A new study conducted by researchers at Marcus Autism Center, Children’s Healthcare of Atlanta and Emory University School of Medicine indicates that children with autism spectrum disorder (ASD) are more than four times as likely to experience general gastrointestinal (GI) complaints compared with peers, are more than three times as prone to experience constipation and diarrhea than peers, and complain twice as much about abdominal pain compared to peers.

The results are reported in the April 28, 2014, online early edition of the journal Pediatrics.

While parents frequently express concern regarding GI symptoms among children with ASD in pediatric settings, this study is the first meta-analysis of all published, peer-reviewed research relating to this topic.

"Our findings corroborate a history of anecdotal reports and case studies suggesting increased risk of GI concerns in autism," says co-author William Sharp, PhD, director of the Pediatric Feeding Disorders Program at Marcus Autism Center and assistant professor of pediatrics at Emory University School of Medicine. "This analysis reinforces the need for greater clinical and research scrutiny in this area to guide best standards of care and to address important questions regarding the detection and treatment of GI symptoms among children with autism."

The process of detecting and studying possible GI concerns in children with ASD is complicated by the unique combination of behavioral, neurological and medical issues associated with the condition. Most notably, limitations in verbal communication in patients with ASD make it difficult for them to communicate information about GI symptoms, making it more challenging for physicians to detect possible underlying GI issues. In such cases, parents and medical professionals must rely on non-verbal signs that fall outside of the routine GI diagnostic evaluation.

"In many cases, the only indication of a possible GI problem in autism may be the emergence or escalation of problem behaviors, such as self-injury, aggression, or irritability, that cannot be otherwise explained," says co-author Barbara McElhanon, MD, pediatric gastroenterologist at Children’s Healthcare of Atlanta and assistant professor of pediatrics at Emory University School of Medicine. "Relying on these atypical signs to detect possible GI concerns can be difficult for practitioners because repetitive and stereotyped patterns of behavior occur so frequently in ASD and no guidelines exist to help parents and clinicians navigate the diagnostic process."

For this reason, McElhanon and her colleagues emphasize the need to develop a standardized screening instrument as well as clinical guidelines for conducting GI examinations among children with ASD, particularly non-verbal children. More detailed, standardized screening procedures would enhance detection, while also increasing awareness in the ASD community regarding what to look for among children suspected of possible GI disorders.

"The important point from this research is that children with autism—who have difficulties in communicating their symptoms—need special attention from physicians to determine whether or not a child is experiencing GI distress" says Sharp. "Unfortunately for parents, the unfounded assertion that vaccinations somehow caused an inflammatory GI disease which then caused autism has significantly hindered progress in this field for years. Many studies have now shown no evidence of an association with vaccines, and vaccines are important for child health. That controversy diverted attention from the GI needs of children with ASD, and we hope that our work helps spur renewed investment for addressing these needs."

In addition to more standardized assessment, the authors recommend studying GI symptoms in ASD with consideration to the high rates of feeding problems and related dietary issues, such as food selectivity, in this population. "If food intake becomes highly restricted, a child is likely to experience issues like GI distress and constipation or diarrhea; but for children with autism, they often can’t communicate those issues in the same way," says McElhanon. "More research is needed to understand the best means of identifying and treating these special health needs of children with ASD."