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Long-Term Exposure to Primary Traffic Pollutants and Lung Function in Children: Cross-Sectional Study and Meta-Analysis.

Barone-Adesi F, Dent JE, Dajnak D, Beevers S, Anderson HR, Kelly FJ, Cook DG, Whincup PH - PLoS ONE (2015)

Bottom Line: There is widespread concern about the possible health effects of traffic-related air pollution.In the meta-analysis, a 10 μg/m3 increase in NO2 was associated with an 8 ml lower FEV1 (95% CI: -14 to -1 ml; p: 0.016).The observed effect was not modified by a reported asthma diagnosis.

View Article: PubMed Central - PubMed

Affiliation: MRC-PHE Centre for Environment and Health, Population Health Research Institute, St George's, University of London, London, United Kingdom.

ABSTRACT

Background: There is widespread concern about the possible health effects of traffic-related air pollution. Nitrogen dioxide (NO2) is a convenient marker of primary pollution. We investigated the associations between lung function and current residential exposure to a range of air pollutants (particularly NO2, NO, NOx and particulate matter) in London children. Moreover, we placed the results for NO2 in context with a meta-analysis of published estimates of the association.

Methods and findings: Associations between primary traffic pollutants and lung function were investigated in 4884 children aged 9-10 years who participated in the Child Heart and Health Study in England (CHASE). A systematic literature search identified 13 studies eligible for inclusion in a meta-analysis. We combined results from the meta-analysis with the distribution of the values of FEV1 in CHASE to estimate the prevalence of children with abnormal lung function (FEV1<80% of predicted value) expected under different scenarios of NO2 exposure. In CHASE, there were non-significant inverse associations between all pollutants except ozone and both FEV1 and FVC. In the meta-analysis, a 10 μg/m3 increase in NO2 was associated with an 8 ml lower FEV1 (95% CI: -14 to -1 ml; p: 0.016). The observed effect was not modified by a reported asthma diagnosis. On the basis of these results, a 10 μg/m3 increase in NO2 level would translate into a 7% (95% CI: 4% to 12%) increase of the prevalence of children with abnormal lung function.

Conclusions: Exposure to traffic pollution may cause a small overall reduction in lung function and increase the prevalence of children with clinically relevant declines in lung function.

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Related in: MedlinePlus

Random effects meta-analysis of the association between concentration of NO2 and FEV1.Linear models. Results expressed as absolute differences in FEV1 for a 10 μg/m3 increase in the levels of NO2.
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pone.0142565.g002: Random effects meta-analysis of the association between concentration of NO2 and FEV1.Linear models. Results expressed as absolute differences in FEV1 for a 10 μg/m3 increase in the levels of NO2.

Mentions: The search yielded 461 papers (Fig 1). Among these, 13 studies met our selection criteria (Tables 4 and 5) [6,8,9,25,29–33]. Eight studies were from Europe, 1 from Asia and 4 from North America. The ages of subjects ranged from 4 to 16 years but the majority (9 studies) included children between the ages of 8 and 12 years. The methods of exposure assessment were study-specific monitors (2), land use regression (10), and dispersion models (1). Linear models were used in 5 studies and CHASE (Table 4, Fig 2), while 8 studies and CHASE used log-linear models (Table 5, Fig 3). All of the linear model studies showed inverse associations of which two were statistically significant. In a random effects meta-analysis, a significant effect of NO2 on lung function was observed (Fig 2). Among the studies using linear models, a 10 μg/m3 increase in NO2 was associated with a slightly lower FEV1 (Effect Size: -8 ml, 95% CI: -14 to -1 ml; p = 0.016) (Fig 2). There was moderate heterogeneity (I2 = 32%), principally driven by the study of Lee and colleagues [32]. Among the 9 studies using log-linear models, 8 showed inverse associations of which only one was statistically significant. Heterogeneity of the estimates of the effect of NO2 on FEV1 was very small (I2<1%). In a random effects meta-analysis, a 10 μg/m3 increase in NO2 was associated with a small decrease in FEV1 (Effect Size: -0.7%, 95% CI: -1.1% to -0.3%; p = 0.001) (Fig 3). In all the analyses, funnel plots were symmetrical and neither the Begg’s nor Egger’s tests suggested small study bias.


