Importance of Estrogen on Bone Health in Turner Syndrome: A Cross-Sectional and Longitudinal Study Using Dual-Energy X-Ray Absorptiometry

Abstract

Osteoporosis and fractures are features in adults with Turner syndrome (TS). Using dual-energy x-ray absorptiometry, correcting bone mineral content (BMC) for height and lean mass (LTM) avoids misclassification of short children as osteopenic. Total body (TB), lumbar spine (LS), and femoral neck (FN) dual-energy x-ray absorptiometry scans were performed on 83 patients with TS (aged 4-24 yr). A prepubertal subgroup (n = 17) receiving GH was followed for 24 months. Age z-scores for height, TB BMC, LTM, the BMC/LTM ratio, and LS volumetric bone mineral density (vBMD) decreased significantly (P < 0.001) with age in prepubertal subjects (n = 51) but were constant in the combined pubertal and postmenarchal group (n = 32). Osteopenia was found in 14.5% (TB), 15.8% (LS), and 28.4% (FN) of patients. In the longitudinal subgroup, TB BMC z-scores decreased by -0.28 (0.31) in subjects remaining prepubertal (n = 11) but increased by 0.71 (0.56) in subjects entering puberty (n = 6; P = 0.007). The z-scores for height and LTM increased in both groups. Our results show a height-independent prepubertal decrease in bone mass accrual, which ceased with puberty. Optimizing bone mass in TS may require earlier induction of puberty than currently recommended. However, reduced FN volumetric bone mineral density and a dissociation of bone and muscle measures were age independent, suggesting an additional intrinsic bone defect.

Body composition is distinctly altered in Turner syndrome: relations to glucose metabolism, circulating adipokines, and endothelial adhesion molecules

“…In a longitudinal study of pre-pubertal girls, LBM z-score (age, but not height or weight adjusted) was found to be reduced, but due to the presentation of data it is not clear whether LBM was genuinely reduced if adjustment for differences in body size had been performed (40). In a study of forearm bone density by peripheral quantitative computed tomography, cross-sectional muscle area was found to be comparable to controls (41).…”

Long-term hormone replacement therapy preserves bone mineral density in Turner syndrome

“…Still, differences in body size and bone scan technique might not be the only explanatory factors for the observed reduction of BMD in TS. Peak bone mass depends on several factors, such as genetic background, nutrition, physical activity, local growth factors, and a number of hormones (31,32). Evidently, many women with TS receive appropriate HRT late in life and for a shorter duration than is recommended (5,33,34).…”

Consensus statement on the management of the GH-treated adolescent in the transition to adult care

“…With regard to their previous GH therapy, these patients require no specific investigations. Endocrine evaluation should include assessment of adult height, thyroid status, hormonereplacement therapy requirements, carbohydrate metabolism and bone mass (18).…”