Bone marrow fat composition as a novel imaging biomarker in postmenopausal women with prevalent fragility fractures

Journal of Bone and Mineral Research, 04/05/2013

Patsch J.M. et al.– The goal of this MR–imaging study was to quantify vertebral bone marrow fat content and composition in diabetic and non–diabetic postmenopausal women with fragility fractures and to compare them with non–fracture controls with and without type–2 diabetes mellitus.The study results suggest that altered bone marrow fat composition is linked with fragility fractures and diabetes. MRS of spinal bone marrow fat may therefore serve as a novel tool for BMD–independent fracture risk assessment.

Methods

  • Sixty–nine postmenopausal women (mean age 63±5 years) were recruited.
  • Thirty–six patients (47.8%) had spinal and/or peripheral fragility fractures.
  • Seventeen fracture patients were diabetic. Thirty–three women (52.2%) were non–fracture controls. Sixteen women were diabetic non–fracture controls.
  • To quantify vertebral bone marrow fat content and composition, patients underwent MR–spectroscopy (MRS) of the lumbar spine at 3 Tesla.
  • Bone mineral density (BMD) was determined by dual–energy X–Ray–absorptiometry (DXA) of the hip and lumbar spine (LS) and quantitative computed tomography (QCT) of the LS.
  • To evaluate associations of vertebral marrow fat content and composition with spinal and/or peripheral fragility fractures and diabetes, the authors used linear regression models adjusted for age, race, and spine vBMD by QCT.
  • At the LS, non–diabetic and diabetic fracture patients had lower vBMD than controls and diabetics without fractures (p=0.018; p=0.005).

Results

  • However, aBMD by DXA did not differ between fracture and non–fracture patients.
  • After adjustment for age, race, and spinal vBMD, the prevalence of fragility fractures was associated with -1.7% lower unsaturation levels (confidence interval [CI] -2.8% to -0.5%, p=0.005) and +2.9% higher saturation levels (CI 0.5% to 5.3%, p=0.017).
  • Diabetes was associated with -1.3% (CI -2.3% to -0.2%, p=0.018) lower unsaturation and +3.3% (CI 1.1% to 5.4%. p=0.004) higher saturation levels.
  • Diabetics with fractures had the lowest marrow unsaturation and highest saturation.
  • There were no associations of marrow fat content with diabetes or fracture.

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