title: Asthma and asthma related symptoms in 23,326 Chinese children in relation to indoor and outdoor environmental factors: the Seven Northeastern Cities (SNEC) Study.
abstract: BACKGROUND
  Both the levels and patterns of outdoor and indoor air pollutants have changed dramatically during the last decade in China. However, few studies have evaluated the effects of the present air pollution on the health of Chinese children. This study examines the association between outdoor and indoor air pollution and respiratory diseases among children living in Liaoning, a heavy industrial province of China.
  
  
  METHODS
  A cross-sectional study of 23,326 Chinese children aged 6 to 13 years was conducted in 25 districts of 7 cities in Northeast China during 2009. Three-year (2006-2008) average concentrations of particles with an aerodynamic diameter of ≤10 μm (PM10), sulfur dioxide (SO2), nitrogen dioxides (NO2), and ozone (O3) were calculated from monitoring stations in each of the 25 districts. We used two-level logistic regression models to examine the effects of yearly variations in exposure to each pollutant, controlling for important covariates.
  
  
  RESULTS
  The prevalence of respiratory symptoms was higher for those dwelling close to a busy road, those living near smokestacks or factories, those living with smokers, those living in one-story houses typically with small yards, and those with home renovation, bedroom carpet or pets. Ventilation device use was associated with decreased odds of asthma in children. The adjusted odds ratio for diagnosed-asthma was 1.34 (95% confidence interval [CI], 1.24-1.45) per 31 μg/m(3) increase in PM10, 1.23 (95%CI, 1.14-1.32) per 21 μg/m(3) increase in SO2, 1.25 (95%CI, 1.16-1.36) per 10 μg/m(3) increase in NO2, and 1.31 (95%CI, 1.21-1.41) per 23 μg/m(3) increase in O3, respectively.
  
  
  CONCLUSIONS
  Outdoor and indoor air pollution was associated with an increased likelihood of respiratory morbidity among Chinese children.
authors.affiliation: Department of Orthodontics, School of Stomatology, China Medical University, Shenyang, Liaoning Province 110001, PR China. Electronic address: liufan-sky@163.com.
authors.forename: Fan
authors.initials: F
authors.lastname: Liu
authors.affiliation: Department of Biostatistics and Epidemiology, School of Public Health, China Medical University, Shenyang, Liaoning Province 110001, PR China. Electronic address: zhaoyang_cmu@126.com.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Biostatistics and Epidemiology, School of Public Health, China Medical University, Shenyang, Liaoning Province 110001, PR China. Electronic address: xinxin_lyq@163.com.
authors.forename: Yu-Qin
authors.initials: YQ
authors.lastname: Liu
authors.affiliation: Department of Biostatistics and Epidemiology, School of Public Health, China Medical University, Shenyang, Liaoning Province 110001, PR China. Electronic address: liuyang071506@126.com.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Biostatistics and Epidemiology, School of Public Health, China Medical University, Shenyang, Liaoning Province 110001, PR China. Electronic address: sunjingjl_2007@126.com.
authors.forename: Jing
authors.initials: J
authors.lastname: Sun
authors.affiliation: Department of Biostatistics and Epidemiology, School of Public Health, China Medical University, Shenyang, Liaoning Province 110001, PR China. Electronic address: gghuangmeimeng@163.com.
authors.forename: Mei-Meng
authors.initials: MM
authors.lastname: Huang
authors.affiliation: Department of Orthodontics, School of Stomatology, China Medical University, Shenyang, Liaoning Province 110001, PR China. Electronic address: liuyi256@126.com.
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Preventive Medicine, School of Public Health, Sun Yat-sen University, Guangzhou, Guangdong Province 510080, PR China. Electronic address: donggh5@mail.sysu.edu.cn.
authors.forename: Guang-Hui
authors.initials: GH
authors.lastname: Dong
mesh_terms: D000397:Air Pollution; D016902:Air Pollution, Indoor / Q000706:statistics & numerical data; D001249:Asthma / Q000453:epidemiology*; D002648:Child; D002681:China / Q000453:epidemiology; D002947:Cities / Q000453:epidemiology; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male
keywords: Air pollution; Asthma; Children; Home renovation; House type; Pets