title: Iron status and its relations with oxidative damage and bone loss during long-duration space flight on the International Space Station.
abstract: BACKGROUND
  Increases in stored iron and dietary intake of iron during space flight have raised concern about the risk of excess iron and oxidative damage, particularly in bone.
  
  
  OBJECTIVE
  The objectives of this study were to perform a comprehensive assessment of iron status in men and women before, during, and after long-duration space flight and to quantify the association of iron status with oxidative damage and bone loss.
  
  
  METHODS
  Fasting blood and 24-h urine samples were collected from 23 crew members before, during, and after missions lasting 50 to 247 d to the International Space Station.
  
  
  RESULTS
  Serum ferritin and body iron increased early in flight, and transferrin and transferrin receptors decreased later, which indicated that early increases in body iron stores occurred through the mobilization of iron to storage tissues. Acute phase proteins indicated no evidence of an inflammatory response during flight. Serum ferritin was positively correlated with the oxidative damage markers 8-hydroxy-2'-deoxyguanosine (r = 0.53, P < 0.001) and prostaglandin F2α (r = 0.26, P < 0.001), and the greater the area under the curve for ferritin during flight, the greater the decrease in bone mineral density in the total hip (P = 0.031), trochanter (P = 0.006), hip neck (P = 0.044), and pelvis (P = 0.049) after flight.
  
  
  CONCLUSIONS
  Increased iron stores may be a risk factor for oxidative damage and bone resorption.
authors.affiliation: Division of Space Life Sciences, Universities Space Research Association, Houston, TX, USA.
authors.forename: Sara R
authors.initials: SR
authors.lastname: Zwart
authors.forename: Jennifer L L
authors.initials: JL
authors.lastname: Morgan
authors.forename: Scott M
authors.initials: SM
authors.lastname: Smith
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000328:Adult; D015415:Biomarkers / Q000097:blood; D015519:Bone Density; D001862:Bone Resorption / Q000503:physiopathology*; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000097:blood; D005260:Female; D005269:Femur / Q000378:metabolism; D005293:Ferritins / Q000097:blood; D006801:Humans; D019190:Iron Overload / Q000097:blood / Q000150:complications / Q000503:physiopathology; D019266:Iron, Dietary / Q000008:administration & dosage / Q000097:blood*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D018384:Oxidative Stress; D013026:Space Flight; D011795:Surveys and Questionnaires
chemical_list: D015415:Biomarkers; D019266:Iron, Dietary; D000080242:8-Hydroxy-2'-Deoxyguanosine; D005293:Ferritins; D003849:Deoxyguanosine