A cross sectional study of colonic diverticulosis in the London Bangladeshi population

Background: Diverticular disease is the most common morphological abnormality of the colon and the fifth most important gastrointestinal disease in terms of cost in the Western world. Tower Hamlets is the poorest borough in London containing a large Bangladeshi community. We observed that emergency admissions with complications of colonic diverticulosis were minimal in the Bangladeshi community. The objective was to compare the background prevalence of colonic diverticulosis in Bangladeshis with other ethnicities in patients undergoing colonoscopy at a single centre in Tower Hamlets. Methods: Four thousand four hundred and fifty-four consecutive colonoscopy reports over a 2-year period were retrospectively analysed. Patients under 40 years of age and repeat colonoscopies were excluded, leaving 3151 patients (mean age: 63 years; 48% male). Demographics including ethnicity and medical background were retrieved from the electronic patient record system and findings correlated with the prevalence of other 'Western' diseases in the cohort. Results: Six hundred and thirty out of 3151 (20%) colonoscopies were performed on Bangladeshis. The prevalence of colonic diverticulosis was significantly lower in Bangladeshis (17/630: 2.7%) than Caucasians (673/1869: 36%), Indians/Pakistanis (16/161: 9.9%), Oriental (15/44: 34%) and Black (90/369: 24.4%) patient groups (chi(2) p<0.0001 for all comparisons). The prevalence of classical sigmoid diverticulosis in the Bangladeshi cohort was only 1.0%, despite significantly more Bangladeshi patients undergoing colonoscopy for abdominal pain (p<0.0001, chi(2)) and diarrhoea (p<0.0034, chi(2)). There was also a significantly greater incidence of type 2 diabetes mellitus and ischaemic heart disease (p<0.0001, chi(2)) in Bangladeshi patients. Conclusions: There is a negligible prevalence of colonic diverticulosis in the Bangladeshi population of London who undergo colonoscopy. This is in spite of a high incidence of type 2 diabetes and ischaemic heart disease. The effect of diet and genetics on the prevalence of colonic diverticulosis in Bangladeshis is not known and merits further investigation.