THE PREVALENCE AND PREDICTION OF PULMONARY FIBROSIS IN AN
Abstract
This thesis describes an ancillary project to the Early Diagnosis of Mesothelioma and
Lung Cancer in Prior Asbestos Workers study and was conducted to determine the
effects of asbestos exposure, pulmonary function and cigarette smoking in the prediction
of pulmonary fibrosis. 613 workers who were occupationally exposed to asbestos for an
average of 25.9 (SD=14.69) years were sampled from Sarnia, Ontario. A structured
questionnaire was administered during a face-to-face interview along with a low-dose
computed tomography (LDCT) of the thorax. Of them, 65 workers (10.7%, 95%CI
8.12—12.24) had LDCT-detected pulmonary fibrosis. The model predicting fibrosis
included the variables age, smoking (dichotomized), post FVC % splines and post-
FEV1% splines. This model had a receiver operator characteristic area under the curve
of 0.738. The calibration of the model was evaluated with R statistical program and the
bootstrap optimism-corrected calibration slope was 0.692. Thus, our model demonstrated
moderate predictive performance.