title: Updated prevalences of asthma, allergy, and airway symptoms, and a systematic review of trends over time for childhood asthma in Shanghai, China.
abstract: BACKGROUND
  The prevalence of asthma among Shanghai children has increased over time. This increase might be associated with changes in environmental exposures. Investigation of the time-trend of asthma and current prevalences is essential to understanding the causes.
  
  
  OBJECTIVE
  To estimate the current prevalences of asthma, allergies and other respiratory symptoms among Shanghai preschool children, and to investigate the time-trend of childhood asthma prevalence of from 1990 to 2011.
  
  
  METHODS
  From April 2011 to April 2012, the CCHH (China, Children, Homes, Health) cross-sectional study was conducted in Shanghai. Questionnaires were distributed to 17,898 parents or guardians of preschool children from 72 kindergartens in 5 districts. Previous similar studies were also summarized by a systematic literature review.
  
  
  RESULTS
  From a total of 14,884 questionnaires for 3-7 year old children, prevalences of the following diseases and symptoms were calculated: asthma 10.2%, wheeze (ever) 28.1%, pneumonia (ever) 33.5%, otitis media 11.0%, rhinitis (ever) 54.1%, hay fever 12.2%, eczema (ever) 22.7%, and food allergy 15.7%. Urban children had higher prevalences of most symptoms than suburban children. The prevalence of asthma has increased significantly, almost five-fold, from 2.1% in 1990 to 10.2% in the present study. The prevalence of asthma in boys was higher than in girls in the present study and in all reviewed studies.
  
  
  CONCLUSIONS
  Asthma, allergy and airway symptoms are common among preschool children in Shanghai. The prevalence of childhood asthma in Shanghai has increased rapidly from 1990 to 2011.
authors: Department of Building Environment and Energy Engineering, School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai, PR China.
authors: Chen
authors: C
authors: Huang
authors: Department of Building Environment and Energy Engineering, School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai, PR China.
authors: Wei
authors: W
authors: Liu
authors: Tongji Architectural Design (Group) Co. Ltd. (TJAD), Shanghai, PR China.
authors: Yu
authors: Y
authors: Hu
authors: Department of Building Environment and Energy Engineering, School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai, PR China.
authors: Zhijun
authors: Z
authors: Zou
authors: Department of Environmental Health, School of Public Health, Key Laboratory of Public Health Safety, Ministry of Education, Fudan University, Shanghai, PR China.
authors: Zhuohui
authors: Z
authors: Zhao
authors: Department of Building Environment and Energy Engineering, School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai, PR China.
authors: Li
authors: L
authors: Shen
authors: 161 Richdale Road, Colts Neck, New Jersey, 07722, United States of America.
authors: Louise B
authors: LB
authors: Weschler
authors: Department of Building Science, School of Architecture, Tsinghua University, Beijing, PR China.
authors: Jan
authors: J
authors: Sundell
mesh_terms: D001249:Asthma / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004485:Eczema / Q000453:epidemiology*; D005260:Female; D005512:Food Hypersensitivity / Q000453:epidemiology*; D006801:Humans; D008297:Male; D010033:Otitis Media / Q000453:epidemiology*; D011014:Pneumonia / Q000453:epidemiology*; D015995:Prevalence; D012135:Respiratory Sounds; D012220:Rhinitis / Q000453:epidemiology*; D006255:Rhinitis, Allergic, Seasonal / Q000453:epidemiology*; D011795:Surveys and Questionnaires; D014507:Urbanization