A significant proportion of the global population, without a medical diagnosis of coeliac disease (CD) or wheat allergy, avoid gluten or wheat in the diet. A prevalence of self-reported wheat sensitivity (SRWS) of between 4% and 13% has been shown. Non-coeliac gluten or wheat sensitivity is a clinical syndrome which is characterised by gastrointestinal (GI) or extraintestinal (EI) symptoms, related to the ingestion of gluten or wheat-containing food, which cannot be explained by other diagnoses. The symptoms attributed to wheat or gluten are similar to those reported by patients with a functional GI disorder, most notably functional dyspepsia or irritable bowel syndrome (IBS).
This study aimed to estimate the prevalence and predictors of SRWS in a general Australian population sample and relate these to several comorbidities including allergic and autoimmune disease, a modified Rome III diagnosis of functional dyspepsis or IBS, and demographic factors. The study also aimed to define the prevalence of doctor-diagnosed CD, and its association with chronic GI symptoms, as well as functional GI disorders including IBS and functional dyspepsia.
A total of 8499 participants, randomly selected from the electoral roll, were sent the Digestive Health and Wellbeing postal survey in 2015. A total of 3542 (43.1%) people returned the survey and 3115 completed all components of the questionnaire required to establish a diagnosis of SRWS and were eligible for risk factor analysis. Those with a doctor diagnosis of inflammatory bowel disease (IBD) or colon cancer/polyps were excluded. The Dillman Total Design Method was used for follow-up of non-responders. The mean age of respondents was 57.1 years old (range: 18-115 years) and 46.9% were male. Responders were slightly more likely to be female and older compared with non-responders.
In this population, 1.2% of the sample had received a medical diagnosis of CD and SRWS affected 14.9% based on the applied definition. Both of these are consistent with previous reporting of prevalence of these conditions. The prevalence of functional dyspepsia and IBS in this sample were 16.2% and 12.9% respectively. Of those, meeting the Rome III IBS criteria, 19.2% had IBS-C, 25.2% had IBS-D, 52.1% had IBS-M and the remaining 3.5% had IBS-U.
Out of the 18 assessed symptoms, all were significantly associated with a diagnosis of SRWS which is also consistent with previous studies which report bloating, abdominal pain and abnormal bowel habit in association with SRWS. All sympmtoms were more prevalent in the SRWS cohort suggesting that wheat, if causal, may induce a wide range of symptoms which is also supportive of previous analysis of symptoms in this patient group. Those with SRWS were more likely to report multiple abdominal symptoms and also report a higher frequency of all symptoms assessed compared to those without SRWS.
A significant association between SRWS diagnosis and functional GI disorders, including IBS and functional dyspepsia, was also observed. In the SRWS cohort, the prevalence of IBS was 35.1%, the prevalence of functional dyspepsia was 31.3% and 45.3% fulfilled the criteria for a functional GI disorder (either IBS or dyspepsia).
In the CD cohort, the prevalence of symptoms consistent with functional dyspepsia was 38.9% compared to 15.9% in the non-affected population. The prevalence of IBS symtoms in the CD cohort was 25% compared with 12.7% in the non-affected cohort. Symptomatic criteria for a functional GI disorder was present in 47.2% of CD patients. Those with CD also reported significantly higher levels of GI symptoms compared with unaffected individuals.
In conclusion, those with SRWS reported a wide range of symptoms at a rate significantly higher than the unaffected population and the syndrome is independently associated with the functional GI disorders, IBS and functional dyspepsia. Almost half of those with SRWS (45%) have an underlying functional GI disorder. Patients with medically diagnosed CD also report higher rates of several GI symptoms and are more likely to fulfil diagnostic criteria for functional dyspepsia and IBS.
Potter MDE, Walker MM, Jones MP et al. American Journal of Gastroenterology 2018; 113(7):1036-1044