Evaluation of the trabecular bone score in 35 children and adults with X-linked hypophosphatemic rickets.

INTRODUCTION

The aim of this study is to evaluate and compare the trabecular bone scores (TBSs) of 11 children and 24 adults with X-linked hypophosphatemic rickets (XLH) and non-XLH subjects from a tertiary center.

MATERIALS AND METHODS

The areal bone mineral density at the lumbar spine (LS-aBMD) and LS-aBMD Z score were analyzed by dual-energy X-ray absorptiometry. The bone mineral apparent density (BMAD) and LS-aBMD Z score adjusted for height Z score (LS-aBMD-HAZ) were calculated. The TBS was determined using TBS iNsight software based on DXA images from the Hologic QDR 4500 device.

RESULTS

The XLH patients exhibited a higher mean LS-aBMD Z score, BMAD, and TBS than the non-XLH subjects (p < 0.01). LS-aBMD-HAZ and BMAD were greater in the XLH children than those in their corresponding non-XLH subjects (p < 0.01 and p = 0.02), and the XLH children trended toward a greater TBS (p = 0.06). The XLH adults had a higher LS-aBMD Z score, BMAD, and TBS than the non-XLH subjects (p < 0.01). When stratified by metabolic status according to the serum values of bone formation markers, compensated adult patients had a higher LS-aBMD Z score, BMAD, and TBS than non-XLH subjects (p < 0.01). Noncompensated patients had higher LS-aBMD Z scores and BMAD results than non-XLH subjects. However, TBS values did not differ statistically significantly between those groups (p = 0.45).

CONCLUSION

The higher LS-aBMD Z score, BMAD, and TBS result in the XLH patients compared to non-XLH subjects indicates an increased amount of trabecular bone within the lumbar spine, regardless of extraskeletal calcifications.