Cortical Microstructure and Estimated Bone Strength in Young Amenorrheic Athletes, Eumenorrheic Athletes and Non-Athletes

Bone. 2012 Oct;51(4):680-7. doi: 10.1016/j.bone.2012.07.019. Epub 2012 Aug 2.

Abstract

Context: Lower bone density in young amenorrheic athletes (AA) compared to eumenorrheic athletes (EA) and non-athletes may increase fracture risk during a critical time of bone accrual. Finite element analysis (FEA) is a unique tool to estimate bone strength in vivo, and the contribution of cortical microstructure to bone strength in young athletes is not well understood.

Objective: We hypothesized that FEA-estimated stiffness and failure load are impaired in AA at the distal radius and tibia compared to EA and non-athletes despite weight-bearing exercise.

Design and setting: Cross-sectional study; Clinical Research Center

Subjects: 34 female endurance athletes involved in weight-bearing sports (17 AA, 17 EA) and 16 non-athletes (14-21 years) of comparable age, maturity and BMI OUTCOME MEASURES: We used HR-pQCT images to assess cortical microarchitecture and FEA to estimate bone stiffness and failure load.

Results: Cortical perimeter, porosity and trabecular area at the weight-bearing tibia were greater in both groups of athletes than non-athletes, whereas the ratio (%) of cortical to total area was lowest in AA. Despite greater cortical porosity in EA, estimated tibial stiffness and failure load was higher than in non-athletes. However, this advantage was lost in AA. At the non-weight-bearing radius, failure load and stiffness were lower in AA than non-athletes. After controlling for lean mass and menarchal age, athletic status accounted for 5-9% of the variability in stiffness and failure load, menarchal age for 8-23%, and lean mass for 12-37%.

Conclusion: AA have lower FEA-estimated bone strength at the distal radius than non-athletes, and lose the advantage of weight-bearing exercise seen in EA at the distal tibia.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adolescent
  • Amenorrhea / physiopathology*
  • Body Composition
  • Bone Density
  • Bone and Bones / physiology*
  • Bone and Bones / ultrastructure*
  • Case-Control Studies
  • Female
  • Humans
  • Menstruation*
  • Multivariate Analysis
  • Sports*
  • Tomography, X-Ray Computed