Lay Abstract Gastrointestinal dysfunction (GID) in children with autism spectrum disorder (ASD) is not well understood. Differences in factors associated with GID, such as eating habits, have been reported between ASD and non-ASD populations, but relationships between these factors and GID have not been examined. There is also the possibility that what we do know about GID in ASD is influenced by parents’ perceptions of GID in their children. Although parents know their children best, they are not necessarily experts in determining GID. This study examined how well parents and pediatric gastrointestinal clinicians agree on GID in children, and how factors thought to relate to GID in ASD, actually do relate to GID. 121 children were studied, in three groups: co-occurring ASD and GID, ASD without GID, and GID without ASD. Clinical evaluations by pediatric gastroenterologists validated parental reports of GID in ASD, with constipation the leading type of GID in ASD. Presence of GID in ASD was not associated with differences in diet or medications, but was associated with language and social impairments. These findings suggest that healthcare providers of children with ASD should be vigilant for GID, particularly in children who lack the ability to communicate verbally. Scientific Abstract The objectives of this study were to characterize gastrointestinal dysfunction (GID) in autism spectrum disorder (ASD), to examine parental reports of GID relative to evaluations by pediatric gastroenterologists, and to explore factors associated with GID in ASD. 121 children were recruited into three groups: co-occurring ASD and GID, ASD without GID, and GID without ASD. A pediatric gastroenterologist evaluated both GID groups. Parents in all three groups completed questionnaires about their child’s behavior and GI symptoms, and a dietary journal. Functional constipation was the most common type of GID in children with ASD (85.0%). Parental report of any GID was highly concordant with a clinical diagnosis of any GID (92.1%). Presence of GID in children with ASD was not associated with distinct dietary habits or medication status. Odds of constipation were associated with younger age, increased social impairment, and lack of expressive language (adjusted odds ratio in nonverbal children: 11.98, 95% CI 2.54 – 56.57). This study validates parental concerns for GID in children with ASD, as parents were sensitive to the existence, although not necessarily the nature, of GID. The strong association between constipation and language impairment highlights the need for vigilance by healthcare providers to detect and treat GID in children with ASD. Medications and diet, commonly thought to contribute to GID in ASD, were not associated with GID status. These findings are consistent with a hypothesis that GID in ASD represents pleiotropic expression of genetic risk factors.

This study investigated the reliability and stability of an autism diagnosis in children under 3 years of age who received independent diagnostic evaluations from two clinicians during two consecutive yearly evaluations. Strong evidence for the reliability and stability of the diagnosis was obtained. Diagnostic agreement between clinicians was higher for the broader discrimination of autism spectrum vs. no autism spectrum than for the more specific discrimination of autism vs. PDD-NOS. The diagnosis of autism at age 2 was more stable than the diagnosis of PDD-NOS at the same age. Social deficits and delays in spoken language were the most prominent DSM-IV characteristics evidenced by very young children with autism.

This study investigated the reliability and stability of an autism diagnosis in children under 3 years of age who received independent diagnostic evaluations from two clinicians during two consecutive yearly evaluations. Strong evidence for the reliability and stability of the diagnosis was obtained. Diagnostic agreement between clinicians was higher for the broader discrimination of autism spectrum vs. no autism spectrum than for the more specific discrimination of autism vs. PDD-NOS. The diagnosis of autism at age 2 was more stable than the diagnosis of PDD-NOS at the same age. Social deficits and delays in spoken language were the most prominent DSM-IV characteristics evidenced by very young children with autism.