Prevalence of Abnormal Vitamin D Levels Among Division I NCAA Athletes

Background: Up to 1 billion people have insufficient or deficient vitamin D levels. Despite the well-documented, widespread prevalence of low vitamin D levels and the importance of vitamin D for athletes, there is a paucity of research investigating the prevalence of vitamin D deficiency in athletes. Hypothesis: We investigated the prevalence of abnormal vitamin D levels in National Collegiate Athletic Association (NCAA) Division I college athletes at a single institution. We hypothesized that vitamin D insufficiency is prevalent among our cohort. Study Design: Cohort study. Level of Evidence: Level 1. Methods: We measured serum 25-hydroxyvitamin D (25(OH) D) levels of 223 NCAA Division I athletes between June 2012 and August 2012. The prevalence of normal (>= 32 ng/mL), insufficient (20 to <32 ng/mL), and deficient (<20 ng/mL) vitamin D levels was determined. Logistic regression was utilized to analyze risk factors for abnormal vitamin D levels. Results: The mean serum 25(OH) D level for the 223 members of this study was 40.1 +/- 14.9 ng/mL. Overall, 148 (66.4%) participants had sufficient 25(OH) D levels, and 75 (33.6%) had abnormal levels. Univariate analysis revealed the following significant predictors of abnormal vitamin D levels: male sex (odds ratio [OR] = 2.83; P = 0.0006), Hispanic race (OR = 6.07; P = 0.0063), black race (OR = 19.1; P < 0.0001), and dark skin tone (OR = 15.2; P < 0.0001). Only dark skin tone remained a significant predictor of abnormal vitamin D levels after multivariate analysis (adjusted OR = 15.2; P < 0.0001). Conclusion: In a large cohort of NCAA athletes, more than one third had abnormal vitamin D levels. Races with dark skin tones are at much higher risk than white athletes. Male athletes are more likely than female athletes to be vitamin D deficient. Our study demonstrates a high prevalence of vitamin D deficiency among healthy NCAA athletes.