Risk Factors For Wheezing In Infant In ZhongShan

BACKGROUNDInfant wheezing, namely the asthmatic disease in infants and young children, is a highly heterogeneous disease. They have similar wheezing symptoms and signs, but different etiologies. Infant wheezing, which exist widely in various countries of the world, is currently one of the most common reasons for infant’s seeing a Doctor and hospitalization,seriously affect their physical and mental health, and cause huge economic burden on society and family, and belong to the important global public health problems. There are more epidemiological data abroad, at least1time of wheezing occurs in25%of Australian infant,45%of American infant, and close to30%of Holland infant younger than1year old; In New England, the wheezing morbidity is39%in infant younger than15months; A multicentre, cross-sectional, large,international cohort study date from Latin American and European show that occasional wheezing(OW) rate of infants is14.9%～38.6%,recurrent wheezing(RW) rate is12.1%-36.3%;other research projects including older children show22%-42%of the wheezing morbidity;Another research reports that approximately one third of children in the first3years of life occur at least1time of wheezing,and to the6th year of life,the cumulative prevalence of wheezing reaches as high as40%,is one of the leading causes of infant death and reduced quality of life.Among them,children under5years old,have the higher hospitalized rate and revisit rate due to recurrent wheezing,especially children in the first year of life. Bronchial asthma is the most common childhood asthmatic disease, about more than80%of children occur before the age of3, and the early onset is not typical, can only show the transient wheezing sometimes. Although around two-thirds of wheezing children before the age of3stop wheezing at the age of6,there are still one third repeating wheeze and most of whom progress as asthma. In China,there is no epidemiology data about infant breathing showing the incidence of it, but the asthma incidence of children aged0to14,increase from0.11%～2.03%in1990up to0.25%～0.25%in2000, presumably, the incidence of infant wheezing is still keeping gradually upward trend in recent years.Wheezing is one of the most common respiratory symptoms in infants and young children, which can not only occur in the respiratory tract infection, but also can be the clinical manifestation of asthma. Wheezing incidence is higher especially in children with a family history of atopy. Common triggers include viral infections, allergens, crying, laughing, movement, smoke and bad air quality, etc. Bronchiolitis is the most common asthmatic disease in infant,which is caused by viral infection,including respiratory syncytial virus (RSV), rhinovirus, adenovirus, influenza virus, parainfluenza virus and the human metapneumovirus (hMPV) of newly discovered, etc. In addition, Mycoplasma pneumoniae (MP), Chlamydia trachomatis (CP) are also important pathogens can lead to wheeze. A part of infant wheezing is asthma, the main causes of which are various indoor and outdoor allergens, such as pollen, mites, atmospheric pollutants, etc. Infantile wheezing is related to bronchial lung development maturity, such as prematurity and infant with passive smoking aer prone to wheeze. Beyond that, trachea, gastroesophageal reflux may directly cause wheezing. Even some factors may increase wheezing, such as congenital heart disease, bronchial pulmonary dysplasia. In recent years, research at home and abroad tend to research potential and independent risk factors of infant wheezing, because of differences in race, region, environment, all risk factors are not the same.There are more related data abroad, but less at home, the most representative research is analysis of risk factors for infants wheezing in Guangzhou, in2010.The clinical manifestation of wheezing induced by different causes are different, including the onset time, seizure frequency, wheezing expiration time and response to therapy, severe wheezing episodes whthout timely and effective treatment may be life-threatening. At present, the classification about the clinical phenotypes are not unified, European Academy of allergy and Clinical Immunology (EAACI) and Academy of AwardAmerican allergy, asthma and Clinical Immunology (AAAAI) joint an expert group to develop the Practice Allergy(PRCTALL) consensus report.In which clinical phenotypes of infant wheezing are divided based on age, course of disease,triggering factors,and clinical manifestations into4clinical phenotype:(1) Transient wheezing;(2)Nonatopic wheezing;(3)Persistent asthma;(4) Severe intermittent wheezing. Because of the fourth phenotype is still difficult to make explicit, objective definition, our country only has summed up3kinds of clinical phenotypes:(1) Transient wheezing;(2) Nonatopic wheezing;(3) Persistent asthma. This phenotype classification, which is based on the research results of epidemiology, has extremely limited practical application on clinician, is more applicable to retrospective analysis epidemiology. Therefore, the European Respiratory Society (ERS) working group proposed a new phenotypes classification for preschool children with wheezing. The episodic (viral) wheeze and multiple trigger wheeze according to different triggers, and this new wheeze phenotype classification may have more practical significance for clinicians.Infancy is an important period of personality formation, the key period of growth and development, also the best period of forming good behavior and habit. This critical period, if it is affected by adverse effects of genetic, maternal pregnancy, environment and other factors will put off children’s healthy growth. It is reported that about one third of children under the age of3accur wheezing at least once,80%children with asthma attack before the age of3, but there are no specific methods and indexes can be used for the exact diagnosis of asthma in preschool children with wheezing at present, wheezing has become a important reason for infant death and the decline quality of life. More and more evidence show that risk factors related to wheezing in