Risk Factors Of Post-Bronchiolitis Wheezing In 400 Bronchiolitis Infants

Background:Bronchiolitish is the most frequent acute low respiratory tract infection disease in infants, which is mainly caused by respiratory syncytial virus (RSV) and human rhino virus. While the relationship between rhinovirus and bronchiolitis had been noted in recent years. The majority are infants who is less than 6 months old, and wheezing is the main manifestation. Most of the patients will recover after treatment, but the airway hyperresponsiveness appeared in some patients and some even developed recurrent wheezing and asthma. Studies have shown that hospitalized children with recurrent wheezing and asthma after bronchiolitis incidence rates were 68% and 30%. Birth weight, feeding practice, atopy and allergic family history were risk factors of post bronchiolitis wheezing. However, there was no clinical indexes to correctly predict post bronchiolitis wheezing.ObjectiveTo investigate the incidence of the recurrent cough and wheezing after bronchiolitis and discuss the correlation factor of recurrent wheezing after bronchiolitis.MethodsThe clinical information of hospitalized patients with the diagnosis of respiratory virus bronchiolitis from June 2009 to December 2012 was collected. The collected clinical information included gender, age, birth history, birth weight, had older siblings, personal atopic history (eczema, allergic rhinitis, and drug allergy), family atopic history (asthma, eczema, allergic rhinitis, and drug allergy),feeding practice, passive smoking, disease severity. Respiratory viruses were detected with multiplex reverse transcriptase polymerase chain reaction (PCR). Seventeen SNPs on 17q21 region were genotyped by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF). Genotype distributions of 17q21 SNPs between post bronchiolitis wheezing patients and post bronchiolitis no wheezing were compared to assess the association between the ORMDL3 polymorphisms and post bronchiolitis wheezing. Follow-up study was performed by telephone to assess weather the patients developed recurrent wheezing (at least three episodes of wheezing). Results:400 children with bronchiolitis were enrolled in this study.175 patients were successfully followed up. The rest children were lost because the telephone numbers were out of service or registered with wrong numbers. There were significant differences between post bronchiolitis wheezing and post bronchiolitis no wheezing patients in birth weight (>4kg),feeding practice, personal atopic history, family atopic history, passive smoking and had older siblings(x2=5.104,11.747,26.388,27.082, 27.082,36.222,16.844, P=0.031,0.001,0.000,0.000,0.000,0.000). However, gender, age, birth history and disease severity did not correlated with post bronchiolitis wheezing (x2=0.299,1.002,0.546 P=0.725, 0.360,0.579)。Respiratory viruses detection:The respiratory viruses detection rate was 82.8% in 175 patients who were diagnosed with bronchiolitis. RSV infection accounted for 57.7%, PIV for 19.4%, RHV for 13.1%, FIV for 15.4%, HBoV for 11.4%, ADV for 4.5%, HMPV for 2.3%, CoV for 0%. They were no significant differences of virus detection between post bronchiolitis wheezing patients and post bronchiolitis no wheezing groups.SNPs genotyping:Comparison of post bronchiolitis wheezing patients and post bronchiolitis no wheezing showed that there were no significant associations with the ORMDL3 variants.Conclusions: The birth weight> 4kg, personal atopy history, family atopy history, passive smoking and had older siblings were the significant risk factors contributed to the post bronchiolitis wheezing in children, and breastfeeding (>4month) was protective factor. However, the factors of gender, age, birth history, disease severity, respiratory viruses detection and ORMDL3 variations did not correlated with post bronchiolitis wheezing.