSM IV criteria for autism, Asperger's or PDD-NOS to meet the general case definition of ASD.

Dave Daigle: Thanks very much, Ben. The next question, operator.

Operator: Stacey Singer, Palm Beach Post.

Stacey Singer: You answered my question, thank you.

Operator: Heidi Splete, Pediatric News, your line is open.

Heidi Splete: Hi. Thanks for taking my question. What is the take home message for pediatricians from these findings? What should they be telling parents at this point?

Catherine Rice: So at this point, in terms of pediatricians, as you may know, the American Academy of Pediatrics has encouraged continuous ongoing developmental screening and recently also included a recommendation that all children are screened for autism at 18 and 24 months. So I think given the fact that we found that the majority of children, somebody was concerned about their development. Typically language development before the age of 2. But there was quite a delay in diagnosis at 4½ years of age. So at this point, what pediatricians should be doing is one, listening to parents if they have a concern about their child's development, but also proactively following the screening guidelines and if they have a concern, referring that child on for further evaluation, whether it's diagnostic or potential intervention, such as provided by the zero to 3 programs in every state.

Dave Daigle: Thank you, Heidi. Next question please, operator.

Operator: Thank you. Again, if you have a question press star 1 and record your name. Next, Delthia Ricks from Newsday, your line is open.

Delthia Ricks: Hello there. I didn't get all of it, you mentioned something about mental retardation. Are children who were once diagnosed as mentally retarded now considered to have an ASD? Can you explain that, please.

Catherine Rice: So in terms of mental retardation, it's now more commonly referred to as intellectual disability. We know there's quite an overlap in intellectual disability and autism spectrum disorders. For many years, the best statistics and estimates told us 75 percent or three-quarters of children with autism also had an intellectual disability. Now the numbers that we're identifying in our study shows us it's more about 40 percent or more specifically 41 percent of children with autism having an intellectual disability. So overall, this is a population with less intellectual impairment, sometimes referred to as more a higher functional population. So there are many theories out there in terms of this diagnostic shifting and how we look at things or are we really seeing a more high functioning population? That is challenging to sort out.

Dave Daigle: Thank you very much, Delthia. Operator, do we have another question?

Operator: Kelly Brewington, the Baltimore Sun. Your line is open.

Kelly Brewington: Hi. Thanks for answering my question. I have a question about comparisons about the boys prevalence and girls. Do you have a number for the figures from 2002? Is there somewhere I could find those?

Catherine Rice: We do have those. I don't have them right off the top of my head right now, but we could try to follow up with you on that.

Dave Daigle: Kelly, we'll run that down for you if you want to give us a call back here at the press office. Operator, I think that was our last question. Do we have anybody else in the queue?

Operator: One more question. Alice Park, Time Magazine, your line is open.

Alice Park: Hi thank you. Could you address the issue of early intervention. We've been hearing in recent years about programs that are getting at many of these children very early and does your statistics reflect any of that?

Catherine Rice: So in terms of early intervention, primarily what this study reflects is the age at which kids are getting diagnosed and the age at which concerns were documented. We don't have detailed information on the interventions that they are receiving at this point. There has been – there is some research out that may speak to that, but this particular study does not.

Dave Daigle: Thank you, Alice. Operator, I think we have one more. We'll make this one our last one.

Operator: The next is from Miriam Falco, CNN, your line is open.

Miriam Falco: Thanks, Dr. Rice. I have one quick question. It's just a little bit. How much did the average age of diagnosis change between 2002 and 2006? Was it one more, five months? How many months?

Catherine Rice: Five.

Miriam Falco: Five months?

Catherine Rice: Five months on average.

Miriam Falco: Thank you.

Catherine Rice: It varied by site how much it changed, but on average, it was five months.

Miriam Falco: Thank you.

Dave Daigle: Thank you, Miriam, and thank you, operator. Thanks to everyone for joining us. We will have a transcript posted hopefully in a matter of hours for this. Take care.


CDC 24/7 – Saving Lives. Protecting People. Saving Money Through Prevention. Learn More About How CDC Works For You…
CDC 24/7 – Saving Lives. Protecting People. Saving Money Through Prevention. Learn More About How CDC Works For You…
Contact Us:
  • Centers for Disease Control and Prevention
    1600 Clifton Rd
    Atlanta, GA 30333
  • 800-CDC-INFO
    TTY: (888) 232-6348
  • Contact CDC-INFO The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Rd. Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO

A-Z Index

  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #