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Project Title:  Vertebral Strength and Fracture Risk following Long Duration Spaceflight Reduce
Fiscal Year: FY 2018 
Division: Human Research 
Research Discipline/Element:
HRP HFBP:Human Factors & Behavioral Performance (IRP Rev H)
Start Date: 01/01/2016  
End Date: 07/01/2018  
Task Last Updated: 10/08/2018 
Download report in PDF pdf
Principal Investigator/Affiliation:   Bouxsein, Mary  Ph.D. / Beth Israel Deaconess Medical Center/Harvard Medical School 
Address:  Department of Orthopedic Surgery 
330 Brookline Ave, RN115 
Boston , MA 02215-5400 
Email: mbouxsei@bidmc.harvard.edu 
Phone: 617-667-4594  
Congressional District:
Web:  
Organization Type: UNIVERSITY 
Organization Name: Beth Israel Deaconess Medical Center/Harvard Medical School 
Joint Agency:  
Comments:  
Co-Investigator(s)
Affiliation: 
Kopperdahl, David  Ph.D. O.N. Diagnostics 
Project Information: Grant/Contract No. NNX16AC15G 
Responsible Center: NASA JSC 
Grant Monitor: Williams, Thomas  
Center Contact: 281-483-8773 
thomas.j.will1@nasa.gov 
Solicitation / Funding Source: 2014-15 HERO NNJ14ZSA001N-Crew Health (FLAGSHIP & NSBRI) 
Grant/Contract No.: NNX16AC15G 
Project Type: FLIGHT,GROUND 
Flight Program:  
TechPort: No 
No. of Post Docs:
No. of PhD Candidates:
No. of Master's Candidates:
No. of Bachelor's Candidates:
No. of PhD Degrees:
No. of Master's Degrees:
No. of Bachelor's Degrees:
Human Research Program Elements: (1) HFBP:Human Factors & Behavioral Performance (IRP Rev H)
Human Research Program Risks: (1) Fracture:Risk of Bone Fracture due to Spaceflight-induced Changes to Bone (IRP Rev F)
(2) Occupant Protection:Risk of Injury from Dynamic Loads (Risk move from HHC to SHFH per IRP Rev F)
(3) Osteo:Risk Of Early Onset Osteoporosis Due To Spaceflight (No longer used, July 2020)
Human Research Program Gaps: (1) Fracture03:We need a validated method to estimate the risk of fracture by evaluating the ratio of applied loads to bone fracture loads for expected mechanically-loaded activities during a mission (IRP Rev E)
(2) OP-04:We do not know the extent to which spaceflight deconditioning decreases injury tolerance for dynamic loads. (Previous title: OP5) (IRP Rev H)
(3) Osteo03:We need a validated clinically relevant method for assessing the effect of spaceflight on osteoporosis or fracture risk in long-duration astronauts (IRP Rev E)
Flight Assignment/Project Notes: NOTE: End date change to 7/1/2018 per NSSC information (Ed., 5/3/18)

NOTE: Element change to Human Factors & Behavioral Performance; previously Space Human Factors & Habitability (Ed., 1/19/17)

NOTE: Period of performance changed to 1/01/2016-12/31/2017 (originally 11/16/2015-11/15/2017) per NSSC information and B. Gore/JSC (Ed., 9/13/16)

Task Description: Mechanical loading is required for maintenance of the musculoskeletal system. Thus, exposure to microgravity induces marked bone loss in both humans and animals, and is a major concern for astronauts exposed to long-duration spaceflight, as they may be at increased risk for skeletal fragility and bone fractures. Most prior studies have relied on dual-energy X-ray absorptiometry (DXA), a 2D technique used to assess bone mass at different skeletal sites, to assess effects of spaceflight on bone strength and fracture risk. However, DXA-based measurements are limited in several regards. Newer technologies, including 3D quantitative computed tomography (QCT) are able to overcome the limitations of DXA. Moreover, QCT images can be used to estimate bone strength using a standard engineering approach called finite element analysis. Indeed, QCT images have been used successfully to demonstrate negative effects of spaceflight on hip bone density and strength. However, a similar examination of the effects of spaceflight on vertebral strength has not been performed. Thus the degree of spinal deconditioning and subsequent risk of vertebral fracture following long-duration spaceflight remains unknown.

Specific Aims:

1) Determine changes in bone density and vertebral strength following long-duration spaceflight in astronauts and cosmonauts, including pre-flight, post-flight, and one-year after return to Earth

2) Use musculoskeletal modeling to compute subject-specific spinal loading and estimate the risk of vertebral fracture (as the load-to-strength ratio) following long-duration spaceflight

3) Determine changes in trunk muscle size and density following long-duration spaceflight.

