title: [Bone loss and bone metabolism in astronauts during long-duration space flight].
abstract: Significant bone loss is one of the most serious medical concerns during long-duration space flight. This article provides the results of bone loss and bone metabolism obtained from American and Russian long-duration human space flight. Bone loss in astronauts before and after long-duration space flight was evaluated by dual energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT). DXA revealed bone loss at rates of 0.9%/month in the lumbar spine and 1.5%/month in the femoral neck. QCT revealed cortical, trabecular and integral BMD in the femoral neck at rates of 0.5%/month, 2.5%/month, and 1.5%/month, respectively. Biochemical markers of bone resorption increased during space flight and several months after landing. Bone formation marker was unchanged during space flight, but since 3 weeks after landing it was significantly higher than before flight. A calcium kinetics study confirmed that bone resorption increased, and intestinal calcium absorption decreased during space flight.
authors.affiliation: Space Medicine Group, Human Space Technology and Astronauts Department, Japan Aerospace Exploration Agency (JAXA).
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohshima
mesh_terms: D015502:Absorptiometry, Photon; D018480:Astronauts; D015415:Biomarkers / Q000032:analysis; D015519:Bone Density; D001862:Bone Resorption / Q000378:metabolism*; D001842:Bone and Bones / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D006801:Humans; D013026:Space Flight
chemical_list: D015415:Biomarkers; D002118:Calcium