Vertebral fractures (VF) are the most common fracture among older persons, afflicting 20-35% of women and 15-25% of men >50 yrs, and leading to profound morbidity, increased mortality, and costs exceeding $1 billion in the US annually. There is strong evidence that factors other than low bone mineral density (BMD) influence VF risk. Yet, the biomechanical factors that contribute to fractures are poorly understood. From a mechanical perspective, a VF occurs when loads applied to the vertebrae exceed its strength. Thus, in this competing renewal, we aim to study several factors that our recent work indicates are related to VF risk, either by affecting vertebral loading and/or vertebra strength. We will build upon our prior cross-sectional findings by studying several novel factors that may contribute to incident vertebral fractures in two, well-characterized cohorts: the Framingham Heart Study Multidetector CT Study and the Age, Gene/Environment Susceptibility- Reykjavik Study (AGES). In the last funding period, we showed that estimates of vertebral loading are highly sensitive to several factors, namely variations in spine curvature, trunk muscle size and trunk muscle density that were not accounted for in our (and others') prior studies and likely led to errors in the in vivo estimates of vertebral loading. Our preliminary dat also show that a novel measure of heterogeneity in the distribution of bone density within the vertebral body is associated with vertebral strength in cadaveric specimens and with prevalent VF, even after adjusting for BMD. Thus we propose to conduct a prospective study of incident VF to determine the contribution of 1) spinal curvature, 2) the size and quality of trunk muscles; and 3) the distribution of bone density within the vertebral body to VF. Further, we will test whether a patient-specific factor-of-risk (ie, load-to-strength ratio) that uses state-of-the art approaches to estimate vertebral strength and in vivo spinal loading predicts incident VF better than aBMD or FRAX alone. In summary, this project is significant because it addresses the need to reduce the growing burden of VF. The proposal is highly innovative and efficient by using existing QCT and clinical data from well-characterized prospective population- based cohorts, along with an experienced team and multidisciplinary approach to gain knowledge about the etiology of VF. Completion of the proposed work will ultimately shift the current paradigm for VF etiology beyond BMD, thereby pointing towards new approaches to identify those at risk for fracture and novel interventions to reduce the occurrence of VF.

Public Health Relevance

The proposed research is relevant to public health because it addresses the mechanisms underlying spine fractures, which are the most common fracture among older adults. The studies will go 'beyond bone mineral density' to determine the contribution of biomechanical factors to age-related deterioration of vertebral strength and fracture. The information will reduce the burden of vertebral fractures by helping clinicians identify and treat those at greatest risk for fracture.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
4R01AR053986-09
Application #
9112856
Study Section
Neurological, Aging and Musculoskeletal Epidemiology (NAME)
Program Officer
Lester, Gayle E
Project Start
2007-08-15
Project End
2017-08-31
Budget Start
2016-09-01
Budget End
2017-08-31
Support Year
9
Fiscal Year
2016
Total Cost
Indirect Cost
Name
Beth Israel Deaconess Medical Center
Department
Type
DUNS #
071723621
City
Boston
State
MA
Country
United States
Zip Code
Allaire, Brett T; DePaolis Kaluza, M Clara; Bruno, Alexander G et al. (2017) Evaluation of a new approach to compute intervertebral disc height measurements from lateral radiographic views of the spine. Eur Spine J 26:167-172
Bachmann, Katherine N; Schorr, Melanie; Bruno, Alexander G et al. (2017) Vertebral Volumetric Bone Density and Strength Are Impaired in Women With Low-Weight and Atypical Anorexia Nervosa. J Clin Endocrinol Metab 102:57-68
Burkhart, Katelyn A; Bruno, Alexander G; Bouxsein, Mary L et al. (2017) Estimating apparent maximum muscle stress of trunk extensor muscles in older adults using subject-specific musculoskeletal models. J Orthop Res :
Bruno, Alexander G; Burkhart, Katelyn; Allaire, Brett et al. (2017) Spinal Loading Patterns From Biomechanical Modeling Explain the High Incidence of Vertebral Fractures in the Thoracolumbar Region. J Bone Miner Res 32:1282-1290
Bruno, Alexander G; Mokhtarzadeh, Hossein; Allaire, Brett T et al. (2017) Incorporation of CT-based measurements of trunk anatomy into subject-specific musculoskeletal models of the spine influences vertebral loading predictions. J Orthop Res 35:2164-2173
Bachmann, Katherine N; Bruno, Alexander G; Bredella, Miriam A et al. (2016) Vertebral Strength and Estimated Fracture Risk Across the BMI Spectrum in Women. J Bone Miner Res 31:281-8
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Anderson, Dennis E; Quinn, Emily; Parker, Emily et al. (2016) Associations of Computed Tomography-Based Trunk Muscle Size and Density With Balance and Falls in Older Adults. J Gerontol A Biol Sci Med Sci 71:811-6
Chan, Jimmy J; Cupples, L Adrienne; Kiel, Douglas P et al. (2015) QCT Volumetric Bone Mineral Density and Vascular and Valvular Calcification: The Framingham Study. J Bone Miner Res 30:1767-74
Meng, Xiangjie; Bruno, Alexander G; Cheng, Bo et al. (2015) Incorporating Six Degree-of-Freedom Intervertebral Joint Stiffness in a Lumbar Spine Musculoskeletal Model-Method and Performance in Flexed Postures. J Biomech Eng 137:101008

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