High Prevalence of Vitamin D Insufficiency in Athletes and Dancers

Objective: Vitamin D insufficiency is prevalent in various populations worldwide but with scarce data on physically active individuals. Vitamin D is important to athletes, affecting bone mass, immunity, and physical performance. This study evaluated the prevalence of vitamin D insufficiency and deficiency among young athletes and dancers. Design: Cross-sectional study. Setting: Sport medicine clinic. Patients: Data on 98 athletes and dancers (age, 14.7 +/- 3.0 years; range, 10-30 years; 53% men), who had undergone screening medical evaluations, were extracted from medical records. Independent Variable: Serum 25(OH)D concentrations. Main Outcome Measures: Serum 25(OH)D concentrations, age, sex, sport discipline, month of blood test, and serum ferritin. Vitamin D insufficiency was defined as serum 25(OH) D concentration <30 ng/mL. Results: Mean serum 25(OH)D concentration was 25.3 +/- 8.3 ng/mL. Seventy-three percent of participants were vitamin D insufficient. Prevalence of vitamin D insufficiency was higher among dancers (94%), basketball players (94%), and Tae Kwon Do fighters (67%) and among athletes from indoor versus outdoor sports (80% vs 48%; P - 0.002). 25(OH)D levels adjusted for age and sex correlated with serum ferritin and season. Conclusions: In this study, conducted among young athletes and dancers from various disciplines in a sunny country, a high prevalence of vitamin D insufficiency was identified. A higher rate of vitamin D insufficiency was found among participants who practice indoors, during the winter months, and in the presence of iron depletion. Given the importance of vitamin D to athletes for several reasons, we suggest that athletes and dancers be screened for vitamin D insufficiency and treated as needed.