Epidemiology and the Changing Paradigm of Autism Spectrum Disorders

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1 Epidemiology and the Changing Paradigm of Autism Spectrum Disorders 9 th Annual Developmental Disabilities Conference UCSF March 11, 2010 Marshalyn Yeargin-Allsopp, MD Medical Epidemiologist Chief, Developmental Disabilities Branch National Center on Birth Defects and Developmental Disabilities Centers for Disease Control and Prevention

2 Overview What is Public Health Surveillance? What is Prevalence? Changes in ASD diagnostic classification systems over time Changes in ASD prevalence estimates over time Use of different surveillance methods ADDM Network Overview New prevalence estimates Future directions Bottom Line: Why is the current prevalence of ASD higher than previously reported?

information. Surveillance provides information necessary for public health decision making.

3 Public Health Surveillance Public health surveillance is the systematic, ongoing assessment of the health of a community, based on the collection, interpretation, and use of health data and information. Surveillance provides information necessary for public health decision making. * * Teutsch SM, Churchill RE. Principles and practice of public health surveillance: 2nd ed. Oxford University Press

4 What is Prevalence? Prevalence= Number of instances of a condition in a given population at a designated time. Calculated as: number of instances of condition Total number of people in the given population

5 Changes in ASD Diagnostic Classification Systems Over Time Kanner criteria (1956) Lack of affective contact; desire for sameness; fascination with objects; mutism or non-communicative language before 30 months of age

6 Autism Prevalence & Epidemiologic Studies: Kanner Criteria Author Rate/1,000 (95% CI) No. Children with Autistic Disorder # children in population M/F Ratio IQ < 70 % Lotter, 1966 (England) Brask, 1972 (Denmark) Treffert, 1970 (USA) Wing & Gould, 1979 (England) Hoshino et al.,1982 (Japan) McCarthy et al., 1984 (Ireland) 0.45 ( ) 0.43 ( ) ( ) 0.49 ( ) 0.23 ( ) 0.43 ( ) 35 78, , NR , NR 17 34, , NR 28 65, NR

7 Changes in ASD Diagnostic Classification Systems Over Time Rutter criteria (1978) Emphasized delayed and unusual social and language development and early onset and unusual behaviors

8 Autism Prevalence and Epidemiologic Studies: Rutter criteria Author Rate/1,000 (95% CI) No. Children with Autistic Disorder # children in population M/F Ratio IQ < 70 % Ishii & Takahashi, 1983 (Japan) 1.6 ( ) 56 35, NR Bohman et al (Sweden) 0.3 ( ) 39 69, NR Steinhausen et al., 1986 (Germany) 0.19 ( ) , %

9 Changes in ASD Diagnostic Classification Systems Over Time DSM-III (1980) Differentiated autism from schizophrenia (not a psychiatric disorder, but developmental) Concept of PDD introduced: infantile autism; childhood onset PDD; atypical PDD

10 Author Gillberg, 1984 (Sweden) Steffenberg & Gillberg, 1986 (Sweden) Autism Prevalence & Epidemiologic Studies: DSM III Criteria Rate/1,000 (95% CI) 0.20 ( ) 0.45 ( ) No. Children with Autistic Disorder # children in population M/F Ratio IQ < 70 % , , NR Matsuishi et al., 1987 (Japan) 1.55 ( ) 51 32, NR Burd et al., 1987 (USA) Bryson et al., 1988 (Canada) Tanoue et al., 1988 (Japan) 0.12 ( ) 1.01 ( ) 1.38 ( ) , NR 21 20, , NR

11 Autism Prevalence & Epidemiologic Studies: DSM III Criteria, continued Author Rate/1,000 (95% CI) No. Children with Autistic Disorder # children in population M/F Ratio IQ < 70 % Ciadella & Mamelle, 1989 (France) 0.51 ( ) , NR Sugiyama & Abe, 1989 (Japan) Ritvo, et al., 1989 (USA) 1.30 ( ) 0.40 ( ) 16 12,263 NR ,

12 Autism Prevalence & Epidemiologic Studies: DSM III-R Criteria DSM-III-R (1987) Concept of PDD continued; autism and PDD-NOS

