Lower Trabecular Bone Score and Spine Bone Mineral Density Are Associated With Bone Stress Injuries and Triad Risk Factors in Collegiate Athletes

The relationship between serum vitamin D, bone mineral density, and injury in collegiate acrobatics and tumbling athletes

Background: Medical staff for indoor aesthetic sports such as acrobatics and tumbling (A&T) is often concerned with athletes' bone mineral density (BMD), serum vitamin D (SvD), and associated injury risks. Aim: To evaluate the relationship between BMD, SvD, and injury among A&T athletes. Methods: 42 (19 tops, 23 bases) female A&T athletes aged 19.6 (±1.17) years participated. Two samples of SvD were taken. Injury and BMD data were provided by support staff. Bivariate and multivariate analysis assessed relationships between and among variables. Results: Participants experienced a decrease in SvD (6.093 ± 10.973). Spine BMD was significantly higher in bases compared to tops (p = 0.039). BMD and SvD did not differ based on injuries sustained. Conclusion: Relationships between SvD, BMD, and injury were not identified. Positional differences in BMD may be related to the demands of each role. Participants possessed low SvD and high BMDs, which may provide useful information for medical staff.

Can Trabecular Bone Score Enhance Fracture Risk Assessment in Long-Distance Runners With Bone Stress Injuries?

OBJECTIVE

To evaluate the trabecular bone score (TBS) Z scores in long-distance runners with bone stress injuries (BSIs) in whom the bone mineral density (BMD) Z score is more than -1.0 (Aim 1) and whether the number of runners with abnormal TBS Z scores would be higher in those with BSI in trabecular-rich sites as compared with cortical-rich sites (Aim 2).

DESIGN

Retrospective cohort study.

SETTING

Institutional sports medicine center.

PATIENTS

We analyzed Z scores derived from the TBS and BMD in 44 long-distance runners aged 18 to 40 years who had sustained BSIs between 2017 and 2023 and undergone a dual-energy x-ray absorptiometry scan with reported TBS measurements within 1 year before or 2 years after their injuries.

INDEPENDENT VARIABLES

Bone mineral density and TBS Z scores.

MAIN OUTCOME MEASURES

Evaluation of BMD and TBS Z scores in long-distance runners with BSIs, further stratified according to cortical-rich and trabecular-rich BSIs.

RESULTS

Bone mineral density assessments revealed an average Z score of -0.96 ± 0.99. In this cohort of 44 runners, 55% (n = 24) of runners were reported to have BMD Z score more than -1.0. Within this subgroup, 54% (n = 13) displayed abnormal TBS. Stratifying BSIs by trabecular- (n = 23) and cortical-rich (n = 19) sites, we found no significant difference in sex, mean BMD, or the number of runners with abnormal TBS between the 2 groups.

CONCLUSIONS

Trabecular bone score Z scores in sports medicine may provide complementary information to BMD in long-distance runners with BSI, particularly when the BMD Z scores are more than -1.0. However, further research is needed to validate the usefulness of TBS Z scores in this context.

STUDY DESIGN

Cohort study.

LEVEL OF EVIDENCE

Retrospective Case Series, IV.

A Descriptive Analysis of the Seasonal Patterns of Bone Stress Injury Incidence in Division I Collegiate Distance Runners

BACKGROUND

A bone stress injury (BSI) is a common overuse injury in collegiate athletes, particularly cross-country and track and field runners. Limited work describes the seasonality of BSIs or the differences in rates and anatomic locations of BSIs in collegiate runners.

PURPOSE

To describe seasonally related trends in anatomic locations of BSIs in National Collegiate Athletic Association (NCAA) Division I male and female middle- and long-distance runners.

STUDY DESIGN

Descriptive epidemiological study.

METHODS

Data from a 7-year prospective study of 2 NCAA Division I cross-country and track and field programs characterized BSIs over the years 2013 to 2020. Femoral neck, pelvic, sacral, lumbar spine, and calcaneal BSIs were considered trabecular-rich. All remaining BSIs were classified as cortical-rich. Total athlete-years of follow-up were calculated by subtracting the number of days an athlete was unable to run from the number of total study participation days. Annual incidence rates were calculated by dividing the number of BSIs by the total athlete-years of follow-up for that year, and monthly incidence rates were calculated by dividing the number of BSIs in a given month by the total athlete-years of follow-up for that month.

