title: Incidence of gastrointestinal symptoms in children with autism: a population-based study.
abstract: OBJECTIVE
  To determine whether children with autism have an increased incidence of gastrointestinal symptoms compared with matched control subjects in a population-based sample.
  
  
  METHODS
  In a previous study including all of the residents of Olmsted County, Minnesota, aged <21 years between 1976 and 1997, we identified 124 children who fulfilled criteria on the basis of Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, for a research diagnosis of autism. Two matched control subjects were identified for each case subject. Through the Rochester Epidemiology Project, all medical diagnoses, are indexed for computerized retrieval. Gastrointestinal diagnoses before 21 years of age were grouped into 5 categories: (1) constipation; (2) diarrhea; (3) abdominal bloating, discomfort, or irritability; (4) gastroesophageal reflux or vomiting; and (5) feeding issues or food selectivity. The cumulative incidence of each category was calculated by using the Kaplan-Meier method. Cox proportional hazards models were fit to estimate the risk ratios (case subjects versus control subjects) and corresponding 95% confidence intervals.
  
  
  RESULTS
  Subjects were followed to median ages of 18.2 (case subjects) and 18.7 (control subjects) years. Significant differences between autism case and control subjects were identified in the cumulative incidence of constipation (33.9% vs 17.6%) and feeding issues/food selectivity (24.5% vs 16.1). No significant associations were found between autism case status and overall incidence of gastrointestinal symptoms or any other gastrointestinal symptom category.
  
  
  CONCLUSIONS
  As constipation and feeding issues/food selectivity often have a behavioral etiology, data suggest that a neurobehavioral rather than a primary organic gastrointestinal etiology may account for the higher incidence of these gastrointestinal symptoms in children with autism.
authors: Division of Pediatric Gastroenterology, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA. ibrahim.samar@mayo.edu
authors: Samar H
authors: SH
authors: Ibrahim
authors: Robert G
authors: RG
authors: Voigt
authors: Slavica K
authors: SK
authors: Katusic
authors: Amy L
authors: AL
authors: Weaver
authors: William J
authors: WJ
authors: Barbaresi
mesh_terms: D000293:Adolescent; D001321:Autistic Disorder / Q000175:diagnosis / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D005767:Gastrointestinal Diseases / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008297:Male; D008910:Minnesota; D016017:Odds Ratio; D016016:Proportional Hazards Models; D012016:Reference Values