2 Pneumology Department, Hospital de Viseu, Portugal.
3 Institute of Public Health, University of Porto, Porto, Portugal.
4 Pulmonology Department, Centro Hospitalar de Vila Nova de Gaia/Espinho, EPE, Vila Nova de Gaia, Portugal; Chest Disease Centre of Vila Nova de Gaia, Vila Nova de Gaia, Portugal.
5 Public Health Department, Regional North Health Administration, Portugal.
6 Pulmonology Department, Centro Hospitalar de Vila Nova de Gaia/Espinho, EPE, Vila Nova de Gaia, Portugal; Chest Disease Centre of Vila Nova de Gaia, Vila Nova de Gaia, Portugal; Epi Unit, Institute of Public Health, University of Porto, Porto, Portugal; Epidemiology Department, Medical School, University of Porto, Porto, Portugal.