The assessment of skeletal status in young patients with Turner syndrome by 2 densitometric techniques: Phalangeal quantitative ultrasound and dual energy X-ray absorptiometry

Background. Studies using dual energy X-ray absorptiometry (DXA) demonstrate a reduction in bone mineral density (BMD) in children and adolescents with Turner syndrome (TS). However, these studies do not take into account changes in bone size, which influence BMD in the case of short-statured patients. Phalangeal quantitative ultrasound (phQUS) measurements have shown an ability to reveal changes due to skeletal growth, aging, and bone and mineral disorders. There is limited data on bone mineral status in girls with TS assessed by 2 different techniques, i.e., DXA and phQUS. Objectives. The aim of this study was to investigate the potential negative impact of TS on bone status and to assess whether densitometric values were related to former fractures. Material and methods. In 43 TS girls aged 5-18 years, we evaluated bone status by 2 different densitometric techniques, DXA and phQUS. Results. The mean lumbar spine areal bone mineral density (LS aBMD) Z-score was significantly lower than 0 (the hypothetical mean) compared to the reference population (p < 0.001). The mean LS aBMD height-adjusted Z-score did not differ significantly from 0. The amplitude-dependent speed of sound (Ad-SoS) Z-score was significantly lower than 0 compared with a Polish reference population. There were no significant differences between fractured and fracture-free patients as regards Ad-SoS Z-score and LS aBMD height-adjusted Z-score. Conclusions. Girls with TS have normal bone density adjusted for height, but significantly decreased phQUS values. Neither DXA nor phalangeal Ad-SoS can identify young TS patients with former fractures.