Case-control study and Logistic analysis of the risk factors of infants with recurrent wheezing in Shanghai Pujiang area

Objective To analyze the relevant risk factors of recurrent wheezing(≥3 attacks) in the first 3 years of life in Shanghai Pujiang. Methods A case-control study was conducted.Two hundred and sixty-two research children were chosen for clinical visits (<3 years old) with wheezing at the Pediatric Department of Shanghai Renji Hospital (South Campus), School of Medicine, Shanghai Jiaotong University, from January to December 2014.According to the frequency of wheezing, the subjects were divided into 75 cases of recurrent wheezing group(≥3 attacks), 110 cases of occasional wheezing group(1-2 attacks) and 77 cases of no wheezing group.Probable risk factors were inquired by using face-to-face questionnaire.The passive agglutination method was used to detect the Mycoplasma pneumoniae antibody immunoglobulin M(IgM). The indirect immunofluorescence was used to detect the respiratory pathogens.The Western blot was used to detect 20 items of serum allergen.Chi-square test was firstly used for univariate analysis, and then the multivariate stepwise Logistic regression was used to analyze the independent risk factors associated with infant recurrent wheezing. Results A total of 20 factors were found relevant to infant recurrent wheezing by univariate analysis, which included boys (OR=4.030, 95%CI: 1.937-8.388), personal atopy (OR=13.125, 95%CI: 5.951-28.946), allergic dermatitis(OR=9.833, 95%CI: 4.663-20.737), allergic rhinitis(OR=40.327, 95%CI: 5.300-306.842), like rubbing eyes or nose(OR=6.487, 95%CI: 3.190-13.191), food allergy(OR=6.689, 95%CI: 1.860-24.051), premature birth(OR=3.795, 95%CI: 1.001-14.385), low birth weight(OR=9.075, 95%CI: 1.106-74.450), parental atopy(OR=10.667, 95%CI: 4.824-23.587), parental allergic dermatitis(OR=8.072, 95%CI: 2.634-24.734), parental allergic rhinitis(OR=6.524, 95%CI: 2.920-14.577), parental allergic conjunctivitis(OR=1.087, 95%CI: 1.017-1.162), parental asthma history(OR=1.119, 95%CI: 1.035-1.210), colds>6 times(OR=9.111, 95%CI: 3.970-20.909), history of bronchopneumonia(OR=7.554, 95%CI: 3.588-15.903), age at first time use of antibiotics less than 6 months(OR=2.388, 95%CI: 1.129-5.052), exposure to cigarette smoking(OR=1.922, 95%CI: 1.004-3.681), maternal passive smoking during pregnancy(OR=2.508, 95%CI: 1.298-4.848), living close to wood stove(OR=3.342, 95%CI: 1.427-7.827) and positive results of inhaled allergens(OR=1.821, 95%CI: 1.420-2.336). Keeping cats was the protective factor(OR=0.922, 95%CI: 0.864-0.984). The forward Logistic regression analysis showed that personal atopy (OR=10.278, 95%CI: 2.503-42.202), like rubbing eyes or nose (OR=10.316, 95%CI: 2.722-39.101), food allergy (OR=10.370, 95%CI: 1.248-86.145), parental atopy (OR=5.402, 95%CI: 1.340-21.778), colds>6 times (OR=7.048, 95%CI: 1.688-29.423), history of bronchopneumonia (OR=7.876, 95%CI: 2.040-30.407) and maternal passive smoking (OR=3.696, 95%CI: 1.013-13.494) during pregnancy were the indepen-dent risk factors of infants recurrent wheezing. Conclusion Personal atopy, like rubbing eyes or nose, food allergy, parental atopy, colds>6 times, history of bronchopneumonia, maternal passive smoking are the independent risk factors of recurrent wheezing in infants less than 3 years old. Key words: Wheezing; Recurrent; Risk factor; Infant; Case-control