ESPE Abstracts

Introduction and Objectives: Data on bone health in young Turner Syndrome (TS) patients (pts) are scarce. aims of the study were: to evaluate lumbar (L1-L4) and total body (TBLH) bone mineral density (BMD) in a cohort of TS between 5-25 yrs; to assess the prevalence and the incidence of fractures (fx), bone turnover markers (BTM) and determinants of dual-X-ray-absorbiometry (DXA) parameters.

Methods: Antropometrics, BMT (BAP, Ctx, Osteocalcin, 25OHD), and bone parameters by DXA (Lunar, GE) were retrospectively collected in 71 TS (n = 27 45X0, n = 8 45X0/46XX, n = 36 other karyotypes) at the mean age of 13.9±4.3 yrs; 35/71 were assessed longitudinally at T0, T1 and T2 between 13.4±3.7 and 17.0±3.7. L1-L4 BMAD values were calculated to adjust for dimensions (Crambtree NJ, 2013). n = 22 had thyroiditis, n = 5 celiac disease, n = 56 underwent rhGH therapy; n = 11 had spontaneous puberty (6/11 up to menarche), n = 33 induced with estrogen-replacement therapy-ERT (26/33 up to Tanner 5), n = 21 were prepubertal. At least 1 fx occurred in n = 13, 2 fx in n = 3.

Results: Overall height was -2.2±1.0, L1-L4 BMD -1.0±0.9 Z-Score (n = 8 <-2 Z-score), L1-L4 BMAD (n = 64) -0,5±0,9 Z-Score (n = 3, meaning 4.7% <-2 Z-score) and TBLH BMD -1.3±0.8 Z-score. No differences were found in bone parameters between pts with different kariotypes and with/without thyroiditis, celiac disease or fractures. Additionally, no relations between DXA parameters and ERT or rhGH therapy duration were found; however, L1-L4 BMAD Z-score was higher in pts with spontaneous puberty compared to those induced by ERT (P = 0,04, ΔZ-score +0,6) and to prepubertal TS (P = 0,05; ΔZ-score +0.7). The 35 pts followed thrice during 3.5±1.72 yrs displayed stable DXA parameters at the spine (between -0.5 and -0.4 Z-score) and at the TBLH (between -1.5 and -1.6 Z-score). 25OHD values were normal (26.4±14.2) and BMT decreased between T0 and T2 (all p’s<0.05). The prevalence of fx was 18.3%; only 1 pt fractured in the longitudinal cohort up to T2.

Conclusion: TS pts present persistent BMD values at the lower limits of norm for age and sex up to 17 yrs, which can be corrected for short stature, as demonstrated by normal L1-L4 BMAD Z-Score values. Only 4.7% of the pts dysplayed low BMAD values without fx. Prevalence of fx was similar to the one reported in healthy subjects, and lower than what previously reported in other cohorts. Consistent with other studies, pts with spontaneous puberty have denser bones than pts who required ERT.