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Association of Serum Vitamin D Levels and Stress Fractures in Collegiate Athletes

D. Millward, Allison D. Root, J. Dubois, Randall P. Cohen, L. Valdivia, Bruce Helming, Justin Kokoskie, Anna L. Waterbrook et al.

Orthopaedic Journal of Sports Medicine, 2020

497 participants · 29 citations

Abstract

Background: Low vitamin D levels along with high-intensity athletic training may put an athlete at increased risk for a stress fracture. Purpose: To assess whether supplementation with vitamin D is associated with a reduced risk of stress fractures in college athletes. We also assessed differences in vitamin D levels among athletes participating in outdoor versus indoor sports. Study Design: Cohort study; Level of evidence, 2. Methods: The study participants included 802 National Collegiate Athletic Association Division I intercollegiate athletes (497 men and 305 women) on a sports team for at least 1 semester from 2012 to 2018. All athletes who had a baseline vitamin D level in their medical record were included. Athletes with vitamin D levels <40 ng/mL were given vitamin D supplements. We assessed differences in the rate of stress fracture among those who maintained or improved vitamin D levels to ≥40 ng/mL and those who did not, as well as differences in average baseline vitamin D levels by sport type (indoor vs outdoor). Results: The rate of stress fracture was 12% higher (95% CI, 6-19; P < .001) for those who remained low in vitamin D compared with those who were low at baseline but improved their vitamin D status to ≥40 ng/mL. The rate of stress fracture was also 12% higher (95% CI, 5-18; P < .001) for those who had low vitamin D levels compared with those who maintained normal levels. The mean baseline vitamin D values were significantly higher for men participating…

How strong is the evidence?

Evidence Hub reads this as a cohort study, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 497 participants or records.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

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