New approach to identifying elite winter sport athletes' risk of relative energy deficiency in sport (REDs).

Objectives: Relative energy deficiency in sport (REDs) is a syndrome resulting from problematic low energy availability (LEA). Low areal bone mineral density (aBMD) is a primary indicator of LEA, measured by dual X-ray absorptiometry (DXA). High-resolution peripheral quantitative CT (HR-pQCT) is an advanced imaging device that provides measures of volumetric BMD (vBMD), bone microarchitecture, geometry and strength. This study aimed to assess the prevalence of REDs in elite winter sport athletes and to observe the associations in bone parameters using HR-pQCT in athletes identified as at-risk or not at-risk of REDs.

Methods: Participants included 101 elite athletes (24.1±4.4 SD years; 52% female). The REDs Clinical Assessment Tool (CAT2) was used to determine REDs risk. HR-pQCT scans of the non-dominant radius and left tibia were analysed on REDs risk grouping.

Results: 17 athletes (17%; 71% female) were at-risk based on the REDs CAT2. After covarying for lean mass, OR suggested a higher likelihood of REDs risk classification for athletes with low cortical thickness, cortical area, total vBMD and bone strength.

Conclusions: Impaired total vBMD, bone strength and cortical bone parameters were approximately twice as likely (OR: 1.9-3.0) in athletes at-risk of REDs. Results agree with the consensus statement that HR-pQCT may identify impaired bone health in athletes at-risk of REDs. Future directions should use HR-pQCT to explore REDs risk longitudinally, using bone change over time, as this may provide greater insight. Using advanced imaging to explore REDs risk in a population of winter high-performance athletes is novel.