Objective: This prospective observational study aimed to examine the prevalence of obesity in a population-based cohort of children and young adults newly diagnosed with inflammatory bowel disease (IBD) and assess their outcome in comparison to newly diagnosed normal/underweight patients.
Methods: Our longitudinal population-based cohort comprised all children younger than 17 years diagnosed with IBD in the province of Manitoba, Canada between 2012 and 2018. Cox regression model with adjustment for a priori covariates was used to examine the time to first relapse among patients who were obese/overweight at the time of IBD diagnosis in comparison to patients who were normal or underweight.
Results: A total of 139 patients with IBD were followed up for a median duration of 1.09 (interquartile range: 0.53-2.62) years. Obesity was more common in children newly diagnosed with ulcerative colitis (UC) compared to those with Crohn disease (CD) (12.7% vs 0.0%; P = 0.005). Age at diagnosis poorly correlated with the body mass index z score (R = 0.23; P = 0.01). The proportions of patients who were underweight at the time of IBD diagnosis among patients with UC and CD were 6.3% and 20.0%, respectively (P = 0.01). The time to initial relapse was not found to be significantly associated with weight category at diagnosis in UC (adjusted hazard ratio = 0.77; 95% confidence interval: 0.40-1.63) or CD (adjusted hazard ratio = 0.83; 95% confidence interval: 0.20-3.51).
Conclusion: Obesity was more common in children and young adults newly diagnosed with UC. The majority of the underweight children had CD.