2.3.2. Respiratory Function 
A PC-based spirometer (MicroQuark, Cosmed, Italy) was used to measure pulmonary function. First, the volunteers were asked to sit comfortably on a bed and hold a personal mouthpiece between their teeth with their lips covering it to prevent exhalation through the nose. The measurement variables included FVC, FEV1, and peak expiratory flow rate (PEF) after measuring maximal expiratory effort using a spirogram. The mouthpiece was immediately separated and disinfected with alcohol for hygiene purposes after each measurement. 