18599
Prevalence of Autism Spectrum Conditions in Mainland China: Pilot and a Whole Population Study

Saturday, May 16, 2015: 11:30 AM-1:30 PM
Imperial Ballroom (Grand America Hotel)
X. Sun1,2,3, C. Allison4, B. Auyeung5, S. Baron-Cohen5 and C. Brayne1, (1)Cambridge Institute of Public Health, University of Cambridge, Cambridge, United Kingdom, (2)Department of Psychiatry, Autism Research Centre, Cambridge, United Kingdom, (3)The Chinese University of Hong Kong, Hong Kong, Hong Kong, (4)Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom, (5)Autism Research Centre, University of Cambridge, Cambridge, United Kingdom
Background:  

The majority of recent prevalence studies of the Autism Spectrum Conditions (ASC) in developed countries have adopted a combination of prospective and retrospective approaches, using standardized diagnostic instruments for case identification. Previous reported prevalence estimates of ASC in mainland China have been much lower than Western estimates (around 1%). This may be partly due to the differences in: 1) study methodology; 2) screening and diagnostic instruments; 3) clinical diagnostic criteria; 4) under-diagnosis of milder subtypes of the spectrum: most children diagnosed are those with classic autism. A recent validation of the Mandarin Chinese Childhood Autism Spectrum Test (CAST) suggested there is an under-estimation of the prevalence of ASC in the general population in Beijing.

Objectives:  

1) To apply validated screening and standardized diagnostic instruments to an entire district population in a moderately developed city to establish a prevalence estimate of ASC in an unselected population in mainland China. 2) To conduct a pilot study to test the feasibility of a national prevalence study of ASC in China.

Methods:  

Based on the residential records, the Mandarin CAST was distributed to all children aged 6 to 11 years old (N = 7,258 children) in Fengman district in Jilin province. The study had 3 stages. Stage 1: All children between 6 and 11 years old in mainstream primary schools were screened. Stage 2: All screened children who scored highly (at or above the cut-off of 15 on the CAST) were assessed by experienced child psychiatrists using DSM-IV criteria, and then further assessed using the ADOS and the ADI-R. A consensus diagnosis was made between instruments’ examiners and psychiatrists. Stage 3: All children (age 6 to 11) in special schools, intervention centres, communities, or at home with an existing diagnosis of ASC, were screened with diagnostic records checked. A random selection of 10 children with an existing diagnosis of ASC who met the cut-off were examined by clinicians and examiners to confirm their diagnostic status. The prevalence estimate was generated after adjusting and imputing for missing values using inverse probability weighting.

Results:  

A total of 6,149 questionnaires (participation rate: 85.8%) from mainstream primary schools (Stage 1) and 91 questionnaires (participation rate: 100%) from children with a diagnosis of ASC (Stage 3) were available for analysis. A total of 477 children (7.8%) in mainstream schools met the cut-off of the CAST, and 72 children (79.1%) with a diagnosis met the cut-off. 9 children from mainstream primary schools and 68 children from other settings in this district were found to meet the consensus diagnostic criteria for ASC (78.5% after adjustment). After adjustment and data imputation, the prevalence in this primary school population in China was 108 per 10,000 (95%CI: 86, 135). The sex ratio (boys: girls) of children with ASC was 7:1.

Conclusions:

Using a comparable method, the prevalence estimate of ASC in a moderately developed city in mainland China is similar to those estimates in developed countries. This study confirms it is feasible to conduct a large population-based epidemiological study for ASC in China.

See more of: Epidemiology
See more of: Epidemiology