the first year of life will also influence the onset of wheezing and persistent wheezing in preschool children, therefore, it is critical to identify risk factors of infant wheezing for preventing persistent wheezing, and early effective intervention to infant wheezing can reduce the possibility of future development of childhood asthma.OBJECTIVE1.This project use the questionnaire, details of which includs genetic factors, maternal factors during pregnancy, children’s fctors, personal atopy and mother’s education, to preliminary explore possible risk factors of wheezing children aged from0to36months in Zhongshan, to provide scientific basis for the prevention of infantile wheezing, and to reduce the possibility of future development of childhood asthma and the other long-term consequences timely and effectively.2.Through the research, our aims are to popularize knowledge related with infant wheezing for people, especially for the main caregivers or guardians of infants and young children, avoid the risk factors leading to wheeze, guide the family prevention work of infant wheezing better, and lay the foundation for the prevention and treatment of infant wheezing in this region.METHODS1.1:1paired logistic regression analysis methodAt present there is no recognized effective, mature calculation formula of sample size for logistic regression analysis, so we estimate the sample size by experience. According to bout ten times of all factors, and1:1paired design, the amount of sample is estimated about600cases. One grade A tertiary hospital, Boai hospital of Zhongshan, was selected as study site. Children hospitalized in hospital’s pediatric respiratory department were selected as study subjects from September,2010to July,2012. We formulated strict inclusion, exclusion criteria, according to which300infants with wheezing were selected as case group, and300age-and sex-matched controls without wheezing were selected as control group during the same period. 2.QuestionnaireThirty possible risk factors were summarized by inventory survey, reading literature, and regional characteristics of ZhongShan, which are contained in six parts, including genetic factors, maternal factors, children’s fctors, personal atopic, environmental factors and the others. Then face-to-face questionnaires were carried out and children’s information were accurately recorded by relevant personnel unified trained.Immunofluorescence assay (DFA) was used for detection of RSV antigen, and ELISA method for detection of MPIgM antibody, then results of them were recorded in questionnaire respectively. After that, we classified questionnaires and organized Data. In the end, independent t test and chi square test were used for single factor analysis to find possible risk factors for infant wheezing, then Logistic regression analysis was used to find independent risk factors for infant wheezing in ZhongShan.RESULTS1. Single factor analysis of related risk factors for infants with wheezingGenetic factors include family history of allergic diseases, especially parental allergic rhinitis or asthma history. Parents who have a history of allergy diseases accounted for32%in the wheezy group, and13%in non-wheezy group, there is statistically significant difference bewteen these two groups(χ2=31.05, P<0.001).Maternal factors include exposure to tobacco, intake of nut, intake of seafood, Vitamin D supplements during pregnancy,pregnancy hypertension,younger maternal age and mode of delivery.The investigation shows that cesarean section rate is significantly higher in wheezy group than that in non-wheezy group (χ2=4.98, P=0.026); the other indexes in two groups were not significantly different(P>0.05).Children’s fctors include Postnatal oxygen Inhalation, Using breathing machine, Exclusive breastfeeding for less than3months, Daycare center attendance, RSV infection, MP infection, Drinking herbal tea, Eating Canton soup, Loving cry, Unhappy parents. Among them, there are statistically significant difference between two groups in RSV infection (χ2=21.38, P<0.001), MP infection (χ2=14.10, P<0.001), loving cry (χ2=14.72, P=0.005), Unhappy parents (χ2=6.26, P=0.044).Personal atopic, namely individual allergic history, refers that children have had food or drug allergies, eczema, urticaria, allergic rhinitis disease history. Personal history of allergy in wheezy group is significantly higher than that in non-wheezy group (χ2=4.04, P=0.044).Environmental factors consist of two parts for indoor and outdoor. The indoor factors include Having siblings, Pet ownership, paved floor, passive smoking, Playing stuffed toys, House dampness, Paint fumes, kitchen fumes; Outdoor factors include Living near the street, Living near the factory. The study has found that all indoor factors beween two groups are not significantly different (P>0.05), while children who live near the street and factory in wheezy group are significantly more than non-wheezy group (χ2=13.02, P<0.001;χ2=5.97, P=0.015).The other mainly refers to the mother’s education. This survey finds that there is no significant difference in maternal cultural degree between wheezy group and non-wheezy group (χ2=7.50, P=0.057).2. Logistic regression analysis of risk factors related to infant wheezingThis investigation shows that parental history of atopy (1.914[OR=3.441,95%CI,6.186), P<0.001], RSV infection [OR=2.910,95%CI (1.793,4.723), P<0.001], MP infection [OR=2.277,95%CI (1.110,4.667), P=0.025], living near the road [OR=2.036,95%CI (1.280,3.239), P=0.003], loving cry[OR=1.521,95%CI (1.049,2.206), P=0.027] are independent risks of infant wheezing in Zhongshan.CONCLUSIONSWe conclude that nine factors,including Parental allergy history, RSV infection, MP infection, Living near the street, Loving cry, Mode of delivery, Unhappy parents, Personal atopy, and Living near the factory are possible risk factors, while the former five ones are independent risk factors for wheezing in infants in ZhongShan. Therefore, to propagandize in public knowledge about infant wheezing, try to avoid some controllable risk factors of it, reduce its incidence and improve the quality of life in infant with wheezing are imperative.