Сohort Study to Evaluate Exacerbations, Respiratory Symptoms, Physical Exercise Intolerance and Lung Functions Among Participants Who Use IQOS With Heatsticks Compared to Smokers of Conventional Cigarettes

Inclusion Criteria: * Male or female * Age 40-59 years inclusive * Smoking history ≥10 pack-years (for both cohorts) * Ability to follow study procedures Exclusion Criteria: Pregnant women; Legally incapable individuals; Patients with history of: * chronic infectious and non-infectious lung disease except asthma (e.g. pulmonary fibrosis, bronchiectasis, cystic fibrosis, tuberculosis, etc.) diagnosed prior to or during the first visit to KAPM COPD Center; * previous surgical excision of at least one lung lobe (or having undergone a lung volume reduction procedure); * active cancer of any localization under treatment; * suspected cancer of any localization; * metallic articles in the chest; * recent eye surgery (during the last 6 month prior to the visit); * episode (s) of myocardial infarction within less than 6 months prior to the visit or another form of acute or chronic coronary heart disease, history of heart rhythm abnormality with episode of arrhythmia within the last 6 months prior to the visit or long lasting that requires continuous drug therapy; * acute episode of cerebrovascular ischemic attack within the last 12 month prior to the visit; * chest or abdominal surgery performed within the last 6 month prior the visit; * contraindications to salbutamol or refusal to inhale salbutamol; * chest radiation therapy within the last 12 month prior to the visit; radiology diagnostic procedures of chest within the last 6 months prior to the visit; * recent (6 weeks before the visit) respiratory tract infection (colds, flus), fever of any etiology with increasing temperature over 37 C at the time of the visit and in the last 2 weeks prior to the visit; * significant history of alcohol abuse or consumption of more than recommended units of alcohol per week (28 units male and 21 units female); * positive screening test for HIV antibodies or positive screening for TB, if available at the time of first visit; * elevated blood pressure (systolic) is ≥160 mmHg at the moment of visit. PMI employees and first degree relatives