Data on heredity, risk factors and comorbidity in microscopic colitis, encompassing collagenous colitis (CC) and lymphocytic colitis (LC), are limited.
The aim was to carry out a case-control study of family history, childhood circumstances, educational level, marital status, smoking and comorbidity in microscopic colitis.
A postal questionnaire was sent in 2008-2009 to microscopic colitis patients resident in Sweden and three population-based controls per patient, matched for age, sex and municipality.
Some 212 patients and 627 controls participated in the study. There was an association with a family history of microscopic colitis in both CC [odds ratio (OR): 10.3; 95% confidence interval (CI): 2.1-50.4, P=0.004] and LC (OR not estimated, P=0.008). Current smoking was associated with CC [OR: 4.7; 95% CI: 2.4-9.2, P