Research Impact/Earth Benefits: This research will help us to better understand risk factors for vertebral fracture. Vertebral fractures are the most common fracture among older adults on Earth, with a prevalence of 30-50% among those over age 50. Improved insight into the factors that increase risk for vertebral fracture could advance the clinical management of older adults and inform better approaches to prevent these fractures.

Task Progress & Bibliography Information FY2018 
Task Progress: The impact of long-duration (i.e., 6 months) spaceflight on vertebral bone strength, trunk muscle atrophy, and risk of spine fracture has not previously been investigated. We used previously collected computed tomography (CT) scans of the lumbar spine taken pre-flight, immediately post-flight, and one to four years after return to Earth in 17 crewmembers with long-duration service on the International Space Station. We used CT-based finite element analysis (CT-FEA) to estimate vertebral compressive strength and subject-specific musculoskeletal models to estimate the compressive forces applied to the vertebral bodies during routine activities as well as a few spaceflight-specific tasks. We found that 6 months of spaceflight led to a mean (±SD) 5.6±4.3% decline in lumbar vertebral strength compared to baseline, with 65% of subjects experiencing deficits of greater than 5%. Notably, vertebral strength remained at this level after one to four years of recovery on Earth. The decline in vertebral strength was greater than the decline in bone mineral density (BMD) assessed by DXA (-3.6 ± 3.0%) and not associated with the decline in spine DXA-BMD. The cross-sectional area and density of paraspinal muscles were also reduced after spaceflight, with consistent recovery of muscle area but not density after one-year readaptation on Earth. Musculoskeletal models of the trunk showed a very slight increase in spinal loading post-flight, but in all individuals and for all simulated activities the ratio of vertebral compressive load to vertebral compressive strength remained well below one, indicating a low risk of vertebral fracture. Additional analyses simulating vertebral strength changes in high-loading rate simulations showed similar results.

Altogether our findings confirm and extend previous studies showing significant declines in bone strength due to 6 months of spaceflight. This study was limited to examining crewmembers with mission durations of only 4-7 months, was conducted prior to availability of iRED (Interim Resistive Exercise Device), and none of the subjects used bisphosphonates. Thus, future studies should investigate whether exercise and/or pharmacologic interventions can mitigate the bone and muscle losses we observed, and should determine nature of bone loss and trunk muscle atrophy in longer-duration missions. In particular, it is important to determine whether bone loss continues at the same rate, accelerates, or plateaus with longer exposure to microgravity.

The following manuscript is in review ; other manuscripts are in preparation for submission:

Burkhart K, Allaire B, Bouxsein ML. Negative Effects of Long-Duration Spaceflight on Paraspinal Muscle Morphology, Spine (in review 2018).

Bibliography Type: Description: (Last Updated: 10/14/2021)  Show Cumulative Bibliography Listing
 
