Coeliac disease in Middle Eastern countries: a challenge for the evolutionary history of this complex disorder?

About 10,000 years ago domestication and farming of wheat and other cereals developed in the 'Fertile Crescent', an area including modern Turkey, Iraq and Iran. Agriculture then slowly spread from Middle East to Europe. Coeliac disease is the permanent intolerance to dietary gluten, the major protein component of wheat. It has been until relatively recently hypothesised that wheat consumption exerted a negative selective pressure on genes predisposing to coeliac disease, eventually leading to higher coeliac disease frequency in Northeastern Europe because of lack of exposure to cereals. This theory is at variance with recent studies showing that coeliac disease is as common in Middle Eastern countries as in Europe. High prevalence of coeliac disease has been found in Iran, in both the general population and at-risk groups, e.g. patients with irritable bowel syndrome or type 1 diabetes. Clinical manifestations of coeliac disease vary markedly with the age of the patient, the duration and the extent of disease. Clinical studies showed that presentation with non-specific symptoms or no symptoms is as common in the Middle East as in Europe. Wheat represented a major component of the Iranian diet for many centuries and it may be argued that the continuous and high level of exposure to wheat proteins has induced some degree of immune tolerance, leading to milder symptoms that may be misdiagnosed as irritable bowel syndrome or unexplained gastrointestinal disorders. The gluten-free diet represents a real challenge to both patients and clinicians in this area. This is particularly difficult in the absence of any supply for gluten-free diet in Middle Eastern countries.

Coeliac disease in Iranian type I diabetic patients.

BACKGROUND: The association between coeliac disease and type I diabetes mellitus has been evaluated in some previous studies, but its prevalence in Iranian diabetic patients remains unknown. AIM: To evaluate the prevalence of coeliac disease in patients with type I diabetes mellitus in Iran. PATIENTS: A total of 250 consecutive patients (102 male and 148 female) with type I diabetes mellitus. METHODS: Total serum immunoglobulin A level and immunoglobulin A endomysial antibody was measured for all patients. Endoscopy and biopsy of the duodenum were performed for immunoglobulin A endomysial antibody-positive patients and pathologic evaluation was done according to modified Marsh classification. RESULT: The mean age of the patients was 18.7 years (range: 2-55 years). Total serum immunoglobulin A was in the normal range for all patients. Immunoglobulin A endomysial antibody was positive in six (2.4%) patients (all of them were females; P = 0.04). Duodenal biopsy samples revealed grade I in two patients, grade II in three patients and grade IIIb in one patient (modified Marsh classification). Patients with coeliac disease and diabetes mellitus were older than patients with diabetes mellitus alone (mean age: 29.5 years versus 18.4 years; P < 0.001). There was a trend for longer duration of diabetes mellitus in coeliac patients than in patients without it (mean age: 17.3 years versus 12.5 years; P = 0.16). CONCLUSION: The prevalence of coeliac disease in Iranian patients with type I diabetes mellitus is relatively high (2.4%). Since almost half of the patients with coeliac disease are asymptomatic, all patients with type I diabetes mellitus should be screened for coeliac disease regardless of the presence of symptoms, at diagnosis of diabetes mellitus and with regular intervals in the follow up.

Coeliac disease presenting with symptoms of irritable bowel syndrome.

BACKGROUND: Coeliac disease may easily mimic symptoms which are parts of the criteria used for diagnosing irritable bowel syndrome. AIM: To find the frequency of coeliac disease among patients diagnosed as irritable bowel syndrome. METHODS: During a period of one year, irritable bowel syndrome patients referred to a university clinic in Tehran were studied. For each patient, an asymptomatic sibling was enrolled as control. Serological tests for coeliac disease were performed in all patients and controls. If positive, duodenal biopsy was performed to confirm the diagnosis. Patients subsequently diagnosed as coeliac disease were placed on a gluten free diet and re-evaluated after 6 months. RESULTS: One hundred and five cases of irritable bowel syndrome and 105 controls were enrolled. Coeliac disease was diagnosed in 12 of the irritable bowel syndrome patients and none of the controls. Eleven coeliac disease patients adhered to a gluten free diet. After 6 months, all 11 patients had significant improvement in symptoms and three were totally asymptomatic. Six allowed repeated endoscopy after 6 months of gluten free diet, of which five showed improvement in histological findings. CONCLUSIONS: Coeliac disease is a common finding among patients labelled as irritable bowel syndrome. In this sub-group, a gluten free diet may lead to a significant improvement in symptoms. Routine testing for coeliac disease may be indicated in all patients being evaluated for irritable bowel syndrome.