Interaction of Ethnicity and H. pylori Infection in the Occurrence of Microscopic Colitis.

BACKGROUND: Previous studies found that microscopic colitis is inversely associated with Helicobacter pylori infection and that microscopic colitis is characterized by a marked ethnic variation. AIM: The aim of the present study was to test whether an underlying ethnic variation of H. pylori infection is responsible for the ethnic variation of microscopic colitis. METHODS: The Miraca Life Sciences Database is a large national electronic repository of histopathologic records of patients distributed throughout the entire USA. A cross-sectional study evaluated the influence of age, gender, ethnicity, and histologic diagnosis of H. pylori on the occurrence of microscopic colitis among subjects who underwent esophago-gastro-duodenoscopies plus colonoscopy. RESULTS: The total study population comprised 228,506 subjects, of whom 28,890 carried a diagnosis of H. pylori gastritis and 3460 microscopic colitis. Female sex, old age, and H. pylori infection exerted the strongest influence on the occurrence of microscopic colitis. In comparison with the population comprising Caucasians and African-Americans, microscopic colitis was less common among subjects of Hispanic (0.34, 0.27-0.47), East Asian (0.13, 0.06-0.22), Indian (0.31, 0.10-0.73), or Middle Eastern descent (0.28, 0.07-0.74). All these ethnic subgroups were also characterized by a higher prevalence of H. pylori than the comparison group. A low prevalence of H. pylori was significantly associated with a high prevalence of microscopic colitis (R 2 = 0.91, p < 0.001). CONCLUSION: Ethnic variations in the gastric infection with H. pylori may be partly responsible for the observed ethnic distribution of microscopic colitis.

Ethnic Distribution of Microscopic Colitis in the United States.

BACKGROUND: A large electronic database of histopathology reports was used to study the ethnic distribution of microscopic colitis in the United States. METHODS: Miraca Life Sciences is a nation-wide pathology laboratory that receives biopsy specimens submitted by 1500 gastroenterologists distributed throughout the United States. In a case-control study, the prevalence of microscopic colitis in 4 ethnic groups (East Asians, Indians, Hispanics, and Jews) was compared with that of all other ethnic groups (composed of American Caucasians and African Americans), serving as reference group. RESULTS: A total of 11,706 patients with microscopic colitis were included in the analysis. In all ethnic groups alike, microscopic colitis was more common in women than men (78% versus 22%, odds ratio = 3.40, 95% confidence interval = 3.26-3.55). In all ethnic groups, the prevalence of microscopic colitis showed a continuous age-dependent rise. Hispanic patients with microscopic colitis were on average younger than the reference group (59.4 ± 16.2 years versus 64.2 ± 13.8 years, P < 0.001). Jewish patients with microscopic colitis were slightly older than the reference group (65.6 ± 13.4 years, P = 0.015). Compared with the reference group (prevalence = 1.20%), microscopic colitis was significantly less common among patients of Indian (prevalence = 0.28%, odds ratio = 0.32, 95% confidence interval = 0.13-0.65), East Asian (0.22%, 0.19, 0.14-0.26), or Hispanic decent (0.48%, 0.40, 0.36-0.45) and significantly more common among Jewish patients (1.30%, 1.10, 1.01-1.21). CONCLUSIONS: Microscopic colitis shows striking variations of its occurrence among different ethnic groups. Such variations could point at differences in the exposure to environmental risk factors.