title: Pneumoconiosis and emphysema in construction workers: results of HRCT and lung function findings.
abstract: OBJECTIVE
  To evaluate the prevalence of HRCT findings in construction workers previously surveyed by chest radiographs classified according to ILO guidelines. To examine the association between HRCT findings and exposure to quartz containing dust, and lung function.
  
  
  METHODS
  The study comprised a questionnaire, dynamic and static lung function measurements, single-breath CO diffusion capacity, chest radiographs and HRCT in 79 individuals. Certified 'B' readers coded radiographs according to the ILO classification. HRCT scans were read according to an international classification system. A qualitative exposure index for cumulative respiratory quartz on a 10-point scale was used.
  
  
  RESULTS
  Agreement between HRCT readers was good (κ>0.60), except for irregular opacities (κ=0.23). In ILO category 0/0, 8% HRCT round, 22% irregular and/or linear opacities and 41% HRCT emphysema was found. HRCT round opacities was associated with high cumulative quartz exposure (OR 7.1; 95% CI 1.3 to 37.8). Emphysema was associated with smoking (OR 10.1; 95% CI 1.2 to 84.2) and showed a reduction in T(L,CO,sb). HRCT round opacities was not associated with lung function. Current smoking was negatively associated with FEV₁/FVC ratio and positively with RV/TLC ratio, and showed a reduction in T(L,CO,sb) (13.4%), adjusted for different HRCT findings.
  
  
  CONCLUSIONS
  Low grade silicosis cannot be excluded in workers with normal chest radiographs (ILO 0/0). In relatively highly exposed construction workers, a sevenfold increased risk of simple (nodular) silicosis was found. Emphysema on HRCT was associated with current or former smokers, but not with exposure, and contributed to reduced diffusion capacity. Airflow limitation was mainly determined by current smoking and was not associated with simple (nodular) silicosis.
authors.affiliation: Institute for Risk Assessment Sciences, Division of Environmental Epidemiology, Utrecht University, PO Box 80178, Utrecht 3508 TD, The Netherlands. e.meijer@uu.nl
authors.forename: E
authors.initials: E
authors.lastname: Meijer
authors.forename: E
authors.initials: E
authors.lastname: Tjoe Nij
authors.forename: T
authors.initials: T
authors.lastname: Kraus
authors.forename: J S
authors.initials: JS
authors.lastname: van der Zee
authors.forename: O
authors.initials: O
authors.lastname: van Delden
authors.forename: M
authors.initials: M
authors.lastname: van Leeuwen
authors.forename: J W
authors.initials: JW
authors.lastname: Lammers
authors.forename: D
authors.initials: D
authors.lastname: Heederik
mesh_terms: D000328:Adult; D000368:Aged; D003252:Construction Materials; D004391:Dust; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects / Q000032:analysis; D011009:Pneumoconiosis / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D011653:Pulmonary Diffusing Capacity / Q000502:physiology; D011656:Pulmonary Emphysema / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D011791:Quartz / Q000633:toxicity; D012907:Smoking / Q000009:adverse effects; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D004391:Dust; D011791:Quartz