Background: Otitis media is the leading reason young children receive antibiotics or visit a physician. We evaluated the impact of ambient air pollution on outpatient physician visits for otitis media in a population-based birth cohort.
Methods: All children born in southwestern British Columbia during 1999-2000 were followed until the age of 2 years. Residential air pollution exposures were estimated for the first 24 months of life by inverse-distance weighting of monitor data (CO, NO, NO2, O3, PM2.5, PM10, SO2), temporally adjusted land-use regression models (NO, NO2, PM2.5, black carbon, woodsmoke), and proximity to roads and point sources. We used generalized estimating equations to longitudinally assess the relationship between physician visits for otitis media (ICD-9) and average pollutant exposure in the 2 months prior to the visit, after adjustment for covariates.
Results: Complete exposure and risk-factor data were available for 45,513 children (76% of all births). A total of 42% of subjects had 1 or more physician visits for otitis media during follow-up. Adjusted estimates for NO, PM2.5, and woodsmoke were consistently elevated (eg, relative risk of 1.10 [95% confidence interval = 1.07-1.12] per interquartile range [IQR] increase in NO; 1.32 [1.27-1.36] per IQR increase in days of woodsmoke exposure). No increased risks were observed for the remaining pollutants (eg, 1.00 [0.98-1.03] per IQR increase in PM10; 0.99 [0.97-1.01] per IQR increase in black carbon).
Conclusions: Modest but consistent associations were found between some measures of air pollution and otitis media in a large birth cohort exposed to relatively low levels of ambient air pollution.
From the aSchool of Environmental Health, University of British Columbia, Vancouver, British Columbia, Canada; bInstitute of Epidemiology, German Research Center for Environmental Health, Neuherberg, Germany; cDepartment of Environmental and Occupational Health Sciences, University of Washington, Washington, USA; dSchool of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada; and eCentre for Health Services and Policy Research, University of British Columbia, Vancouver, British Columbia, Canada.
Submitted October 19, 2009; accepted July 31, 2010; posted 28 October 2010.
Supported by the British Columbia Centre for Disease Control via an agreement with Health Canada under the Border Air Quality Strategy (GEH0402). Additional support was provided by the Center for Health and Environment Research at UBC, funded by the Michael Smith Foundation for Health Research (MSFHR). The Canadian Institutes of Health Research and MSFHR supported E.M. through a UBC Bridge Strategic Training Fellowship, Senior Graduate Studentship and Frederick Banting and Charles Best Canada Graduate Scholarship. M.K. was supported in part by a MSFHR Scholar Award.
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Correspondence: Elaina MacIntyre, Institute of Epidemiology, German Research Center for Environmental Health, Ingolstädter Landstraße 1, D-85764 Neuherberg, Germany. E-mail: firstname.lastname@example.org.