Background: Exposure to particulate matter (PM) has been associated with deficits in lung function growth among children in Western countries. However, few studies have explored this association in developing countries, where PM levels are often substantially higher.
Methods: Children (n = 3273) 6–12 years of age were recruited from 8 schools in 4 Chinese cities. The lung function parameters of forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) were measured using computerized spirometers twice a year for up to 3 years (1993–1996). Dichotomous samplers placed in each schoolyard were used to measure PM2.5 and PM10 (PM with diameter ≤2.5 μm and ≤10 μm, respectively). Multivariable generalized estimating equations were used to examine the association between the quarterly average PM levels and lung function growth during the period of follow-up.
Results: Annual average PM2.5 and PM10 levels in the 4 cities ranged from 57 to 158 μg/m3 and 95 to 268 μg/m3, respectively. In multivariable models, an increase of 10 μg/m3 of PM2.5 was associated with decreases of 2.7 mL FEV1 (95% confidence interval = −3.5 to −2.0), 3.5 mL FVC (−4.3 to −2.7), 1.4 mL/year FEV1 growth (−1.8 to −0.9), and 1.5 mL/year FVC growth (−2.0 to −1.0). Similar results were seen with PM10 exposure.
Conclusions: Exposure to ambient particulate matter was associated with decreased growth in lung function among Chinese children.
From the aDivision of Environmental Epidemiology and Statistics, Environmental and Occupational Health Sciences Institute, Piscataway, NJ; bChina National Environmental Monitoring Center, Beijing, People's Republic of China; cDivision of Statistical Analysis, Office of Science, New Jersey Department of Environmental Protection, Trenton, NJ; dCollege of Public Health Sciences, Chulalongkorn University, Bangkok, Thailand; eDepartment of Environmental Health, University of Medicine and Dentistry of New Jersey-School of Public Health, Piscataway, NJ; and fDepartment of Preventive Medicine, Keck School of Medicine, University of Southern California, CA.
Submitted: 4 April 2011; accepted: 1 November 2011; posted online 8 March 2012.
The study was funded by the U.S. EPA and the Chinese government. The current work of Drs. Zhang and Roy is partly supported by NIEHS Center grants (P30 ES05022, and 5P30ES007048).
The authors reported no other financial interests related to this research.
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Correspondence: Junfeng (Jim) Zhang, Department of Preventive Medicine, Keck School of Medicine, University of Southern California, 1540 Alcazar Street, CHP Suite 236, Los Angeles CA 90033. E-mail: email@example.com.