Association between body mass index and age of disease onset with clinical outcomes in paediatric-onset Crohn's Disease (CD): a UK nation-wide analyses using the NIHR-IBD BioResource.

BACKGROUND: The evidence on the relationship between adiposity and disease outcomes in paediatric Crohn's disease (CD) is limited and lacks consensus. AIM: To investigate the relationship between (a) body mass index (BMI) and clinical CD outcomes (hospitalisation, surgery, disease behaviour, biologic use, extra-intestinal manifestations (EIMs)) and (b) the age of CD onset with clinical outcomes. DESIGN: Clinical outcomes were examined in CD patients diagnosed at age <17 years and enroled in the National Institute for Health Research IBD-UK BioResource at a median age of 24 years. All outcomes and BMI were recorded at the time of enrolment. Participants were categorised into normal (<25 kg/m2) and high (≥25 kg/m2) BMI. Age at disease diagnosis was categorised into pre-puberty/early puberty (<11 years), puberty (11-14 years) and post-puberty (15-17 years). Spearman rank correlation was used to test the associations between continuous variables and chi-square test to compare categorical variables. RESULTS: 848 participants with CD were included (51.8% males) and median age at diagnosis was 14 years. Participants with high BMI experienced a greater frequency of EIMs (P = 0.05) than those with low BMI (1 type of EIM: 18.5% vs. 13.2%, respectively; ≥2 types of EIMs: 7.8% vs. 5.6%, respectively). Age at diagnosis and BMI showed weak correlations with corticosteroid use (ρ = 0.08, P = 0.03 and ρ = -0.09, P = 0.01; respectively). An early diagnosis (<11 years) was associated with higher occurrence of stenosing and penetrating disease behaviour (P = 0.01) and hospitalisations (P < 0.001). CONCLUSIONS: A higher BMI and an earlier age of disease onset are associated with worse CD clinical presentation.

Systematic review: Sarcopenia in paediatric inflammatory bowel disease.

BACKGROUND: Low skeletal muscle mass (MM) and deteriorated function (sarcopenia) can be a frequent complication in paediatric inflammatory bowel disease (IBD). AIM: To conduct a systematic review of the paediatric IBD literature on skeletal muscle function and mass and identify interventions that could affect them. METHODS: Systematic searches (EMBASE, Medline, Cochrane library central for registered control trials and Web of Science) were conducted using the terms 'lean body mass' (LM), 'fat free mass' (FFM) or 'MM' and 'IBD'. RESULTS: Fourteenth studies were included, presenting data from 439 Crohn's disease (CD), 139 ulcerative colitis (UC) and 2 IBD-unclassified participants compared with healthy matched or unmatched groups or reference populations. Six out of 14 studies reported lower LM, whilst 7 studies observed lower MM and FFM in CD patients compared to healthy controls. Research in UC patients reported lower LM in 3 studies, lower MM in 3 studies and lower FFM in 4 studies. Three prospective studies measured the impact of enteral feeding and showed improvement on disease activity and LM or FFM, while one retrospective study did not show any impact on LM. CONCLUSION: Despite the variety of experimental approaches and methods used to assess sarcopenia, most studies showed reduction in MM, LM and FFM in IBD. Nutritional intervention may have a positive effect on LM and FFM. Future research should focus on standardizing the terminology and methodologies used in assessing body composition and investigating sarcopenia in diseased and matched healthy control cohorts in adequately powered studies with a longitudinal design.