Systematic review: Body composition in children with inflammatory bowel disease.

Background: Paediatric inflammatory bowel disease (IBD) is associated with weight loss, growth restriction and malnutrition. Bone mass deficits are well described, little is known about other body composition compartments.

Aims: To define the alterations in non-bone tissue compartments in children with IBD, and explore the effects of demographic and disease parameters.

Methods: A systematic search was carried out in the PubMed (www.ncbi.nlm.nih.gov/pubmed) and Web of Science databases in May 2014 (limitations age <17 years, and composition measurements compared with a defined control population).

Results: Twenty-one studies were included in this systematic review, reporting on a total of 1479 children with IBD [1123 Crohn's disease, 243 ulcerative colitis], pooled mean age 13.1 ± 3.2 years, and 34.9% female. Data were highly heterogeneous, in terms of methodology and patients. Deficits in protein-related compartments were reported. Lean mass deficits were documented in 93.6% of Crohn's disease and 47.7% of ulcerative colitis patients when compared with healthy control populations. Lower lean mass was common to both sexes in Crohn's disease and ulcerative colitis, deficits in females with persisted for longer. Fat-related compartment findings were inconsistent, some studies report reductions in body fat in new diagnosis/active Crohn's disease.

Conclusions: It is clear that almost all children with Crohn's disease and half with ulcerative colitis have reduced lean mass, however, body fat alterations are not well defined. To understand what impact this may have on health and disease in children with IBD, further studies are needed to identify in which tissues these deficits lie, and to quantify body fat and its distribution.