Cortical microstructure and estimated bone strength in young amenorrheic athletes, eumenorrheic athletes and non-athletes

• Published in: Bone (New York, N.Y.) Vol. 51; no. 4; pp. 680 - 687
• Main Authors: Ackerman, Kathryn E., Putman, Melissa, Guereca, Gabriela, Taylor, Alexander P., Pierce, Lisa, Herzog, David B., Klibanski, Anne, Bouxsein, Mary, Misra, Madhusmita
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.10.2012; Elsevier
• Subjects: Adolescent; Adolescents; Amenorrhea - physiopathology; Athletes; Biological and medical sciences; Body Composition; Bone and Bones - physiology; Bone and Bones - ultrastructure; Bone Density; Bone strength; Case-Control Studies; Failure load; Female; Fundamental and applied biological sciences. Psychology; Humans; Menstruation; Multivariate Analysis; Orthopedics; Sports; Stiffness; Tomography, X-Ray Computed; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Stiffness; Failure load; Athletes; Adolescents; Bone strength; Human; Load; Athlete; Morphology; Adolescent; Microstructure; Failure; Cortical bone; Strength
• ISSN: 8756-3282; 1873-2763; 1873-2763
• DOI: 10.1016/j.bone.2012.07.019

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. 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. Cross-sectional study; Clinical Research Center 34 female endurance athletes involved in weight-bearing sports (17 AA, 17 EA) and 16 non-athletes (14–21years) of comparable age, maturity and BMI We used HR-pQCT images to assess cortical microarchitecture and FEA to estimate bone stiffness and failure load. 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%. 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. ► Finite element analysis allows estimation of bone stiffness and failure load. ► Bone strength estimates were assessed in young, weight-bearing endurance athletes. ► Amenorrheic athletes (AA) have lower bone strength at the radius than non-athletes. ► Eumenorrheic athletes have higher bone strength at the tibia than non-athletes. ► In AA, loss of strength at the radius is attenuated at the weight-bearing tibia.