title: Low Back Pain in Microgravity and Bed Rest Studies.
abstract: BACKGROUND
  The prevalence of low back pain (LBP) for astronauts in space (68%) is higher than the 1-mo prevalence for the general population on Earth (39%). It is unclear whether differences occur between healthy subjects and astronauts with a history of LBP. Knowledge of this issue is important to assess whether a history of LBP could have an operational impact.
  
  
  METHODS
  We evaluated LBP prospectively during short duration spaceflight (15 d; N=20) and compared this with similar data collected during two bed rest studies (N=40). Astronauts completed a questionnaire 5-10 d preflight, during each flight day, and 5-10 d postflight.
  
  
  RESULTS
  All astronauts with a history of LBP also developed LBP in flight. These astronauts reported a significantly longer duration of LBP and a different pain location. LBP was most often experienced in the central area of the lower back during spaceflight with an incidence of 70% and a mean pain level of 3 (on a scale of 0-10). Pain resolved within 10 d of flight. No neurological signs were present. The most frequently reported countermeasure was assuming a "knees to chest (fetal tuck) position" combined with stretching. Greater LBP intensity was reported in spaceflight than bed rest with a trend indicating a greater number of days of pain during spaceflight.
  
  
  CONCLUSIONS
  The current study represents a prospective study of LBP in spaceflight. The results indicate that LBP is self-limiting in spaceflight and should not pose an operational risk. Prior LBP on Earth appears to be a risk factor for LBP in spaceflight.
authors.affiliation: Department of Neuroscience, ErasmusMC University, Rotterdam, The Netherlands.
authors.forename: Annelies L
authors.initials: AL
authors.lastname: Pool-Goudzwaard
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Belavý
authors.forename: Julie A
authors.initials: JA
authors.lastname: Hides
authors.forename: Carolyn A
authors.initials: CA
authors.lastname: Richardson
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Snijders
mesh_terms: D000328:Adult; D018480:Astronauts / Q000706:statistics & numerical data; D001510:Bed Rest; D005260:Female; D006801:Humans; D015994:Incidence; D017116:Low Back Pain / Q000453:epidemiology* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D013026:Space Flight; D014893:Weightlessness; D055815:Young Adult