A population-based study of inflammatory bowel disease in Florence over 15 years (1978-92)

Background: In the group of inflammatory bowel disease (IBD), ulcerative colitis (UC) and Crohn's disease (CD) are considered to be more frequent in Western countries and in areas with a high socioeconomic development but relatively infrequent in southern Europe. Sporadic reports have indicated a lower incidence and a milder course of the disease in Mediterranean countries. Although conclusive data on this point are still lacking, recent reports suggest an increase in both incidence and prevalence rates. Methods: The incidence of UC and CD during the period January 1978 to December 1992 and their prevalence on 31 December 1992 were estimated in the 15-year-old population of the metropolitan area of Florence. Clinical, demographic, and follow-up information was collected for all identified IBD patients. Results: A total of 796 residents (345 females and 454 males) were newly diagnosed as having IBD during the study period. Of these 593 had UC and 203 CD. The age-standardized incidence rates, calculated for each of five 3-year consecutive periods, rose from 3.8 (in 1978-80) to 9.6 per 100,000 person-years (in 1990-92) for UC and from 1.9 (in 1978-80) to 3.4 (in 1990-92) for CD. Both trends were statistically significant. The prevalence estimated on 31 December 1992 was 121.0 and 40.0 per 100,000 inhabitants for UC and CD, respectively. Conclusions: Our results confirm that IBD incidence rates and prevalence in this area of central Italy are currently comparable with those reported in northern Europe. These data are necessary for planning adequate health care services for IBD patients.