| Air Pollution, Airway Inflammation, and Lung Function in a Cohort Study of Mexico City Schoolchildren Albino Barraza-Villarreal,1 Jordi Sunyer,2 Leticia Hernandez-Cadena,1 Maria Consuelo Escamilla-Nuñez,1 Juan Jose Sienra-Monge,3 Matiana Ramírez-Aguilar,4 Marlene Cortez-Lugo,1 Fernando Holguin,5 David Diaz-Sánchez,6 Anna Carin Olin,7 and Isabelle Romieu1 1Instituto Nacional de Salud Pública, Cuernavaca, México; 2Environmental Epidemiological Research Centre (CREAL), IMIM, Barcelona, Spain; 3Hospital Infantil de México, Federico Gómez, Mexico, D.F., Mexico; 4Comisión Federal de Protección contra Riesgos Sanitarios (COFEPRIS), México, D.F. Mexico; 5Department of Pulmonary Allergy and Critical Care, Emory University School of Medicine, Atlanta, Georgia, USA; 6Human Studies Division, U.S. Environmental Protection Agency, Chapel Hill, North Carolina, USA; 7Department of Occupational and Environmental Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden Abstract
Background: The biological mechanisms involved in inflammatory response to air pollution are not clearly understood. Objective: In this study we assessed the association of short-term air pollutant exposure with inflammatory markers and lung function. Methods: We studied a cohort of 158 asthmatic and 50 nonasthmatic school-age children, followed an average of 22 weeks. We conducted spirometric tests, measurements of fractional exhaled nitric oxide (FeNO) , interleukin-8 (IL-8) in nasal lavage, and pH of exhaled breath condensate every 15 days during follow-up. Data were analyzed using linear mixed-effects models. Results: An increase of 17.5 µg/m3 in the 8-hr moving average of PM2.5 levels (interquartile range) was associated with a 1.08-ppb increase in FeNO [95% confidence interval (CI) , 1.01–1.16] and a 1.07-pg/mL increase in IL-8 (95% CI 0.98–1.19) in asthmatic children and a 1.16 pg/ml increase in IL-8 (95% CI, 1.00–1.36) in nonasthmatic children. The 5-day accumulated average of exposure to particulate matter < 2.5 µm in aerodynamic diamter (PM2.5) was significantly inversely associated with forced expiratory volume in 1 sec (FEV1) (p = 0.048) and forced vital capacity (FVC) (p = 0.012) in asthmatic children and with FVC (p = 0.021) in nonasthmatic children. FeNO and FEV1 were inversely associated (p = 0.005) in asthmatic children. Conclusions: Exposure to PM2.5 resulted in acute airway inflammation and decrease in lung function in both asthmatic and nonasthmatic children. Key words: air pollution, airway inflammation, asthma, epidemiology, lung function, schoolchildren. Environ Health Perspect 116:832–838 (2008) . doi:10.1289/ehp.10926 available via http://dx.doi.org/ [Online 8 February 2008]
Address correspondence to I. Romieu, Instituto Nacional de Salud Pública, 655 Avenida Universidad, Col. Santa Maria Ahuacatitlán, 62508, Cuernavaca, Morelos, México. Telephone: 52-777-101-2935. Fax: 52-777-311-1148. E-mail: iromieu@correo.insp.mx We thank the schoolchildren who took part in the study, the personnel who carried out the fieldwork, and G. Evans for reviewing the English manuscript and for his editorial support. The study was supported by the Mexican Sciences and Technology Council (CONACYT) , grant 38911-M and Salud-2002-C01-7624. The authors declare they have no competing financial interests. Received 26 September 2007 ; accepted 31 January 2008.
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