20/11/2009

NOTE sur la prévalence des TED dans les études épidémiologiques récentes

Trois études récentes ont recensé l’ensemble des personnes avec TED dans une population de jeunes enfants, selon les critères du DSMIV et avec des techniques de détection optimales (c-à-d maximisant la sensibilité)[1].  Les résultats de prévalence sont remarquablement semblables (environ 60/10.000) mais s’élèvent à plus du double des résultats obtenus en rassemblant les 32 études disponibles depuis 1966 (27,5/10.000).

 

Etudes

Autisme

TED non spécifiés

+ AS

Tous les TED

 

Prévalence

/10.000

% Q.I. normal

Prévalence

/10.000

% Q.I.

normal

Prévalence

/10.000

Bertrand, 2001

40.5

37

27

51

67.5

Baird, 2000

30.8

60

27.1

-

57.9

Chakrabarti, 2001

16.8

29

44.5

94

61.3

Moyenne

29.3

42

32.9

72.5

62.2

 

Avec ces données on peut calculer que, sur l’ensemble des TED identifiés, 58% ont un QI normal.

Le résultat intéressant apparaît lorsque on compare ces données avec les moyennes établies par Fombonne (2003) sur les 32 études épidémiologiques.

 

Etudes

32 études Fombonne

3 études récentes

Différence

Prévalence totale TED /10.000

27.5

62.2

34.7

Prévalence  Q.I. normal /10.000

8.25

36.1

27.85

Prévalence  Q.I. bas /10.000

19.25

26

6.75

 

 

 

 

  

Les conclusions sont pertinentes pour notre étude

·         L’augmentation de la prévalence des TED observée dans les nouvelles études (plus du double, de 27,5/10.000 à 62,2/10.000) est due essentiellement à une bien meilleure détection des TED avec un Q.I. normal par rapport aux études anciennes.

·         Les TED avec Q.I. bas ont à peu près la même prévalence dans les deux groupes d’études ; l’écart entre 19,25 et 26 est de l’ordre des fluctuations habituelles entre les études

·         Donc, les TED avec déficit intellectuel sont bien détectés dans toutes les études alors que la grande majorité des TED sans déficit intellectuel ne le sont pas dans les études plus anciennes (36.1 contre 8.25).

 

La prévalence totale des TED (avec et sans déficit intellectuel) est donc très probablement de  l’ordre de 60/10.000.   Plus de la  moitié (58%) de cette population n’a pas de déficit intellectuel 

 

Avec ces chiffres la population totale (tous les TED adultes) de notre étude serait de 3.965 personnes au lieu de 1.753 et la population cible (TED adultes avec déficit intellectuel) serait de 1.657 au lieu de 1.227



[1] Fombonne, E. (2003); Epidemiological Surveys of Autism and Other Pervasive Developmental Disorders : An Update ; Journal of Autism and Developmental Disorders, Vol 33, N°4, August 2003, p 373

 

Source: http://www.inforautisme.be/Articles/Prevalence_TED.htm

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Une toute dernière étude démontre ne prévalence d'un enfant sur 100:

 

Study: More cases of autism in U.S. kids than previously realized

  • Story Highlights
  • Study indicates about 1% of children 3 to 17 have autism or related disorder
  • Results based on national telephone survey of more than 78,000 parents
  • CDC official: "This is a significant issue that needs immediate attention"
  • Researchers saying finding could reflect heightened awareness of disorder

(CNN) -- A study published Monday in the journal Pediatrics indicates about 1 percent of children ages 3 to 17 have autism or a related disorder, an increase over previous estimates.

Children at the Marcus Autism Center in Atlanta, Georgia, receive instruction on March 5, 2009.

Children at the Marcus Autism Center in Atlanta, Georgia, receive instruction on March 5, 2009.

"This is a significant issue that needs immediate attention," Dr. Ileana Arias, deputy director of the Centers for Disease Control and Prevention said Friday. "A concerted effort and substantial national response is warranted."

The study used data from the federal government's 2007 national survey of children's health. The survey of parents was conducted by the Health Resources and Services Administration, and by the Centers for Disease Control and Prevention.

The results are based on a national telephone survey of more than 78,000 parents of children ages 3 to 17.iReport.com: How has autism affected your family?

In the study, parents were asked whether a health care provider had ever told them their child had an autism spectrum disorder. ASD is a group of brain disorders comprising autism and two less severe disorders: Asperger's disorder and pervasive developmental disorder not otherwise specified.

Children with the disorder show impairment in social interaction and in their ability to communicate. They often display repetitive behavior.

The investigators also asked a follow-up question: Were the children considered to have ASD now? Nearly 40 percent of the parents and guardians said no.

That finding led the authors to question whether some of the children originally diagnosed as having ASD may have been improperly diagnosed, since the disorders are not considered curable.

But Kogan said the two surveys cannot be compared because the earlier investigators did not ask the follow-up question about whether the children were still considered to have the disorder.

Still, based on the findings, lead author Dr. Michael D. Kogan of HRSA's maternal and child health bureau estimated the prevalence of ASD among U.S. children ages 3 to 17 at 110 per 10,000 -- slightly more than 1 percent.

Boys were four times as likely as girls to have ASD, and non-Hispanic black and multiracial children were less likely than non-Hispanic white children.

He estimated that 673,000 children have ASD in the United States.

Monday's findings of nearly 1 in 100 appear to indicate an increase from the average of 1 in 150 that was reported in 2003, the researchers said.

Health Library

The researchers urged caution in interpreting the change, noting that an increase in diagnoses does not necessarily mean that more children have the disorder. It could simply reflect a heightened awareness of the disorder.

"We don't know whether the change in the number over time is a result of the change in the actual condition, in the actual number of conditions or in part due to the fact that the condition is being recognized differently," Arias said.

She said that preliminary results from a separate, CDC-funded study she is working on also indicate that about 1 percent of children in the United States are affected by ASD. That study is to be published later this year, she said.

"This is a behavioral diagnosis, and it's difficult to make, and it's difficult to make at young ages," said Dr. Peter van Dyck, HRSA's associate administrator for maternal and child health.

Half of the cases were considered mild by their parents, the study reported.

The results underscore the importance of creating policies that will result in early identification and intervention, the officials said.

The reports raise "a lot of questions about how we are preparing in terms of housing, employment, social support -- all the issues that many of these people are going to need," said Dr. Tom Insel, director of the National Institute of Mental Health.

"It also raises questions about how well we're prepared in the educational system to provide for the special needs of many of these kids."

Insel said the federal government is beefing up the resources it is mobilizing to address autism and related disorders, with $85 million being appropriated by the National Institutes of Health and $48 million for next year by the HRSA.

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