title: Bone turnover markers do not predict stress fracture in elite combat recruits.
abstract: BACKGROUND
  With bone resorption rates greater than formation, stress fracture pathogenesis plausibly involves bone remodeling imbalance. If this is the case, one would anticipate serum levels of bone turnover markers would be higher in patients with stress fractures than in those without.
  
  
  OBJECTIVE
  We therefore asked whether: (1) bone turnover markers differ between soldiers who will or will not have stress fractures during basic training; (2) bone turnover markers change during basic training; and (3) serial bone formation or bone resorption markers differ between subjects with and without stress fractures during basic training?
  
  
  METHODS
  We performed serial determinations of serum bone formation (bone alkaline phosphatase [BAP] and procollagen type I amino-terminal propeptide [PINP]), and resorption (tartrate-resistant acid phosphatase [TRAP5b] and cross-linked collagen telopeptide [CTx]) biomarkers, measured at 2- to 4-week intervals (during 18 weeks) in 69 male soldiers in the Israeli Defense Forces during elite basic training. Twenty-two soldiers (32%) were diagnosed with stress fractures. The mean training week at diagnosis was 8.0±2.0 weeks.
  
  
  RESULTS
  We observed no differences in bone turnover markers between soldiers with and without stress fractures. During basic training, the mean values of all subjects for bone turnover markers (BAP, PINP, and CTx) changed in comparison to their mean levels at induction (43.9 versus 37.3 μg/L, 110.4 versus 78.0 μg/L, 1.4 versus 1.1 ng/mL, respectively). We found no changes in bone formation and resorption markers between subjects with and without stress fractures.
  
  
  CONCLUSIONS
  These specific bone turnover markers cannot be considered as either diagnostic or predictive tools for stress fracture detection in young male military recruits.
  
  
  METHODS
  Level II prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.
authors.affiliation: Institute of Military Physiology, IDF Medical Corps, Tel-Hashomer, Israel.
authors.forename: Ran
authors.initials: R
authors.lastname: Yanovich
authors.forename: Rachel K
authors.initials: RK
authors.lastname: Evans
authors.forename: Eitan
authors.initials: E
authors.lastname: Friedman
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Moran
mesh_terms: D000135:Acid Phosphatase / Q000097:blood; D000293:Adolescent; D000469:Alkaline Phosphatase / Q000097:blood; D000704:Analysis of Variance; D000886:Anthropometry; D015415:Biomarkers / Q000097:blood*; D001862:Bone Resorption / Q000097:blood*; D015775:Fractures, Stress / Q000097:blood*; D006801:Humans; D007527:Isoenzymes / Q000097:blood; D007557:Israel; D008297:Male; D008666:Metalloendopeptidases / Q000097:blood; D008889:Military Personnel; D010446:Peptide Fragments / Q000097:blood; D011237:Predictive Value of Tests; D011347:Procollagen / Q000097:blood; D000071681:Tartrate-Resistant Acid Phosphatase
chemical_list: D015415:Biomarkers; D007527:Isoenzymes; D010446:Peptide Fragments; D011347:Procollagen; C047202:procollagen Type I N-terminal peptide; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase; D008666:Metalloendopeptidases; C050681:collagen telopeptidase