Articles in Peer-reviewed Journals Burkhart K, Allaire B, Bouxsein M. "Negative effects of long-duration spaceflight on paraspinal muscle morphology." Spine (Phila Pa 1976). 2019 Jun 15;44(12):879-86. https://doi.org/10.1097/BRS.0000000000002959 ; PubMed PMID: 30624302 , Jun-2019
Articles in Peer-reviewed Journals Burkhart K, Allaire B, Anderson DE, Lee D, Keaveny TM, Bouxsein ML. "Effects of long-duration spaceflight on vertebral strength and risk of spine fracture." J Bone Miner Res. 2020 Feb;35(2):269-76. https://doi.org/10.1002/jbmr.3881 ; PubMed PMID: 31670861 , Feb-2020
Project Title:  Vertebral Strength and Fracture Risk following Long Duration Spaceflight Reduce
Fiscal Year: FY 2017 
Division: Human Research 
Research Discipline/Element:
HRP HFBP:Human Factors & Behavioral Performance (IRP Rev H)
Start Date: 01/01/2016  
End Date: 07/01/2018  
Task Last Updated: 09/12/2016 
Download report in PDF pdf
Principal Investigator/Affiliation:   Bouxsein, Mary  Ph.D. / Beth Israel Deaconess Medical Center/Harvard Medical School 
Address:  Department of Orthopedic Surgery 
330 Brookline Ave, RN115 
Boston , MA 02215-5400 
Email: mbouxsei@bidmc.harvard.edu 
Phone: 617-667-4594  
Congressional District:
Web:  
Organization Type: UNIVERSITY 
Organization Name: Beth Israel Deaconess Medical Center/Harvard Medical School 
Joint Agency:  
Comments:  
Co-Investigator(s)
Affiliation: 
Kopperdahl, David  Ph.D. O.N. Diagnostics 
Project Information: Grant/Contract No. NNX16AC15G 
Responsible Center: NASA JSC 
Grant Monitor: Williams, Thomas  
Center Contact: 281-483-8773 
thomas.j.will1@nasa.gov 
Solicitation / Funding Source: 2014-15 HERO NNJ14ZSA001N-Crew Health (FLAGSHIP & NSBRI) 
Grant/Contract No.: NNX16AC15G 
Project Type: FLIGHT,GROUND 
Flight Program:  
TechPort: No 
No. of Post Docs:
No. of PhD Candidates:
No. of Master's Candidates:
No. of Bachelor's Candidates:
No. of PhD Degrees:
No. of Master's Degrees:
No. of Bachelor's Degrees:
Human Research Program Elements: (1) HFBP:Human Factors & Behavioral Performance (IRP Rev H)
Human Research Program Risks: (1) Fracture:Risk of Bone Fracture due to Spaceflight-induced Changes to Bone (IRP Rev F)
(2) Occupant Protection:Risk of Injury from Dynamic Loads (Risk move from HHC to SHFH per IRP Rev F)
(3) Osteo:Risk Of Early Onset Osteoporosis Due To Spaceflight (No longer used, July 2020)
Human Research Program Gaps: (1) Fracture03:We need a validated method to estimate the risk of fracture by evaluating the ratio of applied loads to bone fracture loads for expected mechanically-loaded activities during a mission (IRP Rev E)
(2) OP-04:We do not know the extent to which spaceflight deconditioning decreases injury tolerance for dynamic loads. (Previous title: OP5) (IRP Rev H)
(3) Osteo03:We need a validated clinically relevant method for assessing the effect of spaceflight on osteoporosis or fracture risk in long-duration astronauts (IRP Rev E)
Flight Assignment/Project Notes: NOTE: End date change to 7/1/2018 per NSSC information (Ed., 5/3/18)

NOTE: Element change to Human Factors & Behavioral Performance; previously Space Human Factors & Habitability (Ed., 1/19/17)

NOTE: Period of performance changed to 1/01/2016-12/31/2017 (originally 11/16/2015-11/15/2017) per NSSC information and B. Gore/JSC (Ed., 9/13/16)

Task Description: Mechanical loading is required for maintenance of the musculoskeletal system. Thus, exposure to microgravity induces marked bone loss in both humans and animals, and is a major concern for astronauts exposed to long-duration spaceflight, as they may be at increased risk for skeletal fragility and bone fractures. Most prior studies have relied on dual-energy X-ray absorptiometry (DXA), a 2D technique used to assess bone mass at different skeletal sites, to assess effects of spaceflight on bone strength and fracture risk. However, DXA-based measurements are limited in several regards. Newer technologies, including 3D quantitative computed tomography (QCT) are able to overcome the limitations of DXA. Moreover, QCT images can be used to estimate bone strength using a standard engineering approach called finite element analysis. Indeed, QCT images have been used successfully to demonstrate negative effects of spaceflight on hip bone density and strength. However, a similar examination of the effects of spaceflight on vertebral strength has not been performed. Thus the degree of spinal deconditioning and subsequent risk of vertebral fracture following long-duration spaceflight remains unknown.

Specific Aims:

1) Determine changes in lumbar vertebral strength in long-duration International Space Station (ISS) astronauts

2) Compute subject-specific load-to-strength ratio to estimate risk of vertebral fracture in long-duration ISS astronauts

3) Perform Biomechanical Computed Tomography (BCT) analysis — aka finite element analysis of QCT scans on spine scans for up to 18 astronauts at up to visits (pre, post, and 1 Year, for all n=18; one additional visit for n=8), and analyzing two vertebral levels per subject (total number of BCT analyses = 124)

Research Impact/Earth Benefits: This research will help us to better understand risk factors for vertebral fracture. Vertebral fractures are the most common fracture among older adults on Earth, with a prevalence of 30-50% among those over age 50. Improved insight into the factors that increase risk for vertebral fracture could advance the clinical management of older adults and inform better approaches to prevent these fractures.

Task Progress & Bibliography Information FY2017 
Task Progress: In the first 8 months, we have secured IRB (Institutional Review Board) approval from both Beth Israel Deaconess Medical Center (BIDMC) in Boston and NASA’s Johnson Space Center in Houston. We have worked with NASA personnel to clarify what data will be transferred to BIDMC. Transfer of all astronaut CT images and other data should take place in the near future, and then data analysis can commence.

