Data mining the ScanBrit study of a gluten- and casein-free dietary intervention for children with autism spectrum disorders: behavioural and psychometric measures of dietary response.

We previously reported results based on the examination of a gluten- and casein-free diet as an intervention for children diagnosed with an autism spectrum disorder as part of the ScanBrit collaboration. Analysis based on grouped results indicated several significant differences between dietary and non-dietary participants across various core and peripheral areas of functioning. Results also indicated some disparity in individual responses to dietary modification potentially indicative of responder and non-responder differences. Further examination of the behavioural and psychometric data garnered from participants was undertaken, with a view to determining potential factors pertinent to response to dietary intervention. Participants with clinically significant scores indicative of inattention and hyperactivity behaviours and who had a significant positive changes to said scores were defined as responders to the dietary intervention. Analyses indicated several factors to be potentially pertinent to a positive response to dietary intervention in terms of symptom presentation. Chronological age was found to be the strongest predictor of response, where those participants aged between 7 and 9 years seemed to derive most benefit from dietary intervention. Further analysis based on the criteria for original study inclusion on the presence of the urine compound, trans-indolyl-3-acryloylglycine may also merit further investigation. These preliminary observations on potential best responder characteristics to a gluten- and casein-free diet for children with autism require independent replication.

The ScanBrit randomised, controlled, single-blind study of a gluten- and casein-free dietary intervention for children with autism spectrum disorders.

There is increasing interest in the use of gluten- and casein-free diets for children with autism spectrum disorders (ASDs). We report results from a two-stage, 24-month, randomised, controlled trial incorporating an adaptive 'catch-up' design and interim analysis. Stage 1 of the trial saw 72 Danish children (aged 4 years to 10 years 11 months) assigned to diet (A) or non-diet (B) groups by stratified randomisation. Autism Diagnostic Observation Schedule (ADOS) and the Gilliam Autism Rating Scale (GARS) were used to assess core autism behaviours, Vineland Adaptive Behaviour Scales (VABS) to ascertain developmental level, and Attention-Deficit Hyperactivity Disorder - IV scale (ADHD-IV) to determine inattention and hyperactivity. Participants were tested at baseline, 8, and 12 months. Based on per protocol repeated measures analysis, data for 26 diet children and 29 controls were available at 12 months. At this point, there was a significant improvement to mean diet group scores (time*treatment interaction) on sub-domains of ADOS, GARS and ADHD-IV measures. Surpassing of predefined statistical thresholds as evidence of improvement in group A at 12 months sanctioned the re-assignment of group B participants to active dietary treatment. Stage 2 data for 18 group A and 17 group B participants were available at 24 months. Multiple scenario analysis based on inter- and intra-group comparisons showed some evidence of sustained clinical group improvements although possibly indicative of a plateau effect for intervention. Our results suggest that dietary intervention may positively affect developmental outcome for some children diagnosed with ASD. In the absence of a placebo condition to the current investigation, we are, however, unable to disqualify potential effects derived from intervention outside of dietary changes. Further studies are required to ascertain potential best- and non-responders to intervention. The study was registered with ClincialTrials.gov, number NCT00614198.