Microscopic colitis-defining incidence rates and risk factors: a population-based study

Area of Science:

• Gastroenterology
• Epidemiology

Background:

• Microscopic colitis (MC) burden and determinants in North America require definition.
• This study aimed to determine MC incidence and risk factors in a North American population.

Purpose of the Study:

• To establish the incidence rate of microscopic colitis (MC) in North America.
• To identify key risk factors associated with developing MC.

Main Methods:

• A population-based cohort study was conducted from April 2002 to March 2004.
• Pathologic MC diagnoses were identified, and chart reviews confirmed diagnoses and risk factors.
• Risks were reported as rate ratios (RRs) with 95% confidence intervals (CIs).

Main Results:

• The annual incidence rate of MC was 10.0 per 100,000 person-years (lymphocytic colitis: 5.4; collagenous colitis: 4.6).
• Individuals over 65 were over 5 times more likely to develop MC (RR, 5.6).
• Women, celiac disease, hypothyroidism, and malignancy were associated with increased MC risk.

Conclusions:

• Incidence rates align with previous North American and European population-based studies.
• An increased incidence of MC was observed in specific disease states.
• A novel finding indicates an increased risk of MC associated with malignancy.