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.