Incidence of Bowel Disease in Kids Nearly Quadrupled Over 40 Years

Incidence of pediatric inflammatory bowel disease (IBD) in one region of Denmark nearly quadrupled over four decades, according to a new population-based cohort study.

In the Pediatric NorDIBD cohort of 468 children diagnosed with IBD from 1978-2020, the standardized incidence rate of pediatric IBD diagnoses rose from 4 per 100,000 person-years before 1990 to 15 per 100,000 person-years during 2010-2020 (95% CI 13.0-17.3), resulting in a 272% increase, according to Mads Lie, MD, of Aalborg University in Denmark, and colleagues.

The annual percentage change in Crohn’s disease incidence was 5.05% (95% CI 3.85-6.27), outpacing the 2.71% annual increase seen in ulcerative colitis, with the proportion of Crohn’s disease diagnoses increasing from 30% before 1990 to 55.4% during the 2010s (P=0.005), they reported in the American Journal of Gastroenterology.

“The newly established unselected population-based Pediatric NorDIBD cohort shows an increase in both incidence and extensiveness of newly diagnosed pediatric IBD over the last four decades and provides a foundation for future research into the long-term outcomes of pediatric IBD,” the researchers wrote.

The percentage of children presenting with pancolitis — inflammation affecting the entire colon — rose from 31.7% during 2006-2010 to 51.4% during 2016-2020. Ileocolonic Crohn’s disease, involving inflammation in both the small intestine and colon, climbed from 31% before 1996 to 47.2% between 2016 and 2020. Penetrating Crohn’s disease at diagnosis rose from less than 10% during 2000-2009 to 16% during 2010-2020 (P=0.041).

While those findings suggest “a possible trend toward more extensive disease at diagnosis,” the investigators cautioned that diagnostic guidelines changed multiple times over the study period, meaning the shift “is likely a product of both a changing biology of disease, as well as a changing clinical approach to diagnosing IBD in children.”

The median age at ulcerative colitis diagnosis also increased significantly, from 14.2 years before 1990 to 16.1 during 2010-2020 (P=0.006). For Crohn’s disease, the increase was smaller — from 14.7 to 15.5 years — and fell short of statistical significance.

However, children with a first-degree relative with IBD were diagnosed with ulcerative colitis nearly 3 years earlier than those with sporadic disease (12.8 vs 15.6 years, P<0.001).

​​”Whether our findings are due to an increased awareness of IBD within the families with existing IBD or a genetic disposition to earlier disease onset is unknown, though a positive family history has been shown to significantly increase the life-long risk of developing IBD,” the authors wrote.

The Pediatric NorDIBD cohort consisted of 244 children diagnosed with ulcerative colitis and 224 diagnosed with Crohn’s disease. Median age at diagnosis was 15.4 years across the cohort and 13% had a first-degree relative with IBD; 54.9% of ulcerative colitis patients and 48.2% of Crohn’s disease patients were girls.

The authors acknowledged several limitations, including incomplete data on disease extent for some children diagnosed in the cohort’s early years. Colonoscopies and MRIs were not as widely available in earlier decades, and the manual nature of data collection introduced the possibility of random or systematic error.