'MoBa' in the title of this post, refers to the Norwegian Mother and Child Cohort Study and a handy resource which has already impacted on autism research (see here for example).
Now MoBa has turned its epidemiological clout to an issue which less and less is encountering scientific resistance: are gastrointestinal (GI) symptoms over-represented when it comes to a diagnosis of autism? Further, when do such bowel issues start to present?
The answer, shown in the paper by Michaeline Bresnaha and colleagues  is yes, functional bowel symptoms are seemingly more frequently reported when it comes to autism as per the results of quite a few other studies. To quote from the authors: "maternally reported GI symptoms are more common and more often persistent during the first 3 years of life in children with ASD [autism spectrum disorder] than in children with TD [typical development] or DD [developmental delay]." Said symptoms also seemed to present pretty early on; quite a bit before many children are diagnosed with autism. Some further coverage of these findings can be seen here and here.
Including a couple of giants in research terms on the authorship list - Mady Hornig and Ian Lipkin - who also continue to push the research boundaries in relation to another diagnosis which crops up on this blog (CFS/ME or SEID as it may well be eventually known) - MoBa was put to use.
Authors "defined 3 groups of children: children with ASD (n = 195), children with DD and delayed language and/or motor development (n = 4636), and children with TD (n = 40 295)." Maternal reports garnered prospectively covering various GI symptoms including "constipation, diarrhea, and food allergy/intolerance" were analysed across the groups covering children at 6, 18 and 36 months of age.
The results suggested that constipation and food allergy/intolerance were more likely to be reported in children with autism during the 6-18 month old age range compared with typically developing controls. Diarrhoea and food allergy/intolerance were also more likely to be reported in children with autism in the 18-36 month age range again, compared with TD controls. Children with autism/ASD were also more likely to present with "1 or more GI symptom in either the 6- to 18-month or the 18- to 36-month-old age period and more than twice as likely to report at least 1 GI symptom in both age periods compared with mothers of children with TD or DD." Some might quibble about the use of maternal report in discussing the presentation of bowel issues in children but I'm not one of them (see here) as the Gorrindo findings  drift back into my consciousness.
The press release attached to this study also contains an intriguing quote from Mady Hornig: "Although the connection of GI disturbances to autism remains unclear, the presence of GI symptoms in early life may not only help to identify a subset of children with autism who require clinical input for their GI issues, it may also open new avenues for determining the underlying nature of the disorder in that subgroup." The implication being that (a) GI symptoms, early GI symptoms, are not a universal (or exclusive) feature of autism, but are present in quite a few infants, and (b) among the increasingly pluralised view of autism (see here), the idea that said GI symptoms might represent something quite fundamental to some cases of autism offers something of an opportunity to perhaps intervene and treat/manage both bowel symptoms and potentially impact on behavioural features linked to autism. On this point I'm drawn back to some of the research from Micah Mazurek and colleagues talking about sensory issues and anxiety completing a triad with bowel issues with autism in mind (see here).
I'm probably repeating myself here but quite a bit more research is required on the relationship between autism and the presentation of GI issues. I'd be inclined to suggest that a few research areas might be useful to explore: (a) the link between functional bowel issues and more pathological bowel states (see here), (b) the link between inflammation / inflammatory markers and bowel issues (see here) taking into account the work of people like Harumi Jyonouchi for example (see here), (c) the possibility that bowel issues might have some connection back to the gut microbiota as per other work by Hornig/Lipkin (see here), and (d) how said GI issues might impact on issues such as pharmacotherapy in terms of drug availability and absorption issues (see here). This isn't an exhaustive list, just a few ideas to play around with.
 Bresnahan M. et al. Association of Maternal Report of Infant and Toddler Gastrointestinal Symptoms With Autism Evidence From a Prospective Birth Cohort. JAMA Psychiatry. 2015. March 25.
 Gorrindo P. et al. Gastrointestinal dysfunction in autism: parental report, clinical evaluation, and associated factors. Autism Res. 2012 Apr;5(2):101-8.
Bresnahan, M., Hornig, M., Schultz, A., Gunnes, N., Hirtz, D., Lie, K., Magnus, P., Reichborn-Kjennerud, T., Roth, C., Schjølberg, S., Stoltenberg, C., Surén, P., Susser, E., & Lipkin, W. (2015). Association of Maternal Report of Infant and Toddler Gastrointestinal Symptoms With Autism JAMA Psychiatry DOI: 10.1001/jamapsychiatry.2014.3034