Brief Report: The Characterization of Medical Comorbidity Prior to Autism Diagnosis in Children Before Age Two.

The ASD and control groups were identified from billing codes, and the codes were not verified by chart review, so they may not represent confirmed diagnoses. The sample came from one medical center in the Southeastern United States, so it may not represent other regions or populations. The ASD group was mainly boys, about 5 boys for every girl, which is higher than the cited population estimate, so results may reflect boys diagnosed with ASD more than all children later diagnosed with ASD. Some conditions were rare in the sample, so their estimates may be imprecise. The control group had a younger age at first visit and more prematurity, and the average age at first ASD code was 5.2 years, so the records may not match current diagnosis patterns. ASD diagnoses before age two were excluded because early ASD codes are not stable, so this analysis describes conditions before a later diagnosis, not confirmed early diagnoses.

Zachary Williams disclosed consulting for Roche and serving on the family advisory committee of the Autism Speaks Autism Care Network Vanderbilt site and the autistic researcher review board of the Autism Intervention Research Network on Physical Health. The remaining authors reported no conflicts.

Do not treat convulsive epilepsy, strabismus, irregular eye movements, delayed milestones, or lack of normal physiological development as confirmed predictors of autism. The study used unverified billing codes from a single-center sample and showed associations only, not that any condition causes or predicts ASD diagnosis.