Task Progress:
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The original intent of this study (“Hip QCT”) was to conduct a pilot study of 10 long-duration crewmembers who were already participating in other research studies involving pre and post-flight QCT scans of the hip. These subjects had already participated, or were scheduled to participate, in QCT testing as part of the Bisphosphonate SMO (supplemntary medical objective) or Sprint flight studies: preflight, R+1 week and R+1 year scans in the case of the SMO; and preflight and R+1 week scans in the case of the Sprint study. Sprint study subjects who consented to participate in the Hip QCT study were asked to participate in an additional scan at R+1 yr. All 10 subjects agreed to participate in a final, additional scan at R+2 years, but only if R+1-year testing indicated incomplete recovery in bone mineral density (BMD) of the trabecular compartment of the hip. Of the 10 subjects, 5 met the R+1-year criterion for further testing, and all 5 participated in R+2-year scans. In addition to the 10 original subjects, the study was allowed to include an 11th subject—one crewmember of the 1-year ISS flight—who would participate in the same QCT testing schedule (preflight, R+1 week, R+1 year, and R+2-year if recovery at 1 year was incomplete). In addition to the QCT scans, bone densitometry data by dual energy X-ray absorptiometry (DXA) and bone-related biochemistry data were requested on all subjects and obtained via data-sharing with other studies or medical requirements.
All scheduled testing sessions for the 10 original subjects and the 1-year mission subject were completed by March 2018. QCT scans were submitted to Dr. T. Lang at UCSF (University of California San Francisco) for analysis, including measures of cortical and trabecular BMD, as well as estimates of bone strength computed from Finite Element modeling of the QCT scans. The resulting data have been reduced and analyzed, and preliminary results from the n=10 group were presented at the NASA Human Research Program Investigators’ Workshop in Galveston, TX, (January 2018).
Final results from the n=10 group are now being written up in a manuscript to be submitted for publication in a peer-reviewed scientific journal. Data from the 1-year-mission subject are excluded from this manuscript due to the confounding effects of longer space flight duration, but may be written up as part of a larger, multidisciplinary, effort to document results from the 1-year mission.
There are two manuscript deliverables from the data generated by this study. i) “Supplemental Use of Quantitative Computed Tomography Hip Scans of Astronauts for Clinical Assessments at NASA” to be submitted to journal Aerospace Med Human Performance (Authors: J.D. Sibonga , E.R. Spector , B.E. Lewandowski , S.R. Zwart , S.M. Smith , T.F. Lang ) and ii) “The Utility of Hip Scans by Quantitative Computed Tomography (QCT) to Assess the Mitigation of Skeletal Changes during Spaceflights” to be submitted to journal Bone. (Authors: J.D. Sibonga , E.R. Spector , A.D. Leblanc , B. Lewandowski , M.E. Downs , L. Ploutz - Snyder , T. Lang).
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Articles in Peer-reviewed Journals
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Sibonga JD, Spector ER, Johnston SL, Tarver WJ. "Evaluating bone loss in ISS astronauts." Aerosp Med Hum Perform. 2015 Dec;86(12 Suppl):A38-A44. https://doi.org/10.3357/AMHP.EC06.2015 ; PubMed PMID: 26630194
, Dec-2015
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Articles in Peer-reviewed Journals
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Sibonga JD, Spector ER, Keyak JH, Zwart SR, Smith SM, Lang TF. "Use of quantitative computed tomography to assess for clinically-relevant skeletal effects of prolonged spaceflight on astronaut hips." J Clin Densitom. 2020 Apr-Jun;23(2):155-64. Epub 2019 Aug 26. https://doi.org/10.1016/j.jocd.2019.08.005 ; PubMed PMID: 31558405 , May-2020
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