Functional gastrointestinal disorders (FGID) just got more complicated with new Australian research highlighting an association with both atopy and autoimmune diseases.

A history of doctor-diagnosed food allergy, psoriasis or rheumatoid arthritis was associated with IBS, while asthma and food allergy were associated with functional dyspepsia, according to results from a population survey of more than 3,500 randomly selected people.

The Newcastle University (NSW) Digestive Health & Wellbeing survey included measures of FGID symptoms, self-reported medical diagnoses, an assessment of psychological distress and lifestyle factors.

About 13% of participants fulfilled the Rome criteria for IBS and 17% for functional dyspepsia.

The prevalences of allergic conditions included asthma (16%), pollen allergy (7.5%), food allergy (6%) and animal allergy (4%). The most common autoimmune disorders were diabetes (10%), rheumatoid arthritis (6.5%) and psoriasis (4%).

About 20% of people with asthma also had IBS; a similar proportion of people with rheumatoid arthritis also met the criteria for IBS.

The study, from the Australian Gastrointestinal Research Alliance, found the associations between functional dyspepsia, IBS and immune disorders to be independent of psychological distress.

“This suggests that different peripheral pathways may be involved in the pathogenesis of certain FGIDs,” the authors said.

They proposed that HLA polymorphisms seen in both asthma and IBS might be one of the links between atopy and FGID.

“In a similar fashion HLA‐DRB1 and DQA1‐DQB1 haplotypes have been associated with autoimmune diseases, including rheumatoid arthritis and type 1 diabetes.”

“Interestingly, patients with psoriasis have elevated levels of serum eosinophil cationic protein, increased numbers of EG2 positive eosinophils and tryptase positive mast cells in the duodenal stroma and patients with IBS and FD also have been found to have elevated eosinophils, mast cells and immune dysregulation.”