13 Autism Prevalence & Epidemiologic Studies: DSM III-R Criteria Author Rate/1,000 (95% CI) No. Children with Autistic Disorder # children in population M/F Ratio IQ < 70 % Gillberg et al., 1991 (Sweden) 0.95 ( ) 74 78, Webb et al., 1997 (Wales) Powell et al., 2000 (England) Croen et al., 2001 (USA) 0.72 ( ) 0.96 ( ) 1.1 ( ) 53 73, NR 28 29, NR million 4.0 NR

Changes in ASD Diagnostic Classification Systems Over Time ICD-10 (1992) Greatly expanded PDD concept autism; atypical autism; Rett syndrome; other

14 Changes in ASD Diagnostic Classification Systems Over Time ICD-10 (1992) Greatly expanded PDD concept autism; atypical autism; Rett syndrome; other childhood disintegrative disorder; overactive disorder associated with MR/ID and stereotyped movements; Asperger syndrome; other PDDs; PDD, unspecified

15 Autism Prevalence & Epidemiologic Studies: ICD-10 Author Rate/1,000 (95% CI) No. Children with Autistic Disorder # children in population M/F Ratio IQ < 70 % Fombonne & Mazaubrun, 1992 (France) Honda et al., 1996 (Japan) Fombonne et al., 1997 (France) 0.49 ( ) 2.11 ( ) 0.54 ( ) , , , Arvidsson et al., 1997 (Sweden) 3.10 ( )

16 Autism Prevalence & Epidemiologic Studies: ICD-10, cont. Author Rate/1,000 (95% CI) No. Children with Autistic Disorder # children in population M/F Ratio IQ < 70 % Sponheim & Skjedae, 1998 (Norway) Kadesjo et al., 1999 (Sweden) Baird et al., 2000 (England) Magnusson & Saemundsen, 2000 (Iceland) Lingam et al, 2003 (England) 0.38 ( ) 6.0 ( ) 3.1 ( ) 0.86 ( ) 1.5 ( ) 25 65, , , ,206 ~4.8 NR

17 Autism Prevalence & Epidemiologic Studies: ICD-10, cont. Author Rate/1,000 (95% CI) No. Children with Autistic Disorder # children in population M/F Ratio IQ < 70 % Lauritsen et al., 2004 (Denmark) Baird, et al., 2006 (United Kingdom) Williams et al., 2008 (United Kingdom) 1.2 ( ) 3.89 ( ) 6.19 ( ) ,397 ~3.5 NR ,946 ~ ,

18 Changes in ASD Diagnostic Classification Systems Over Time DSM-IV (1994) and DSM-IV TR (2000) Also expanded PDD concept autistic disorder; Asperger syndrome; Rett syndrome; CDD; PDD-NOS

19 Autism Prevalence & Epidemiologic Studies: DSM-IV Author Rate/1,000 (95% CI) No. Children with Autistic Disorder # children in population M/F Ratio IQ < 70 % Kielinen et al., 2000 (Finland) Chakrabarti & Fombonne, 2001 (England) Fombonne, et al (United Kingdom) 1.22 ( ) 1.68 ( ) 2.61 ( ) , , , Bertrand et al., 2001 (USA) 4.0 ( ) 36 8,

20 Autism Prevalence & Epidemiologic Studies: DSM-IV, continued Author Rate/1,000 (95% CI) No. Children with Autistic Disorder # children in population M/F Ratio IQ < 70 % Yeargin-Allsopp et al., 2003 (USA) Gurney et al., 2003 (USA) Icasiano et al., 2004 (Australia) Fombonne et al., 2006 (Canada) Wong & Hui, 2007 (China) Rice et al., 2007 (USA) 3.4 ( ) 4.4 ( ) 3.9 ( ) 2.16 ( ) 1.61 NR 6.7 ( ) , ,454 NR NR , , NR 682 4,247, NR ,

21 Autism Prevalence & Epidemiologic Studies: DSM-IV, continued Author Rate/1,000 (95% CI) No. Children with Autistic Disorder # children in population M/F Ratio IQ < 70 % Rice et al., 2007 (USA) Rice et al., 2009 (USA) 6.6 ( ) 8.0 ( ) , , , Rice et al., 2009 (USA) 9.0 ( ) 2, , Brugha et al., 2009 (England) 10.0 (5-20) 19 (Adults) 2854 (Adults) 1.8 NR

Historical perspective on Autism prevalence before 2009 Prior to1990s 1990-2006 2007 1 in 2,000 1 in 500 1 in 150 Four times more common in boys Intellectual impairment is important co-morbidity

22 Historical perspective on Autism prevalence before 2009 Prior to1990s in 2,000 1 in in 150 Four times more common in boys Intellectual impairment is important co-morbidity (approximately 50-70% in earlier studies; less in recent studies) Trend studies: Attributed increases (mostly ASD) to increased awareness and service availability, improved recognition and methodological changes.

