Dataset Information

Effects of ambient pollen concentrations on frequency and severity of asthma symptoms among asthmatic children.

ABSTRACT: BACKGROUND:Previous studies on the associations between ambient pollen exposures and daily respiratory symptoms have produced inconsistent results. We investigated these relationships in a cohort of asthmatic children using pollen exposure models to estimate individual ambient exposures. METHODS:Daily symptoms of wheeze, night symptoms, shortness of breath, chest tightness, persistent cough, and rescue medication use were recorded in a cohort of 430 children with asthma (age 4-12 years) in Connecticut, Massachusetts, and New York. Daily ambient exposures to tree, grass, weed, and total pollen were estimated using mixed-effects models. We stratified analyses by use of asthma maintenance medication and sensitization to grass or weed pollens. Separate logistic regression analyses using generalized estimating equations were performed for each symptom outcome and pollen type. We adjusted analyses for maximum daily temperature, maximum 8-hour average ozone, fine particles (PM2.5), season, and antibiotic use. RESULTS:Associations were observed among children sensitized to specific pollens; these associations varied by use of asthma maintenance medication. Exposures to even relatively low levels of weed pollen (6-9 grains/m(3)) were associated with increased shortness of breath, chest tightness, rescue medication use, wheeze, and persistent cough, compared with lower exposure among sensitized children on maintenance medication. Grass pollen exposures ? 2 grains/m(3) were associated with wheeze, night symptoms, shortness of breath, and persistent cough compared with lower exposure among sensitized children who did not take maintenance medication. CONCLUSION:Even low-level pollen exposure was associated with daily asthmatic symptoms.

SUBMITTER: DellaValle CT

PROVIDER: S-EPMC3246281 | biostudies-literature | 2012 Jan

REPOSITORIES: biostudies-literature

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Effects of ambient pollen concentrations on frequency and severity of asthma symptoms among asthmatic children.

DellaValle Curt T CT Triche Elizabeth W EW Leaderer Brian P BP Bell Michelle L ML

Epidemiology (Cambridge, Mass.) 20120101 1

<h4>Background</h4>Previous studies on the associations between ambient pollen exposures and daily respiratory symptoms have produced inconsistent results. We investigated these relationships in a cohort of asthmatic children using pollen exposure models to estimate individual ambient exposures.<h4>Methods</h4>Daily symptoms of wheeze, night symptoms, shortness of breath, chest tightness, persistent cough, and rescue medication use were recorded in a cohort of 430 children with asthma (age 4-12 ...[more]

PMID: 22082997

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Project description:BackgroundAlthough ambient air pollution has been linked to reduced lung function in healthy children, longitudinal analyses of pollution effects in asthmatic patients are lacking.ObjectiveWe sought to investigate pollution effects in a longitudinal asthma study and effect modification by controller medications.MethodsWe 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.ResultsSame-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.ConclusionsAir 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.

Project description:The diagnosis of asthma is made on the basis of variable respiratory symptoms and supported by objective evidence of variable airflow limitation. However, spirometry and bronchoprovocation tests may not be routinely available in resource-scarce settings or in the context of large-scale epidemiological studies. There is a gap in knowledge about the predictive value of respiratory symptoms for the diagnosis of pollen-induced asthma.The aim of this study was to investigate the predictive value of self-reported respiratory symptoms for diagnosing pollen-induced asthma.We recruited 1,161 patients with respiratory symptoms who presented to the respiratory medicine outpatient clinic of two central hospitals in Inner Mongolia during the pollen season of July-September 2015. All patients were interviewed by a respiratory physician and completed a questionnaire survey, lung function tests and skin prick tests for common inhaled allergens.A total of 392 patients (33.8%) were diagnosed with asthma and 292 (25.2%, 160 adults, 132 children) with pollen-induced asthma. Respiratory symptoms of cough, wheezing, dyspnea, chest pain and nocturnal awakenings due to breathlessness were all associated with increased odds of being diagnosed with pollen-induced asthma, with cough being the most common symptom in both adults and children, giving a sensitivity of 90.6% in adults and 88.6% in children. Wheezing was the most specific symptom (78% and 89.5% in adults and children, respectively) compared to other symptoms. Overall, the positive predictive value of respiratory symptoms was poor for diagnosing pollen-induced asthma, with the exception of wheezing in children which had a high positive predictive value of 72.7%.Cough was the predominant symptom in adults and children with pollen-induced asthma. Wheezing was a reliable predictor of pollen-induced asthma in children. In adults, respiratory symptoms were not sufficiently reliable for diagnosing pollen-induced asthma.

Dataset Information

Effects of ambient pollen concentrations on frequency and severity of asthma symptoms among asthmatic children.

Publications

Effects of ambient pollen concentrations on frequency and severity of asthma symptoms among asthmatic children.

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