Risk Factors, Co-Morbid Conditions and Epidemiology of Autism in Children

A retrospective case-cohort study was formed with 48,762 children with Autistic Spectrum Disorders (ASD) aged 2-18 years enrolled in the Military Health System from 2000-13. Children with ASD were matched 1:5 by age, gender, and enrollment time to children without ASD. International Classification of Diseases, 9th Revision, Clinical Modification and Current Procedural Terminology codes were extracted to examine associations and co-morbidities. Of perinatal conditions, seizures in the first 90 days of life were most highly associated with ASD. Specific seizure types such as absence seizures and infantile spasms have high associations with ASD, with children with ASD 4 times more likely to have seizures labeled as intractable. Seizures also account for most of the 17% increase in injury risk. Obesity and its complications are twice as common in children with ASD. However, children with ASD also are at risk for deficiencies in macro- and micronutrients, such as iron and vitamin D. Other comorbid conditions can be masked by ASD and lead to complications of missed or late diagnoses. Eosinophilic esophagitis is most strongly associated with a feeding disorder and not with ASD itself. Children with ASD who develop appendicitis are more likely to have perforation and sepsis, and those with otitis media are more likely to have perforation and cholesteatoma. Sleep disorders have a prevalence of 30% in children with ASD, and they are more likely to undergo procedures for their sleep issues. ASD is associated with multiple conditions throughout childhood, and the presence of ASD affects how clinicians diagnose and treat these conditions. These results provide clinicians with data to better screen and manage ASD patients.