Abstract
Upper respiratory tract infections are the most common infections reported by elite athletes. Low vitamin D status has been associated with an increased risk of upper respiratory tract infections. The aim of this study was to investigate associations between serum 25-hydroxyvitamin D (25(OH) D), salivary immunoglobulin A (S-IgA) concentrations, and acute respiratory tract infections (colds/fl u) (ARI) in elite rowers and rugby players. A total of 53 (23 rugby players, 30 rowers) elite New Zealand athletes volunteered to participate in an interview, and to provide a blood and a saliva sample. Testing occurred twice, 6 months apart. Athletes' serum 25(OH) D concentrations and s-IgA levels were both signifi cantly higher in summer, 108.9 (CI 102.8, 115.4) nmol/L, than in winter, 86.8 (CI 81.8, 92.1) nmol/L (p < 0.01, p = 0.028). The occurrence of an acute respiratory tract infection did not differ signifi cantly between the time points (p = 0.322). However, ARI duration was signifi cantly longer in winter than in summer (6.9 +/- 4.3 days vs 4.8 +/- 3.0 days; p = 0.044). There were no signifi cant correlations between athletes' 25(OH) D levels and their s-IgA levels (p > 0.05) nor with acute respiratory tract infection occurrence (p > 0.05) nor duration (p > 0.05) in summer or winter. These findings suggest there may not be any associations between serum 25(OH) D concentrations and acute respiratory tract infections in this population. However, this null finding may be attributed to the high vitamin D concentrations seen in these athletes.