1045 - Female Runners Sustain Higher Rate of Bone Stress Injuries than Male Runners: Results from the Healthy Runner Project

Objectives: Bone Stress Injury (BSI) is a form of overuse injury in runners and can be season-ending. Limited studies have evaluated the incidence of BSI in collegiate runners, including differences by sex or anatomical location of injury. We hypothesized that female runners would sustain a higher incidence of BSI than male runners and explored the anatomical distribution of injury.

Design: The Healthy Runner Project was a seven-year prospective study characterizing risk factors for BSI and evaluating whether a nutrition intervention would reduce rates of BSI. Data from this study are a secondary analysis evaluating incident BSI in female and male runners. To be included, BSI was sustained during the sport of running, diagnosed by the team physician and confirmed using imaging (x-ray or magnetic resonance imaging). Rate ratio and 95% confidence interval (RR; 95%CI) were used to evaluate differences in BSI by sex with P< 0.05 defined as threshold of statistical significance. Anatomical location of BSI by sex was descriptive.

Results: 78 women (mean age and SD: 18.8±1.1 years) and 107 men (18.8±1.3 years) were followed for 166 and 249 years of observation, respectively. The incidence of BSI lower in males than females (RR; 95%CI: 0.46; 0.31, 0.67; P< 0.0001). While male runner sustained fewer BSI than female runners (N=48 vs 104), the anatomical location for injury was similar. BSI in males was most common in the tibia (N=12), sacrum (N=11), femoral shaft (N=9) and metatarsal (N=8). Similar locations were observed in female runners including the tibia (N=33), sacrum (N=19), metatarsal (N=15) and femoral shaft (N=14).

Conclusions: Findings suggest that female runners sustain a higher rate of BSI than male runners. However, the anatomical sites of injury are similar by sex. These results suggest the need to consider sex-specific differences in risk factors to optimize prevention of BSI.