The changing pattern of Crohn's disease incidence according to age in northern France: a continuing increase in the 10-19-year-old age bracket (1988-2007)

Background: Crohn's disease (CD) incidence rates have stabilized in industrialized countries since the 1980's. Conversely, a continuing increase in childhood-onset CD incidence has been reported. Aim: To confirm trends in inflammatory bowel disease (IBD) incidence in northern France over an extended time period (1988-2007) with a focus on childhood-onset CD. Methods: IBD patients recorded in the EPIMAD registry between 1988 and 2007 were included. Standardized incidence rates were calculated for CD and ulcerative colitis (UC) in the entire population, and separately according to age. Evolution of phenotypes at diagnosis was also studied. Results: 12,084 incident IBD cases (7,428 CD and 4,656 UC) were recorded. CD incidence rates increased from 5.2 cases/100,000 persons in 1988-1990 to 6.7 in 2006-2007 (+29%), stabilizing after a peak at 7.1 in 1997-1999. CD incidence rates in the 10-19-year age category increased by 71%, from 6.5 (1988-1990) to 11.1 (2006-2007). The frequency of initial ileo-colonic localization increased from 52.9% in 1988-1990 to 68.6% in 2006-2007 (p