Sex differences in the age of childhood autism diagnosis and the impact of co-occurring conditions.

Of 7916 patients with at least one autism code, only 1438 met all study criteria, so the analysed group is a subset of children with autism-related codes. The study used billing codes, not confirmed clinical diagnoses, to identify autism and co-occurring conditions. The autism code method was validated at Duke but is not a gold standard diagnosis. Co-occurring condition codes were not validated and may reflect provider concerns rather than confirmed diagnoses. Only the two years before autism diagnosis were examined, and the exact timing or number of codes within that window was not analysed. Care outside Duke was not available, so children diagnosed elsewhere or with incomplete records were excluded. The sample came from one academic health system and may not represent all US children. The study cannot prove that co-occurring conditions or service visits caused earlier or later diagnosis. Missed autism diagnoses were not counted, so true sex differences may differ from recorded differences.

The article is tagged as NIH extramural research support. Geraldine Dawson reports advisory board roles with Akili Interactive, Zynerba, Nonverbal Learning Disability Project, and Tris Pharma; consulting roles with Apple, Gerson Lehrman Group, and Guidepoint Global; book royalties from Guilford Press and Springer Nature; and says she developed technology licensed to Apple that financially benefited her and Duke. Matthew Engelhard reports consulting fees from OpiAID and Salutary. Other authors report no relevant financial conflicts.

Do not conclude that speech, audiology, or physical or occupational therapy causes earlier autism diagnosis. The study only found associations in health records, and it reported that encounters with these services occurred at similar rates in boys and girls, so lower service use does not explain later diagnosis in girls.