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Review of NASA's Evidence Reports on Human Health Risks 2017 Letter Report (2018) / Chapter Skim
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Risk of Bone Fracture Due to Spaceflight-Induced Changes to Bone
Pages 5-11

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From page 5...
... RIS OF BONE FRACTUR DUE TO SK E RE SPACEFL LIGHT-IND DUCED CHA ANGES TO B BONE Boones break when an appli force exce w ied eeds bone str rength. Thus, a , fractur may occur -- re -- and freque ently does -- e even in young healthy bon g nes if they are subjected to sufficient force.
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From page 6...
... Atypical fractures provide evidence that a DXA measurement of bone density does not adequately address bone architecture and that information on other qualities of bone, such as composition and turnover, is needed to better understand and estimate bone strength and fracture risk. Other modalities, such as quantitative computed tomography (QCT)
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From page 7...
... For example, when stating that the risk of fracture in low Earth orbit is negligible, the authors consider both the absence of fracture reports to date and the low loading imposed by a fall in reduced gravity. However, the latter ignores the risk associated with a sudden deceleration of the astronaut and the impact imposed by spacecraft acceleration, either during orbital maneuvers or docking or associated with landing on another surface (for further information see Caldwell et al., 2012)
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From page 8...
... The future risk of bone fracture will surely rise in the era of extensive human exploration of planets and return to the moon, and, later, in the era of working on other planetary bodies rather than merely visiting them. Adjusting to movement on a planetary body after transit in zero-G will require time and care that may, at least transiently, interfere with balance and thereby increase risk of falls and thus fractures (Chappell et al., 2017)
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From page 9...
... • What lessons can be learned from pharmacologic manipulation of bone metabolism to attempt to enhance fracture healing in os teoporotic adults in terrestrial medicine? • What can be learned from the clinical history of osteoporosis and fractures in the quadriplegic/paraplegic population?
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From page 10...
... Is urinary calcium excretion an adequate marker, or do other metrics need to be developed so that countermeasures can be tailored to the needs of each individual astronaut? • How should countermeasures, including the use of anabolic or antiresorptive pharmaceuticals, be altered if deterioration in bone health measures or fracture occurs during a mission?
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From page 11...
... Has the Evidence Report Addressed Previous Recommendations Made by the IOM in the 2008 Letter Report? The addition of this and other evidence reports related to bone demineralization reflect the growing recognition that this issue is of significance.
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Key Terms

  • bone mineral
  • evidence reports
  • mineral density
  • bone fracture
  • bone density

  • bone loss
  • fracture risk
  • atypical fractures
  • bone metabolism
  • bone architecture

  • atypical fracture
  • fracture healing
  • fracture due
  • fracture management
  • density associated

  • risk associated
  • antiresorptive therapy
  • planetary body
  • earth orbit
  • resistive exercise

  • low earth
  • observed changes
  • fractional gravity
  • address bone
  • bone str

  • include bone
  • bone weakened
  • metabolic bone
  • eeds bone
  • bone densi


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