AIM OF THE STUDY
The aim of this study was to describe in a population-‐based cohort of pediatric age, the variations, if any, that occurred in the last two decades in children and adolescents with a probable or definite diagnosis of IBD (CD, UC or IBD-‐U). Data were obtained from a registry developed in the North-‐West of France (with its headquarters based in Lille) that enrolled all cases (children and adults) of Inflammatory Bowel Diseases in a population-‐based manner (Registre des maladies inflammatoires chroniques de l'intestin du Nord-‐Ouest, EPIMAD) (http://www3.univ-‐ lille2.fr/epiweb/travaux/epimad).
In particular, we looked for variation in the incidence, in the clinical presentation and in the changes of the diagnostic work-‐up that occurred for these diseases over a period of 21 years (1988-‐2008) in pediatric patients (diagnosis < 17 years). In addition, we searched for any factors that could influence the delay in diagnosis, either positively or negatively.