Long-Term Exposure to Primary Traffic Pollutants and Lung Function in Children: Cross-Sectional Study and Meta-Analysis.

Barone-Adesi F, Dent JE, Dajnak D, Beevers S, Anderson HR, Kelly FJ, Cook DG, Whincup PH - PLoS ONE (2015)

Random effects meta-analysis of the association between concentration of NO2 and FEV1.Linear models. Results expressed as absolute differences in FEV1 for a 10 μg/m3 increase in the levels of NO2.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664276&req=5

pone.0142565.g002: Random effects meta-analysis of the association between concentration of NO2 and FEV1.Linear models. Results expressed as absolute differences in FEV1 for a 10 μg/m3 increase in the levels of NO2.
Mentions: The search yielded 461 papers (Fig 1). Among these, 13 studies met our selection criteria (Tables 4 and 5) [6,8,9,25,29–33]. Eight studies were from Europe, 1 from Asia and 4 from North America. The ages of subjects ranged from 4 to 16 years but the majority (9 studies) included children between the ages of 8 and 12 years. The methods of exposure assessment were study-specific monitors (2), land use regression (10), and dispersion models (1). Linear models were used in 5 studies and CHASE (Table 4, Fig 2), while 8 studies and CHASE used log-linear models (Table 5, Fig 3). All of the linear model studies showed inverse associations of which two were statistically significant. In a random effects meta-analysis, a significant effect of NO2 on lung function was observed (Fig 2). Among the studies using linear models, a 10 μg/m3 increase in NO2 was associated with a slightly lower FEV1 (Effect Size: -8 ml, 95% CI: -14 to -1 ml; p = 0.016) (Fig 2). There was moderate heterogeneity (I2 = 32%), principally driven by the study of Lee and colleagues [32]. Among the 9 studies using log-linear models, 8 showed inverse associations of which only one was statistically significant. Heterogeneity of the estimates of the effect of NO2 on FEV1 was very small (I2<1%). In a random effects meta-analysis, a 10 μg/m3 increase in NO2 was associated with a small decrease in FEV1 (Effect Size: -0.7%, 95% CI: -1.1% to -0.3%; p = 0.001) (Fig 3). In all the analyses, funnel plots were symmetrical and neither the Begg’s nor Egger’s tests suggested small study bias.

Bottom Line: There is widespread concern about the possible health effects of traffic-related air pollution.In the meta-analysis, a 10 μg/m3 increase in NO2 was associated with an 8 ml lower FEV1 (95% CI: -14 to -1 ml; p: 0.016).The observed effect was not modified by a reported asthma diagnosis.

View Article: PubMed Central - PubMed

Affiliation: MRC-PHE Centre for Environment and Health, Population Health Research Institute, St George's, University of London, London, United Kingdom.

ABSTRACT

Background: There is widespread concern about the possible health effects of traffic-related air pollution. Nitrogen dioxide (NO2) is a convenient marker of primary pollution. We investigated the associations between lung function and current residential exposure to a range of air pollutants (particularly NO2, NO, NOx and particulate matter) in London children. Moreover, we placed the results for NO2 in context with a meta-analysis of published estimates of the association.

Methods and findings: Associations between primary traffic pollutants and lung function were investigated in 4884 children aged 9-10 years who participated in the Child Heart and Health Study in England (CHASE). A systematic literature search identified 13 studies eligible for inclusion in a meta-analysis. We combined results from the meta-analysis with the distribution of the values of FEV1 in CHASE to estimate the prevalence of children with abnormal lung function (FEV1<80% of predicted value) expected under different scenarios of NO2 exposure. In CHASE, there were non-significant inverse associations between all pollutants except ozone and both FEV1 and FVC. In the meta-analysis, a 10 μg/m3 increase in NO2 was associated with an 8 ml lower FEV1 (95% CI: -14 to -1 ml; p: 0.016). The observed effect was not modified by a reported asthma diagnosis. On the basis of these results, a 10 μg/m3 increase in NO2 level would translate into a 7% (95% CI: 4% to 12%) increase of the prevalence of children with abnormal lung function.

Conclusions: Exposure to traffic pollution may cause a small overall reduction in lung function and increase the prevalence of children with clinically relevant declines in lung function.

Show MeSH
Related in: MedlinePlus