Lung function
Spirometry was performed using a Spirostik spirometer (Jaeger, Germany)
with a Blue Cherry diagnostic software platform, following the American
Thoracic Society‐European Respiratory Society (ATS/ERS) guidelines28. The main variables collected were
FEV1, forced vital capacity (FVC), and the ratio between
FEV1 and FVC. Data were interpreted according to the
unified approach of the Global Lung Initiative (GLI), establishing as a
limit of normality (LIN) a z-score value for FEV1between − 1.64 and + 1.64.