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Ozone and childhood respiratory disease in three US cities: evaluation of effect measure modification by neighborhood socioeconomic status using a Bayesian hierarchical approach

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ABSTRACT

Background: Ground-level ozone is a potent airway irritant and a determinant of respiratory morbidity. Susceptibility to the health effects of ambient ozone may be influenced by both intrinsic and extrinsic factors, such as neighborhood socioeconomic status (SES). Questions remain regarding the manner and extent that factors such as SES influence ozone-related health effects, particularly across different study areas.

Methods: Using a 2-stage modeling approach we evaluated neighborhood SES as a modifier of ozone-related pediatric respiratory morbidity in Atlanta, Dallas, & St. Louis. We acquired multi-year data on emergency department (ED) visits among 5–18 year olds with a primary diagnosis of respiratory disease in each city. Daily concentrations of 8-h maximum ambient ozone were estimated for all ZIP Code Tabulation Areas (ZCTA) in each city by fusing observed concentration data from available network monitors with simulations from an emissions-based chemical transport model. In the first stage, we used conditional logistic regression to estimate ZCTA-specific odds ratios (OR) between ozone and respiratory ED visits, controlling for temporal trends and meteorology. In the second stage, we combined ZCTA-level estimates in a Bayesian hierarchical model to assess overall associations and effect modification by neighborhood SES considering categorical and continuous SES indicators (e.g., ZCTA-specific levels of poverty). We estimated ORs and 95% posterior intervals (PI) for a 25 ppb increase in ozone.

Results: The hierarchical model combined effect estimates from 179 ZCTAs in Atlanta, 205 ZCTAs in Dallas, and 151 ZCTAs in St. Louis. The strongest overall association of ozone and pediatric respiratory disease was in Atlanta (OR = 1.08, 95% PI: 1.06, 1.11), followed by Dallas (OR = 1.04, 95% PI: 1.01, 1.07) and St. Louis (OR = 1.03, 95% PI: 0.99, 1.07). Patterns of association across levels of neighborhood SES in each city suggested stronger ORs in low compared to high SES areas, with some evidence of non-linear effect modification.

Conclusions: Results suggest that ozone is associated with pediatric respiratory morbidity in multiple US cities; neighborhood SES may modify this association in a non-linear manner. In each city, children living in low SES environments appear to be especially vulnerable given positive ORs and high underlying rates of respiratory morbidity.

Electronic supplementary material: The online version of this article (doi:10.1186/s12940-017-0244-2) contains supplementary material, which is available to authorized users.

No MeSH data available.


Related in: MedlinePlus

Study area maps for main analyses. Gray areas represent the ZCTAs included in analyses (≥50 respiratory disease ED visits). Hash mark areas represent excluded ZCTAs (<50 respiratory disease ED visits). a represents the Atlanta study area; b represents the Dallas study area; c represents the St. Louis study area. Abbreviations: ED, Emergency Department; ZCTA, ZIP Code Tabulation Area
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Fig1: Study area maps for main analyses. Gray areas represent the ZCTAs included in analyses (≥50 respiratory disease ED visits). Hash mark areas represent excluded ZCTAs (<50 respiratory disease ED visits). a represents the Atlanta study area; b represents the Dallas study area; c represents the St. Louis study area. Abbreviations: ED, Emergency Department; ZCTA, ZIP Code Tabulation Area

Mentions: Our complete ED visit database for respiratory disease among children aged 5–18 years included 211 530 ED visits during the years 2002–2008 in Atlanta, 96 983 ED visits during the years 2006–2008 in Dallas, and 113 285 ED visits during the years 2002–2007 in St. Louis. Due to model convergence issues in the first stage of our analysis, we excluded all ZCTAs that reported fewer than 50 ED counts over their respective study periods. This resulted in the exclusion of 12 ZCTAs in Atlanta, 48 ZCTAs in Dallas, and 105 ZCTAs in St. Louis; these ZCTAs contributed very few ED visits to our overall study and the exclusion of these ZCTAs from analyses resulted in less than 2% of the total number of ED visits from each city to be excluded. Figure 1 presents maps of the included and excluded ZCTAs of the Atlanta, Dallas, and St. Louis study areas. Table 2 summarizes differences in ED data between our complete ED database and the analytical ED database, restricted to data from ZCTAs with at least 50 ED counts.Fig. 1