RESULTS

Participants included 221 collegiate distance runners (114 female, 107 male). There were 154 BSIs across 482 total athlete-years, resulting in an incidence rate of 32 BSIs per 100 athlete-years. The female BSI rate was more than double that of the male BSI rate: 45 versus 20 BSIs per 100 athlete-years, respectively. The highest monthly BSI rates occurred during competitive months, with the lowest monthly BSI rates occurring during noncompetitive months. Tibial and femoral shaft BSI rates peaked during the early competitive phases of each season, whereas metatarsal BSI rates remained relatively constant. Cortical-rich BSI rates varied by sex and seasonal phase, whereas trabecular-rich BSI rates remained relatively consistent.

CONCLUSION

BSIs were common in collegiate distance runners, especially among female athletes, with higher rates during the competitive phases of the running season. Tibial and femoral shaft BSI rates were highest during the competitive phases and lowest during the noncompetitive phases, while metatarsal BSI rates remained consistent throughout the season. Cortical-rich BSI rates varied by seasonal phase and sex, whereas trabecular-rich BSI rates were relatively constant.

Lower Bone Mineral Density in Female Elite Athletes With Menstrual Dysfunction From Mixed Sports

Menstrual dysfunction (MD) in female athletes might be indicative of the syndrome of relative energy deficiency in sports (REDs), associated with, e.g., impaired bone health, an increased risk of injury, and decreased performance. In the present study, we investigated differences in objective indicators of REDs, bone mineral density (BMD), and blood-based biomarkers in female elite athletes with self-reported MD or eumenorrhoea (CON) from mixed sport disciplines. Athletes reporting < 9 menstrual bleedings within the last year were recruited in the MD group, whereas eumenorrheic athletes with no symptoms of eating disorders were recruited for CON. Of the 24 athletes included, 19 completed the examinations (9 MD; 10 CON, mean age ± SD: 24.8 ± 5.5 years). Dual-energy x-ray absorptiometry (DXA) was used to assess body composition and BMD. Fasted rested blood sampling was performed to assess blood-based biomarkers of bone and endocrine status. Two MD athletes were excluded from the analysis due to suspected polycystic ovary syndrome. Results showed that MD was associated with lower BMD Z-scores across several sites compared to CON (between-group differences ± SE); whole-body Z-score: -1.4 ± 0.5, p=0.03; lumbar spine Z-score: -1.4 ± 0.6, p=0.03; proximal femur: -1.6 ± 0.6, p=0.02). However, no between-group differences in biomarkers of bone turnover were observed. MD was associated with lower plasma concentrations of luteinizing hormone (p=0.02), prolactin (p < 0.001), and free T 3 (p=0.01). In conclusion, the present data indicate impairment in bone health and endocrine homeostasis in female elite athletes with current MD and underline the importance of MD as a potential indicator of REDs in female elite athletes. Furthermore, these findings call for regular screening of symptoms for early identification of athletes at risk in all sport disciplines and more education of athletes, coaches, and medical staff regarding this issue.

The association between overuse and musculoskeletal injuries and the female athlete triad in Division I collegiate athletes

INTRODUCTION

Although the female athlete triad (Triad) has been associated with increased risk of bone-stress injuries (BSIs), limited research among collegiate athletes has addressed the associations between the Triad and non-BSI injuries.

OBJECTIVE

To elucidate the relationship between Triad and both BSI and non-BSI in female athletes.

DESIGN

Retrospective cohort study.

SETTING

Primary and tertiary care student athlete clinic.

PARTICIPANTS

National Collegiate Athletic Association Division I female athletes at a single institution.

INTERVENTION

Participants completed a pre-participation questionnaire and dual-energy x-ray absorptiometry, which was used to generate a Triad cumulative risk assessment score (Triad score). The number of overuse musculoskeletal injuries that occurred while the athletes were still competing collegiately were identified through chart review.

MAIN OUTCOME MEASURE

BSI and non-BSI were treated as count variables. The association between BSI, non-BSI, and Triad score was measured using Poisson regression to calculate rate ratios.

