Incidence of inflammatory bowel disease in Primorsko-goranska County, Croatia, 2000-2004: A prospective population-based study

Objective. It has been suggested that the incidence of inflammatory bowel disease ( IBD), which includes ulcerative colitis ( UC) and Crohn's disease ( CD), is higher in northern than in southern Europe. Recent epidemiological studies showed the loss of the previously described geographical north - south gradient. The aim of this study was to investigate the incidence of UC and CD in Primorsko- goranska County, Croatia. Material and methods. In the period 1 January 2000 to 31 December 2004 ( 5 years) all new patients diagnosed with IBD were prospectively identified according to a standard protocol for case ascertainment and definition. A total of 178 residents ( 81 F, 97 M) were newly diagnosed as having IBD during the study period. Of these, 70 had UC and 100 CD. Eight patients had indeterminate IBD. The data on patients were collected using a data form completed by gastroenterologists. Results. Annual age- standardized incidence rates were 4.3/ 10(5) ( 95% CI 2.6 - 6.0) for UC and 7.0/ 10 5 ( 95% CI 3.4 - 10.6) for CD. The highest incidence rate was observed in the age group 35 - 44 years for UC and the 25 - 34 years age group for CD. The incidence of IBD was higher in the urban than in the rural population, with the exception of on the islands. Conclusions. The incidence of IBD was higher than previously observed in Croatia. Our results suggest that CD incidence rates in the northern coastal part of Croatia are currently comparable with those reported in northern Europe.