Table 4.
Studies on gastrointestinal (GI) symptoms and gut microbiota composition in autism spectrum disorder (ASD).
| Authors and Year | Type of Study | Participants (N) | Methods | Findings |
|---|---|---|---|---|
| McElhanon et al., 2014 [181] | Systematic meta-analysis | ASD group: 2215; comparison group: 50664 |
15 studies included in the systematic review | Greater prevalence of GI symptoms among children with ASD compared with control children |
| Adams et al., 2011 [182] | Cross-sectional study | 58 ASD children; 39 healthy controls | GI symptoms: assessed with a modified six-item GI Severity Index (6-GSI) questionnaire; autistic symptoms: assessed with the Autism Treatment Evaluation Checklist (ATEC) |
Correlations between GI symptoms and autism severity |
| Kang et al., 2017 [183] | Open-label trial | 18 ASD-diagnosed children | MTT |
|
| Gondalia et al., 2012 [196] | Cross-sectional study | 28 autistic children with GI dysfunction; 23 autistic children without GI dysfunction; 53 neurotypical siblings | Comparing gut microbiota | No significant difference between groups |
| Sandler et al., 2000 [201] | Open-label trial | 11 children with regressive-onset autism | Administration of vancomycin | Short-term behavioural improvement |
Legend: MTT—microbiota transfer therapy.