RESULTS

Of 239 athletes, 43% of athletes (n = 103) sustained at least one injury. Of those, 40% (n = 95) sustained at least one non-BSI and 10% (n = 24) sustained at least one BSI over an average follow-up 2.5 years. After accounting for sport type (non-lean, runner, other endurance sport, or other lean advantage sport) and baseline age, we found that every additional Triad score risk point was associated with a significant 17% increase in the rate of BSI (rate ratio [RR] 1.17, 95% confidence interval [CI] 1.03-1.33; p = .016). However, Triad score was unrelated to non-BSI (1.00, 95% CI 0.91-1.11; p = .99). Compared with athletes in non-lean sports (n = 108), athletes in other lean advantage sports (n = 30) had an increased rate of non-BSI (RR: 2.09, p = .004) whereas distance runners (n = 46) had increased rates of BSI (RR: 7.65, p < .001) and non-BSI (RR: 2.25, p < .001).

CONCLUSIONS

Higher Triad score is associated with an increased risk of BSI but not non-BSI in collegiate athletes.

High prevalence of low bone mineral density but normal trabecular bone score in Norwegian elite Para athletes

Background

Low bone mineral density (BMD) increases the risk of bone stress injuries (BSI) and is one of several clinical concerns in Para athlete sports medicine. However, whether bone microarchitecture is altered in Para athletes is not known.

Objective

We aimed to investigate BMD, bone microarchitecture and incidence of bone stress injuries in Norwegian elite Para athletes.

Design

In this cross-sectional study in Para athletes, Dual energy x-ray absorptiometry (iDXA, Lunar, GE Health Care) derived areal BMD, trabecular bone score (TBS), a surrogate marker for bone microarchitecture, and body composition (body weight (BW), lean body mass (LBM), fat mass (FM), fat percentage) were investigated and compared between ambulant and non-ambulant athletes. Also, the association between BMD, TBS and body composition variables was investigated. Incidence of BSI was assessed with a questionnaire and confirmed by a sports physician in a clinical interview. BMD Z-score <-1 was defined as low and ≤-2 as osteoporotic. TBS ≥ 1.31 was normal, 1.23-1.31 intermediate and <1.23 low.

Results

Among 38 athletes (26 ± 6 yrs, 14 females), BMD Z-score was low in 19 athletes, and osteoporotic in 11 athletes' lumbar spine (LS) or femoral neck (FN). BMD was lower in non-ambulant vs. ambulant athletes both in LS (1.13 ± 0.19 vs. 1.25 ± 0.14 g/cm2, p = 0.030) and FN (0.90 ± 0.15 vs. 1.07 ± 0.16 g/cm2, p = 0.003). TBS was normal for all athletes. BMD Z-score in LS was positively associated with TBS (r = 0.408, p = 0.013), body weight (r = 0.326, p = 0.046) and lean body mass (r = 0.414, p = 0.010), but not with fat mass or fat percentage. None of the athletes reported any BSI.

Conclusions

Half of the Norwegian elite Para athletes had low BMD, and 29% had BMD Z-score <-2 suggesting osteoporosis. Non-ambulant athletes were more prone to low BMD than ambulant athletes. However, despite high prevalence of low BMD, TBS was normal in all athletes, and BSI was absent in this young population.

Higher Triad Risk Scores Are Associated With Increased Risk for Trabecular-Rich Bone Stress Injuries in Female Runners

OBJECTIVE

Bone stress injuries (BSIs) in trabecular-rich bone are associated with greater biological risk factors compared with cortical-rich bone. We hypothesized that female runners with high Female Athlete Triad (Triad)-related risk would be at greater risk for trabecular-rich BSIs than runners with low Triad-related risk.

DESIGN

Prospective cohort study.

SETTING

Two NCAA institutions.

PARTICIPANTS

Female runners were followed prospectively for up to 5 years.

INTERVENTION

The intervention consisted of team nutrition presentations focused on optimizing energy availability plus individualized nutrition sessions. Triad Cumulative Risk Assessment (CRA) categories were assigned yearly based on low-energy availability, menstrual status, age of menarche, low body mass index, low bone mineral density, and prior BSI.

