Abstract
BackgroundIndoor particulate matter (PM) has been linked to respiratory symptoms in former smokers with COPD. While subjects with COPD and atopy have also been shown to have more frequent respiratory symptoms, whether they exhibit increased susceptibility to PM as compared to their non-atopic counterparts remains unclear. The aim of this study was to determine whether atopic individuals with COPD have greater susceptibility to PM compared to non-atopic individuals with COPD.MethodsFormer smokers with moderate to severe COPD were enrolled (n = 77). PM2.5, PM with diameter <2.5 micrometers, was measured in the main living area over three one-week monitoring periods at baseline, 3, and 6 months. Quality of life, respiratory symptoms and medication use were assessed by questionnaires. Serum was analyzed for specific IgE for mouse, cockroach, cat, dog and dust mite allergens. Atopy was established if at least one test was positive. Interaction terms between PM and atopy were tested and generalized estimating equation analysis determined the effect of PM concentrations on health outcomes. Multivariate models were adjusted for age, sex, education, race, season, and baseline lung function and stratified by atopic status.ResultsAmong atopic individuals, each 10 μg/m3 increase in PM was associated with higher risk of nocturnal symptoms (OR, 1.95; P = 0.02), frequent wheezing (OR, 2.49; P = 0.02), increased rescue medication use (β = 0.14; P = 0.02), dyspnea (β = 0.23; P < 0.001), higher St. George’s Respiratory Quality of Life score (β = 2.55; P = 0.01), and higher breathlessness, cough, and sputum score (BCSS) (β = 0.44; P = 0.01). There was no association between PM and health outcomes among the non-atopic individuals. Interaction terms between PM2.5 and atopy were statistically significant for nocturnal symptoms, frequency of rescue medication use, and BCSS (all P < 0.1).ConclusionsIndividuals with COPD and atopy appear to be at higher risk of adverse respiratory health effects of PM exposure compared to non-atopic individuals with COPD.
Highlights
Indoor particulate matter (PM) has been linked to respiratory symptoms in former smokers with Chronic obstructive pulmonary disease (COPD)
We have previously shown that indoor air pollution, particulate matter less than 2.5 micron in diameter (PM2.5), even at relatively low concentrations observed in US homes, was associated with increased respiratory symptoms and risk of severe COPD exacerbations in former smokers with moderate to severe COPD [4]
Baseline participant characteristics and pollutant concentrations All participants (n = 77) had moderate or severe COPD with a mean baseline post-bronchodilator Forced expiratory volume in 1 second (FEV1) % predicted of 52.3%
Summary
Indoor particulate matter (PM) has been linked to respiratory symptoms in former smokers with COPD. While subjects with COPD and atopy have been shown to have more frequent respiratory symptoms, whether they exhibit increased susceptibility to PM as compared to their non-atopic counterparts remains unclear. There is some evidence to suggest that allergic sensitization to aeroallergens is associated with increased susceptibility to the adverse health effects of PM in patients with asthma. Whether atopic individuals with COPD are more susceptible to the effect of PM exposure compared to those without atopy has not previously been studied. The goal of this analysis was to investigate whether atopic individuals with moderate to severe COPD were more susceptible to the adverse effects of PM2.5 on respiratory health than non-atopic individuals
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