Vitamin D Status Relative to Diet, Lifestyle, Injury, and Illness in College Athletes

HALLIDAY, T. M., N. J. PETERSON, J. J. THOMAS, K. KLEPPINGER, B. W. HOLLIS, and D. E. LARSON-MEYER. Vitamin D Status Relative to Diet, Lifestyle, Injury, and Illness in College Athletes. Med. Sci. Sports Exerc., Vol. 43, No. 2, pp. 335-343, 2011. Vitamin D deficiency is endemic in the general population; however, there is much to be learned about the vitamin D status of athletes. Purpose: The purposes of this study were to assess the prevalence of vitamin D insufficiency in collegiate athletes and to determine whether 25(OH)D concentrations are related to vitamin D intake, sun exposure, body composition, and risk for illness or athletic injury. Methods: 25(OH) vitamin D concentrations were measured in 41 athletes (18 men/23 women, 12 indoor/29 outdoor athletes) throughout the academic year. Dietary intake and lifestyle habits were assessed via questionnaire, bone density was measured by dual energy x-ray absorptiometry, and injury and illness were documented as part of routine care. Results: The 25(OH) D concentrations changed across time (P = 0.001) and averaged 49.0 +/- 16.6, 30.5 +/- 9.4, and 41.9 +/- 14.6 ng.mL(-1) (mean +/- SD) in the fall, winter, and spring, respectively, and were higher in outdoor versus indoor athletes in the fall (P < 0.05). Using 40 ng.mL(-1) as the cutoff for optimal status, 75.6%, 15.2%, and 36.0% of athletes had optimal status in the fall, winter, and spring, respectively. 25(OH) D concentrations were significantly (P < 0.05) correlated with multivitamin intake in the winter (r = 0.39) and tanning bed use in the spring (r = 0.48); however, status was otherwise not related to intake, lifestyle factors, or body composition. 25(OH) D concentrations in the spring (r = -0.40, P = 0.048) was correlated with frequency of illness. Conclusions: Our results suggest that collegiate athletes can maintain sufficient status during the fall and spring but would benefit from supplementation during the winter to prevent seasonal decreases in 25(OH) D concentrations. Results further suggest that insufficient vitamin D status may increase risk for frequent illness. Future research is needed to identify whether vitamin D status influences injury risk during athletic training or competition.