Microscopic Colitis May Be More Common Than Thought
Population-based cohort study suggests that the incidence may have increased since 1985
FRIDAY, April 13 (HealthDay News) -- The incidence of microscopic colitis may be increasing, researchers report in the April issue of Gut. In a Minnesota study, cases of microscopic colitis increased from 1.1 per 100,000 in 1985 to 19.6 per 100,000 in 2001.
Darrell S. Pardi, M.D., of the Mayo Clinic College of Medicine in Rochester, Minn., and colleagues identified 130 incident cases of microscopic colitis that were diagnosed in Olmsted County, Minn., between Jan. 1, 1985 and Dec. 31, 2001.
The researchers found an overall incidence rate of 8.6 cases per 100 000 person-years, with an increase from 1.1 per 100,000 early in the study to 19.6 per 100,000 at its conclusion. Incidence rates were 3.1 per 100,000 for collagenous colitis and 5.5 per 100,000 for lymphocytic colitis.
"Whether the increase in incidence is real or a result of diagnostic bias due to increased use of colonoscopy with biopsy in patients with diarrhea is unknown," the authors write. "However, microscopic colitis is more common than previously recognized, and is particularly common in elderly patients. Collagenous colitis, but not lymphocytic colitis, is more common in women, and in our experience, lymphocytic colitis is more common than collagenous colitis."