Oral Presentation ESA-SRB-APEG-NZSE 2022

Impaired bone formation and reduced strength in young adults with inflammatory bowel disease (IBD): pieces of the fracture-risk puzzle (#229)

Madhuni Herath 1 2 3 , Anke Nguyen 2 4 , Gregory T Moore 2 4 , Roger Zebaze 2 , Peter R Ebeling 1 2 , Frances Milat 1 2 3
  1. Department of Endocrinology, Monash Health, Melbourne, VIC
  2. Department of Medicine, Monash University, Melbourne, VIC
  3. Centre for Endocrinology and Metabolism, Hudson Institute of Medical Research, Melbourne
  4. Department of Gastroenterology, Monash Health, Melbourne, VIC, Australia

IBD affects >100,000 Australians, commonly affecting adults aged <30 years. Fracture risk is increased and adds to significant morbidity in these young adults with IBD (IBD-YAs). Assessment of areal bone mineral density (aBMD) by dual energy x-ray absorptiometry (DXA) does not accurately identify most individuals at risk of fracture. Our aim is to identify clinically useful imaging techniques to facilitate fracture risk-stratification in IBD-YAs. Given their young age, we hypothesised that IBD-YAs have features of impaired bone formation and reduced strength, identifiable through high resolution peripheral quantitative tomography (HRpQCT).

A cross-sectional study of 29 IBD-YAs requiring biologic therapy, and 26 YAs without IBD (hYAs), was conducted. Participants underwent HRpQCT imaging (n=37) and biochemical testing (n=50). aBMD and hip structural analysis (HSA) data were measured by DXA (n=55).

Mean (± SD) age was 30.9±11.7 years in IBD-YAs and 33.6±5.9 years in hYAs. Median disease duration was seven years (range <1–37 years). Vitamin D deficiency was identified in six (24%) hYAs and 10 (40%) IBD-YAs; none had severe vitamin D deficiency (<25 nmol/L).

HRpQCT at the tibia showed reduced trabecular thickness (0.246±0.021; hYAs 0.275±0.025, p=0.001) with less inhomogeneity (0.256±0.043 vs 0.297±0.058, p=0.038). Strength was reduced with lower stiffness (203837±516230 vs 253879±60744, p=0.023) and failure load (-11127.7±2640.7 vs. -13567.3±3013.5 p=0.030) in IBD-YAs compared to hYAs. IBD-YAs had lower femoral neck aBMD (0.907±0.355g/cm2 vs. 1.052±0.127g/cm2, p=0.02). HSA identified reduced cross-sectional area (154.1±31.1 vs. 171.0±35.3, p=0.037) and shaft cortical width (4.517±1.401 vs. 5.437±1.785, p=0.027).

Consistent with reduced strength and both impaired bone formation and increased bone loss, IBD-YAs have lower failure load, reduced bone size and cortical width as well as reduced aBMD and trabecular changes, all indices previously associated with increased fracture risk.1,2 Longitudinal studies of larger IBD cohorts are required to confirm these findings and identify the variable with most clinical utility.

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