| Early Childhood Lower Respiratory Illness and Air Pollution Irva Hertz-Picciotto,1 Rebecca James Baker2
(posthumous), Poh-Sin Yap,1 Miroslav Dostál,3
Jesse P. Joad,4 Michael Lipsett,5 Teri Greenfield,1
Caroline E.W. Herr,1,6 Ivan Benes,7 Robert
H. Shumway,8 Kent E. Pinkerton,9 and Radim Srám3 1Department of Public Health Sciences, University of
California, Davis, California, USA; 2Department of Epidemiology,
University of North Carolina, Chapel Hill, North Carolina, USA; 3Laboratory
of Genetic Ecotoxicology, Institute of Experimental Medicine, AS CR
and Health Institute of Central Bohemia, Prague, Czech Republic; 4Department
of Pediatrics, University of California, Davis, California, USA; 5Department
of Epidemiology and Biostatistics, University of California, San Francisco,
California, USA; 6Institute of Hygiene and Environmental
Medicine, University of Giessen, Giessen, Germany; 7Health
Institute Usti n.L., Branch Teplice, Czech Republic; 8Department
of Statistics, University of California, Davis, California, USA; 9Department
of Rheumatology, Allergy and Clinical Immunology, University of California,
Davis, California, USA Abstract
Background: Few studies of air pollutants address morbidity in preschool children. In this study we evaluated bronchitis in children from two Czech districts: Teplice, with high ambient air pollution, and Prachatice, characterized by lower exposures. Objectives: Our goal was to examine rates of lower respiratory illnesses in preschool children in relation to ambient particles and hydrocarbons. Methods: Air monitoring for particulate matter < 2.5 µm in diameter (PM2.5) and polycyclic aromatic hydrocarbons (PAHs) was conducted daily, every third day, or every sixth day. Children born May 1994 through December 1998 were followed to 3 or 4.5 years of age to ascertain illness diagnoses. Mothers completed questionnaires at birth and at follow-up regarding demographic, lifestyle, reproductive, and home environmental factors. Longitudinal multivariate repeated-measures analysis was used to quantify rate ratios for bronchitis and for total lower respiratory illnesses in 1,133 children. Results: After adjustment for season, temperature, and other covariates, bronchitis rates increased with rising pollutant concentrations. Below 2 years of age, increments in 30-day averages of 100 ng/m3 PAHs and of 25 µg/m3 PM2.5 resulted in rate ratios (RRs) for bronchitis of 1.29 [95 % confidence interval (CI) , 1.07–1.54] and 1.30 (95% CI, 1.08–1.58) , respectively ; from 2 to 4.5 years of age, these RRs were 1.56 (95% CI, 1.22–2.00) and 1.23 (95% CI, 0.94–1.62) , respectively. Conclusion: Ambient PAHs and fine particles were associated with early-life susceptibility to bronchitis. Associations were stronger for longer pollutant-averaging periods and, among children > 2 years of age, for PAHs compared with fine particles. Preschool-age children may be particularly vulnerable to air pollution–induced illnesses. Key words: air pollution, bronchitis, children's health, infant, particulate matter, PM2.5, PAHs, polycyclic aromatic hydrocarbons, respiratory illness, volatile organic compounds. Environ Health Perspect 115: 1510–1518 (2007) . doi:10.1289/ehp.9617 available via http://dx.doi.org/ [Online 22 May 2007]
Address correspondence to I. Hertz-Picciotto, Department of Public Health Sciences, Division of Epidemiology, TB #168 University of California, Davis, CA 95616 USA. Telephone: (530) 752-7844. Fax: (530) 752-3239. E-mail: ihp@ucdavis.edu This report is dedicated to the memory of Rebecca James Baker, my student, colleague, and friend, without whom this study would have been nearly impossible, or at best might have been a shadow of what it is. This paper represents an expansion of her dissertation. Her insights, patience, hard work, persistence and thoroughness, an understated acumen, and always, a quiet but powerful presence shine from every page. We gratefully acknowledge J. Dejmek, who initiated and directed the Pregnancy Outcome Study and made available the data collected in that study ; the hospital obstetric nurses who recruited mothers into the Immune Biomarker Study ; the hospital obstetricians who abstracted medical data ; the many pediatricians and pediatric nurses in the two districts who located families, collected the questionnaires, and abstracted the children's medical records ; L. Dostalova, who carried out virtually all of the follow-up data entry ; and E. Dejmkova, who assisted in secretarial tasks. This work was supported in part by the Czech Ministry of Environment (Teplice Program) , the U.S. Environmental Protection Agency (CR no. 820076) , the U.S. Agency for International Development, the Commission of the European Community (PHARE II, EC/HEA 18/CZ) , Health Effects Institute, National Institute of Environmental Health Sciences grants P30-ES05707, R01-ES11634, P01-ES11269, R01-CA96525, Fogarty International Center R03-TW007152-01A1, and U.S. Environmental Protection Agency STAR grants R829388 and RD-83154001. The authors declare they have no competing financial interests. Received 15 August 2006 ; accepted 22 May 2007.
Correction In "Respiratory illnesses," some of the numbers of events under various ICD-10 codes ; the rates of croup in "Respiratory illness rates" ; and some values in Table 3 for "Day of the week" were incorrect in the manuscript originally published online. They have been corrected here. Also, different averaging periods are presented for correlations of temperature and air pollutants. A new paragraph on studies of PAHs has been added to the "Discussion."
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