The early stool patterns of young children with autistic spectrum disorder

Aim: To investigate whether children with autistic spectrum disorder (ASD) have bowel symptoms consistent with underlying enterocolitis. Methods: Information on children's stool patterns and gut symptoms collected by questionnaire at 4 weeks and at 6, 18, 30 and 42 months of age were available for 12 984 children from the Avon Longitudinal Study of Parents and Children (ALSPAC). Data on the 78 children identified by local health and/or education systems to have special educational provision for ASD were compared with the 12 906 remaining children in the cohort. Results: Comparison of the ASD and control group during the first 3.5 years of life showed no major differences in stool colour or consistency, or in frequency of diarrhoea, constipation, bloody stools or abdominal pain. The ASD children had similar stool frequency up to 18 months, but there was a trend for ASD children to pass more stools at 30 months (OR 3.73, 95% CI 1.11 to 12.6; p = 0.004) and at 42 months (OR 6.46, 95% CI 1.83 to 22.7; p<0.001), although only three children passed more than 4 stools/day. Repeating the analysis on only those cases diagnosed as having classical childhood autism resulted in very similar findings. Conclusions: During the first 42 months of life, ASD children had a stool pattern that was very similar to that of other children, apart from a slight increase in stool frequency at 30 and 42 months. There were no symptoms to support the hypothesis that ASD children had enterocolitis.