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Asthma incidence in children growing up close to traffic: a registry-based birth cohort.

Lindgren A, Stroh E, Björk J, Jakobsson K - Environ Health (2013)

Bottom Line: Recent reviews conclude an association between traffic-related pollution and incidence of asthma in children, but not all studies agree.Similar results were found for inhaled corticosteroids, and in relation to NOX.This may depend on the low levels of traffic pollution in the area, mainly well below the WHO-guideline for NO2.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Occupational and Environmental Medicine, Lund University, Lund, Sweden. anna.lindgren@med.lu.se.

ABSTRACT

Background: Recent reviews conclude an association between traffic-related pollution and incidence of asthma in children, but not all studies agree. Studies have almost exclusively relied on parental-reported symptoms or parental-reported diagnoses of asthma and wheeze. Our aim was to investigate if traffic exposure is associated with higher incidence of early onset asthma, using registry-based outcome data.

Methods: We investigated a birth cohort in southern Sweden, consisting of N = 26,128 children with outcome and exposure data (born July 2005-2010). Of these children, N = 7898 had additional covariate information. The cohort was followed to the end of 2011.Traffic intensity, and dispersion-modeled concentrations of NOX (100×100 m grid), at residential addresses, were linked with registry data on dispensed asthma medication (the Swedish Prescribed Drug Register), and hospital and primary health care diagnoses of bronchiolitis, obstructive bronchitis and asthma (The Scania Health Care Register).Covariate information was obtained from questionnaires distributed to parents at Child Health Care-centre visits, eight months after birth. Cox proportional hazards regression was used for the statistical analyses.

Results: Living in close proximity to a road with ≥8640 cars/day (compared to 0-8640 cars/day), was not associated with higher incidence of first purchase of inhaled β2-agonist (adjusted hazard ratio (adj.HR) = 0.9, 95% CI: 0.8-1.0); third year purchase of inhaled β2-agonist (adj.HR = 0.7, 95% CI: 0.6-0.9); bronchiolitis (adj.HR = 0.7, 95% CI: 0.6-0.9), obstructive bronchitis (adj.HR = 1.0, 95% CI: 0.9-1.2), or asthma (adj.HR = 0.7, 95% CI: 0.6- 0.9). Similar results were found for inhaled corticosteroids, and in relation to NOX.

Conclusions: Traffic-related exposure was not associated with higher incidence of asthma medication, or diagnoses of asthma, bronchiolitis, or obstructive bronchitis, in children 0-6 years in southern Sweden. This may depend on the low levels of traffic pollution in the area, mainly well below the WHO-guideline for NO2.

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Distribution of modeled annual mean NOx at birth address, by traffic intensity (n = 7895). Upper and lower borders of boxplots represent the 75th and 25th percentiles and the bold line is the median. The whiskers extend to the minimum and maximum of the NOx-concentrations.
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Figure 2: Distribution of modeled annual mean NOx at birth address, by traffic intensity (n = 7895). Upper and lower borders of boxplots represent the 75th and 25th percentiles and the bold line is the median. The whiskers extend to the minimum and maximum of the NOx-concentrations.

Mentions: The percentage of the study population living ≤100 m from a traffic intensity of 0–8640 cars/day at birth address was 73.8%, compared to 26.2% with traffic intensity of ≥ 8640 cars/day at birth address. We classified modeled NOX levels into ≤15, 15–25 and >25 μg/m3. For exposure at birth address, the percentage of the population living in respective category was 34%, 57% and 9%. Mean NOX at birth year was 17 μg/m3, and the percentile distribution was 9.2, 11.8, 17.6, 21.1, and 24.6 μg/m3 (10th, 25th, 50th, 75th, and 90th percentile). Min, Max = (6.1, 45.9) μg/m3. The distribution of NOX by traffic intensity, is displayed in Figure 2.


Asthma incidence in children growing up close to traffic: a registry-based birth cohort.

Lindgren A, Stroh E, Björk J, Jakobsson K - Environ Health (2013)

Distribution of modeled annual mean NOx at birth address, by traffic intensity (n = 7895). Upper and lower borders of boxplots represent the 75th and 25th percentiles and the bold line is the median. The whiskers extend to the minimum and maximum of the NOx-concentrations.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4016196&req=5

Figure 2: Distribution of modeled annual mean NOx at birth address, by traffic intensity (n = 7895). Upper and lower borders of boxplots represent the 75th and 25th percentiles and the bold line is the median. The whiskers extend to the minimum and maximum of the NOx-concentrations.
Mentions: The percentage of the study population living ≤100 m from a traffic intensity of 0–8640 cars/day at birth address was 73.8%, compared to 26.2% with traffic intensity of ≥ 8640 cars/day at birth address. We classified modeled NOX levels into ≤15, 15–25 and >25 μg/m3. For exposure at birth address, the percentage of the population living in respective category was 34%, 57% and 9%. Mean NOX at birth year was 17 μg/m3, and the percentile distribution was 9.2, 11.8, 17.6, 21.1, and 24.6 μg/m3 (10th, 25th, 50th, 75th, and 90th percentile). Min, Max = (6.1, 45.9) μg/m3. The distribution of NOX by traffic intensity, is displayed in Figure 2.

Bottom Line: Recent reviews conclude an association between traffic-related pollution and incidence of asthma in children, but not all studies agree.Similar results were found for inhaled corticosteroids, and in relation to NOX.This may depend on the low levels of traffic pollution in the area, mainly well below the WHO-guideline for NO2.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Occupational and Environmental Medicine, Lund University, Lund, Sweden. anna.lindgren@med.lu.se.

ABSTRACT

Background: Recent reviews conclude an association between traffic-related pollution and incidence of asthma in children, but not all studies agree. Studies have almost exclusively relied on parental-reported symptoms or parental-reported diagnoses of asthma and wheeze. Our aim was to investigate if traffic exposure is associated with higher incidence of early onset asthma, using registry-based outcome data.

Methods: We investigated a birth cohort in southern Sweden, consisting of N = 26,128 children with outcome and exposure data (born July 2005-2010). Of these children, N = 7898 had additional covariate information. The cohort was followed to the end of 2011.Traffic intensity, and dispersion-modeled concentrations of NOX (100×100 m grid), at residential addresses, were linked with registry data on dispensed asthma medication (the Swedish Prescribed Drug Register), and hospital and primary health care diagnoses of bronchiolitis, obstructive bronchitis and asthma (The Scania Health Care Register).Covariate information was obtained from questionnaires distributed to parents at Child Health Care-centre visits, eight months after birth. Cox proportional hazards regression was used for the statistical analyses.

Results: Living in close proximity to a road with ≥8640 cars/day (compared to 0-8640 cars/day), was not associated with higher incidence of first purchase of inhaled β2-agonist (adjusted hazard ratio (adj.HR) = 0.9, 95% CI: 0.8-1.0); third year purchase of inhaled β2-agonist (adj.HR = 0.7, 95% CI: 0.6-0.9); bronchiolitis (adj.HR = 0.7, 95% CI: 0.6-0.9), obstructive bronchitis (adj.HR = 1.0, 95% CI: 0.9-1.2), or asthma (adj.HR = 0.7, 95% CI: 0.6- 0.9). Similar results were found for inhaled corticosteroids, and in relation to NOX.

Conclusions: Traffic-related exposure was not associated with higher incidence of asthma medication, or diagnoses of asthma, bronchiolitis, or obstructive bronchitis, in children 0-6 years in southern Sweden. This may depend on the low levels of traffic pollution in the area, mainly well below the WHO-guideline for NO2.

Show MeSH
Related in: MedlinePlus