23 Use of Different Surveillance Methods Administrative datasets (single administrative source, e.g., service provider databases and state-wide agencies that coordinate services for children with DD) Community surveys National surveys Multiple source record review

24 Multiple Source Record Review CDC s Approach to ASD Prevalence Population-based screening Abstraction of evaluation records Reliable application of coding scheme to determine case status

(educational, clinical, service sources) 5 Disabilities: Mental Retardation/

25 Metropolitan Atlanta Developmental Disabilities Surveillance Program (MADDSP) Ongoing, active monitoring program since counties of metro Atlanta Multiple sources (educational, clinical, service sources) 5 Disabilities: Mental Retardation/ Intellectual Disability Cerebral Palsy Hearing Loss Vision Impairment Autism Spectrum Disorders (since 1996)

26 How do the rates of ASDs compare with other disabilities? Rates of Developmental Disabilities in Metropolitan Atlanta (8-year-olds, 2000) Intellectual Disability 12.0 per 1,000 Autism* 6.5 per 1,000 Cerebral Palsy 3.1 per 1,000 Hearing Loss 1.2 per 1,000 Vision Impairment 1.2 per 1,000 Karapurkar-Bhasin, Brocksen, Avchen, Van Naarden Braun. Prevalence of four developmental disabilities among children aged 8 years - the Metropolitan Atlanta Developmental Disabilities Surveillance Program, 1996 and MMWR SS 2005;55;1 9. * Centers for Disease Control and Prevention. Prevalence of Autism Spectrum Disorders --- Autism and Developmental Disabilities Monitoring Network, Six Sites, United States, MMWR SS 2007; 56;1-11.

28 Goals: Accurate and comparable population-based estimates of the prevalence of Autism Spectrum Disorder (ASD) in selected regions of U.S. Describe the characteristics of children with Autism Examine trends in prevalence

ADDM Network Methods Active case-finding with broad retrospective records-based screening for ASD classifications or behaviors. Focus on children at age 8 to identify peak prevalence.

29 ADDM Network Methods Active case-finding with broad retrospective records-based screening for ASD classifications or behaviors. Focus on children at age 8 to identify peak prevalence. Multiple health and education sources of information. Detailed behavioral, developmental, and testing information collected. Ongoing quality control within and across sites. Independent review and clinician confirmation of ASD case status based on the DSM-IV criteria. Standard for setting ASD prevalence estimates in the U.S.

30 ADDM 2002 ASD Prevalence Results (Published in MMWR, 2007) Findings across 14 sites: Approximately 10% of US 8-year-old children 2,685 children were identified with an ASD. The average prevalence was 6.6 per 1,000. Range of 3.3 (AL) to 10.6 (NJ) per 1,000 children; however, for 12 of the 14 sites ASD prevalence was in a tighter range from 5.2 to 7.6 per 1,000. Baseline: An average of 1:150 Children in the US has an ASD Estimated: 560,000 children between 0-21 years Centers for Disease Control and Prevention (CDC). Prevalence of Autism Spectrum Disorders --- Autism and Developmental Disabilities Monitoring Network, 14 Sites, United States, MMWR SS 2007;56(No.SS-1).

estimates: 2006 Surveillance Year for 11 sites Prevalence changes from 2002

31 Prevalence of Autism Spectrum Disorders (ASDs) Autism and Developmental Disabilities Monitoring (ADDM) Network, 2006* Updated ASD prevalence estimates: 2006 Surveillance Year for 11 sites Prevalence changes from 2002 to Surveillance Year (optional year in appendix) for 8 sites *December, 2009

32 ADDM 2006 ASD Prevalence Results Average prevalence of ASD about 1% of 8-year-old children Average = about 1 in 110 children (range 1 in 80 to 1 in 240) Approximately 1 in 70 boys and 1 in 315 girls Similar to other recent studies in Europe, Asia, and North America. Prevalence increased 57% between 2002 and 2006 No single factor explains changes in ASD prevalence Some increases due to better documentation in records Despite slight improvements in age of diagnosis, significant delays persist

33 ADDM 2006 Surveillance Year: Health Source Access Only (5/11 sites) Site Area 8-year-olds in Population in Alabama 32 counties 35, Florida 1 county 27, Missouri 5 counties 26, Pennsylvania 1 county 17, Wisconsin 10 counties 34, sites continued

ADDM 2006 Surveillance Year: Health and Education Source Access (6/11 sites) Site Area 8-year-olds in Population in 2006 6. Arizona 1 county 41,650 7. Colorado 1 county 7,184 8.

