title: Ulcerative colitis in Olmsted County, Minnesota, 1940-1993: incidence, prevalence, and survival.
abstract: BACKGROUND
  There is significant geographic variation in the reported incidence of ulcerative colitis.
  
  
  OBJECTIVE
  To update the incidence and prevalence of ulcerative colitis in Olmsted County, Minnesota, examine temporal trends, and determine overall survival.
  
  
  METHODS
  All Olmsted County residents diagnosed with ulcerative colitis between 1940 and 1993 (incidence cases), and all residents with ulcerative colitis alive on 1 January 1991 (prevalence cases).
  
  
  METHODS
  Incidence and prevalence rates were adjusted using 1990 US census figures for whites. The effects of age, sex, and calendar year on incidence rates were evaluated using Poisson regression. Survival from diagnosis was compared with that expected for US north-central whites.
  
  
  RESULTS
  Between 1940 and 1993, 278 incidence cases were identified, for an adjusted incidence rate of 7.6 cases per 100 000 person years (95% confidence interval (CI), 6.7 to 8.5). On 1 January 1991, there were 218 residents with definite or probable ulcerative colitis, for an adjusted prevalence rate of 229 cases per 100 000 (95% CI, 198 to 260). Increased incidence rates were associated with later calendar years (p<0.002), younger age (p<0.0001), urban residence (p<0.0001), and male sex (p<0.003). Overall survival was similar to that expected (p>0.2).
  
  
  CONCLUSIONS
  The overall incidence rate of ulcerative colitis in Olmsted County increased until the 1970s, and remained stable thereafter. Incidence rates among men and urban residents were significantly higher. The prevalence rate in Rochester in 1991 was 19% higher than that in 1980. Overall survival was similar to that of the general population.
authors.affiliation: Division of Gastroenterology and Hepatology, Inflammatory Bowel Disease Clinic, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA.
authors.forename: E V
authors.initials: EV
authors.lastname: Loftus
authors.forename: M D
authors.initials: MD
authors.lastname: Silverstein
authors.forename: W J
authors.initials: WJ
authors.lastname: Sandborn
authors.forename: W J
authors.initials: WJ
authors.lastname: Tremaine
authors.forename: W S
authors.initials: WS
authors.lastname: Harmsen
authors.forename: A R
authors.initials: AR
authors.lastname: Zinsmeister
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D015331:Cohort Studies; D003093:Colitis, Ulcerative / Q000453:epidemiology* / Q000401:mortality; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D015995:Prevalence; D017678:Sex Distribution; D015996:Survival Rate