ABSTRACT
<p><b>OBJECTIVE</b>To study the association of vitamin D level with asthma control and pulmonary function in children with asthma.</p><p><b>METHODS</b>A total of 150 children with asthma were enrolled as observation group, and 55 healthy children were enrolled as control group. According to the level of asthma control, the children were divided into good control group, partial control group, and non-control group. Chemiluminescence microparticle immunoassay was used to measure the serum level of 25-hydroxyvitamin D [25(OH)D] for all groups. According to the level of 25(OH)D, the asthmatic children were divided into normal vitamin D group, vitamin D insufficiency group, and vitamin D deficiency group. Pulmonary function was measured for all asthmatic children.</p><p><b>RESULTS</b>The observation group had a significantly lower serum level of 25(OH)D than the control group (25± 7 ng/mL vs 29± 4 ng/mL; P<0.05). The normal vitamin D group had the highest asthma control rate, followed by the vitamin D insufficiency group and the vitamin D deficiency group (P<0.05). There was no significant difference in pulmonary function among the three groups (P>0.05).</p><p><b>CONCLUSIONS</b>Asthmatic children have a lower serum level of 25(OH)D than healthy children. The serum level of 25(OH)D is associated with the level of asthma control and has no association with pulmonary function.</p>