title: Spaceflight-induced bone loss: is there an osteoporosis risk?
abstract: Currently, the measurement of areal bone mineral density (aBMD) is used at NASA to evaluate the effects of spaceflight on the skeletal health of astronauts. Notably, there are precipitous declines in aBMD with losses >10 % detected in the hip and spine in some astronauts following a typical 6-month mission in space. How those percentage changes in aBMD relate to fracture risk in the younger-aged astronaut is unknown. Given the unique set of risk factors that could be contributing to this bone loss (eg, adaptation to weightlessness, suboptimal diet, reduced physical activity, perturbed mineral metabolism), one might not expect skeletal changes due to spaceflight to be similar to skeletal changes due to aging. Consequently, dual-energy X-ray absorptiometry (DXA) measurement of aBMD may be too limiting to understand fracture probability in the astronaut during a long-duration mission and the risk for premature osteoporosis after return to Earth. Following a brief review of the current knowledge-base, this paper will discuss some innovative research projects being pursued at NASA to help understand skeletal health in astronauts.
authors.affiliation: NASA Johnson Space Center, 2101 NASA Parkway, Houston, TX 77058, USA. Jean.sibonga-1@NASA.gov
authors.forename: Jean D
authors.initials: JD
authors.lastname: Sibonga
mesh_terms: D015502:Absorptiometry, Photon; D018480:Astronauts; D015519:Bone Density; D020342:Finite Element Analysis; D006801:Humans; D010024:Osteoporosis / Q000175:diagnosis / Q000209:etiology*; D013026:Space Flight; D014481:United States; D014893:Weightlessness / Q000009:adverse effects*
references.citation: J Clin Endocrinol Metab. 2010 May;95(5):2248-53
references.pmid: 20305005
references.citation: J Bone Miner Res. 2005 Feb;20(2):208-18
references.pmid: 15647814
references.citation: Bone. 2010 Jan;46(1):176-81
references.pmid: 19747992
references.citation: Am J Physiol. 1999 Jul;277(1 Pt 2):R1-10
references.pmid: 10409251
references.citation: Bone. 2007 Dec;41(6):973-8
references.pmid: 17931994
references.citation: J Bone Miner Res. 2008 Feb;23(2):205-14
references.pmid: 17937534
references.citation: J Bone Miner Res. 2009 Mar;24(3):475-83
references.pmid: 19049327
references.citation: Ann Biomed Eng. 2009 Nov;37(11):2337-59
references.pmid: 19707874
references.citation: Bone. 2011 Jun 1;48(6):1239-45
references.pmid: 21419886
references.citation: Lancet. 2000 May 6;355(9215):1607-11
references.pmid: 10821365
references.citation: Clin Orthop Relat Res. 2005 Aug;(437):219-28
references.pmid: 16056052
references.citation: J Bone Miner Res. 2008 Dec;23(12):1974-82
references.pmid: 18684084
references.citation: J Clin Endocrinol Metab. 2012 Sep;97(9):E1736-40
references.pmid: 22767636
references.citation: Bone. 2008 Apr;42(4):775-87
references.pmid: 18234577
references.citation: J Musculoskelet Neuronal Interact. 2000 Dec;1(2):157-60
references.pmid: 15758512
references.citation: J Bone Miner Res. 2004 Jun;19(6):1006-12
references.pmid: 15125798
references.citation: Bone. 2009 Mar;44(3):449-53
references.pmid: 19100348
references.citation: J Bone Miner Res. 2012 Feb;27(2):352-9
references.pmid: 22006831
references.citation: J Bone Miner Res. 2006 Aug;21(8):1224-30
references.pmid: 16869720
references.citation: J Bone Miner Res. 2008 Aug;23(8):1326-33
references.pmid: 18348697
references.citation: J Clin Endocrinol Metab. 1998 Oct;83(10):3584-91
references.pmid: 9768669
references.citation: J Biol Chem. 2008 Feb 29;283(9):5866-75
references.pmid: 18089564
references.citation: J Bone Miner Res. 2012 Sep;27(9):1896-906
references.pmid: 22549960
references.citation: J Bone Miner Res. 2010 May;25(5):994-1001
references.pmid: 19874201