Distribution and Manifestations of Inflammatory Bowel Disease in Asians, Hispanics, and African Americans: A Systematic Review

OBJECTIVES: Although inflammatory bowel disease (IBD) has been reported worldwide, most studies have focused on Caucasian populations. Our aim was to summarize the existing epidemiological literature, identify temporal trends, and highlight areas for future research. METHODS: We carried out a systematic review following standard guidelines to evaluate the incidence, prevalence, temporal trends, disease characteristics, and extra-intestinal manifestations (EIMs) of IBD in African American, Hispanic, and Asian adult patients. Two investigators independently identified eligible studies through 2008 using structured keyword searches in PubMed, applied several inclusion and exclusion criteria, and abstracted the data. RESULTS: Twenty-eight publications were included, encompassing 1,272 Hispanic, 547 African American, and 35,844 Asian patients with IBD. Greater proportions of Hispanic (36.7-84.3%) and Asian (30.6-74.7%) patients were diagnosed with ulcerative colitis (UC) than with Crohn's disease (CD) compared with African Americans (27.6-40.6%). The prevalence rates of IBD in Hispanics in Puerto Rico varied between 5 (rural) and 62 (urban) per 100,000. Crude prevalence rates in Asia varied between 6 (Singapore) and 136 (South Asians in UK) per 100,000 for UC, and between 3 (Singapore) and 33 (South Asians in UK) per 100,000 for CD. Three studies reported a rising annual incidence rate among Hispanics (from 2.6 to 7.5 per 100,000) and Asians (from 0.22 to 3.62 per 100,000). Fistulizing CD was reported in nearly one-third of Hispanic patients, up to one-quarter of African-American patients, and up to one-half of Asian patients. Ileocolonic disease was the most common site of CD among the three racial/ethnic groups, with skin and joint manifestations noted as the most common EIMs. CONCLUSIONS: Prevalence and incidence rates in Hispanics and Asians have recently increased. There are many similarities and differences in disease location and behavior among racial/ethnic groups. There is a paucity of literature on all aspects of the disease in Hispanics, in the incidence and prevalence of IBD in African Americans, and in Asians with IBD outside Asia.