title: Microscopic colitis: a descriptive clinical cohort study of 795 patients with collagenous and lymphocytic colitis.
abstract: OBJECTIVE
  Microscopic colitis is a common cause of chronic diarrhoea in the Scandinavian countries. This report comprises demographic data, clinical and endoscopic features, and occurrence of coeliac and inflammatory bowel disease (IBD) in a large urban cohort of patients with lymphocytic colitis (LC) and collagenous colitis (CC).
  
  
  METHODS
  A total of 795 patients with microscopic colitis from two hospitals in Stockholm were included. Medical records were reviewed and clinical data, including endoscopic and histological findings, were compiled.
  
  
  RESULTS
  Forty-three percent had CC (female:male ratio 3.7:1) and 57% had LC (female:male ratio 2.7:1). The mean age at diagnosis of CC was 63 years and of LC was 59 years (p = 0.005). Clinical features were similar in both entities, but the intensity of symptoms differed. Watery diarrhoea was reported in 55% in CC patients versus in 43% in LC patients (p = 0.0014), and nocturnal diarrhoea in 28% versus 18% (p = 0.002). Subtle endoscopic mucosal findings were reported in 37% of the CC patients and in 25% of the LC patients (p = 0.0011). Colorectal adenomatous polyps were found in 5.3% of all patients. Coeliac disease occurred in 6% and IBD occurred in 2.1% of all patients.
  
  
  CONCLUSIONS
  Clinical features of LC and CC are similar but not identical. CC seems to be a more severe type of bowel inflammation and LC tends to occur earlier in life. Both forms might indeed feature endoscopic findings despite the designation 'microscopic'. Our study confirms the strong association with coeliac disease.
authors.affiliation: a Department of Gastroenterology and Hepatology , Karolinska Institute, Karolinska University Hospital , Solna , Sweden ;
authors.forename: Marie-Rose
authors.initials: MR
authors.lastname: Mellander
authors.affiliation: b Epidemiology Unit, Department of Medicine , Karolinska Institute, Karolinska University Hospital , Solna , Sweden ;
authors.forename: Anders
authors.initials: A
authors.lastname: Ekbom
authors.affiliation: a Department of Gastroenterology and Hepatology , Karolinska Institute, Karolinska University Hospital , Solna , Sweden ;
authors.forename: Rolf
authors.initials: R
authors.lastname: Hultcrantz
authors.affiliation: c IBD Unit, Karolinska Institute, Sophiahemmet , Stockholm , Sweden ;
authors.forename: Robert
authors.initials: R
authors.lastname: Löfberg
authors.affiliation: d Department of Pathology and Cytology , Medilab , Täby , Sweden.
authors.forename: Åke
authors.initials: Å
authors.lastname: Öst
authors.affiliation: a Department of Gastroenterology and Hepatology , Karolinska Institute, Karolinska University Hospital , Solna , Sweden ;
authors.forename: Jan
authors.initials: J
authors.lastname: Björk
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D002908:Chronic Disease; D046729:Colitis, Collagenous / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology; D046730:Colitis, Lymphocytic / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology; D046728:Colitis, Microscopic / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology; D003113:Colonoscopy / Q000379:methods*; D003937:Diagnosis, Differential; D003967:Diarrhea / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007413:Intestinal Mucosa / Q000473:pathology*; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult
keywords: Chronic diarrhoea; coeliac disease; collagenous colitis; inflammatory bowel disease; lymphocytic colitis