Traffic exposure associated with allergic asthma and allergic rhinitis in adults. A cross-sectional study in southern Sweden - Download this document for free, or read online. Document in PDF available to download.
BackgroundThere is conflicting evidence that traffic-related air pollution is a risk factor for allergic conditions. Few studies have investigated this in adults. In adults, a high proportion of asthma, rhinitis and eczema is triggered by non-allergic factors. We investigated traffic as a risk factor for allergic versus non-allergic asthma and rhinitis, and eczema, in adults.
A questionnaire from 2000 n = 9319, 18–77 years provided individual data about disease outcome and self-reported traffic exposure. Additional exposure assessments were obtained using Geographical Informations Systems GIS. Residential addresses were linked to the national Swedish Road Database and to a pollutant database with modelled annual means of NOx Nitrogen Oxids.
ResultsLiving within 100 m from a road with a traffic intensity of >10 cars-min 24 hour mean was associated with prevalence of current asthma reported to be triggered by allergic factors OR = 1.83, 95% CI = 1.23–2.72 and with allergic rhinitis OR = 1.30, 95%CI = 1.05–1.61. No relation was seen with asthma or rhinitis triggered by other factors. Living within 100 m of a road with >10 cars-min was also associated with hand-eczema during the last 12 months OR = 1.63, 95% CI = 1.19–2.23, but not with allergic eczema or diagnosed hand-eczema. Consistent results were seen using self-reported traffic, but the associations with NOx were less consistent.
ConclusionExposure to traffic was associated with a higher prevalence of allergic asthma and allergic rhinitis, but not with asthma or rhinitis triggered by non-allergic factors. This difference was suggested by the overall pattern, but only clear using GIS-measured traffic intensity as a proxy for traffic exposure. An association was also found with hand-eczema during the last 12 months. We suggest that asthma and rhinitis should not be treated as homogenous groups when estimating effects from traffic in adults.
Electronic supplementary materialThe online version of this article doi:10.1186-1476-072X-8-25 contains supplementary material, which is available to authorized users.