Trajectory of body mass index and obesity in children with Crohn's disease compared to healthy children.

Abstract

There is increasing recognition that children with Crohn's Disease (CD) can develop obesity. Using the RISK Study, an inception cohort of pediatric CD participants, and Bone Mineral Density in Childhood Study (BMDCS), a longitudinal cohort of healthy children, multivariable linear mixed effects, generalized linear mixed effects, and logistic regression models were used to evaluate factors associated with change in body mass index z-score (BMIZ), obesity, and excessive weight gain, respectively. 1029 CD participants (625 exposed to antitumor necrosis factor (anti-TNF) therapy) and 1880 healthy children were included. Change in BMIZ was higher in CD exposed to anti-TNF as compared to CD unexposed to anti-TNF and the healthy reference group. Sex, age, baseline BMIZ, C-reactive protein, anti-TNF, and steroids were associated with changes in BMIZ in CD. CD exposed (odds ratio [OR] 4.81, confidence interval [CI] 4.00-5.78) and unexposed (OR 3.14, CI 2.62-3.76) had a greater likelihood of becoming obese versus the healthy reference group. While the prevalence of obesity was higher at baseline in the healthy reference group (21.3%) versus CD participants (8.5% exposed vs. 11.1% unexposed), rates of obesity were similar by the end of follow-up (21.4% healthy vs. 20.3% exposed vs. 22.5% unexposed). Anti-TNF therapy was an independent risk factor for the development of obesity and excessive weight gain in CD participants. Patients with CD have dynamic changes in BMIZ over time, and while for most, this is restorative, for some, this can lead to obesity and excessive weight gain. It is important to understand the factors that may lead to these changes, including anti-TNF therapy. Counseling of patients and early lifestyle intervention may be necessary.