title: The epidemiology of autism spectrum disorders.
abstract: Autism spectrum disorders (ASDs) are complex, lifelong, neurodevelopmental conditions of largely unknown cause. They are much more common than previously believed, second in frequency only to mental retardation among the serious developmental disorders. Although a heritable component has been demonstrated in ASD etiology, putative risk genes have yet to be identified. Environmental risk factors may also play a role, perhaps via complex gene-environment interactions, but no specific exposures with significant population effects are known. A number of endogenous biomarkers associated with autism risk have been investigated, and these may help identify significant biologic pathways that, in turn, will aid in the discovery of specific genes and exposures. Future epidemiologic research should focus on expanding population-based descriptive data on ASDs, exploring candidate risk factors in large well-designed studies incorporating both genetic and environmental exposure data and addressing possible etiologic heterogeneity in studies that can stratify case groups and consider alternate endophenotypes.
authors: Department of Epidemiology and Biostatistics, Drexel University School of Public Health, Philadelphia, PA 19102, USA. cnewscha@drexel.edu
authors: Craig J
authors: CJ
authors: Newschaffer
authors: Lisa A
authors: LA
authors: Croen
authors: Julie
authors: J
authors: Daniels
authors: Ellen
authors: E
authors: Giarelli
authors: Judith K
authors: JK
authors: Grether
authors: Susan E
authors: SE
authors: Levy
authors: David S
authors: DS
authors: Mandell
authors: Lisa A
authors: LA
authors: Miller
authors: Jennifer
authors: J
authors: Pinto-Martin
authors: Judy
authors: J
authors: Reaven
authors: Ann M
authors: AM
authors: Reynolds
authors: Catherine E
authors: CE
authors: Rice
authors: Diana
authors: D
authors: Schendel
authors: Gayle C
authors: GC
authors: Windham
mesh_terms: D001321:Autistic Disorder / Q000453:epidemiology* / Q000209:etiology / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D019966:Substance-Related Disorders / Q000150:complications; D013723:Teratogens / Q000633:toxicity
chemical_list: D013723:Teratogens