Osteoporosis International

, Volume 22, Issue 5, pp 1441–1450

Bone mineral density in Klinefelter syndrome is reduced and primarily determined by muscle strength and resorptive markers, but not directly by testosterone

  • A. Bojesen
  • N. Birkebæk
  • K. Kristensen
  • L. Heickendorff
  • L. Mosekilde
  • J. S. Christiansen
  • C. H. Gravholt
Original Article

DOI: 10.1007/s00198-010-1354-7

Cite this article as:
Bojesen, A., Birkebæk, N., Kristensen, K. et al. Osteoporos Int (2011) 22: 1441. doi:10.1007/s00198-010-1354-7

Abstract

Summary

Klinefelter syndrome (KS) patients have lower bone mineral density (BMD) at the spine, hip and forearm compared to healthy subjects, but frank osteoporosis is not common. Muscle strength and bone markers predicted BMD but KS itself and serum testosterone did not. Low vitamin D and high PTH were frequent among KS.

Introduction

The long-term consequence of KS on bone health is not well described. The objective of this study is to investigate the regional BMD and its determinants in KS.

Methods

This is a cross-sectional study. BMD at the spine, hip and forearm are measured by DXA and correlated to biochemical markers of bone turnover, vitamin D metabolites, PTH, sex hormones, growth factors as well as muscle strength and anthropometric measures. The setting is at a university clinical research centre. The study involves 70 adult KS patients and 71 age-matched healthy subjects.

Results

In KS, BMD was universally lowered in all regions. Markers of bone formation or bone resorption were not altered in KS, but 25-OH-Dvitamin was lower (55 vs. 82 nmol/L, p < 0.0001) than in healthy subjects. Significantly more KS patients had low BMD (Z-scores below −2) at the forearm (15 KS vs. two healthy subjects, p = 0.001) but not at the spine or hip. Muscle strength (bicep and quadriceps) was lower among KS patients. Multivariate analysis revealed that muscle strength, treatment with testosterone (ever/never), age at diagnosis, SHBG, bone-specific alkaline phosphatase and 1CTP were all independent predictors of BMD, but androgens was not.

Conclusions

KS patients had lower BMD at the spine, hip and forearm compared to age-matched healthy subjects, but frank osteoporosis was not common. Muscle strength, previous history of testosterone treatment, age at diagnosis and bone markers were predictors of BMD, but testosterone was not. Signs of secondary hyperparathyroidism were present among KS. Dietary intake of vitamin D or sun exposure may be lower in KS patients.

Keywords

Bone mineral densityHypogonadismKlinefelter syndromeMuscle strengthVitamin D

Copyright information

© International Osteoporosis Foundation and National Osteoporosis Foundation 2010

Authors and Affiliations

  • A. Bojesen
    • 1
    • 2
  • N. Birkebæk
    • 3
  • K. Kristensen
    • 4
  • L. Heickendorff
    • 5
  • L. Mosekilde
    • 6
  • J. S. Christiansen
    • 2
  • C. H. Gravholt
    • 2
  1. 1.Department of Clinical GeneticsVejle HospitalVejleDenmark
  2. 2.Department of Endocrinology & Internal Medicine and Medical Research LaboratoriesAarhus University HospitalAarhus CDenmark
  3. 3.Department of PediatricsAarhus University HospitalAarhus NDenmark
  4. 4.Department of PediatricsRanders HospitalRandersDenmark
  5. 5.Department of Clinical BiochemistryAarhus University HospitalAarhus CDenmark
  6. 6.Department of Endocrinology & Internal MedicineAarhus University HospitalAarhus CDenmark