Inflammatory markers and adaptive behavior in Egyptian children with autism spectrum disorder: on considering gastrointestinal symptoms

Abstract Objectives This study aimed to compare the prevalence of gastrointestinal (GI) symptoms in children with autism spectrum disorder (ASD) and typically developing (TD) children. It also intended to determine whether inflammatory marker levels and adaptive behavior scores were related to GI symptoms in ASD children. Methods Fifty-six children with ASD aged 3–12 years and 40 age- and sex-matched TD children were included in this case-control study. ASD diagnosis was confirmed according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), and severity was assessed using the Childhood Autism Rating Scale (CARS). GI symptoms were evaluated using a standardized GI history questionnaire. The Vineland Adaptive Behavior Scales, Second Edition (VABS-II) was used to measure adaptive behavior. The enzyme-linked immunosorbent assay (ELISA) was used to measure the levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and C-reactive protein (CRP) in the serum. Results The age and gender of ASD children showed no statistically significant differences compared to the control group. Children with ASD experienced GI symptoms at a considerably higher rate than TD peers (83.9% vs. 60.0%, p = 0.008). Mean serum level of IL-6, TNF-α and CRP showed no statistically significant differences between the ASD group and the control group. Mean values of the adaptive behavior standard scores in ASD children were more deficient than those of TD children and this relation was statistically highly significant (P< 0.01). Correlation between the inflammatory markers’ levels and the age in ASD group was non- significant (P> 0.05). In ASD group, correlations between the general adaptive composite score, the adaptive behavior standard scores, and the total CARS score on one side and the age on the other side were not significant. In contrary, the motor standard score was the only variant that reported high positive significant correlation (P< 0.01) with the age. Children with ASD who experienced frequent vomiting or diarrhea had significantly higher TNF-α levels than those without these symptoms (P< 0.05). Linear regression analysis for TNF-α in autistic patients showed positive significance with diarrhea. In TD group, comparisons of the inflammatory markers with the diverse GI symptoms were not significant. Children with mild ASD had significantly lower CRP levels than children with moderate and severe ASD (P< 0.05). While linear regression analysis for prediction of inflammatory markers levels in ASD group in relation to the severity of the disease was non-significant. In ASD group, comparisons between the general adaptive composite score and the adaptive behavior standard scores in relation to GI symptoms were non-significant using non-parametric tests. Conclusion The prevalence of GI disturbances in ASD children was high. GI troubles were irrelevant to the poor adaptive behavior scores. The ASD severity could not be predicted by the levels of the inflammatory markers. TNF-α was found to be positively correlated with diarrhea.