Bone-Mineral Density and Other Features of the Female Athlete Triad in Elite Endurance Runners: A Longitudinal and Cross-Sectional Observational Study

Abstract

Low bone-mineral density (BMD) is associated with menstrual dysfunction and negative energy balance in the female athlete triad. This study determines BMD in elite female endurance runners and the associations between BMD, menstrual status, disordered eating, and training volume. Forty-four elite endurance runners participated in the cross-sectional study, and 7 provided longitudinal data. Low BMD was noted in 34.2% of the athletes at the lumbar spine, and osteoporosis in 33% at the radius. In cross-sectional analysis, there were no significant relationships between BMD and the possible associations. Menstrual dysfunction, disordered eating, and low BMD were coexistent in 15.9% of athletes. Longitudinal analysis identified a positive association between the BMD reduction at the lumbar spine and training volume (p=.026). This study confirms the presence of aspects of the female athlete triad in elite female endurance athletes and notes a substantial prevalence of low BMD and osteoporosis. Normal menstrual status was not significantly associated with normal BMD, and it is the authors' practice that all elite female endurance athletes undergo dual-X-ray absorptiometry screening. The association between increased training volume, trend for menstrual dysfunction, and increased loss of lumbar BMD may support the concept that negative energy balance contributes to bone loss in athletes.

Update on stress fractures in female athletes: epidemiology, treatment, and prevention

“…Some medical professionals have suggested that all female elite endurance athletes be screened with DXA because of the increased risk for impaired bone health in that population [54]. DXA provides information about BMD and composition and serves as a proxy for bone health [55].…”

Definition and Epidemiology of the Female Athlete Triad

“…However, only four studies assessing prevalence of all three Triad components have been conducted since the 2007 ACSM update [17,[19][20][21], and even then they did not all operationalize the constructs of the Triad according to the 2007 ACSM standard (see Table 1.1). One of these four studies, conducted by Schtscherbyna et al [21] in a sample of 78 elite female swimmers (mean age = 14.6 years, SD = 2.0 years), did not incorporate the concept of energy availability into the measurement of prevalence, assessing only disordered eating using three validated written measures of disordered eating risk.…”

“…Pollock et al [20] assessed the prevalence of the conditions of the Triad in a sample of 44 elite female endurance runners (mean age 22.9 years, SD = 6.0 years). BMD was measured at several locations on the body, with Z-scores varying by location.…”

“…A total of ten studies published since 1975 have assessed the prevalence of all three components of the Triad [16,17], with prevalence estimates for all three components ranging from 0 % in a sample of 82 physically active females (mean age 31 years, standard deviation (SD) = 7) [18], and 0 % in a sample of 15 women on a club triathlon team (mean age = 35, SD = 6) [19] to 15.9 % in a sample of 44 elite female endurance athletes [20]. However, only four studies assessing prevalence of all three Triad components have been conducted since the 2007 ACSM update [17,[19][20][21], and even then they did not all operationalize the constructs of the Triad according to the 2007 ACSM standard (see Table 1.1).…”

The Female Athlete Triad: A Metabolic Phenomenon

“…Low energy availability impairs skeletal health by uncoupling the turnover of bone in a manner that lowers bone mineral density over time (Christo et al, 2008;De Souza et al, 2008;Pollock et al, 2010). Like other tissues, bone is constantly turning over as osteoclast cells resorb old bone and osteoblast cells form new bone.…”