Associations Between Serum 25-Hydroxyvitamin D Concentration, Sun Exposure Index, Body Composition, and Repeated Sprint Ability in Male Soccer Referees

ABSTRACT: Despite the high prevalence of hypovitaminosis D among athletes and the proposed role of vitamin D in musculoskeletal health and performance, data on vitamin D status in soccer referees and its relationship with body composition and performance remain scarce. This cross-sectional study evaluated 25(OH)D concentrations and their associations with the sun exposure index (SEI), body composition, and performance in a sample of 21 male referees (30.6 ± 3.4 years) from the Brazilian Football Confederation. Serum 25(OH)D concentration was assessed from blood samples, SEI by questionnaire, body fat percentage (BF%), fat free mass, and bone mineral density (BMD) by dual-energy X-ray absorptiometry, calcium and carbohydrate intake by 24-h recall, and performance by the repeated sprint ability (RSA) test. Associations were examined using linear regression analysis adjusted for (1) age, (2) fat free mass, and (3) carbohydrate or calcium intake. 76% presented serum 25(OH)D concentrations < 30 ng/mL. 25(OH)D was positively associated with SEI (β = 1.17; p = 0.04, Cohen’s f² = 0.19), whereas no significant associations were observed with BMD, BF% or RSA, even after adjustments. There is a high prevalence of hypovitaminosis D among the soccer referees evaluated. Although 25(OH)D was not significantly associated with body composition or performance, its positive association with SEI reinforces the importance of sun exposure.