Epidemiology of Ulcerative Colitis in South Asia

Puri, Amarender Singh

Abstract

The South Asian region comprising of India, Pakistan, Bangladesh, Nepal, and Sri Lanka is multi-ethnic with vast cultural differences. Yet they have in common, a strong predisposition for inflammatory bowel disease especially ulcerative colitis (UC). The vast majority of the population is rural with limited access to health care facilities. Community based studies on epidemiology of UC are sparse making it difficult to extrapolate data for the whole region. India has the highest incidence and prevalence of UC in Asia which is higher than the published figures for Korea and Japan, the two leading industrialized countries in Asia. Asian diaspora studies have revealed an unmasking of the disease when natives of this region migrate to countries with a higher prevalence of the disease. Data mainly from the UK suggests a higher incidence of the disease in Asian migrants compared to the indigenous population. Incidence data from within the sub-continent suggests a higher incidence of the disease in India as compared to its southern neighbour Sri Lanka suggesting a north-south gradient. Time trend studies from India do not suggest an increasing incidence of disease as has been observed in other parts of Asia. Some data point to phenotypically different disease in south Asian patients as compared to Caucasians. Familial clustering and cumulative colectomy rates are higher in Western patients as compared to their Asian counterparts. Asian patients with UC have a significantly lower risk of development of colorectal carcinoma vis a vis the Caucasian population. There is a pressing need for more studies on the epidemiology, long-term outcome and natural history of the disease in this region.