Ozone and childhood respiratory disease in three US cities: evaluation of effect measure modification by neighborhood socioeconomic status using a Bayesian hierarchical approach
Study area maps for main analyses. Gray areas represent the ZCTAs included in analyses (≥50 respiratory disease ED visits). Hash mark areas represent excluded ZCTAs (<50 respiratory disease ED visits). a represents the Atlanta study area; b represents the Dallas study area; c represents the St. Louis study area. Abbreviations: ED, Emergency Department; ZCTA, ZIP Code Tabulation Area
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5382444&req=5

Fig1: Study area maps for main analyses. Gray areas represent the ZCTAs included in analyses (≥50 respiratory disease ED visits). Hash mark areas represent excluded ZCTAs (<50 respiratory disease ED visits). a represents the Atlanta study area; b represents the Dallas study area; c represents the St. Louis study area. Abbreviations: ED, Emergency Department; ZCTA, ZIP Code Tabulation Area
Mentions: Our complete ED visit database for respiratory disease among children aged 5–18 years included 211 530 ED visits during the years 2002–2008 in Atlanta, 96 983 ED visits during the years 2006–2008 in Dallas, and 113 285 ED visits during the years 2002–2007 in St. Louis. Due to model convergence issues in the first stage of our analysis, we excluded all ZCTAs that reported fewer than 50 ED counts over their respective study periods. This resulted in the exclusion of 12 ZCTAs in Atlanta, 48 ZCTAs in Dallas, and 105 ZCTAs in St. Louis; these ZCTAs contributed very few ED visits to our overall study and the exclusion of these ZCTAs from analyses resulted in less than 2% of the total number of ED visits from each city to be excluded. Figure 1 presents maps of the included and excluded ZCTAs of the Atlanta, Dallas, and St. Louis study areas. Table 2 summarizes differences in ED data between our complete ED database and the analytical ED database, restricted to data from ZCTAs with at least 50 ED counts.Fig. 1

View Article: PubMed Central - PubMed

ABSTRACT

Background: Ground-level ozone is a potent airway irritant and a determinant of respiratory morbidity. Susceptibility to the health effects of ambient ozone may be influenced by both intrinsic and extrinsic factors, such as neighborhood socioeconomic status (SES). Questions remain regarding the manner and extent that factors such as SES influence ozone-related health effects, particularly across different study areas.

Methods: Using a 2-stage modeling approach we evaluated neighborhood SES as a modifier of ozone-related pediatric respiratory morbidity in Atlanta, Dallas, &amp; St. Louis. We acquired multi-year data on emergency department (ED) visits among 5&ndash;18 year olds with a primary diagnosis of respiratory disease in each city. Daily concentrations of 8-h maximum ambient ozone were estimated for all ZIP Code Tabulation Areas (ZCTA) in each city by fusing observed concentration data from available network monitors with simulations from an emissions-based chemical transport model. In the first stage, we used conditional logistic regression to estimate ZCTA-specific odds ratios (OR) between ozone and respiratory ED visits, controlling for temporal trends and meteorology. In the second stage, we combined ZCTA-level estimates in a Bayesian hierarchical model to assess overall associations and effect modification by neighborhood SES considering categorical and continuous SES indicators (e.g., ZCTA-specific levels of poverty). We estimated ORs and 95% posterior intervals (PI) for a 25&nbsp;ppb increase in ozone.

Results: The hierarchical model combined effect estimates from 179 ZCTAs in Atlanta, 205 ZCTAs in Dallas, and 151 ZCTAs in St. Louis. The strongest overall association of ozone and pediatric respiratory disease was in Atlanta (OR&thinsp;=&thinsp;1.08, 95% PI: 1.06, 1.11), followed by Dallas (OR&thinsp;=&thinsp;1.04, 95% PI: 1.01, 1.07) and St. Louis (OR&thinsp;=&thinsp;1.03, 95% PI: 0.99, 1.07). Patterns of association across levels of neighborhood SES in each city suggested stronger ORs in low compared to high SES areas, with some evidence of non-linear effect modification.

Conclusions: Results suggest that ozone is associated with pediatric respiratory morbidity in multiple US cities; neighborhood SES may modify this association in a non-linear manner. In each city, children living in low SES environments appear to be especially vulnerable given positive ORs and high underlying rates of respiratory morbidity.

Electronic supplementary material: The online version of this article (doi:10.1186/s12940-017-0244-2) contains supplementary material, which is available to authorized users.

No MeSH data available.


Related in: MedlinePlus