BODY MASS INDEX (BMI) OF IBD CHILDREN AT DIAGNOSIS; THE EFFECTS OF OBESITY EPIDEMIC

Abstract

Purpose: Low BMI is a common feature of IBD at diagnosis. Previous studies report weight loss at diagnosis in 63–75% of Crohn's disease (CD) and 17% of ulcerative colitis (UC) in children, resulting in the common perception that newly diagnosed children with IBD have low BMI and decreased weight for height. Overweight (85–94 BMI %) and obesity (>95 BMI %) continue to increase in the pediatric and adolescent population; the USA National Health and Nutrition Examination Surveys (NHANES) 3 report that 23% of children are above 85th% for BMI, and 10.5% are above 95th%. We hypothesize that the increasing weight of children in the general population would also be seen in children with new onset IBD, resulting in improved weight and BMI % than previously reported. Methods: Since Jan 2002, 18 US/Canadian pediatric GI centers prospectively enrolled newly diagnosed children with IBD in an observational registry designed to assess clinical characteristics and to study the natural history of IBD in children. Weight, weight for age %, height, and height for age % at diagnosis were extracted from the database. All measurements were obtained before any treatment had been initiated. BMI and BMI % were calculated in both CD and UC children at diagnosis using CDC standards BMI chart for children. Results: Mean age was 12.3 for CD and 11.8 for UC at diagnosis. BMI % data are shown in table. 34/335 CD (9%) and 14/109 (13%) UC subjects had BMI % >84% (overweight or obese). A majority of CD and UC subjects had BMI % which fell in the normal range. Only 147/444 (32%) of IBD children presented with low BMI (< 10%) at diagnosis.TableConclusions: The majority of newly diagnosed IBD children have weight and BMI % within the normal range (10–84th%). Only 34% of CD and 32% of UC had BMI of 10% or less at presentation. More importantly, 10% of newly diagnosed IBD children were either overweight or obese at presentation. Changing anthropometric data on North American youth appear to be altering the BMI of children presenting with IBD. IBD must be considered in all children with suggestive symptoms regardless of weight or BMI%.