<p>Vitamin D3 Supplementation and Stress Fractures in High-Risk Collegiate Athletes – A Pilot Study</p>

Abstract

Introduction: Vitamin D is paramount to bone health and little is known about vitamin D's role in the prevention of stress fractures in high-risk athletes. This study consists of a prospective, cross-sectional analysis accompanied by a retrospective review for control comparison of vitamin D3 supplementation in high-risk athletes. Our hypothesis is that supplemental vitamin D3 treatment will decrease the occurrence of stress fractures in highrisk collegiate athletes. Materials and Methods: A total of 118 NCAA Division I athletes were recruited from 6 high-risk collegiate teams. Blood draws in August and February established 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. A 5-year retrospective chart review of athletes from the same sports teams was conducted to determine the incidence of any reported stress fractures in the past. Results: Prospective: 112 of the 118 enrolled subjects were tested in August. Sixty-one demonstrated vitamin D sufficiency (40.2 ng/mL ±8.28) and 51 were either insufficient or deficient (22.7 ng/mL ±4.89). Of the 118 enrolled subjects, 104 were tested in February. Fifty-six demonstrated vitamin D sufficiency (40.7 ng/mL ±9.47) and 48 were insufficient or deficient (21.6 ng/mL ±5.87). Two stress fractures were diagnosed amongst our cohort of 118 student athletes (1.69%). Retrospective: 34 stress fractures were diagnosed in 453 subjects from 01/2010-05/2015 (7.51%). Amongst our athletic teams, the cross-country team specifically demonstrated a statistically significant decrease in stress fracture incidence (p<0.05).We also found a statistically significant reduction in stress fracture incidence amongst the current overall cohort compared to our retrospective cohort (p<0.05). Conclusion:In our population, almost half of the tested athletes proved to be vitamin D deficient. Hypovitaminosis D was prevalent throughout the winter months compared with the summer. With vitamin D3 supplementation, the stress fracture rate in our overall cohort demonstrated a statistically significant decrease from 7.51% to 1.65% (p=0.009).

Epidemiology of NCAA Bone Stress Injuries: A Comparison of Athletes in Divisions I, II, and III

“…Various preventive strategies have been proposed, yet few have been validated in large studies and studied in collegiate athletes. Strategies include addressing abnormal biomechanics and considering shock-absorbing shoe inserts, 26 supplementing with daily calcium 19 and vitamin D, 33 ensuring adequate rest and a progressive increase in physical activity, 26 and modifying identified risk factors such as smoking and drinking >10 alcoholic drinks per week. 22 Athlete education can include the female athlete triad and subsequent increased risk of injury, proper nutrition and supplementation to optimize energy availability, and strength and conditioning programs to optimize biomechanics that prevent training overload (eg, incorporating strength training sessions in cross-country workouts to improve core strength and prevent decline in form that occurs with fatigue at the end of training sessions or races).…”

Training Load Capacity, Cumulative Risk, and Bone Stress Injuries: A Narrative Review of a Holistic Approach

“…In addition to post-exercise, other nutritional factors, specific to athletes, are important to consider as potential BSI risk factors, such as vitamin D, calcium, iron, ferritin, and energy deficiency. Vitamin D is a key modulator of bone remodeling (McCabe et al, 2012;Williams et al, 2020), and low levels appear related to BSI incidence as recently reported in other papers (Miller and Best, 2016;Abbott et al, 2019a). Although vitamin D's utility as a preventive measure, as well as what constitutes the optimal vitamin D level, is not clear, a recommended therapeutic goal for bone health is a serum 25-hydroxyvitamin D [25(OH)D] level of 50-100 nmol/L dependent on the individual (McCabe et al, 2012;Sale and Elliott-Sale, 2019).…”

Vitamin D and Stress Fractures in Sport: Preventive and Therapeutic Measures—A Narrative Review

“…25(OH)D deficiency is highly prevalent in both the general [ 12 ] and the athletic population [ 16 , 71 , 72 ], where professional athletes have a high prevalence of 25(OH)D deficiency [ 73 ]. The surprisingly high prevalence of inadequate 25(OH)D levels in athletes depends on different factors such as the geographic location, the time of day and year, the local climate conditions, and the sports disciplines (i.e., indoor vs. outdoor) [ 74 ].…”

“…A study investigating 5201 female Navy recruit volunteers showed that a total of 309 subjects were diagnosed with a stress fracture resulting in an incidence of 5.9% per 8 weeks [ 81 ]. A study investigating 118 NCAA Division I athletes showed two stress fractures (1.69%) in a prospective arm and 34 stress fractures (7.51%) in 453 subjects in a retrospective arm of the study [ 72 ].…”

“…In case of a 25(OH)D insufficiency, normal blood levels of ≥30 ng/mL may be restored by optimizing the athlete’s lifestyle and, if appropriate, by oral substitution of 25(OH)D. This concentration of ≥30 ng/mL is associated with a protective effect and an enhancement of physical performance [ 74 ]. A very recent pilot study showed a significant decrease in stress fractures from 7.51% to 1.65% with 25(OH)D supplementation [ 72 ].…”