Validity Factors that may affect lung function and inflammatory markers in sputum Age, height, BMI and sex will be recorded for the study. Height in meters will be entered into the computer program for calculating spirometry values. Weight (body mass index) affects lung function and will be measured before the examination. The investigators will also record possible acute respiratory infections during the preceding 12 months. An upper respiratory infection during the preceding three weeks may affect the level of inflammatory cells and markers in sputum.