title: [Welders' siderosis: a retrospective cohort study on welder's pneumoconiosis patients with small round opacities on chest radiograph].
abstract: OBJECTIVE
  To study the radiographycal changes and prognosis of welders' pneumoconiosis patients diagnosed within the last few years.
  
  
  METHODS
  Occupational hygienics data (including years on welding work, welding materials exposed to and work environment), symptoms, lung function test results and follow-up data of 136 welders' pneumoconiosis patients were collected retrospectively. The follow-up lasted up till June 30, 2014, with follow-up interval being one year. Chest radiographs were read/reviewed together by 3 senior experts experienced in pneumoconiosis diagnosing and shape and size of small opacity, overall profusion, affected lung zones and pneumoconiosis stages were all logged.
  
  
  RESULTS
  Of all 136 pneumoconiosis cases, five were of stage II and 131 were stage I, and they had been engaged in welding work for 9.2±6.34 years. All patients were present with slight symptoms including coughing, chest distress and dyspnea, while their lung function remained normal. Small round opacities were found on chest radiographs of 88.9% of the 136 cases. Years of follow-up on 131 cases of stage I Welder's pneumoconiosis showed that irregular small opacities remained fundamentally unchanged, while small round opacities tended to gradually lessen instead of coalescence. Two years after primary diagnosing, the total affected lung zones of follow-up objects were noticed to start lessening, and reduced by 0.02 per patient among the 48 follow-up subjects. Of the 48 cases followed up up to six years after primary diagnosing, the affected lung zone number was reduced by 0.54 per patient while 4 cases (8%) went down to below stage I. As of the 36 patients followed up 10 years after after primary diagnosis, the number of affected lung areas decreased by 1.14, and 22% (8 cases) appeared less than stage I on chest radiograph.
  
  
  CONCLUSIONS
  It seemed that the so-called welders' pneumoconiosis featuring small round opacities tended to get improved over time, which suggested the diagnosis of siderosis.
authors.affiliation: Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Mao
authors.affiliation: Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Shi
authors.affiliation: Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China.
authors.forename: Zidan
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China.
authors.forename: Jingbo
authors.initials: J
authors.lastname: Zhang
mesh_terms: D015331:Cohort Studies; D006801:Humans; D008168:Lung; D016273:Occupational Exposure / Q000009:adverse effects*; D011009:Pneumoconiosis / Q000000981:diagnostic imaging* / Q000473:pathology; D013902:Radiography, Thoracic; D012189:Retrospective Studies; D012806:Siderosis / Q000000981:diagnostic imaging* / Q000473:pathology; D035423:Thoracic Cavity; D014896:Welding