High prevalence of vitamin D insufficiency among elite Spanish athletes; the importance of outdoor training adaptation

Introduction: The discovery of vitamin D muscle receptors in the last few years suggested a significant role in muscle tissue, pointing out athletes as a special group. Specific data are scarce. Aim: The main aim of the current paper was to provide, for the first time, comparable data about vitamin D status in elite Spanish athletes by sport, age, season and training environment. Methods: Four hundred and eight elite athletes with a mean age of 22.8 +/- 8.4 years were recruited from the High-performance sport centre in Barcelona for this cross-sectional study. Athletes from 34 different sports modalities were analysed. Data were available for vitamin I) status, training environment, seasonality and number of medical visits. All data were analysed using SPSS version 18.0. Results: Mean 25(OH)D of all athletes was 56.7 +/- 23.4 nmol/L. Approximately 82% of the athletes were below the optimal levels, (<75 nmol/l), 45% had moderate deficient levels (<50 nmol/L) and 6% had severe deficiency (<27.5 nmol/L). We have observed a steady increase in 25(OH)D concentrations with increasing age (p<0.01) Highest levels were observed in those subjects training outdoors compared with those training indoor (p<0.01). Differences between sport modalities were observed. Even during summer, 87% of the athletes had insufficient 25(OH)D concentrations. Conclusion: There is a high prevalence of vitamin D insufficiency among elite Spanish athletes. Outdoor training could ensure vitamin D sufficiency and differences between sports modalities should be taken into account for future research. The results contribute to identify the need of optimizing vitamin D status across athletes.