MAIN OUTCOME MEASURES

The outcome was the annual incidence of trabecular- and cortical-rich BSI. Generalized Estimating Equations (GEE, to account for the correlated nature of the observations) with a Poisson distribution and log link were used for statistical modeling.

RESULTS

Cortical-rich BSI rates were higher than trabecular-rich BSI rates (0.32 vs 0.13 events per person-year). Female runners with high Triad-related risk had a significantly higher incidence rate ratio of trabecular-rich BSI (RR: 4.40, P = 0.025) and cortical-rich BSI (RR: 2.87, P = 0.025) than women with low Triad-related risk. Each 1-point increase in Triad CRA score was associated with a significant 26% increased risk of trabecular-rich BSI ( P = 0.0007) and a nonsignificant 14% increased risk of cortical-rich BSI ( P = 0.054).

CONCLUSIONS

Increased Triad CRA scores were strongly associated with increased risk for trabecular-rich BSI. Incorporating Triad CRA scores in clinical care could guide BSI prevention.

Review of the scientific rationale, development and validation of the International Olympic Committee Relative Energy Deficiency in Sport Clinical Assessment Tool: V.2 (IOC REDs CAT2)-by a subgroup of the IOC consensus on REDs

Relative Energy Deficiency in Sport (REDs) has various different risk factors, numerous signs and symptoms and is heavily influenced by one's environment. Accordingly, there is no singular validated diagnostic test. This 2023 International Olympic Committee's REDs Clinical Assessment Tool-V.2 (IOC REDs CAT2) implements a three-step process of: (1) initial screening; (2) severity/risk stratification based on any identified REDs signs/symptoms (primary and secondary indicators) and (3) a physician-led final diagnosis and treatment plan developed with the athlete, coach and their entire health and performance team. The CAT2 also introduces a more clinically nuanced four-level traffic-light (green, yellow, orange and red) severity/risk stratification with associated sport participation guidelines. Various REDs primary and secondary indicators have been identified and 'weighted' in terms of scientific support, clinical severity/risk and methodological validity and usability, allowing for objective scoring of athletes based on the presence or absence of each indicator. Early draft versions of the CAT2 were developed with associated athlete-testing, feedback and refinement, followed by REDs expert validation via voting statements (ie, online questionnaire to assess agreement on each indicator). Physician and practitioner validity and usability assessments were also implemented. The aim of the IOC REDs CAT2 is to assist qualified clinical professionals in the early and accurate diagnosis of REDs, with an appropriate clinical severity and risk assessment, in order to protect athlete health and prevent prolonged and irreversible outcomes of REDs.

Healthy Runner Project: a 7-year, multisite nutrition education intervention to reduce bone stress injury incidence in collegiate distance runners

Objectives

We evaluated the effect of a nutrition education intervention on bone stress injury (BSI) incidence among female distance runners at two NCAA Division I institutions.

Methods

Historical BSI rates were measured retrospectively (2010-2013); runners were then followed prospectively in pilot (2013-2016) and intervention (2016-2020) phases. The primary aim was to compare BSI rates in the historical and intervention phases. Pilot phase data are included only for descriptive purposes. The intervention comprised team nutrition presentations focused on optimising energy availability plus individualised nutrition sessions for runners with elevated Female Athlete Triad risk. Annual BSI rates were calculated using a generalised estimating equation Poisson regression model adjusted for age and institution. Post hoc analyses were stratified by institution and BSI type (trabecular-rich or cortical-rich).

Results

The historical phase included 56 runners and 90.2 person-years; the intervention phase included 78 runners and 137.3 person-years. Overall BSI rates were not reduced from the historical (0.52 events per person-year) to the intervention (0.43 events per person-year) phase. Post hoc analyses demonstrated trabecular-rich BSI rates dropped significantly from 0.18 to 0.10 events per person-year from the historical to intervention phase (p=0.047). There was a significant interaction between phase and institution (p=0.009). At Institution 1, the overall BSI rate dropped from 0.63 to 0.27 events per person-year from the historical to intervention phase (p=0.041), whereas no decline was observed at Institution 2.

Conclusion

Our findings suggest that a nutrition intervention emphasising energy availability may preferentially impact trabecular-rich BSI and depend on team environment, culture and resources.

