Inflammatory Bowel Disease in Children and Young People Living With Overweight or Obesity: A Critical Narrative Review.

Inflammatory bowel disease is a chronic inflammatory disorder affecting the gastrointestinal tract. It mainly comprises of Crohn's disease and ulcerative colitis. Its global prevalence has risen simultaneously with overweight and obesity among children and young people over the last decades. This critical narrative review aims to explore how living with overweight or obesity contributes to the development of inflammatory bowel disease (IBD) as well as the disease course in children and young people. Approximately, 24% of children and young people with the disease are living with overweight or obesity, with the majority being diagnosed with ulcerative colitis. Obesity appears to be associated with increased disease activity, adverse effects, with increased adiposity contributing to IBD pathogenesis though multiple mechanisms. Here, we offer a novel mechanistic pathway to how obesity impacts on IBD pathogenesis. Increased adiposity appears to contribute to its pathogenesis through increased proinflammatory cytokines and microbiota imbalance leading to inflammation and increased intestinal permeability. Additionally, adiposity appears to exacerbate micronutrient deficiencies associated with inflammatory bowel disease, including iron and vitamin D. Obesity is also shown to be associated with increased disease activity. Finally, we review possible weight management interventions available to children and young people living with obesity and overweight and IBD. In conclusion, living with overweight and obesity are proposed to have adverse effects on inflammatory bowel disease in children and young people, with an urgent need for greater research to better understand their impacts and assist in guiding effective tailored interventions.