Abstract
We retrospectively identified autism spectrum disorder (ASD) incident cases among 31,220 individuals in a population-based birth cohort based on signs and symptoms uniformly abstracted from medical and educational records. Inclusive and narrow research definitions of ASD (ASD-R I and ASD-R N , respectively) were explored, along with clinical diagnoses of ASD (ASD-C) obtained from the records. The incidence of ASD-R I, ASD-R N , and ASD-C increased significantly from 1985 to 1998, then ASD-R I and ASD-R N plateaued while the rate of ASD-C continued to increase during 1998–2004. The rising incidence of research-defined ASD may reflect improved recognition and documentation of ASD signs and symptoms. Although the frequency of threshold ASD symptoms stabilized, the rate of ASD-C continued to increase, narrowing the gap between clinical ascertainment and symptom documentation.
Original language | English (US) |
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Pages (from-to) | 1455-1474 |
Number of pages | 20 |
Journal | Journal of Autism and Developmental Disorders |
Volume | 49 |
Issue number | 4 |
DOIs | |
State | Published - Apr 1 2019 |
Keywords
- Autism spectrum disorder
- Epidemiology
- Incidence
- Time trends
ASJC Scopus subject areas
- Developmental and Educational Psychology