“…When studies were pooled according to the method of administration of the questionnaire, again there were significant differences in prevalence between individual studies. When the Rome III questionnaire was administered at an interview in 29 studies, 20,22,23,31,[33][34][35]37,[39][40][41][42][45][46][47][48][49][51][52][53]60,61,[65][66][67]69,70,75,79 the prevalence of IBS ranged from 0.4% in India and Ghana, 79 to 20.9% in Singapore, 61 with a pooled prevalence of 5.9% (95% CI 4.6% to 7.4%). When the same questionnaire was self-completed in 22 studies 24,28-30,32,36,38,43,44,50,54,56,58,59,62-64,68,71,77-79 the prevalence ranged from 2.0% in the USA, 58 to 29.2% in Croatia, 24 with a pooled prevalence of 12.0% (95% CI 9.6% to 14.6%).…”