Low levels of vitamin D in professional basketball players after wintertime: relationship with dietary intake of vitamin D and calcium

Introduction
Although vitamin D deficiency has a high worldwide prevalence among the general population, very little is known about vitamin status in athletes.
Aim
To investigate serum vitamin D (25[OH]D) levels after wintertime in male elite basketball players, and to relate these levels to the dietary intake of vitamin D and calcium.
Methods
Subjects were 21 players from the same professional Spanish team. Blood samples to assess 25(OH)D levels were collected after wintertime during the 2008/2009 (April) and 2009/2010 (March) seasons. In addition, athletes completed 4-day dietary records to estimate energy consumption and a food frequency questionnaire to determine dietary vitamin D and calcium intake. Serum 25(OH)D levels were 47.8±21.8 nmol/L, with twelve subjects (57%) being vitamin D deficient (<50 nmol/L).
Results
Vitamin D intake was 139±78 IU/day and calcium intake was 948±419 mg/day. Serum 25(OH)D levels correlated with the daily dietary intake of vitamin D (r=0.65; P=0.001) and calcium (r=0.82; P<0.001).
Conclusion
Professional basketball players are at higher risk of hypovitaminosis D after wintertime. Adequate intake of dietary calcium and vitamin D is required if athletes are to avoid low serum 25(OH)D levels when exposure to sunlight is limited.