title: Higher incidence of bone stress injuries with increasing female athlete triad-related risk factors: a prospective multisite study of exercising girls and women.
abstract: BACKGROUND
  Identifying the risk factors associated with a bone stress injury (BSI), including stress reactions and stress fractures, may aid in targeting those at increased risk and in formulating prevention guidelines for exercising girls and women.
  
  
  OBJECTIVE
  To evaluate the effect of single or combined risk factors as defined by the female athlete triad-a syndrome involving 3 interrelated spectrums consisting of energy availability, menstrual function, and bone mass-with the incidence of BSIs in a multicenter prospective sample of 4 cohorts of physically active girls and women.
  
  
  METHODS
  Cohort study; Level of evidence, 3.
  
  
  METHODS
  At baseline, participants' (N = 259; mean age, 18.1 ± 0.3 years) anthropometric characteristics, eating attitudes and behaviors, menstrual function, sports participation or exercise activity, and pathological weight control behaviors were assessed. Dual-energy x-ray absorptiometry (DXA) measured the bone mass of the whole body, total hip, femoral neck, lumbar spine, and body composition. Participants were followed prospectively for the occurrence of injuries; those injuries confirmed by a physician were recorded.
  
  
  RESULTS
  Twenty-eight participants (10.8%) incurred a BSI. Forty-six percent of those who had ≥12 h/wk of purposeful exercise, a bone mineral density (BMD) Z score <-1.0, and who exhibited 3 to 4 of the following: BMI <21.0 kg/m2, oligo- or amenorrhea, elevated dietary restraint, and/or participation in a leanness sport exercise/activity at baseline, incurred a BSI during the prospective study period. Single factors significantly (P < .05) associated with the development of a BSI included ≥12 h/wk of purposeful exercise (14.7%), BMI <21.0 kg/m2 (15.3%), and low bone mass (BMD Z score <-1.0; 21.0%). The strongest 2- and 3-variable combined risk factors were low BMD (Z score <-1.0) + ≥12 h/wk of exercise, with 29.7% incurring a BSI (odds ratio [OR], 5.1; 95% CI, 2.2-12.1), and ≥12 h/wk of exercise + leanness sport/activity + dietary restraint, with 46.2% incurring a BSI (OR, 8.7; 95% CI, 2.7-28.3).
  
  
  CONCLUSIONS
  In the sample, which included female adolescents and young adults participating in competitive or recreational exercise activities, the risk of BSIs increased from approximately 15% to 20% for significant single risk factors to 30% to 50% for significant combined female athlete triad-related risk factor variables. These data support the notion that the cumulative risk for BSIs increases as the number of Triad-related risk factors accumulates.
authors.affiliation: Michelle T. Barrack, California State University, Northridge, 18111 Nordhoff Street, Northridge, CA 91330, USA. michellebarrack@gmail.com.
authors.forename: Michelle T
authors.initials: MT
authors.lastname: Barrack
authors.forename: Jenna C
authors.initials: JC
authors.lastname: Gibbs
authors.forename: Mary Jane
authors.initials: MJ
authors.lastname: De Souza
authors.forename: Nancy I
authors.initials: NI
authors.lastname: Williams
authors.forename: Jeanne F
authors.initials: JF
authors.lastname: Nichols
authors.forename: Mitchell J
authors.initials: MJ
authors.lastname: Rauh
authors.forename: Aurelia
authors.initials: A
authors.lastname: Nattiv
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D000886:Anthropometry; D015519:Bone Density; D002140:California / Q000453:epidemiology; D004032:Diet; D002149:Energy Intake; D005260:Female; D053716:Female Athlete Triad Syndrome / Q000150:complications* / Q000453:epidemiology / Q000517:prevention & control; D015775:Fractures, Stress / Q000453:epidemiology* / Q000209:etiology* / Q000517:prevention & control; D006801:Humans; D015994:Incidence; D009864:Ontario / Q000453:epidemiology; D010414:Pennsylvania / Q000453:epidemiology; D011446:Prospective Studies; D012307:Risk Factors; D013177:Sports; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: amenorrhea; dietary restraint; female athlete triad; low bone mineral density; stress fracture