Clinical characteristics of acute attacks of BA in school-age children in Kashgar region and correlation analysis of 25（OH）D3 levels with disease severity

Objective To explore the clinical characteristics of acute attacks of bronchial asthma （BA） in children in Kashgar region， and analyze the impact of 25-hydroxyvitamin D3 （25（OH）D3） levels on disease severity. Methods Children with acute BA attacks， aged 6-14 years， admitted to a certain thirdtier A-level Hospital of Kashgar were enrolled and divided into different groups according to disease severity （mild， moderate and severe） and 25（OH）D3 levels （normal， insufficiency and deficiency）. Clinical characteristics were compared among different groups. The correlation between 25（OH）D3 levels and disease severity was analyzed. Results A total of 112 children were enrolled， with a male-to-female ratio of 2.61∶1， with a median age of 9.0 （7.0-11.0） years old. The highest incidence was found in spring （42.9%）. The positive rate of allergens is 74.1%（83/112）， with inhaled allergens as the main type （89.1%）， and the tree combination had the highest positive rate （47.0%）.Based on disease severity， 36 cases were assigned into the mild group， 51 cases in the moderate group， and 25 cases in the severe group. As the disease severity was aggravated， the forced vital capacity （FVC）， forced expiratory volume at 1 second （FEV1）， and the ratio of FEV1 to FVC（FEV1/FVC） were gradually decreased （all P <0.001）. The eosinophil （EOS） count in the severe group was higher than that in the mild group （P < 0.05）. According to 25（OH）D3levels， 28 cases had normal 25（OH）D3 levels， 21 cases with insufficient 25（OH）D3 levels， and 35 cases with 25（OH）D3 deficiency. The FVC， FEV1， FEV1/FVC， and peak expiratory flow （PEF） in the 25（OH）D3 deficiency group were significantly lower than those in the insufficient and normal 25（OH）D3 groups （all P < 0.05）. The disease severity significantly differed among three groups （H = 9.538， P = 0.008）. Serum 25 （OH） D3 levels were negatively correlated with the severity of BA attacks （τ = -0.304， P =0.002）. Conclusions Spring is the peak season of acute attacks of BA in school-age children from Kashgar. Inhaled allergens are mainly composed of tree combination. As the severity of this condition deteriorates， lung function of the affected children are gradually declined. Serum 25 （OH） D3 levels are associated with lung function and the severity of acute attacks in children with BA.