Defining adipose tissue profiles in children with Crohn's disease

Adipose tissue measures are poorly defined in pediatric Crohn's disease (CD). Visceral adipose tissue (VAT) plays a role in regulating innate immunity and obesity-related diseases, contributing to poorer long-term health outcomes.

Abdominal tissue volumes and liver fat were quantified using magnetic resonance imaging and magnetic resonance spectrometry in children with CD. Dietary, adipokine, and metabolic profiles were analyzed in subjects with CD. Multivariable linear regression analysis was performed to evaluate the factors associated with tissue volumes.

We recruited 25 children with CD and 8 healthy controls. Children with CD exhibited significantly higher VAT and subcutaneous adipose tissue (SCAT) volumes than their healthy counterparts, with increases of 0.33 L (95% CI, 0.12-0.52, P < .01) and 1.83 L (95% CI, 1.34-2.45, P < .01), respectively. Muscle measures were lower in children with CD, while liver fat measurements and BMI-z scores remained within healthy reference ranges. Disease duration, male sex, and C-reactive protein (CRP) levels were significant predictors of VAT in children with CD. SCAT was associated with plasma leptin levels, and VAT correlated with plasma triglyceride levels. Children with CD had diets low in calories and high in non-milk extrinsic sugars.

This study describes a specific adiposity pattern in children with Crohn's disease; 'Thin on Outside Fat on the Inside Crohn's associated Obesity' (TOFICO). This is characterized by increased visceral and subcutaneous adipose tissue in the context of normal liver fat and BMI. We have shown that visceral obesity is a robust marker of bowel inflammation in Crohn's disease and is not affected by anthropometric factors, unlike BMI.