Heavy vehicle traffic is related to wheeze among schoolchildren: a population-based study in an area with low traffic flows

Martin Andersson,Bertil Forsberg,Linnea Hedman,Eva Rönmark,Lars Modig

doi:10.1186/1476-069x-10-91

Martin Andersson, Bertil Forsberg + Show 3 more

Open Access

https://doi.org/10.1186/1476-069x-10-91

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Journal: Environmental Health	Publication Date: Oct 13, 2011
Citations: 46	License type: cc-by

Affiliation: Umeå University, Sunderby sjukhus

Abstract

BackgroundAn association between traffic air pollution and respiratory symptoms among children has been reported. However, the effects of traffic air pollution on asthma and wheeze have been very sparsely studied in areas with low traffic intensity in cold climate with poor dispersion. We evaluated the impact of vehicle traffic on childhood asthma and wheeze by objective exposure assessment.MethodsAs a part of the Obstructive Lung Disease in Northern Sweden (OLIN) studies, a questionnaire was sent to the families of all children attending first or second grade in Luleå (72,000 inhabitants) in Northern Sweden in 2006. The age of the children was 7-8 years and the participation rate was 98% (n = 1357). Skin prick tests were performed in 1224 (89%) children. The home addresses were given geographical coordinates and traffic counts were obtained from the local traffic authorities. A proximity model of average daily traffic and average daily heavy vehicle traffic within 200 meters from each participant's home address was used. The associations between traffic exposure and asthma and wheeze, respectively, were analysed in an adjusted multiple logistic regression model.ResultsExposure to high traffic flows was uncommon in the study area; only 15% of the children lived within 200 meters from a road with a traffic flow of ≥8000 vehicles per day. Living closer than 200 meters from a road with ≥500 heavy vehicles daily was associated with current wheeze, odds ratio 1.7 (confidence interval 1.0-2.7). A dose-response relation was indicated. An increased risk of asthma was also seen, however not significant, odds ratio 1.5 (confidence interval 0.8-2.9). Stratified analyses revealed that the effect of traffic exposure was restricted to the non-sensitized phenotype of asthma and wheeze. The agreement between self-reported traffic exposure and objective measurements of exposure was moderate.ConclusionsThis study showed that already at low levels of exposure, vehicle traffic is related to an increased risk of wheeze among children. Thus, the global burden of traffic air pollution may be underestimated.

Highlights

An association between traffic air pollution and respiratory symptoms among children has been reported
Within the Obstructive Lung Disease in Northern Sweden studies (OLIN), studies of prevalence, incidence and risk factors for asthma and allergic sensitization among children are in progress since 1996 [15,16,17]
22.9% had a road with ≥4000 vehicles per day within 200 meters from the home address and 11.7% had a road with ≥500 heavy vehicles per day within the same radius (Table 1)

Summary

Introduction

An association between traffic air pollution and respiratory symptoms among children has been reported. Exposure assessment is a crucial part of epidemiological studies of respiratory symptoms and morbidity. Selfreported levels of traffic intensity have often been used as a measure of exposure in studies of respiratory symptoms among children. Over-reporting of air pollution exposure by parents of symptomatic children has in some studies been suggested as a source of bias [12,13], but not in others [14]. Recent results include a major increase in allergic sensitization and a moderate increase in physician-diagnosed asthma among children 7 to 8 years of age, from 5.7% in 1996 to 7.4% in 2006, while the prevalence of current wheeze did not change significantly [16]. Self-reporting of living close to heavy trafficked roads was a risk factor for allergic sensitization in 2006, OR 1.3 (CI 1.0-1.6) [15]

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