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ABSTRACT: Background
Although ambient air pollution has been linked to reduced lung function in healthy children, longitudinal analyses of pollution effects in asthmatic patients are lacking.Objective
We sought to investigate pollution effects in a longitudinal asthma study and effect modification by controller medications.Methods
We examined associations of lung function and methacholine responsiveness (PC20) with ozone, carbon monoxide (CO), nitrogen dioxide, and sulfur dioxide concentrations in 1003 asthmatic children participating in a 4-year clinical trial. We further investigated whether budesonide and nedocromil modified pollution effects. Daily pollutant concentrations were linked to ZIP/postal code of residence. Linear mixed models tested associations of within-subject pollutant concentrations with FEV1 and forced vital capacity (FVC) percent predicted, FEV1/FVC ratio, and PC20, adjusting for seasonality and confounders.Results
Same-day and 1-week average CO concentrations were negatively associated with postbronchodilator percent predicted FEV1 (change per interquartile range, -0.33 [95% CI, -0.49 to -0.16] and -0.41 [95% CI, -0.62 to -0.21], respectively) and FVC (-0.19 [95% CI, -0.25 to -0.07] and -0.25 [95% CI, -0.43 to -0.07], respectively). Longer-term 4-month CO averages were negatively associated with prebronchodilator percent predicted FEV1 and FVC (-0.36 [95% CI, -0.62 to -0.10] and -0.21 [95% CI, -0.42 to -0.01], respectively). Four-month averaged CO and ozone concentrations were negatively associated with FEV1/FVC ratio (P < .05). Increased 4-month average nitrogen dioxide concentrations were associated with reduced postbronchodilator FEV1 and FVC percent predicted. Long-term exposures to sulfur dioxide were associated with reduced PC20 (percent change per interquartile range, -6% [95% CI, -11% to -1.5%]). Treatment augmented the negative short-term CO effect on PC20.Conclusions
Air pollution adversely influences lung function and PC20 in asthmatic children. Treatment with controller medications might not protect but rather worsens the effects of CO on PC20. This clinical trial design evaluates modification of pollution effects by treatment without confounding by indication.
SUBMITTER: Ierodiakonou D
PROVIDER: S-EPMC4742428 | biostudies-literature | 2016 Feb
REPOSITORIES: biostudies-literature
Ierodiakonou Despo D Zanobetti Antonella A Coull Brent A BA Melly Steve S Postma Dirkje S DS Boezen H Marike HM Vonk Judith M JM Williams Paul V PV Shapiro Gail G GG McKone Edward F EF Hallstrand Teal S TS Koenig Jane Q JQ Schildcrout Jonathan S JS Lumley Thomas T Fuhlbrigge Anne N AN Koutrakis Petros P Schwartz Joel J Weiss Scott T ST Gold Diane R DR
The Journal of allergy and clinical immunology 20150714 2
<h4>Background</h4>Although ambient air pollution has been linked to reduced lung function in healthy children, longitudinal analyses of pollution effects in asthmatic patients are lacking.<h4>Objective</h4>We sought to investigate pollution effects in a longitudinal asthma study and effect modification by controller medications.<h4>Methods</h4>We examined associations of lung function and methacholine responsiveness (PC20) with ozone, carbon monoxide (CO), nitrogen dioxide, and sulfur dioxide c ...[more]