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

BackgroundBoth 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. MethodsA cross-sectional study of 23,326 Chinese children aged 6 to 13years 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 ≤10μm (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. ResultsThe 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 31μg/m3 increase in PM10, 1.23 (95%CI, 1.14–1.32) per 21μg/m3 increase in SO2, 1.25 (95%CI, 1.16–1.36) per 10μg/m3 increase in NO2, and 1.31 (95%CI, 1.21–1.41) per 23μg/m3 increase in O3, respectively. ConclusionOutdoor and indoor air pollution was associated with an increased likelihood of respiratory morbidity among Chinese children.