ESPE Yearbook of Paediatric Endocrinology

Brief summary: This prospective longitudinal study of childhood-onset inflammatory bowel disease (IBD) analysed areal bone mineral density (aBMD) and alterations of bone microstructure in 49 young adult male patients with childhood-onset IBD, compared to 249 controls from the same region and matched for age, sex and height.

Dual x-ray-absorptiometry (DXA) is routinely used in clinical practice to evaluate aBMD and the related risk of fracture, but it is unable to give information about bone microstructure, as provided by high-resolution peripheral quantitative computed tomography (HR-pQCT). This study evaluated bone structure in IBD patients, using both DXA and HR-pQCT, and correlated bone parameters with skeletal muscle index and physical exercise.

IBD patients had smaller cortical area, lower median total vBMD, thinner median cortical layer, lower median trabecular volume fraction, reduced trabecular thickness and greater median trabecular separation. Patients affected by ulcerative colitis had mostly cortical impairment, while patients with Crohn’s disease more likely had trabecular modifications. Skeletal muscle index was positively and independently associated with total, cortical, and trabecular areas, as well as with total vBMD, in both patients and controls. After adjusting for skeletal muscle index, physical exercise was not independently associated with bone geometry, vBMD, or microstructural measurements.

A strength of this study is the concomitant evaluation using both DXA and HR-pQCT. On the other hand, data were lacking on biochemical parameters of bone metabolism, dietary habits, sun exposure, concomitant calcium and/or vitamin D intake. The message that emerges is that it is essential to prevent poor bone quality in childhood-onset IBD patients by promoting regular physical activity, to increase skeletal muscle and consequently improve bone architecture and strength.