title: The survival analyses of 2738 patients with simple pneumoconiosis.
abstract: OBJECTIVE
  To explore whether the inhalation of coal mine dust increases the risk of premature death in miners, a survival analysis was conducted in a cohort of 2738 patients with simple pneumoconiosis in the Huai-Bei coal mine, in China.
  
  
  METHODS
  Age specific mortalities were calculated by disease severity in terms of pneumoconiotic category with the life table method. The progressions from simple pneumoconiosis to death or progressive massive fibrosis (PMF) were analysed with the Cox's regression model with time as the dependent variable to identify risk factors.
  
  
  RESULTS
  During a follow up period (mean 8 y) 3.2% of patients with simple pneumoconiosis developed PMF. The patients with development of PMF presented higher age specific mortalities than those remaining in a state of simple pneumoconiosis (SMR: 3.42; P < 0.01). After adjustment for tuberculosis and duration of work, the relative risk of premature death due to development of PMF was 2.4. Tuberculosis was found to be a main risk factor which not only facilitated premature death (relative risk (RR): 2.0; P < 0.01), but was also a strong facilitator for development of PMF (RR: 7.0; P < 0.01). Also, a long term of work underground and drilling as a main job were identified as risk factors for development of PMF.
  
  
  CONCLUSIONS
  The results imply that patients with simple pneumoconiosis will have altered survival, and premature death among them is related to an increased risk of the development of PMF and the complication of tuberculosis.
authors.affiliation: Department of Pathobiology, Purdue University, West Lafayette, IN 47906, USA.
authors.forename: Q
authors.initials: Q
authors.lastname: Yi
authors.forename: Z
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D002681:China / Q000453:epidemiology; D018450:Disease Progression; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011009:Pneumoconiosis / Q000150:complications / Q000401:mortality*; D011658:Pulmonary Fibrosis / Q000401:mortality; D012044:Regression Analysis; D012307:Risk Factors; D016019:Survival Analysis; D014397:Tuberculosis, Pulmonary / Q000150:complications