About 75% of patients with severe or uncontrolle asthma were vitamin D insufficient as defined by a level of 30 ng/ml or less. Patients with severe and uncontrolled asthma had the lowest 25(OH)D levels (23.7 ±12.3 ng/ml) compared with patients with intermittent, mild or moderate and controlled or partly controlled asthma (27.1 ± 11.7 ng/ml, p = 0.014).