Validation of the Global Lung Function Initiative 2012 Spirometry Reference Values in a Healthy Italian Working Population

Background: Several studies showed important differences in the interpretation of spirometry based on different reference values, in particular by comparing European Respiratory Society (ERS) 1993 and Global Lung Function Initiative (GLI) 2012. The validation of new reference values in local populations is essential before they can be used in an appropriate manner. This study aimed to investigate the fit of GLI reference values in a healthy Italian working population. Methods: Spirometry data were collected in 1355 workers during their health surveillance medical examination conducted for exposure to chemical and biological risk factors. A single portable spirometer that met the ATS/ERS recommendations for occupational testing was used and calibrated daily. Results: Average z-score were -0.13 (with a median of -0.17), -0.25 (with a median of -0.24), and 0.18 (with a median of 0.17) for FEV1, FVC, and FEV1/FVC ratio, respectively. Considering only the normal-weighted workers, the average z-scores were -0.07 (with a median of -0.16), -0.15 (with a median of -0.16), and 0.07 (with a median of 0.02) for FEV1, FVC, and FEV1/FVC ratio, respectively. Conclusions: GLI 2012 reference values fit the Italian data satisfactorily, resulting as more accurate than ERS 1993, especially in women, normal-weighted subjects, aged 30-50 years, and for height < 165 cm.