Autism spectrum disorders are defined by ASD
diagnoses (autistic
disorder, Asperger
disorder, and pervasive development
disorder, not otherwise specified [International Classification
of Diseases, Ninth Revision, Clinical Modification codes 299.0, 299.8, 299.9, respectively]-RRB- recorded in KPNC's pediatric electronic
medical records on at least 2 occasions from birth through June 30, 2015.