Osteoporosis International

, Volume 1, Issue 4, pp 250–256 | Cite as

The impact of measurement errors on the diagnostic value of bone mass measurements: Theoretical considerations

  • C. Hassager
  • S. B. Jensen
  • A. Gotfredsen
  • C. Christiansen
Original Article


It has become clear over the last decade that correlations between measurements of forearm bone mineral .content (BMCarm)by single-photon absorptiometry (SPA) and measurements of spinal bone mineral density (BMDspinc) by dual-photon absorptiometry (DPA) in healthy subjects and patients with spinal fractures are invariably significant, but not very powerful (i.e.r=0.5–0.7). Nonetheless, several recent studies have shown, that .appendicular bone mass measurements discriminate between spinal fracture and non-fracture at least as well as do spinal DPA measurements. Correlations of a given parameter withmeasured BMDspine are less important than those withtrue BMDspine. To establish the latter we made the following assumptions: (1) accuracy errors or SPA BMCarm and DPA BMDspine measurements of 2%–4% and 8%–10%, respectively; and (2) a measured biological variation of SD=14% for both BMCarm and BMDspine, corresponding to that of healthy women at the menopause. On these assumptions, we found that a correlation betweentrue BMCarm andtrue BMDspine at aboutr=0.8–0.9 yields a correlation between measured BMCarm and measured BMDspine at aboutr=0.6-corresponding to experimental data in healthy women at the menopause. Furthermore, we found that the correlation between DPAmeasured BMDspine andtrue BMDspine is about the same as that between the SPAmeasured BMCarm and the true BMDspine. Thus, with the assumptions given above, spinal (DPA) and forearm (SPA) measurements appears to predict equally thetrue BMDspine in healthy perimenopausal women.


Bone mass measurement Measurement errors 


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  1. 1.
    Consensus development conference: prophylaxis and treatment of osteoporosis. Br Med J 1987; 295: 914–15.Google Scholar
  2. 2.
    Barrett-Connor E. Postmenopausal estrogen replacement and breast cancer. N Engl J Med 1989; 321: 319–20.PubMedGoogle Scholar
  3. 3.
    Ross PD, Wasnich RD, Vogel JM. Detection of prefracture spinal osteoporosis using bone mineral absorptiometry. J Bone Miner Res 1988; 3: 1–11.CrossRefPubMedGoogle Scholar
  4. 4.
    Cummings SR, Black DM, Nevitt MCet al. Appendicular bone density and age predict hip fracture in women. JAMA 1990; 263: 665–8.CrossRefPubMedGoogle Scholar
  5. 5.
    Christiansen C, Riis BJ, Rødbro P. Prediction of rapid bone loss in postmenopausal women. Lancet 1987; i: 1105–8.CrossRefGoogle Scholar
  6. 6.
    Mazess RB. Diagnostic sensitivity of bone densitometry. J Bone Miner Res 1988; 4: 121–3.CrossRefGoogle Scholar
  7. 7.
    Riggs BL, Wahner HW, Dunn WL, Mazess RB, Offord KP, Melton LJ. Differential changes in bone mineral density of the appendicular and axialskeleton with aging. J Clin Invest 1981; 67: 328–35.CrossRefPubMedGoogle Scholar
  8. 8.
    Eastell R, Wahner HW, O’Fallon M, Amadio PC, Melton III LJ, Riggs BL. Unequal decrease in bone density of lumbar spine and ultradistal radius in Colles’ and vertebral fracture syndromes. J Clin Invest 1989; 83: 168–74.CrossRefPubMedGoogle Scholar
  9. 9.
    Gotfredsen A, Pødenphant J, Nilas L, Christiansen C. Discriminative ability of total body bone mineral measured by dual-photon absorptiometry. Scand J Clin Lab Invest 1989; 49: 125–34.CrossRefPubMedGoogle Scholar
  10. 10.
    Nordin BEC, Wishart JM, Horowitz M, Need AG, Bridges A, Bellon M. The relation between forearm and vertebral mineral density and fractures in postmenopausal women. Bone Miner 1988; 5: 21–33.CrossRefPubMedGoogle Scholar
  11. 11.
    Ott SM, Kilcoyne RF, Chesnut CH. Ability of four different techniques of measuring bone mass to diagnose vertebral fractures in postmenopausal women. J. Bone Miner Res 1987; 2: 201–10.CrossRefPubMedGoogle Scholar
  12. 12.
    Hansen MA, Riis BJ, Overgaard K, Hassager C, Christiansen C. Bone Mass measured by photon absorptiometry. Scand J Clin Lab Invest 1990; 50: 517–23.CrossRefPubMedGoogle Scholar
  13. 13.
    Gotfredsen A, Pødenphant J, Nørgaard H, Nilas L, Nielsen VH, Christiansen C. Accuracy of lumbar spine bone mineral content by dual-photon absorptiometry. J Nucl Med 1988; 29: 248–54.PubMedGoogle Scholar
  14. 14.
    Wahner HW, Dunn WL, Mazess RB et al. Dual-photon Gd-153 absorptiometry of bone. Radiology 1985; 156: 203–6.PubMedGoogle Scholar
  15. 15.
    Mazess RB, Cameron JR, Miller M. Direct readout of bone mineral content using radionuclide absorptiometry. Int J Appl Rad Isotopes 1972; 23: 471–9.CrossRefGoogle Scholar
  16. 16.
    Nibs L, Christiansen C. Rates of bone loss in normal women: evidence of accelerated trabecular bone loss after the menopause. Eur J Clin Invest 1988; 18: 529–34.CrossRefGoogle Scholar
  17. 17.
    Ho CP, Kim RW, Schaffer MB, Sartoris DJ. Accuracy of dual-energy radiographic absorptiometry of the lumbar spine: Cadaver study. Radiology 1990; 176: 171–3.PubMedGoogle Scholar
  18. 18.
    Cochran WG. Errors of measurement in statistics. Technometrics 1968; 10: 637–66.CrossRefGoogle Scholar
  19. 19.
    Anderson TW. An introduction to multivariate statistical analysis, 2nd edn. New York: John Wiley; 1984.Google Scholar

Copyright information

© European Foundation for Osteoporosis 1991

Authors and Affiliations

  • C. Hassager
    • 1
  • S. B. Jensen
    • 1
  • A. Gotfredsen
    • 1
  • C. Christiansen
    • 1
  1. 1.Department of Clinical ChemistryGlostrup HospitalGlostrupDenmark

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