title: Physiologic and behavioral indicators of energy deficiency in female adolescent runners with elevated bone turnover.
abstract: BACKGROUND
  Female adolescent runners have an elevated prevalence of low bone mass for agemdashan outcome that may be partially due to inadequate energy intake.
  
  
  OBJECTIVE
  The objective was to evaluate diet, menstrual history, serum hormone concentrations, and bone mass in female adolescent runners with normal or abnormal bone turnover.
  
  
  METHODS
  Thirty-nine cross-country runners (age: 15.7 plusmn 0.2 y) participated in the study, which included a 7-d dietary assessment with the use of a food record and daily 24-h dietary recalls; serum measures of insulin-like growth factor I, estradiol, leptin, parathyroid hormone, progesterone, triiodothyronine, 25-hydroxycholecalciferol, bone-specific alkaline phosphatase (BAP), and cross-linked C-telopeptides of type I collagen (CTX); an evaluation of height, weight, bone mass, and body composition with the use of dual-energy X-ray absorptiometry; and a questionnaire to assess menses and sports participation. Age- and sex-specific BAP and CTX concentrations of at least the 97th percentile and no greater than the third percentile, respectively, were considered abnormal.
  
  
  RESULTS
  All abnormal BAP and CTX concentrations fell within the elevated ( ge 97%) range. Runners with an elevated bone turnover (EBT) (n = 13) had a lower body mass, fewer menstrual cycles in the past year, lower estradiol and 25-hydroxycholecalciferol concentrations, and a higher prevalence of body mass index lt 10% for age, vitamin D insufficiency, amenorrhea, and low bone mass. Girls with EBT consumed less than the recommended amounts of energy and had a higher prevalence of consuming lt 1300 mg Ca than did those with normal bone turnover.
  
  
  CONCLUSIONS
  Runners with EBT had a profile consistent with energy deficiency. Nutritional support to increase energy, calcium intake, and 25-hydroxycholecalciferol concentrations may improve bone mineral accrual in young runners with EBT. This trial was registered at clinicaltrials.gov as NCT01059968.
authors.affiliation: University of California Davis, USA. michellebarrack@gmail.com
authors.forename: Michelle T
authors.initials: MT
authors.lastname: Barrack
authors.forename: Marta D
authors.initials: MD
authors.lastname: Van Loan
authors.forename: Mitchell J
authors.initials: MJ
authors.lastname: Rauh
authors.forename: Jeanne F
authors.initials: JF
authors.lastname: Nichols
mesh_terms: D000293:Adolescent; D000469:Alkaline Phosphatase / Q000097:blood*; D000568:Amenorrhea / Q000097:blood; D056352:Athletes; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D001835:Body Weight; D015519:Bone Density; D016723:Bone Remodeling / Q000502:physiology*; D002136:Calcium, Dietary / Q000008:administration & dosage; D024042:Collagen Type I / Q000097:blood*; D004032:Diet; D015930:Diet Records; D004034:Diet Surveys; D002149:Energy Intake; D004958:Estradiol / Q000097:blood; D005260:Female; D006801:Humans; D008598:Menstruation / Q000502:physiology; D010455:Peptides / Q000097:blood*; D012420:Running / Q000502:physiology*; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood
chemical_list: D015415:Biomarkers; D002136:Calcium, Dietary; D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D014807:Vitamin D; D004958:Estradiol; C104450:25-hydroxyvitamin D; D000469:Alkaline Phosphatase