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 (R2  = 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.