The exponential increase in hip fracture incidence with age cannot be explained either by the age-related decrease in area! bone mineral density (aBMD) or by the increase of fall risk with age. Recent studies have outlined age-related changes in hip structure that appear to result in increased fragility but that may not be reflected in bone density measurements. We propose to examine the effect of aging on proximal femoral structure and strength and to relate these measures to hip fracture risk. To accomplish this end, we will carry out two studies using quantitative computed tomography (QCT): a longitudinal study to examine age-related changes in proximal femoral geometry and strength and a prospective study relating these properties to incident hip fracture. The analytical methods will include structural analysis of the hip from high resolution QCT scans and patient specific finite element modeling (FEM) to estimate hip strength in loading conditions simulating a single-legged stance and a fall to the side. Our longitudinal cohort will be a subset of 500 patients selected from the 5000 elderly subjects in the Age Gene/Environment -Reykjavik (AGES-R) study. In the prospective fracture study the AGES-R fracture registry will be employed to determine which of the subjects scanned at baseline have sustained fracture of the hip. The scans of these subjects will be analyzed along with a set of gender and age-matched controls. In this study, we expect to derive clinically relevant information regarding the effect regarding how the structural characteristics of the proximal femur and its strength change with age and how they contribute to fracture risk.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
5R01AG028832-04
Application #
7825279
Study Section
Skeletal Biology Structure and Regeneration Study Section (SBSR)
Program Officer
Sherman, Sherry
Project Start
2007-07-15
Project End
2012-04-30
Budget Start
2010-05-15
Budget End
2011-04-30
Support Year
4
Fiscal Year
2010
Total Cost
$357,339
Indirect Cost
Name
University of California San Francisco
Department
Radiation-Diagnostic/Oncology
Type
Schools of Medicine
DUNS #
094878337
City
San Francisco
State
CA
Country
United States
Zip Code
94143
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Keyak, J H; Sigurdsson, S; Karlsdottir, G S et al. (2013) Effect of finite element model loading condition on fracture risk assessment in men and women: the AGES-Reykjavik study. Bone 57:18-29
Carballido-Gamio, Julio; Harnish, Roy; Saeed, Isra et al. (2013) Proximal femoral density distribution and structure in relation to age and hip fracture risk in women. J Bone Miner Res 28:537-46
Lang, T F; Sigurdsson, S; Karlsdottir, G et al. (2012) Age-related loss of proximal femoral strength in elderly men and women: the Age Gene/Environment Susceptibility Study--Reykjavik. Bone 50:743-8
Keyak, J H; Sigurdsson, S; Karlsdottir, G et al. (2011) Male-female differences in the association between incident hip fracture and proximal femoral strength: a finite element analysis study. Bone 48:1239-45
Carpenter, R D; Sigurdsson, S; Zhao, S et al. (2011) Effects of age and sex on the strength and cortical thickness of the femoral neck. Bone 48:741-7