Clinical, Radiological and Lung Functional Variables
At recruitment (first hospitalization for a COPD exacerbation)
all patients answered a questionnaire including information on
socio-demographic and lifestyle factors, providing their complete
occupational history. Clinical, functional characterization and
high-resolution CT (HRCT) were performed 3 months after
enrollment or later under stable conditions. Detailed information
on the methods applied and their standardization has been
described elsewhere [13]. An interviewer-led questionnaire from
the European Community Respiratory Health Survey included a
variety of host and lifestyle factors as well as respiratory symptoms
[14]. Chronic bronchitis was defined as regular cough with
phlegm at least 3 months a year. Dyspnea was assessed using the
Modified Medical Research Council (mMRC) scale [15]. Health