Gastrointestinal Issues in Children with Autism Spectrum Disorders Compared to Children with Developmental Delays and a Population Based Sample in the Study to Explore Early Development (SEED)

Background:  Gastrointestinal (GI) problems are commonly reported in children with autism spectrum disorders (ASD), with prevalence ranging from 9 to 70%. However, many studies do not include comparison groups; thus, it has been difficult to assess whether GI problems in children with ASD differ in frequency from children with developmental delays (DD) or children with typical development.

Objectives:  Determine the prevalence of parent-reported GI problems and the use of treatments for constipation in children with ASD compared to children with DD recruited from community sources serving children with developmental concerns and children recruited from the general population (POP) in the Study to Explore Early Development (SEED).

Methods: SEED is a multi-site, case-control study designed to thoroughly characterize phenotypes of ASD in children ages 2 to 5 years and to examine potential genetic and environmental risk factors for ASD. The cohort includes children born between the years 2003 and 2006. Children classified as ASD (n=672), DD (n=994), and POP (n=911), whose parent completed a GI questionnaire were included in this analysis (80.5% of the total sample). These analyses are limited to questions related to current GI issues (occurring greater than 2 times per month) such as vomiting, diarrhea, constipation, abdominal pain and gas; treatment for constipation in the previous 30 days with stool softeners, laxatives, or fiber supplements; and GI problems that were present in the past but were not present at the time of the survey. Chi-square tests were used to assess overall group differences. Between group differences were explored through univariable logistic regression.  

Results: Parents reported current GI problems in 35% of children with ASD, 22% of children with DD, and 12% of POP children (p<0.0001). Children with ASD were more likely to have current GI problems than POP children (OR= 4.01, 95% CI= 3.10, 5.21) or children with DD (OR=1.96, 95% CI= 1.56, 2.44).  Parents reported past GI problems in 28% of children with ASD, 19% of children with DD, and 14% of POP children (p<0.0001). Children with ASD were more likely to have past GI problems than POP children (OR= 4.51, 95%CI= 1.95, 3.26) or children with DD (OR=1.68, 95% CI 1.32, 2.12). Parents reported use of treatment for constipation in 16% of children with ASD, 13% of children with DD, and 8% of children in the POP group (p<0.0001). Children with ASD were more likely to use treatments for constipation than POP children (OR=2.24; 95% CI 1.63, 3.09).  However, the use of treatments for constipation was not significantly different between the ASD and the DD groups (OR= 1.27; 0.96, 1.68).

Conclusions:  Based on parent report, children with ASD had a higher frequency of current and past GI problems than children with DD and children from the POP group. Children with ASD and DD had greater use of treatments for constipation compared with the POP group. These findings have implications for clinical management.  The findings are also informative for understanding phenotypic subtypes in future genetic analyses of risk for ASD.