Sixty-year study of incidence of childhood ulcerative colitis finds eleven-fold increase beginning in 1990s

We sought to define the point at which a recently noted marked increase in the incidence of ulcerative colitis (UC) had occurred in children in Victoria, Australia. A 60-year retrospective review (1950-2009) of children age 16 years or less diagnosed with UC in the state's major pediatric centers was performed. In all, 342 children were diagnosed with UC (male to female ratio of 1.25:1.0, median age 10.9 years, interquartile range [IQR] 7.0, 13.2). The overall median annual incidence of UC was 0.36/10(5) children ≤ 16 years of age (IQR 0.18, 0.66). The number of reported cases increased by 11-fold during the study period (P < 0.001). This marked increase appeared to occur from the early 1990s and has yet to plateau. Children diagnosed during the last two decades were older at diagnosis (median 10 years vs. 11.6, P < 0.0001), and had higher weight- and height-for-age z scores than those diagnosed during the first 40 years (mean weight-for-age [standard deviation] 1950-1989: -0.80 [1.56] vs. 1990-2009: -0.11 [1.17], P < 0.001; mean height-for-age 1950-1989: -0.50 [1.15] vs. 1990-2009: -0.13 [1.12], P < 0.05). More recently diagnosed children also had more extensive disease (1950-1989: 52% vs. 1990-2009: 71%, P < 0.01). The incidence of UC has increased markedly in Victorian children since 1990. Although some of this change may be attributable to earlier diagnosis, it is unlikely that this can provide a complete explanation for this still-increasing condition.