Study design: This is a retrospective analysis of total serum 25-hydroxyvitamin D (25[OH]D) in Swiss elite wheelchair athletes.
Objectives: The aim was to investigate the occurrence of vitamin D deficiency in Swiss elite wheelchair athletes over the whole year and to detect differences between winter and summer months, and between indoor and outdoor athletes.
Setting: This study was conducted in Switzerland.
Methods: A total of 164 blood samples from 72 Swiss elite wheelchair athletes (mean±s.d.: age 32±13 years) were analyzed for total serum 25[OH]D. All participants were members of the national team in their discipline. The following disciplines have been included: rugby, athletics, cycling, tennis, ski alpine, curling and basketball. According to general guidelines, insufficient vitamin D status was defined between 50 and 75 nmol l-1, deficiency below 50 nmol l-1 and severe deficiency below 27.5 nmol l-1.
Results: In all, 73.2% of all samples showed an insufficiency/deficiency in vitamin D status. Total serum 25[OH]D was significantly higher during summer compared with winter months (69.5±21.4 nmol l-1 vs 51.5±21.9 nmol l-1; P<0.001). Indoor sports showed a higher amount of vitamin D insufficiency/deficiency (80.9%) than outdoor sports (70.1%), with a significantly higher 25[OH]D concentration in outdoor sports (P=0.042).
Conclusion: A high percentage of vitamin D deficiency was found among Swiss elite wheelchair athletes. Conclusively, we recommend supplementation with vitamin D-especially during winter-to prevent a deficiency and an impairment of performance.