title: Pleural plaques and their effect on lung function in Libby vermiculite miners.
abstract: BACKGROUND
  Multiple studies have investigated the relationship between asbestos-related pleural plaques (PPs) and lung function, with disparate and inconsistent results. Most use chest radiographs to identify PPs and simple spirometry to measure lung function. High-resolution CT (HRCT) scanning improves the accuracy of PP identification. Complete pulmonary function tests (PFTs), including spirometry, lung volumes, and diffusing capacity of the lung for carbon monoxide, provide a more definitive assessment of lung function. The goal of this study was to determine, using HRCT scanning and complete PFTs, the effect of PPs on lung function in Libby vermiculite miners.
  
  
  METHODS
  The results of HRCT scanning and complete PFTs performed between January 2000 and August 2012 were obtained from the medical records of 166 Libby vermiculite miners. Multivariate regression analyses with Tukey multivariate adjustment were used to assess statistical associations between the presence of PPs and lung function. Adjustments were made for age, BMI, smoking history, duration of employment, and years since last occupational asbestos exposure.
  
  
  RESULTS
  Nearly 90% of miners (n = 149) had evidence of PPs on HRCT scan. No significant differences in spirometry results, lung volumes, or diffusing capacity of the lung for carbon monoxide were found between miners with PPs alone and miners with normal HRCT scans. Miners with both interstitial fibrosis and the presence of PPs had a significantly decreased total lung capacity in comparison with miners with normal HRCT scans (P = .02). Age, cumulative smoking history, and BMI were significant covariates that contributed to abnormal lung function.
  
  
  CONCLUSIONS
  Asbestos-related PPs alone have no significant effect on lung function in Libby vermiculite miners.
authors.affiliation: Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC.
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Clark
authors.affiliation: Health Network America, Tinton Falls, NJ.
authors.forename: J Jay
authors.initials: JJ
authors.lastname: Flynn
authors.affiliation: Gradient Corporation, Cambridge, MA; Department of Epidemiology, Harvard School of Public Health, Boston, MA.
authors.forename: Julie E
authors.initials: JE
authors.lastname: Goodman
authors.affiliation: Gradient Corporation, Cambridge, MA.
authors.forename: Ke
authors.initials: K
authors.lastname: Zu
authors.affiliation: Division of Epidemiology, Biostatistics and Environmental Health, School of Public Health, University of Memphis, Memphis, TN.
authors.forename: Wilfried J J
authors.initials: WJJ
authors.lastname: Karmaus
authors.affiliation: Department of Medicine, Medical University of South Carolina, Charleston, SC; Department of Public Health Sciences, Medical University of South Carolina, Charleston, SC; Environmental Biosciences Program, Medical University of South Carolina, Charleston, SC. Electronic address: mohrlc@musc.edu.
authors.forename: Lawrence C
authors.initials: LC
authors.lastname: Mohr
mesh_terms: D000368:Aged; D000538:Aluminum Silicates / Q000009:adverse effects*; D001194:Asbestos / Q000009:adverse effects; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D008906:Mining; D010995:Pleural Diseases / Q000000981:diagnostic imaging / Q000209:etiology*; D011653:Pulmonary Diffusing Capacity / Q000502:physiology; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D013147:Spirometry; D014057:Tomography, X-Ray Computed
chemical_list: D000538:Aluminum Silicates; C003760:vermiculite; D001194:Asbestos