Impact of race and ethnicity on inflammatory bowel disease

Inflammatory bowel disease (IBD) is now increasingly recognized in diverse ethnic populations. In the United States, IBD among the minority populations, especially Mexican Americans, has not been extensively studied. Apart from the known genetic influences that differ among the IBD subtypes [ulcerative colitis (UC) vs. Crohn's disease (CD)], serologic markers may differentiate UC and CD, including perinuclear antineutrophilic cytoplasmic antibody (p-ANCA) and anti-Saccharomyces cerevisiae antibody (ASCA) in UC and CD.

One hundred forty-eight patients with IBD seen in a university gastroenterology practice in Houston, Texas, between June 1999 and November 2003 were analyzed to determine whether there were significant differences among racial/ethnic groups. Whites comprised 40%, African Americans 37%, Mexican Americans 20%, and Asians 3% of the total IBD patients.

We found that African Americans and whites predominantly had CD, whereas Mexican Americans predominantly had UC. There was no difference between African Americans and Mexican Americans when separately compared to whites in terms of intestinal manifestations of CD and UC, respectively. However, African Americans with CD had a significantly higher incidence of IBD-associated arthritis (p= 0.004) and ophthalmological manifestations, notably uveitis (p= 0.028), compared to whites with CD. Among UC patients, in comparison to the Mexican Americans, whites had significantly higher incidences of joint symptoms (p < 0.0001) and osteoporosis (p= 0.001). Whites had a stronger family history of IBD and colorectal carcinoma compared to the other ethnic groups. p-ANCA served as a sensitive marker for UC among Mexican Americans. All the Mexican Americans with UC tested had positive p-ANCA compared to only 40% of whites (p= 0.033).

There are significant differences in IBD subtypes and serologic markers among racial/ ethnic groups with IBD in the United States.