title: Factors associated with menstrual dysfunction and self-reported bone stress injuries in female runners in the ultra- and half-marathons of the Two Oceans.
abstract: OBJECTIVE
  To investigate factors associated with menstrual dysfunction, self-reported bone stress injuries and energy balance in women runners.
  
  
  METHODS
  613 runners were randomly sampled during the registration period for an endurance event. Demographic information, including self-reported height and weight, training and injury history and menstrual history, was collected by questionnaire.
  
  
  RESULTS
  Ultra-marathon (ULTRA) participants (n = 276) were significantly older (mean (SD) 39 (8.2) vs 34 (10.5) years; p<0.001), lighter (58.2 (6.6) vs 59.6 (8.3) kg; p<0.05) and reported a higher training volume (p<0.001) than half-marathon (HALF) participants (n = 337). Significantly more ULTRA subjects than HALF subjects reported a previous bone stress injury (21% vs 14%; p<0.05). There was no difference between the groups for menstrual status, but age at menarche was later (p<0.01) in the ULTRA group. Data were combined according to the absence (REG; n = 368/602 (61%)) or presence (IRREG; n = 234/602 (39%)) of a history of menstrual irregularity. Subject morphology was similar between groups, but the IRREG group had a higher self-reported measure on the self-loathing subscale (SLSS; p<0.01). The whole group was then classified according to current menstrual status, with 165 women being classified as currently irregular. (OLIGO/AMEN; 11.6%) and 445 women as currently regular (EUMEN; 88.4%). There were no morphological differences between the groups, however the OLIGO/AMEN group had a later age of menarche (p<0.01) than the EUMEN group. Further, women who reported a previous bone stress injury had higher SLSS scores than those who did not (2.91 (0.98) vs 2.68 (0.84); p<0.05).
  
  
  CONCLUSIONS
  There may be two independent mechanisms associated with energy balance, which are related to bone stress injuries, but may not necessarily be related to menstrual dysfunction.
authors.affiliation: UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, UCT School of Health Sciences, University of Cape Town, South Africa. lisam@sports.uct.ac.za
authors.forename: L K
authors.initials: LK
authors.lastname: Micklesfield
authors.forename: J
authors.initials: J
authors.lastname: Hugo
authors.forename: C
authors.initials: C
authors.lastname: Johnson
authors.forename: T D
authors.initials: TD
authors.lastname: Noakes
authors.forename: E V
authors.initials: EV
authors.lastname: Lambert
mesh_terms: D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D001835:Body Weight; D015519:Bone Density / Q000502:physiology*; D001068:Feeding and Eating Disorders / Q000150:complications*; D005260:Female; D015775:Fractures, Stress / Q000209:etiology*; D006801:Humans; D008572:Menarche / Q000502:physiology; D008599:Menstruation Disturbances / Q000150:complications / Q000503:physiopathology*; D008875:Middle Aged; D012420:Running / Q000293:injuries / Q000502:physiology*; D011795:Surveys and Questionnaires