In summary, the present study demonstrates for the first time that 25(OH)D levels are associated with clinical
parameters of asthma severity and asthma control in adult patients with asthma. Frequency of vitamin D insufficiency
is highest in patients with severe and uncontrolled asthma. This is even more relevant given that the risk of vitamin D
insufficiency is significantly increased in patients on oral corticosteroids or with eosinophilic disease.