EPIDEMIOLOGIC-STUDY ON THE INCIDENCE OF I NFLAMMATORY BOWEL-DISEASE IN 4 AREAS OF SPAIN

BACKGROUND: The incidence of inflammatory bowel disease (IBD) shows ma rked geographical variations. The aim of this study was to determine a nd compare the incidence of IBD in four Spanish areas: Sabadell (North east), Vigo (Northwest), Mallrca island and Motril South). PATIENTS AN D METHODS: Prospective survey based on inception cohorts over a two-ye ars period ( 1 October 1991 to September 1993). Subjects were the pati ents resident in these areas and diagnosed of IBD according to a stand ard protocol for case ascertainment and definition. RESULTS: Altogethe r 328 cases were identified, of whom 191 were diagnosed as ulcerative colitis (UC), 135 as Crohn's disease (CD) and 2 as indeterminate colit is. The overall adjusted incidence rate per 100.000 persons between ag es 15-64 years of UC and Co were respectively 9.8 and 5.2 in Sabadell, 7.7 and 5.0 in Vigo, 7.8 and 5.8 in Mallorca and 4.3 and 6.5 in Motri l.The Incidence rate ratio showed no significant differences for eithe r conditions among these areas. The global adjusted incidence rate of UC in Spanish areas (8.0; IC 95%: 6.3-9.7) was significantly lower to that of Northern European countries while that of CD (5.5; IC 95%: 4.1 -6.9) was between that of Northern and Southern Europe with no signifi cant differences. CONCLUSIONS: The incidence of IBD did not show diffe rences among the Spanish areas, and rates are between 2 and 6 times hi gher than those previously reported. The incidence of UC is significan tly lower than that observed in the North of Europe, while for CD the incidence is between that of Northern and Southern Europe.