Effect of vitamin D supplementation on exercise-induced laryngeal obstruction in elite athletes

Body: We found that vitamin D (25OHD) deficiency favors exercise-induced laryngospasm (EILO), detectable by recording maximal mid-inspiratory flow (MIF50). Aim: We investigated the effect of vitamin D supplementation on EIB/EILO in athletes with 25OHD deficiency Methods: 30 elite athletes, aged 15-19 yrs performed spirometry and treadmill exercise test (ET) before and after 3 months supplementation with vitamin D. FEV1 and MIF50 were recorded before and 1 -5-10-15-20 minutes after the end of ET, as the respective indices of bronchospasm (EIB) and EILO: EIB was diagnosed when FEV1 fell by at least 10%, EILO if MIF50 fell by 25%. Results: All the athletes had 25OHD deficiency: 7 mild (21-29 ng/ml), 17 moderate (10-20 ng/ml), 6 severe ( Conclusion: Vitamin D deficiency was found in all of the athletes and favored exercise-induced laryngospasm, but not bronchospasm. After vitamin D supplementation, EILO reversed in most athletes, while EIB was scarcely modified.