Abstract: Objective:To explore the differences in the levels of 25 hydroxy vitamin D3(vitamin D3) of the asthmatic children with different control levels, to analyze the relationships between the vitamin D3 level and the pulmonary function indexes, and to clarify the effects of vitamin D3 level on the asthma control and the pulmonary function. Methods:A total of 64 asthmatic patients who aged from 6 to 14 years old were selected as asttma group, and then according to the control level, asthma groups were divided into well-controlled group, partially controlled group and uncontrolled group.Eighteen healthy children who aged from 6 to 14 years old were selected as control group.The general materials of subjects in gwo groups were collected. The levels of serum vitamin D3 of the subjects in two groups were detected by Roche electrochemiluminescence, and the pulmonary function indexes(FEV1,FEV1% pred, FEV1/FVC%, and FVC)were measured by spirometry. The levels serum of vitamin D3 of the subjects in asthma and control groups were analyzed by Wilcoxon rank sum test, the differences of vitamin D3 levels among different control level groups were analyzed by Kruskal-Wallis test, and the relationships between the vitamin D3 level and the pulmonary function indexes were analyzed by Spearman correlation analysis. Results:The serum vitamin D3 level of the children in asthma group was significantly lower than that in control group (P<0.05). The level of serum vitamin D3 of the children in well-controlled group was higher than that in uncontrolled group (P<0.05), but the level of serum vitamin D3 of the children in partially controlled group had no differences neither with well-controlled group nor with uncontrolled group (P>0.05). The percentage of children with vitamin D3 deficiency in uncontrolled group was significantly higher than that in well-controlled group (P<0.05). The vitamin D3 level was positively correlated with FEV1 and FEV1/FVC%(r=0.651,P<0.01;r=0.642,P<0.01). Conclusion:The level of serum vitamin D3 of the asthmatic children affects the control level of asthma and pulmonary function, so vitamin D3 inefficiency or deficiency should be paid attention in the treatment of asthma. Vitamin D3 supplementation is expected to be an important means of adjuvant treatment for asthma.

Key words: bronchial asthma, vitamin D3, asthma control, pulmonary function