Standardized Spirometry Measurements in Korean Population

As described in detail previously [23 (link)], spirometry was performed using a dry rolling seal spirometer (Model 2130; Sensor Medics, Yorba Linda, CA, USA). Trained clinical technicians obtained spirometry data including FEV1, FVC, and FEV1/FVC on site and transferred them to an internet review center for processing. The data were compared against criteria metrics for acceptability, reproducibility, and quality control by a principal investigator to validate the data and to store them in a Korea Centers for Disease Control repository management system, in accordance with the ATS/ERS recommendations [1 (link)]. Two criteria were applied to the spirometry data: 1) two or more acceptable spirometry curves to ensure correct inspiration and 6s expiration and 2) 150-ml inter-measurement variability in FVC and FEV1. The spirometry tests were undertaken without the use of a bronchodilator. Age-, sex-, and height-adjusted normal predicted values of FVC and FEV1 in the general Korean population were used to calculate the values of percent-predicted FVC and FEV1.