In our study we found an insignificant increase in the incidence of both CD and UC, indicating that the previously reported rising incidence might be levelling out.

The height-for-age and the BMI-for-age, as evaluated by z-scores, of children with ulcerative colitis (UC) did not differ from those of normal Danish children, but Crohn's disease (CD) children had significantly lower height and BMI values, both when compared to normal children and children with UC. In contrast to UC, CD is frequently complicated by malnutrition and growth retardation at the time of diagnosis.