title: [The effects of breastfeeding on asthma and asthma related symptoms among children].
abstract: OBJECTIVE
  To evaluate the effect of breastfeeding on asthma and asthma related symptoms among children.
  
  
  METHODS
  Using a cluster random sampling method, 2 elementary schools and 1 kindergarten were randomly selected from each of the 5 districts of Shenyang, and a total of 10 elementary schools and 5 kindergartens were included, and 8733 children from the selected schools were recruited in this survey. The information about the type of feeding, living environment and respiratory diseases of the selected children from the time they were born was collected by an international standard questionnaire. Evaluating the effect of breastfeeding on asthma and asthma related symptoms (asthma, current asthma, current wheeze, persistent cough, persistent phlegm, and allergic rhinitis) by χ² test and logistic regression.
  
  
  RESULTS
  There were 8733 children involved in this study. The age was (8.00 ± 2.88) years old. There were 6830 breastfed children. The percentage of breastfed children was 78.21%. In breastfed children, the prevalence of asthma, persistent phlegm and allergic rhinitis were 6.12% (418/6830), 3.97% (271/6830), 4.17% (285/6830), respectively. In non-breastfed children, the prevalence of asthma, persistent phlegm and allergic rhinitis were 7.41% (141/1903), 6.04% (115/1903), 5.89% (112/1903), respectively. Compared to the non-breastfed children, the breastfed children had significantly lower prevalence (all P values < 0.05). After adjustment for 302 cases of atopy history of children's mother, the results showed that in breastfed children, the prevalence of asthma, persistent phlegm and allergic rhinitis were 14.69% (36/245), 4.08% (10/245), 7.35% (18/245), respectively. In non-breastfed children, the prevalence of asthma, persistent phlegm and allergic rhinitis were 33.33% (19/57), 14.04% (8/57), 17.54% (10/57), respectively. The breastfed children had statistically lower prevalence (all P values < 0.05). Multivariate analysis showed that breastfeeding was significantly associated with lower prevalence of asthma (OR = 0.78, 95%CI: 0.64 - 0.96), allergic rhinitis (OR = 0.72, 95%CI: 0.57 - 0.90), persistent cough (OR = 0.81, 95%CI: 0.69 - 0.96) and persistent expectoration (OR = 0.61, 95%CI: 0.48 - 0.76).
  
  
  CONCLUSIONS
  Breastfed children had lower prevalence of asthma and asthma related symptoms compared with non-breastfed children.
authors.affiliation: Department of Biostatistics, School of Public Health, China Medical University, Shenyang 110001, China.
authors.forename: Yu-qin
authors.initials: YQ
authors.lastname: Liu
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhao
authors.forename: Miao-miao
authors.initials: MM
authors.lastname: Liu
authors.forename: Da
authors.initials: D
authors.lastname: Wang
authors.forename: Wan-hui
authors.initials: WH
authors.lastname: Ren
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.forename: Guang-hui
authors.initials: GH
authors.lastname: Dong
mesh_terms: D001249:Asthma / Q000453:epidemiology*; D001942:Breast Feeding; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D012307:Risk Factors; D011795:Surveys and Questionnaires