title: Indoor pollutant exposure is associated with heightened respiratory symptoms in atopic compared to non-atopic individuals with COPD.
abstract: BACKGROUND
  Indoor 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.
  
  
  METHODS
  Former 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.
  
  
  RESULTS
  Among atopic individuals, each 10 μg/m(3) 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).
  
  
  CONCLUSIONS
  Individuals 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.
authors.forename: Deepak A
authors.initials: DA
authors.lastname: Kaji
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Belli
authors.forename: Meredith C
authors.initials: MC
authors.lastname: McCormack
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Matsui
authors.forename: D'Ann L
authors.initials: DL
authors.lastname: Williams
authors.forename: Laura
authors.initials: L
authors.lastname: Paulin
authors.forename: Nirupama
authors.initials: N
authors.lastname: Putcha
authors.forename: Roger D
authors.initials: RD
authors.lastname: Peng
authors.forename: Gregory B
authors.initials: GB
authors.lastname: Diette
authors.forename: Patrick N
authors.initials: PN
authors.lastname: Breysse
authors.affiliation: Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA. nhansel1@jhmi.edu.
authors.forename: Nadia N
authors.initials: NN
authors.lastname: Hansel
mesh_terms: D000368:Aged; D016902:Air Pollution, Indoor / Q000009:adverse effects*; D000818:Animals; D003058:Cockroaches / Q000276:immunology; D003371:Cough / Q000209:etiology; D063607:Dander / Q000276:immunology; D004417:Dyspnea / Q000209:etiology; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000150:complications*; D007073:Immunoglobulin E / Q000097:blood; D019570:Inhalation Exposure / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D008925:Mites / Q000276:immunology; D052638:Particulate Matter / Q000633:toxicity*; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000188:drug therapy; D011788:Quality of Life; D012135:Respiratory Sounds / Q000209:etiology; D012720:Severity of Illness Index; D013183:Sputum; D013997:Time Factors
chemical_list: D052638:Particulate Matter; D007073:Immunoglobulin E