More than one-third of Division I college athletes may have low vitamin D levels

Up to 1 billion people globally have insufficient or deficient vitamin D levels. Vitamin D is found in fish, regularly added to milk and dairy products in the U.S., and available as a supplement. Vitamin D also is produced in the body through sun exposure.

"Although multiple studies have demonstrated a high prevalence of vitamin D insufficiency across various populations, there is a paucity of data regarding elite level athletes," said orthopaedic surgeon and lead study author Diego Villacis, MD, administrative chief resident physician at the University of Southern California. "Recent studies also have demonstrated that vitamin D levels have a direct relationship with muscle power, force, velocity and optimal bone mass."

In this study, which appeared in the February 2014 online issue of Sports Health, researchers measured the serum 25-hydroxyvitamin D (serum 25) levels of 223 National Collegiate Athletic Association (NCAA) athletes (121 men and 102 women) between June 2012 and August 2012. The mean serum 25 level for the athletes, enrolled in a broad range of indoor and outdoor sports, was 40.1 ±14.9 ng/mL (?32 ng/mL is considered normal; 20 to <32 ng/mL, insufficient; and <20 ng/mL, deficient). Overall, 66.4 percent of participants had sufficient vitamin D levels and 33.6 percent, insufficient or deficient levels.

Men were 2.8 times more likely to have an abnormal vitamin D level, according to the results, and athletes with darker skin tones also faced a "much higher risk" for insufficient vitamin D. Black athletes were 19.1 times more likely to have abnormal vitamin D levels compared to white athletes, and Hispanics, 6.1 times more likely.

"Our study demonstrated abnormal vitamin D levels in nearly one out of three elite NCAA Division I athletes tested," said Dr. Villacis. "Although there is much more work to be done, our results open the possibility for improved performance and most importantly decreased risk of injury with correction of vitamin D levels. This may potentially be achieved simply and safely through modification of diet, sunlight exposure, and vitamin D supplementation."