Gastrointestinal Symptoms in Chinese Children with Autism Spectrum Disorder: Association with Emotional Symptoms?

Background:

Autism spectrum disorder (ASD) is a complex neuro-developmental disorder with a wide range of physical and psychiatric co-morbidities. Identification of subgroups, e.g., in terms of comorbidities, has the potential to help clarify and disentangle the heterogenous aetiologies of the disorder. The comorbidity of gastrointestinal (GI) symptoms in a proportion of children with ASD has been put forward as a subgroup marker, and complex gut-brain interaction is thought to contribute to pathogenesis in this subgroup.

Objectives:

This study evaluated whether Chinese children with ASD did have an elevated rate of GI symptoms. Its design improved on previous studies by controlling a wide range of potential confounds which might in fact be the agents contributing to the increased rate of GI symptoms such as co-morbid emotional problems. The latter by themselves were well known to be associated with GI symptoms. Those previous studies could not be conclusive when failing to control such confounds.

Methods:

This study compared the rates of GI symptoms between Chinese children with ASD and typically developing community controls using the Questionnaire on Pediatric Gastrointestinal Symptoms – Rome III Version (QPGS-III). Confounding variables examined included the children’s age, gender, co-morbid psychopathologies, diets, and parental anxiety and depression.

Results:

Our results were similar to western findings in that Chinese children with ASD were twice as likely to suffer from GI symptoms compared to typically developing children in the community. The types of increased GI symptoms most commonly reported were constipation, abdominal migraine and aerophagia. Of all the potential confounds examined, comorbid emotional problems exhibited a main effect in predicting increased GI symptoms, in addition to a main effect of ASD diagnosis in the regression analysis. More intriguingly, there was also an interaction effect between ASD and emotional symptoms to predict GI symptoms. In other words, while the presence of emotional symptoms was associated with an increased rate of GI symptoms in both the ASD and the community groups, the increase was significantly greater for children with ASD than for children without.

Conclusions:

Our findings indicate that ASD, emotional problems and GI symptoms form a multiplicative relationship. Despite that ASD and emotional problems are known to each contribute to an increased rate of GI symptoms, a multiplicative relationship is a new finding not reported previously. Such relationship warrants further investigation as a marker of an ASD subtype with potential distinctiveness in terms of etiologies, course of development, prognosis and treatment, etc.