Female Athlete Triad Risk Factors Are More Strongly Associated With Trabecular-Rich Versus Cortical-Rich Bone Stress Injuries in Collegiate Athletes

Background:

Bone stress injuries (BSIs) are common in athletes. Risk factors for BSI may differ by skeletal anatomy and relative contribution of trabecular-rich and cortical-rich bone.

Hypothesis:

We hypothesized that Female Athlete Triad (Triad) risk factors would be more strongly associated with BSIs sustained at trabecular-rich versus cortical-rich skeletal sites.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

The study population comprised 321 female National Collegiate Athletic Association Division I athletes participating in 16 sports from 2008 to 2014. Triad risk factors and a Triad cumulative risk score were assessed using responses to preparticipation examination and dual energy x-ray absorptiometry to measure lumbar spine and whole-body bone mineral density (BMD). Sports-related BSIs were diagnosed by a physician and confirmed radiologically. Athletes were grouped into those sustaining a subsequent trabecular-rich BSI, a subsequent cortical-rich BSI, and those without a BSI. Data were analyzed with multinomial logistic regression adjusted for participation in cross-country running versus other sports.

Results:

A total of 19 participants sustained a cortical-rich BSI (6%) and 10 sustained a trabecular-rich BSI (3%) over the course of collegiate sports participation. The Triad cumulative risk score was significantly related to both trabecular-rich and cortical-rich BSI. However, lower BMD and weight were associated with significantly greater risk for trabecular-rich than cortical-rich BSIs. For every value lower than 1 SD, the odds ratios (95% CIs) for trabecular-rich versus cortical-rich BSI were 3.08 (1.25-7.56) for spine BMD; 2.38 (1.22-4.64) for whole-body BMD; and 5.26 (1.48-18.70) for weight. Taller height was a significantly better predictor of cortical-rich than trabecular-rich BSI.

Conclusion:

The Triad cumulative risk score was significantly associated with both trabecular-rich and cortical-rich BSI, but Triad-related risk factors appeared more strongly related to trabecular-rich BSI. In particular, low BMD and low weight were associated with significantly higher increases in the risk of trabecular-rich BSI than cortical-rich BSI. These findings suggest Triad risk factors are more common in athletes sustaining BSI in trabecular-rich than cortical-rich locations.

Dietary-Lifestyle Patterns Associated with Bone Turnover Markers, and Bone Mineral Density in Adult Male Distance Amateur Runners—A Cross-Sectional Study

Background: Excessive mileage can be detrimental to bone mineral density among long-distance runners. The negative effects of mileage could be alleviated by appropriate nutrition. The purpose of this study was to analyse the dietary-lifestyle patterns in relation to bone mineral density and bone turnover markers among amateur marathoners. Methods: A total of 53 amateur male distance runners were divided into two clusters by k-means cluster analysis. Bone mineral density was measured by dual X-ray absorptiometry (DXA). Blood was drawn to analyse bone resorption marker C-terminal telopeptide (cTX) and bone formation marker amino-terminal propeptide of type I collagen (PINP). Food frequency intake and lifestyle information were measured by multicomponent questionnaire KomPAN^®. Yearly average mileage per month was taken from each participant. Results: There were two distinguished clusters: Less-healthy-more-active-low-Z-score (LessHA) (n = 33) and More-healthy-less-active-high-Z-score (MoreHLA) (n = 20). LessHA had a lower frequency intake of pro-healthy food groups, a lower number of meals during a typical day, and a higher mileage training than the group of athletes who followed the MoreHLA. Athletes following the LessHA pattern also had a lower Z-score in the lumbar spine and femoral bone and a lower PINP. Conclusion: The current study suggests that pro-healthy dietary patterns and lower mileage may favour higher bone mineral density in male amateur marathoners.

