Distribution of bone density in the proximal femur and its association with hip fracture risk in older men: The osteoporotic fractures in men (MrOS) study

Lang Yang, Annabel C. Burton, Mike Bradburn, Carrie M. Nielson, Eric S. Orwoll, Richard Eastell

Research output: Contribution to journalReview article

37 Scopus citations

Abstract

This prospective case-cohort study aimed to map the distribution of bone density in the proximal femur and examine its association with hip fracture. We analyzed baseline quantitative computed tomography (QCT) scans in 250 men aged 65 years or older, which comprised a randomly-selected subcohort of 210 men and 40 cases of first hip fracture during a mean follow-up period of 5.5 years. We quantified cortical, trabecular, and integral volumetric bone mineral density (vBMD), and cortical thickness (CtTh) in four quadrants of cross-sections along the length of the femoral neck (FN), intertrochanter (IT), and trochanter (TR). In most quadrants, vBMDs and CtTh were significantly (p < 0.05) lower in cases compared to the subcohort and these deficits were present across the entire proximal femur. To examine the association of QCT measurements with hip fracture, we merged the two quadrants in the medial and lateral aspects of the FN, IT, and TR. At most sites, QCT measurements were associated significantly (p < 0.001) with hip fracture, the hazard ratio (HR) adjusted for age, body mass index (BMI), and clinical site for a 1-SD decrease ranged between 2.28 (95% confidence interval [CI], 1.44-3.63) to 6.91 (95% CI, 3.11-15.53). After additional adjustment for total hip (TH) areal BMD (aBMD), trabecular vBMDs at the FN, TR, and TH were still associated with hip fracture significantly (p < 0.001), the HRs ranged from 3.21 (95% CI, 1.65-6.24) for the superolateral FN to 6.20 (95% CI, 2.71-14.18) for medial TR. QCT measurements alone or in combination did not predict fracture significantly (p > 0.05) better than TH aBMD. With an area under the receiver operating characteristic curve (AUC) of 0.901 (95% CI, 0.852-0.950), the regression model combining TH aBMD, age, and trabecular vBMD predicted hip fracture significantly (p < 0.05) better than TH aBMD alone or TH aBMD plus age. These findings confirm that both cortical and trabecular bone contribute to hip fracture risk and highlight trabecular vBMD at the FN and TR as an independent risk factor.

Original languageEnglish (US)
Pages (from-to)2314-2324
Number of pages11
JournalJournal of Bone and Mineral Research
Volume27
Issue number11
DOIs
StatePublished - Nov 1 2012

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Keywords

  • BONE MINERAL DENSITY
  • HIP FRACTURE
  • OSTEOPOROSIS
  • QUANTITATIVE COMPUTED TOMOGRAPHY

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Orthopedics and Sports Medicine

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