Vitamin D3 Supplementation and Stress Fracture Occurrence in High-Risk Collegiate Athletes

Abstract

Previous vitamin D research analyzes the regulation of calcium and phosphate levels, as well as bone mineralization and turnover. Very little is known about vitamin D’s role in the prevention of stress fractures in high level athletes. PURPOSE: We aim to investigate vitamin D’s role in the prevention of stress fractures in collegiate athletes METHODS: Prospective: 118 NCAA Division I athletes were recruited from the high risk sports of track and field, cross country, soccer, and basketball. Blood samples were procured in August and February to determine fall and spring baseline 25(OH)D levels. Subjects with serum 25(OH)D <30 ng/ml were supplemented with 50,000 IU of vitamin D3/week for 8 weeks. Treated subjects were re-tested to ensure serum 25(OH)D levels rose to sufficient status. All enrolled subjects were monitored for the development of stress fractures. Retrospective: A retrospective chart review of non-supplemented athletes from the same sports teams was conducted to determine the incidence of any reported stress fractures. RESULTS: Prospective: 112 of the 118 enrolled subjects were tested in August. 61 were of sufficient status (40.2 ng/ml ±8.28) and 51 were either insufficient or deficient (22.7 ng/ml ±4.89). 104 of the 118 enrolled subjects were tested in February. 56 were of sufficient status (40.7 ng/ml ±9.47) and 48 were insufficient or deficient (21.6 ng/ml ±5.87). 2 stress fractures were diagnosed in 118 currently enrolled subjects (1.69%). Retrospective: 34 stress fractures were diagnosed in 453 subjects from 01/2010-05/2015 (7.51%). CONCLUSIONS: In our population, almost half of the tested athletes proved to be vitamin D insufficient or deficient by the current normative value standards. Despite vitamin D supplementation, hypovitaminosis D was prevalent throughout the winter months. With vitamin D supplementation in this particular year, the stress fracture rate in our particular cohort significantly decreased from 7.51% to 1.65% (p=0.009) following vitamin D supplementation.