title: Proximal femoral structure and the prediction of hip fracture in men: a large prospective study using QCT.
abstract: The structure of the femoral neck contributes to hip strength, but the relationship of specific structural features of the hip to hip fracture risk is unclear. The objective of this study is to determine the contribution of structural features and volumetric density of both trabecular and cortical bone in the proximal femur to the prediction of hip fracture in older men. Baseline QCT scans of the hip were obtained in 3347 men >or=65 yr of age enrolled in the Osteoporotic Fractures in Men Study (MrOS). All men were followed prospectively for an average of 5.5 yr. Areal BMD (aBMD) by DXA was also assessed. We determined the associations between QCT-derived measures of femoral neck structure, volumetric bone density, and hip fracture risk. Forty-two men sustained incident hip fractures during follow-up: an overall rate of 2.3/1000 person-years. Multivariable analyses showed that, among the QCT-derived measures, lower percent cortical volume (hazard ratio [HR] per SD decrease: 3.2; 95% CI: 2.2-4.6), smaller minimal cross-sectional area (HR: 1.6; 95% CI: 1.2-2.1), and lower trabecular BMD (HR: 1.7; 95% CI: 1.2-2.4) were independently related to increased hip fracture risk. Femoral neck areal BMD was also strongly related to hip fracture risk (HR: 4.1; 95% CI: 2.7-6.4). In multivariable models, percent cortical volume and minimum cross-sectional area remained significant predictors of hip fracture risk after adjustment for areal BMD, but overall prediction was not improved by adding QCT parameters to DXA. Specific structural features of the proximal femur were related to an increased risk of hip fracture. Whereas overall hip fracture prediction was not improved relative to aBMD, by adding QCT parameters, these results yield useful information concerning the causation of hip fracture, the evaluation of hip fracture risk, and potential targets for therapeutic intervention.
authors.affiliation: Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California 94107, USA. dblack@psg.ucsf.edu
authors.forename: Dennis M
authors.initials: DM
authors.lastname: Black
authors.forename: Mary L
authors.initials: ML
authors.lastname: Bouxsein
authors.forename: Lynn M
authors.initials: LM
authors.lastname: Marshall
authors.forename: Steven R
authors.initials: SR
authors.lastname: Cummings
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Lang
authors.forename: Jane A
authors.initials: JA
authors.lastname: Cauley
authors.forename: Kristine E
authors.initials: KE
authors.lastname: Ensrud
authors.forename: Carrie M
authors.initials: CM
authors.lastname: Nielson
authors.forename: Eric S
authors.initials: ES
authors.lastname: Orwoll
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D005269:Femur / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D006620:Hip Fractures / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology*; D006801:Humans; D008297:Male; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012372:ROC Curve; D012307:Risk Factors; D014057:Tomography, X-Ray Computed; D014481:United States / Q000453:epidemiology