34 ADDM 2006 Surveillance Year: Health and Education Source Access (6/11 sites) Site Area 8-year-olds in Population in Arizona 1 county 41, Colorado 1 county 7, Georgia 5 counties 46, Maryland 6 counties 26, North Carolina 10 counties 22, South Carolina 23 counties 22, site total 308,038; ~8% of US 8-year-olds

35 ADDM Network Overall Identified ASD Prevalence, Surv Year Birth Year # sites 8-year-old Population 8-year-old children with an ASD Average Prev / 1,000 Range ,761 1, ,578 2, ,335 1, ,038 2, (14) In process

36 ADDM 2006 Surveillance Year Overall Prevalence From 4.2 per 1,000 (FL) to 12.1 per 1,000 8-year-old children (AZ and MO) Average across all 11 sites of 9.0 per 1,000, about 1% of 8 year-old children About 1 in 110 children

37 ADDM 2006 ASD Prevalence Overall and Based on Previously Documented ASD Classification Embargoed confidential data for MADDSP stakeholders Presentation Only

38 ADDM 2006 Surveillance Year Prevalence by Sex Males and Females Average ASD prevalence for Males = 14.5 per 1,000 Females = 3.2 per 1,000 About 1 in 70 males and 1 in 315 females Average 4.5 males to every female with ASD

ADDM 2006 Surveillance Year Prevalence by Race or Ethnicity Race/ethnicity White, non-hispanic children with highest ASD prevalence, but variability White, non-hispanic: average 9.

39 ADDM 2006 Surveillance Year Prevalence by Race or Ethnicity Race/ethnicity White, non-hispanic children with highest ASD prevalence, but variability White, non-hispanic: average 9.9 per 1,000 (1 in 100 children), Ranging from 3.4 to 14.8 per 1,000 children. Black, non-hispanic: average 7.2 per 1,000 (1 in 140 children), Ranging from 1.6 to 12.9 per 1,000 children. Hispanic: average 5.9 per 1,000 (1 in 170 children) Ranging from 0.6 to 8.3 per 1,000 children.

ADDM 2006 Surveillance Year Developmental Concerns and Age of Earliest Documented ASD Diagnosis 70-95% with a documented developmental concern before the age of 3 years 13

40 ADDM 2006 Surveillance Year Developmental Concerns and Age of Earliest Documented ASD Diagnosis 70-95% with a documented developmental concern before the age of 3 years 13 30% of children had a reported developmental regression by 24 months of age Average age of earliest ASD diagnosis was 4 years, 6 months; ranging from 3 years, 6 months to 5 years

41 9 ADDM 2006: Special Education Services

42 Change in ASD Prevalence from 2002 to 2006 by Total, Gender, & Race or Ethnicity (10 Sites) % Change Average Total Males Females White non- Hispanic Black non- Hispani c Hispanic 57% 60% 48% 55% 41% 91% Overall, data reflect increases in identified ASD prevalence and among subgroups site variation exists.

44 Change in ASD Prevalence from 2002 to 2006 by Cognitive Functioning Level Cognitive Impairment (IQ70) Borderline (IQ=71-85) Average to Above Average (IQ>85) % Change, Average 35% 90% 72% There were increases across all levels of cognitive functioning In 2006SY, between 29-51% of children with cognitive impairment (average 41%)

45 Conclusions: ADDM 2006SY Average prevalence of ASD about 1% of 8-year-old children Average = about 1 in 110 children (range 1 in 80 to 1 in 240) Approximately 1 in 70 boys and 1 in 315 girls Prevalence estimates increased 57% between 2002 and 2006 No single factor explains changes in ASD prevalence Some increases due to better documentation in records Despite slight improvements in age of diagnosis, significant delays persist

