epidemiological, demographic, and colonic extension of ulcerative colitis in iran: a systematic review

background ulcerative colitis (uc), as the prototype of inflammatory bowel disease of the large bowel, is increasing in iran and other developing countries. there are few studies that discuss the properties of this disease in the islamic republic of iran. the result of this review may provide a general consensus about the epidemiological features of uc in iran. methods this was a qualitative, systematic review that investigated the incidence, prevalence, and demographic properties of uc in iran. we evaluated all published studies in the pubmed database, iranmedex, magiran, and scientific information database (sid) that pertained to the epidemiology and demographic features of uc in iran from january1987 to january 2012. after searching with defined keywords and implementing the inclusion and exclusion criteria, 11 case series and 2 case-control studies fulfilled the criteria for inclusion. results the estimated prevalence of uc is 15 per 10 5 persons, and the reported incidences were 3.04 and 3.25 per 10 5 persons in two iranian provinces. the disease was more commonly observed in women and people in their fourth decade of life. cigarette smoking conferred protection and familial association seemed to be similar to developed countries. uc did not appear to be more common among the higher socioeconomic class. in addition it less commonly involved the proximal colon and rectum. conclusion although the data is limited, the prevalence and incidence of uc in iran shows an increasing pattern similar to other countries in the region. there is no clear association with socioeconomic status. milder forms of the disease are common in iran. a comprehensive nationwide data bank is needed for a better definition of the disease characteristics.