Bibliography Type: Description: (Last Updated: 10/14/2021)  Show Cumulative Bibliography Listing
 
 None in FY 2017
Project Title:  Vertebral Strength and Fracture Risk following Long Duration Spaceflight Reduce
Fiscal Year: FY 2016 
Division: Human Research 
Research Discipline/Element:
HRP HFBP:Human Factors & Behavioral Performance (IRP Rev H)
Start Date: 11/16/2015  
End Date: 11/15/2017  
Task Last Updated: 01/14/2016 
Download report in PDF pdf
Principal Investigator/Affiliation:   Bouxsein, Mary  Ph.D. / Beth Israel Deaconess Medical Center/Harvard Medical School 
Address:  Department of Orthopedic Surgery 
330 Brookline Ave, RN115 
Boston , MA 02215-5400 
Email: mbouxsei@bidmc.harvard.edu 
Phone: 617-667-4594  
Congressional District:
Web:  
Organization Type: UNIVERSITY 
Organization Name: Beth Israel Deaconess Medical Center/Harvard Medical School 
Joint Agency:  
Comments:  
Co-Investigator(s)
Affiliation: 
Kopperdahl, David  Ph.D. O.N. Diagnostics 
Project Information: Grant/Contract No. NNX16AC15G 
Responsible Center: NASA JSC 
Grant Monitor: Whitmore, Mihriban  
Center Contact: 281-244-1004 
mihriban.whitmore-1@nasa.gov 
Solicitation / Funding Source: 2014-15 HERO NNJ14ZSA001N-Crew Health (FLAGSHIP & NSBRI) 
Grant/Contract No.: NNX16AC15G 
Project Type: FLIGHT,GROUND 
Flight Program:  
TechPort: No 
No. of Post Docs:  
No. of PhD Candidates:  
No. of Master's Candidates:  
No. of Bachelor's Candidates:  
No. of PhD Degrees:  
No. of Master's Degrees:  
No. of Bachelor's Degrees:  
Human Research Program Elements: (1) HFBP:Human Factors & Behavioral Performance (IRP Rev H)
Human Research Program Risks: (1) Fracture:Risk of Bone Fracture due to Spaceflight-induced Changes to Bone (IRP Rev F)
(2) Occupant Protection:Risk of Injury from Dynamic Loads (Risk move from HHC to SHFH per IRP Rev F)
(3) Osteo:Risk Of Early Onset Osteoporosis Due To Spaceflight (No longer used, July 2020)
Human Research Program Gaps: (1) Fracture03:We need a validated method to estimate the risk of fracture by evaluating the ratio of applied loads to bone fracture loads for expected mechanically-loaded activities during a mission (IRP Rev E)
(2) OP-04:We do not know the extent to which spaceflight deconditioning decreases injury tolerance for dynamic loads. (Previous title: OP5) (IRP Rev H)
(3) Osteo03:We need a validated clinically relevant method for assessing the effect of spaceflight on osteoporosis or fracture risk in long-duration astronauts (IRP Rev E)
Task Description: Mechanical loading is required for maintenance of the musculoskeletal system. Thus, exposure to microgravity induces marked bone loss in both humans and animals, and is a major concern for astronauts exposed to long-duration spaceflight, as they may be at increased risk for skeletal fragility and bone fractures. Most prior studies have relied on dual-energy X-ray absorptiometry (DXA), a 2D technique used to assess bone mass at different skeletal sites, to assess effects of spaceflight on bone strength and fracture risk. However, DXA-based measurements are limited in several regards. Newer technologies, including 3D quantitative computed tomography (QCT) are able to overcome the limitations of DXA. Moreover, QCT images can be used to estimate bone strength using a standard engineering approach called finite element analysis. Indeed, QCT images have been used successfully to demonstrate negative effects of spaceflight on hip bone density and strength. However, a similar examination of the effects of spaceflight on vertebral strength has not been performed. Thus the degree of spinal deconditioning and subsequent risk of vertebral fracture following long-duration spaceflight remains unknown.

Specific Aims:

1) Determine changes in lumbar vertebral strength in long-duration International Space Station (ISS) astronauts

2) Compute subject-specific load-to-strength ratio to estimate risk of vertebral fracture in long-duration ISS astronauts

3) Perform Biomechanical Computed Tomography (BCT) analysis — aka finite element analysis of QCT scans on spine scans for up to 18 astronauts at up to visits (pre, post, and 1 Year, for all n=18; one additional visit for n=8), and analyzing two vertebral levels per subject (total number of BCT analyses = 124)

Research Impact/Earth Benefits:

Task Progress & Bibliography Information FY2016 
Task Progress: New project for FY2016.

Bibliography Type: Description: (Last Updated: 10/14/2021)  Show Cumulative Bibliography Listing
 
 None in FY 2016