46 Why has the prevalence of ASD reported from ADDM increased from 2002 to 2006? No single explanation likely multiple factors at play Need to continue monitoring over time to follow trends Identification issues which contributed to small increases across sites: more evaluation records (4 vs. 5) better quality of documentation some sites, able to locate more records some sites, more stable population some sites, better identification of Hispanic children (AZ) some sites, more identification of children without cognitive impairment

47 Implications ASDs are an urgent public health issue Prevalence estimates can be used to plan policy, educational, and intervention services. Coordinated and collaborative response is needed to: Intensify search for risk factors; Improve early identification/access to EI services; Better understand how to intervene to help reduce the debilitating symptoms of ASDs; Address needs of persons with ASD and provide coordinated support services

Where do we go from here? Expand surveillance to include additional populations Older/Younger Cohorts Other conditions (i.e. ADHD, Fragile X, FAS, LD,

48 Where do we go from here? Expand surveillance to include additional populations Older/Younger Cohorts Other conditions (i.e. ADHD, Fragile X, FAS, LD, Epilepsy) Special investigations Continue working with government/nongovernment partners to take a comprehensive approach to ASD surveillance/research (IACC)

49 Bottom Line Changes in diagnoses? Awareness? Availability of services? Real increase in symptoms? Regardless more children with ASD identified and the impact on the families and service systems is real!

For more information ADDM Reports in CDC s MMWR Surveillance Summaries www.cdc.gov/mmwr ADDM Video http://www.cdc.gov/ncbddd/autism/videos/addm/index.

50 For more information ADDM Reports in CDC s MMWR Surveillance Summaries ADDM Video html Updated autism website Learn the Signs. Act Early.

51 MADDSP Staff Marshalyn Yeargin- Allsopp Alana Aisthorpe Andrew Autry Jon Baio Claudia Bryant Owen Devine Nancy Doernberg Santrell Green Susie Graham Christine Hill Nancy Hobson Lekeisha Jones Rita Lance Katrina Langston Charmaine McKenzie Michael Morrier Amy Pakula Mary Philips Lori Plummer Catherine Rice Julia Richardson Matthew Rudy Diana Schendel Laura Schieve Darlene Sowemimo Melody Stevens Melissa Talley Ignae Thomas Kim Van Naarden Braun Lisa Wiggins Susan Williams Joanne Wojcik

52 Principal investigators and Project Coordinators: CDC: Catherine Rice, Jon Baio, Kim Van Naarden Braun, Marshalyn Yeargin-Allsopp, Susan Graham, and Anita Washington; Alabama: Beverly Mulvihill, Martha Wingate, Russell S. Kirby, Meredith Hepburn, Neva Garner; Arizona: Sydney Pettygrove, Chris Cunniff, F. John Meaney, Kristen Clancy Mancilla; Colorado: Lisa Miller, Cordelia Robinson, Gina Quintana, Yolanda Castillo, and Andria Ratchford; Florida: Marygrace Yale Kaiser and Claudia Rojas; Maryland: Li-Ching Lee, Rebecca Landa, Craig Newschaffer, and Maria Kolotos; Missouri: John Constantino and Robert Fitzgerald; North Carolina: Julie Daniels and Paula Bell; Pennsylvania: Ellen Giarelli, Jennifer Pinto-Martin, Susan E. Levy, and Rachel Meade Reiss; South Carolina: Jane Charles, Joyce Nicholas, and Lydia King; Wisconsin: Maureen Durkin, and Carrie Arneson. Additional assistance was provided by project staff including data abstractors, clinician reviewers, epidemiologists, and data management/programming staff. Ongoing ADDM Network support was provided by: Nancy Doernberg, Joanne Wojcik, Rita Lance, Lori Plummer, and Lekeisha Jones.

53 Thank You! The findings and conclusions in this presentation are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention

What is Autism? Overview. Autism Spectrum Disorders: Definition, Detection and Prevalence. Marshalyn Yeargin-Allsopp, M.D.

What is Autism? Overview. Autism Spectrum Disorders: Definition, Detection and Prevalence. Marshalyn Yeargin-Allsopp, M.D. Autism Spectrum Disorders: Definition, Detection and Prevalence Marshalyn Yeargin-Allsopp, M.D. National Center on Birth Defects and Developmental Disabilities Centers for Disease Control and Prevention