Residential exposure to motor vehicle emissions and the risk of wheezing among 7-8 year-old schoolchildren in Nicosia, Cyprus
Journal
European Journal of Epidemiology
Date Issued
September 2009
DOI
10.1007/s10654-009-9380-5
Abstract
Background: First-time investigation into the frequency of asthmatic
symptoms among Cypriot children showed increased prevalence in
the capital compared to all other areas. Exposure to traffic pollutants
have been repeatedly shown to be associated with a range of cardiorespiratory
effects. Differences in asthma prevalence on an island the
size of Cyprus may reflect such environmental factors. Objective: To
investigate the association between residential exposure to traffic
pollution and the risk of asthmatic symptoms within the city of
Nicosia. Methods: The addresses of participating children in Nicosia
were geo-coded (N = 1,735) and levels of exposure were assessed
using both (a) distance-based and (b) emissions-based indicators e.g.
estimated levels of traffic pollutants at all roads within a pre-defined
distance around the residence. Odds ratios of self-reported symptoms
in relation to exposure were estimated in logistic regression models
adjusting for person-based risk factors and co-morbidity as well as
intra-school clustering. Results: Up to 2-fold differences in symptoms
were observed; however, increased risk seemed to concentrate at
distances less than 50 m from a main road and/or only among those
experiencing the highest levels of cumulative exposure. Associations
persisted after adjusting for other risk factors. While the direction of
effect was apparent at longer distances, differences were not statistically
significant. Adjusted odds ratios for current wheezing were
2.33 (95% CI 1.27, 4.30) amongst the quartile of participants exposed
to the highest levels of particulate matter (PM) at all roads 50 m of
their residence and 2.14 (95% CI 1.05, 4.35) for levels of nitrogen
oxides (NOx). Conclusions: Children with the highest vehicular
emissions burden around their residence seem to be at higher risk of
reporting symptoms. However, due to the small number of children
residing at close proximity to main roads and with no evidence of
effect at longer distances, this alone would not explain the generally
higher prevalence observed in the urban areas in Nicosia.
symptoms among Cypriot children showed increased prevalence in
the capital compared to all other areas. Exposure to traffic pollutants
have been repeatedly shown to be associated with a range of cardiorespiratory
effects. Differences in asthma prevalence on an island the
size of Cyprus may reflect such environmental factors. Objective: To
investigate the association between residential exposure to traffic
pollution and the risk of asthmatic symptoms within the city of
Nicosia. Methods: The addresses of participating children in Nicosia
were geo-coded (N = 1,735) and levels of exposure were assessed
using both (a) distance-based and (b) emissions-based indicators e.g.
estimated levels of traffic pollutants at all roads within a pre-defined
distance around the residence. Odds ratios of self-reported symptoms
in relation to exposure were estimated in logistic regression models
adjusting for person-based risk factors and co-morbidity as well as
intra-school clustering. Results: Up to 2-fold differences in symptoms
were observed; however, increased risk seemed to concentrate at
distances less than 50 m from a main road and/or only among those
experiencing the highest levels of cumulative exposure. Associations
persisted after adjusting for other risk factors. While the direction of
effect was apparent at longer distances, differences were not statistically
significant. Adjusted odds ratios for current wheezing were
2.33 (95% CI 1.27, 4.30) amongst the quartile of participants exposed
to the highest levels of particulate matter (PM) at all roads 50 m of
their residence and 2.14 (95% CI 1.05, 4.35) for levels of nitrogen
oxides (NOx). Conclusions: Children with the highest vehicular
emissions burden around their residence seem to be at higher risk of
reporting symptoms. However, due to the small number of children
residing at close proximity to main roads and with no evidence of
effect at longer distances, this alone would not explain the generally
higher prevalence observed in the urban areas in Nicosia.