In pediatric settings, parents often raise concerns about possible gastrointestinal (GI) symptoms in autism spectrum disorder (ASD), yet the specificity of these concerns are not well studied.
To conduct a meta-analysis of research investigating GI symptoms among children with ASD.
We searched Medline, PsycINFO, and PubMed databases (1980–2012) in peer-reviewed journals. Analysis involved studies with a comparison group presenting quantitative data on GI symptoms using combinations of terms for ASD and GI indicators. The systematic search yielded 15 studies. We calculated effect sizes and 95% confidence intervals (CIs) using a random-effects model.
Children with ASD experience significantly more general GI symptoms than comparison groups, with a standardized mean difference of 0.82 (0.24) and a corresponding odds ratio (OR) of 4.42 (95% CI, 1.90–10.28). Analysis also indicated higher rates of diarrhea (OR, 3.63; 95% CI, 1.82–7.23), constipation (OR, 3.86; 95% CI, 2.23–6.71), and abdominal pain (OR, 2.45; 95% CI, 1.19–5.07).
Results indicate greater prevalence of GI symptoms among children with ASD compared with control children. Identified studies involved high methodological variability and lack of comprehensive data prohibited analysis of GI pathophysiologies (eg, gastroesophageal reflux) typically associated with organic etiologies, limiting conclusions about the underpinnings of the observed association. Future research must address critical questions about the causes and long-term impact of GI symptoms in ASD. Such analyses will require more systematic research and clinical activities, including improved diagnostic screening, standardized assessment, and exploration of potential moderators (eg, dietary restrictions).
Comments
Inflammatory Bowel Disease and Autism : New Research - New Insights
Readers of this article would be interested to know that Issac Kohane (2012) and fellow researchers (Harvard Medical School) have clearly evidenced Inflammatory Bowel Disease in Autism. In Kohane's work examining the medical records of some 14,000 children and young adults Inflammatory Bowel Disease (IBD) was found at significantly higher rates than controls. ( 0.83% vs. 0.54% ). Further "Three of the studied comorbidities increased significantly when comparing ages 0-17 vs 18-34" ... IBD (0.68% vs. 1.99%)"
Epilepsy was found at almost 9x the rate and other significant associations found included Type 1 Diabetes, Bowel Disorders, Schizophrenia, CNS/Cranial abnormalities, muscular dystrophy and sleep disorders.
Following on from this research in 2013 (Doshi-Valez / Kohane) further analysis of ASD patients identified "Three distinct patterns of medical trajectories": The first was characterised by seizures / epilepsy (77.5%). The second by "multisystem disorders including gastrointestinal disorders (prevalence 24.3%) and auditory disorders and infections(prevalence 87.8%)". The third by psychiatric disorder. A fourth group could not be further resolved.
All groups had elements of seizures and gastrointestinal disorders. Seizures ranged from
Group 1 77.50 Epilepsy Group
Group 2 42.13 Multisystem / GI Group
Group 3 33.02 Psychiatric Group
Group 4 18.16 Unresolved
Gastrointestinal Disorder ranged from -
Group 1 14.17 Epilepsy Group
Group 2 24.37 Multisystem / GI Group
Group 3 10.85 Psychiatric Group
Group 4 3.43 Unresolved
The multisystem/GI group was also characterised by these elements:
"* Correlation with cardiac and auditory disorders, asthma and other autoimmune disorders,and congenital anomalies involving the ear, eye, and cranial nerve.
* Characterized by "relatively severe" autism
* Abnormal immune response to infection
* Increased ear infections"
Researchers commented "The prevalence of psychiatric disorders was uncorrelated with seizure activity (P = .17), but a significant correlation existed between gastrointestinal disorders and seizures."
Two previous studies have identified significantly high rates of "CPEA-defined regression ((loss of language and/or other skills following acquisition)" In a 2008 Hornig study it was 88% and in later 2011 work by Williams et al 87% in ASD children with Gastrointestinal disorder/dysfunction.
In April this year researchers from Johns Hopkins University undertook a comprehensive study of "164 children with ASD evaluated at a pediatric neurology practice."
They found GI dysfunction in 49% of the children.
They also reported that in children who had undergone endoscopic and colonoscopic evaluations 6 out of 12 had inflammation present.
References
The Co-Morbidity Burden of Children and Young Adults with Autism Spectrum Disorders Kohane et al Plos One April 12, 2012
Comorbidity clusters in autism spectrum disorders: an electronic health record time-series analysis. Doshi-Velez F, Ge Y, Kohane I. Pediatrics. 2014 Jan
Gastrointestinal Dysfunction in Children With Autism Spectrum Disorders. Kang et al Autism Research. 2014 Apr 21
Lack of Association between Measles Virus Vaccine and Autism with Enteropathy: A Case-Control Study Hornig et al Plos One September 04, 2008
Impaired Carbohydrate Digestion and Transport and Mucosal Dysbiosis in the Intestines of Children with Autism and Gastrointestinal Disturbances Williams et al Plos One September 11 2011
Conflict of Interest:
Father of ASD son