title: Factors determining the severity of pulmonary function impairment in silicotic patients.
abstract: OBJECTIVE
  Silicosis is the most common occupational lung disease in Thailand. Determinants of pulmonary function impairment in Thai silicotic patients have not been mentioned before.
  
  
  METHODS
  The present study was conducted in silicotic patients who attended the Siriraj Occupational Lung Clinic in the year 2006. Patients were classified according to the forced expiratory volume in one second (FEV1) into the severe impairment group (< 50% predicted) and the non-severe group (FEV1 > 50% predicted) which includes normal FEV1. Comparison between the two groups in terms of demographic characteristics, smoking history, history of pulmonary tuberculosis, and radiographic features were assessed.
  
  
  RESULTS
  Thirty-four patients of which 24 were female (70.6%) had an overall mean age of 53.7 years. Seven patients (20.6%) had severe impairment, four were female, three were smokers, and two had a history of pulmonary tuberculosis. All of the severe impairment patients had nodule profusion in category 2 and had large opacity. Only the presence of large opacity was significantly associated with the severity of pulmonary function impairment (p = 0.002).
  
  
  CONCLUSIONS
  Only the presence of large opacity in a chest radiograph can determine the severity of pulmonary function impairment in Thai silicotic patients.
authors.affiliation: Division of Respiratory Disease and Tuberculosis, Department of Medicine, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand. tmwcr@mahidol.ac.th
authors.forename: Nitipatana
authors.initials: N
authors.lastname: Chierakul
authors.forename: Tiraporn
authors.initials: T
authors.lastname: Boonyarattaphun
authors.forename: Arth
authors.initials: A
authors.lastname: Nana
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012129:Respiratory Function Tests; D012829:Silicosis / Q000150:complications / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000503:physiopathology*; D013785:Thailand / Q000453:epidemiology