Risk Factors Affected Severity Of Bronchiolitis And Asthma After Bronchiolitis

PartⅠStudy on risk factors for severity of bronchiolitis in infant【objectives】Bronchiolitis is a common cause of hospitalizations in children and severe respiratory syncytial virus (RSV) bronchiolitis has been increasingly identified as a risk factor in the development of asthma.Little is known about what determines the severity of bronchiolitis. It is helpful to investigate the factors affecting severity of bronchiolitis.【Methods】In stage I. Dates collected from 904 bronchiolitis enrolled between January 2002 and May 2003 at Children's Hospital were inclding age, gender, season, parental asthma ,birth weight , eczema, mild or severe , total and specific immunoglobulin-E (IgE), overweight and countryside dwelling and hospital days.In stage II. Significant risk factors for these outcomes were identified by logistic regression analysis . Statistical analyses were performed using Version 8.2 of the SAS software system.【Results】1. Respiratory syncytial virus (RSV) is an important pathogen in children less than 2 years old(5.28±2.92months old)and minimum age was 1 months and 2-6 months was morbility peak(70.8% ). Mean birth-weight is (3.25±0.49)kg and The seasonality of bronchiolitis showed a biennial pattern with peaks in the spring and winter. Moreover, Obesity(56%) and eczema( 52.5%)was common in bronchiolitis and length of stay is (6.53±2.94) days.The rate of family asthma history is 23.7% and that of first degree relatives is 9.8%.2. There was a significant association between severe bronchiolitis and young age , low birth-weight, congenital heart disease and countryside dwelling and hospital days and corresponding correlation coefficient respectively is 0.840,0.542,15.412,5.305和1.173 (all p<0.05).【Conlusions】1. The positive rate of the eczema from 571 infants with bronchiolitis was 52.5% and the rate of obesity was 56.0%. 2. The factors that contribute to increased risk of severe bronchiolitis is low birth-weight, young age , congenital heart disease and countryside dwelling(p<0.05) . but There was no significant effect of gender or season or familial asthma or overweight or eczema or IgE on severity of bronchiolitis(p>0.05). PartⅡRisk factors for asthma after bronchiolitis【objectives】Although most studies describing the association between RSV and airway high reaction(AHR) are observational, it is still unclear whether RSV infection alone causes the development of pulmonary sequelae or whether the combination of predisposing factors coupled with RSV infection early in life contributes to respiratory sequelae and AHR in later childhood. Well known risk factors for developing RSV-associated AHR include maternal smoking, infants with smaller airways, or infants with a familial history of asthma or atopy. However, most children with RSV bronchiolitis who develop recurrent wheezing and AHR do not have clear predisposing risk factors. The problems most frequently faced by the pediatrician is absence of unified, or standardized, clinical evaluation with which to examine factors associated with a diagnosis of asthma after bronchiolitis.【Methods】Data from 115 bronchiolitis were collected including age, gender, season, family asthma history,birth weight,eczema,mild and severe,total and specific immunoglobulin-E (IgE),overweight and a length of hospital stay ,then follow-up date from discharge to 5-6 years of age about low respiratory tract infection frequency during the first years of life,wheezing and complains and symptom and telephoned for asking informations about living pollution,smoking during pregnancy, bottle-feeding.cats or dogs contact. To obtain the independent effect of risk factors, logistic regression models were created for each outcome variable. Stepwise foreward logistic regression was used for this purpose.【Results】1. 33.9% of brochiolitis developed asthma. 2. There was a significant association between asthma and season,severe bronchiolitis,familial asthma,eczema and recurrent low respiratory tract infection and OR is respectively 0.494,3.825,6.127,3.766 and 3.144(all p<0.05.【Conlusions】1. Morbidity of asthma is high after bronchiolitis. 2. Falling ill in spring,severe bronchiolitis, familial asthma,eczema and recurrent low respiratory tract infection are all associated with development of asthma after bronchiolitis.