The association of bone stress injuries with body mass index percentile drop and eating disorder diagnoses in adolescent athletes

Context: Adolescence is a critical period for bone development. Due to an elevated risk for low body mass index (BMI) and/or low energy availability, certain adolescent athletes are at increased risk of bone stress injury (BSI) and eating disorders (ED). Despite this risk, the incidence of ED in patients with BSI is unclear. Objectives: To compare the incidence of premorbid drop in BMI percentile in a sample of adolescent athletes diagnosed with a BSI between 2005 to 2016. We also evaluated the relative risk of developing an ED for this sample, compared to a sex-, age- (+/-6 months), and time matched (+/-2 years) sample of active adolescents with knee pain. Design: Retrospective cohort study Setting: Data collected through the Rochester Epidemiology Project. Patients: 187 adolescent (ages 13-18) athletes with BSI and 187 active adolescents with knee pain. Main Outcome Measures: Conditional logistic regression was used to assess whether premorbid weight loss was a risk factor for BSI. A stratified log-rank test was used to evaluate the association between ED diagnosis and case-control status up to 5 years post-injury. Results: Patients with BSI had 1.53 times the odds of premorbid BMI percentile drop compared to controls (95% CI: 0.83-2.12, p = 0.17). A total of 14 patients with BSI had ED diagnoses following injury compared with 8 controls (p = 0.13). Patients from weight-based/aesthetic sports had 1.93 times the odds of BSI compared to controls (95% CI 1.23-3.02, p =0.0040). The Kaplan-Meier estimates indicate that the case group had greater risk of ED diagnosis. Conclusions: Results suggest a trend toward greater drop in BMI percentile and increased frequency of ED diagnoses in the BSI group compared to controls. The documented co-occurrence of weight loss, stress fractures and EDs in adolescent athletes should inform guidelines for screening and treatment of adolescent athletes with BSI.