Low Energy Availability Associated With Lower BMD And Bone Stress Injury Site In Female Athletes

Abstract

Low energy availability (LEA) is a risk factor for impaired bone health and bone stress injury (BSI). Additionally, those with BSI at trabecular-rich bone sites are at higher risk for low BMD vs. those with BSI at only cortical-rich sites. PURPOSE: To evaluate the association of LEA with BMD and site of BSI in female athletes. METHODS: 1000 female athletes (ages 15-30 years) presenting to a sports medicine clinic completed a 400+ question survey covering topics related to relative energy deficiency in sport (RED-S), including female athlete triad risk factors and athletic activity. Comprehensive chart review was completed to identify athletes with history of BSI and available dual energy x-ray absorptiometry (DXA). LEA was defined as meeting ≥ 1 criterion: self-reported history of eating disorder/disordered eating (ED/DE), high score on the Brief Eating Disorder in Athletes Questionnaire (BEDA-Q), and/or high score on the Eating Disorder Screen for Primary Care (ESP). Athletes with BSI of the pelvis, femoral neck, sacrum, and/or calcaneus were categorized into the trabecular-rich BSI group; all others were categorized into the cortical-rich BSI group. Associations between EA status, BSI location, and DXA were assessed by chi-squared or t-test analysis (p<0.05). RESULTS: Of the 1000 patients surveyed, 126 had a history of both BSI and available DXA. Of these patients, 53.2% had LEA. Patients with LEA had lower BMD Z-scores than those with normal EA at the lumbar spine (-0.92±1.06 vs. -0.49±0.98, p=0.022), total hip (-0.27±0.75 vs. 0.29±0.77, p=0.009), and femoral neck (-0.34±0.87 vs. 0.23±0.97, p=0.028). Patients with ≥ 1 trabecular BSI accounted for 21.4% of the sample. In the trabecular-rich BSI group, 70.4% had LEA, while 48.5% of those in the cortical-rich group had LEA (p=0.043). Additionally, those with trabecular-rich BSI had lower BMD than the cortical-rich BSI group at the lumbar spine (-1.19±1.10 vs. -0.58±0.99, p=0.015), but not at other sites assessed by DXA. CONCLUSIONS: Our findings support the well-established relationship between LEA and impaired BMD. We also found that trabecular-rich BSI is associated with low EA and independently associated with low BMD. Therefore, trabecular BSI may serve as a clinical indicator for further bone health evaluation and assessment for LEA, including ED/DE.