Body mass index in children with newly diagnosed inflammatory bowel disease: observations from two multicenter North American inception cohorts.

OBJECTIVE: To conduct a systematic review of children with newly diagnosed inflammatory bowel disease (IBD) from 2 prospective inception cohorts to examine body mass index (BMI) status at presentation. STUDY DESIGN: Clinical, demographic, and BMI data were obtained from 783 patients with newly diagnosed IBD. National Health and Nutrition Examination Survey data for 2748 healthy children were used as a control. RESULTS: Most children with Crohn's disease and ulcerative colitis had a BMI in the normative range (5%-84%). Low BMI (<5%) was seen in 22% to 24% of children with Crohn's disease and 7% to 9% of children with ulcerative colitis. Ten percent of children with Crohn's disease and 20% to 30% of children with ulcerative colitis had a BMI at diagnosis consistent with overweight or risk for overweight. CONCLUSION: Children with IBD are affected by current population trends toward overweight. A significant subgroup of children with newly diagnosed IBD has a BMI categorized as overweight or at risk for overweight. Clinicians should be aware of possible IBD diagnosis in the presence increased BMI.