@article{b8da9fe56fda40339e9270fbd0edcbea,
title = "Hip load capacity cut-points for Astronaut Skeletal Health NASA Finite Element Strength Task Group Recommendations",
abstract = "Concerns raised at a 2010 Bone Summit held for National Aeronautics and Space Administration Johnson Space Center led experts in finite element (FE) modeling for hip fracture prediction to propose including hip load capacity in the standards for astronaut skeletal health. The current standards for bone are based upon areal bone mineral density (aBMD) measurements by dual X-ray absorptiometry (DXA) and an adaptation of aBMD cut-points for fragility fractures. Task Group members recommended (i) a minimum permissible outcome limit (POL) for post-mission hip bone load capacity, (ii) use of FE hip load capacity to further screen applicants to astronaut corps, (iii) a minimum pre-flight standard for a second long-duration mission, and (iv) a method for assessing which post-mission physical activities might increase an astronaut{\textquoteright}s risk for fracture after return. QCT-FE models of eight astronaut were analyzed using nonlinear single-limb stance (NLS) and posterolateral fall (NLF) loading configurations. QCT data from the Age Gene/Environment Susceptibility (AGES) Reykjavik cohort and the Rochester Epidemiology Project were analyzed using identical modeling procedures. The 75th percentile of NLS hip load capacity for fractured elderly males of the AGES cohort (9537N) was selected as a post-mission POL. The NLF model, in combination with a Probabilistic Risk Assessment tool, was used to assess the likelihood of exceeding the hip load capacity during post-flight activities. There was no recommendation to replace the current DXA-based standards. However, FE estimation of hip load capacity appeared more meaningful for younger, physically active astronauts and was recommended to supplement aBMD cut-points.",
author = "Michalski, {Andrew S.} and Shreyasee Amin and Cheung, {Angela M.} and Cody, {Dianna D.} and Keyak, {Joyce H.} and Lang, {Thomas F.} and Nicolella, {Daniel P.} and Orwoll, {Eric S.} and Boyd, {Steven K.} and Sibonga, {Jean D.}",
note = "Funding Information: A.S.M. authored the manuscript under the mentorship of his doctoral advisor S.K.B. and NASA mentor J.D.S. S.A., as co-principal investigator of the Mayo Clinic Rochester Bone Health Study, donated the QCT scans from the Mayo Clinic for this study. T.F.L., on behalf of Dr Vilmundur Gudnason principal investigator of AGES, donated QCT scans from the AGES cohort for use in this study. J.H.K. generated FE models from QCT scans and performed FE analysis to estimate hip load capacity used in this study. S.A., T.F.L., A.M.C., D.D.C., J.H.K., D.P.N. and E.S.O. as investigators using FE models in human research provided recommendations on the FE cut-points for skeletal standards, as well as input/review to the manuscript. J.D.S. is the principal investigator of this Directed Study funded by the NASA Human Research Program. Funding Information: We acknowledge the contributions of Dr Sundeep Khosla (Division of Endocrinology, Diabetes, Metabolism and Nutrition, Department of Internal Medicine, Mayo Clinic, Rochester, USA) for his donation of the Mayo cohort QCT and DXA scans and Dr Vilmundur Gudnason (Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland) for his donation of the AGES cohort QCT scans, both of which were used in the analysis of this manuscript. Furthermore, we acknowledge Dr Tony Keaveny (Department of Mechanical Engineering, University of California, Berkeley, USA) for his involvement and feedback with FE Strength Task Group I. We thank Elisabeth Spector (NASA Health and Human Performance, NASA Johnson Space Center, Houston, USA) for her management of the astronaut and population cohort data. Finally, we recognize Dr Beth Lewandowski (Bioscience and Technology Branch, NASA Glenn Research Center, Cleveland, USA) for her work and data provided from the Digital Astronaut Project, and Dr Alan Feiveson (Division of Biomedical Research & Environmental Sciences, NASA Johnson Space Center, Houston, USA) for his time and thoughtful discussions of data. This work was funded in part by the NASA Human Research Program. The Age, Gene/Environment Susceptibility Reykjavik Study is funded by NIH contract N01-AG-12100, the NIA Intramural Research Program, Hjartavernd (the Icelandic Heart Association), and the Althingi (the Icelandic Parliament). The study was approved by the Icelandic National Bioethics Committee (VSN: 00-063) and the Data Protection Authority. This study was also made possible by the Rochester Epidemiology Project. Publisher Copyright: {\textcopyright} 2019, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.",
year = "2019",
month = dec,
day = "1",
doi = "10.1038/s41526-019-0066-3",
language = "English (US)",
volume = "5",
journal = "npj Microgravity",
issn = "2373-8065",
publisher = "Nature Publishing Group",
number = "1",
}