Modelling Changes in Bone and Body Composition Over a Season in Elite Male Footballers

This study investigated the change in bone and body composition characteristics of elite football players and recreationally active control participants across the course of a season. Fortysix participants (20 footballers and 26 recreationally active controls) were assessed by dual-energy x-ray absorptiometry and peripheral Quantitative Computed Tomography for a range of bone and body composition characteristics at four points over the course of a competitive season. Multilevel modelling was used to examine changes. Footballers had higher characteristics than controls for 24 out of 29 dual-energy x-ray absorptiometry and peripheral Quantitative Computed Tomography variables (all p<0.05). However, there was also significant random inter-individual variation in baseline values for all variables, for both footballers and controls (p < 0.05). Wholebody bone mineral density, leg and whole-body bone mineral content, tibial bone mass and area (38%) increased across the season in footballers (p < 0.05), and there was significant random inter-individual variation in the rate of increase of leg and whole-body bone mineral content (p<0.05). Whole-body bone mineral density, leg and whole-body bone mineral content, tibial bone mass and area (38%) increased over the course of the season in elite football players. The modelling information on expected changes in bone characteristics provides practitioners with a method of identifying those with abnormal bone response to football training and match-play.

The Influence of Low Energy Availability on Bone Mineral Density and Trabecular Bone Microarchitecture of Pubescent Female Athletes: A Preliminary Study

The influence of low energy availability (LEA) on bone mineral density (BMD) and trabecular bone microarchitecture in pubescent female athletes is unclear. This study aimed to investigate the influence of LEA on BMD and trabecular bone microarchitecture in 21 pubescent female athletes (age, 12−15 years; 11 track and field athletes, 10 gymnasts). We used two indices to assess LEA: energy availability and the percent of ideal body weight. Dual-energy X-ray absorptiometry was used to obtain total body less head, lumbar spine BMD Z-scores, and lumbar trabecular bone scores (TBS). Pearson’s or Spearman’s correlation coefficients were used to assess the relationship among EA, percent of ideal body weight, and bone parameters. The threshold for statistical significance was set at p < 0.05. The percent of ideal body weight was significantly correlated with the BMD Z-scores of the total body less head (r = 0.61; p < 0.01), lumbar spine (r = 0.55; p < 0.01), and lumbar TBS (r = 0.47; p = 0.03). However, energy availability was not correlated with bone parameters. These findings suggest that screening for low ideal body weight may be a useful predictor of low BMD and insufficient trabecular bone microarchitecture in pubescent female athletes.

Anthropometric Factors Associated With Bone Stress Injuries in Collegiate Distance Runners: New Risk Metrics and Screening Tools?

BACKGROUND

Lower limb bone stress injury (BSI) of the pelvis, femur, and tibia is prevalent in collegiate track and field distance runners. Bone mineral density (BMD), body composition (BComp), and anthropometric parameters before initial collegiate injury have not been compared between runners with BSI and their noninjured counterparts.

PURPOSE

To characterize bone health in relation to BComp and anthropometric measurements from total-body dual x-ray absorptiometry (DXA) scans in collegiate male and female distance runners before BSI and develop BMD prediction models.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Distance runners (N = 79) from a single university track and field team were retrospectively enrolled into this study. The runners completed a DXA scan during the fall season (August-November) and participated in sport activities before the scan. Three months after scanning, electronic medical records were reviewed for the occurrence of BSI. An independent-sample t test was used to compare BMD (total and regional [spine, pelvis, and legs]), BComp (% body fat, fat mass, and lean mass), and anthropometric measurements (shoulder width and leg, arm, and trunk length) between runners with versus without BSI (included subgroup analysis by sex). Multiple linear regression with stepwise removal was used to determine variables most predictive of BMD.

RESULTS

Of the 79 enrolled participants (42 male, 37 female), 18 runners (22.8%; 11 female, 7 male) sustained a lower limb BSI. Compared with the noninjured group, injured runners had lower total and regional BMD (P < .001 for all) and shorter leg and arm lengths (P < .05 for both), whereas injured male runners had lower fat mass and injured female runners had lower lean mass in the legs (P < .05 for both). Injured runners' age-matched total BMD Z score (-0.1 ± 0.6) was considered clinically normal. BComp and anthropometric measures were predictive of total and regional BMD (P < .05; R 2 = 0.64-0.80; percentage error = 3.8%-4.8%).

CONCLUSION

The DXA scans of injured runners prior to incidence indicated lower BMD compared with noninjured runners. Shorter limb lengths, lower fat mass (male), and lower leg lean mass (female) may also be indicative of risk. Certain BComp and anthropometric measures were predictive of BMD.