Response to High-Dose Vitamin D Supplementation Is Specific to Imaging Modality and Skeletal Site

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.

Bone Quality in Competitive Athletes: A Systematic Review

The study objective was to assess bone quality measured by high resolution peripheral quantitative computed tomography (HR-pQCT) in competitive athletes. Medline, EMBASE and Sport Discus were searched through May 2022. Prior to submission, a follow-up database search was performed (January 2023). Studies of competitive athletes using HR-pQCT to assess bone quality were included. Athletes were aged between 14 and 45 years. Data extraction included study design and location (country), skeletal imaging modality and site, bone variables and any additional musculoskeletal-related outcome. Information identifying sports and athletes were also extracted. This review included 14 manuscripts and a total of 928 individuals (male: n=75; female: n=853). Athletes comprised 78% (n=722) of the included individuals and 93% of athletes were female. Assessment scores indicate the studies were good to fair quality. The athletes included in this review can be categorized into three groups: 1) healthy athletes, 2) athletes with compromised menstrual function (e.g., amenorrhoea), and 3) athletes with compromised bone health (e.g., bone stress injuries). When assessing bone quality using HR-pQCT, healthy competitive athletes had denser, stronger and larger bones with better microarchitecture, compared with controls. However, the same cannot be said for athletes with amenorrhoea or bone stress injuries.

Comparison of Bone Quality Among Winter Endurance Athletes with and Without Risk Factors for Relative Energy Deficiency in Sport (REDs): A Cross-Sectional Study

Relative Energy Deficiency in Sport (REDs) is a syndrome describing the relationship between prolonged and/or severe low energy availability and negative health and performance outcomes. The high energy expenditures incurred during training and competition put endurance athletes at risk of REDs. The objective of this study was to investigate differences in bone quality in winter endurance athletes classified as either low-risk versus at-risk for REDs. Forty-four participants were recruited (M = 18; F = 26). Bone quality was assessed at the distal radius and tibia using high resolution peripheral quantitative computed tomography (HR-pQCT), and at the hip and spine using dual X-ray absorptiometry (DXA). Finite element analysis was used to estimate bone strength. Participants were grouped using modified criteria from the REDs Clinical Assessment Tool Version 1. Fourteen participants (M = 3; F = 11), were classified as at-risk of REDs (≥ 3 risk factors). Measured with HR-pQCT, cortical bone area (radius) and bone strength (radius and tibia) were 6.8%, 13.1% and 10.3% lower (p = 0.025, p = 0.033, p = 0.027) respectively, in at-risk compared with low-risk participants. Using DXA, femoral neck areal bone density was 9.4% lower in at-risk compared with low-risk participants (p = 0.005). At-risk male participants had 21.9% lower femoral neck areal bone density (via DXA) than low-risk males (p = 0.020) with no significant differences in females. Overall, 33.3% of athletes were at-risk for REDs and had lower bone quality than those at low-risk.