title: Finite element analysis of the proximal femur and hip fracture risk in older men.
abstract: Low areal BMD (aBMD) is associated with increased risk of hip fracture, but many hip fractures occur in persons without low aBMD. Finite element (FE) analysis of QCT scans provides a measure of hip strength. We studied the association of FE measures with risk of hip fracture in older men. A prospective case-cohort study of all first hip fractures (n = 40) and a random sample (n = 210) of nonfracture cases from 3549 community-dwelling men > or =65 yr of age used baseline QCT scans of the hip (mean follow-up, 5.6 yr). Analyses included FE measures of strength and load-to-strength ratio and BMD by DXA. Hazard ratios (HRs) for hip fracture were estimated with proportional hazards regression. Both femoral strength (HR per SD change = 13.1; 95% CI: 3.9-43.5) and the load-to-strength ratio (HR = 4.0; 95% CI: 2.7-6.0) were strongly associated with hip fracture risk, as was aBMD as measured by DXA (HR = 5.1; 95% CI: 2.8-9.2). After adjusting for age, BMI, and study site, the associations remained significant (femoral strength HR = 6.5, 95% CI: 2.3-18.3; load-to-strength ratio HR = 4.3, 95% CI: 2.5-7.4; aBMD HR = 4.4, 95% CI: 2.1-9.1). When adjusted additionally for aBMD, the load-to-strength ratio remained significantly associated with fracture (HR = 3.1, 95% CI: 1.6-6.1). These results provide insight into hip fracture etiology and demonstrate the ability of FE-based biomechanical analysis of QCT scans to prospectively predict hip fractures in men.
authors.affiliation: Bone and Mineral Unit, Oregon Health & Science University, Portland Oregon 97239, USA. orwoll@ohsu.edu
authors.forename: Eric S
authors.initials: ES
authors.lastname: Orwoll
authors.forename: Lynn M
authors.initials: LM
authors.lastname: Marshall
authors.forename: Carrie M
authors.initials: CM
authors.lastname: Nielson
authors.forename: Steven R
authors.initials: SR
authors.lastname: Cummings
authors.forename: Jodi
authors.initials: J
authors.lastname: Lapidus
authors.forename: Jane A
authors.initials: JA
authors.lastname: Cauley
authors.forename: Kristine
authors.initials: K
authors.lastname: Ensrud
authors.forename: Nancy
authors.initials: N
authors.lastname: Lane
authors.forename: Paul R
authors.initials: PR
authors.lastname: Hoffmann
authors.forename: David L
authors.initials: DL
authors.lastname: Kopperdahl
authors.forename: Tony M
authors.initials: TM
authors.lastname: Keaveny
mesh_terms: D000368:Aged; D000375:Aging / Q000473:pathology*; D016022:Case-Control Studies; D005269:Femur / Q000473:pathology*; D020342:Finite Element Analysis; D006620:Hip Fractures / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008953:Models, Anatomic; D016016:Proportional Hazards Models; D012372:ROC Curve; D012307:Risk Factors; D014481:United States / Q000453:epidemiology