Switching From Usual Brand Cigarettes to a Tobacco-heating Cigarette or Snus

A randomized, multi-center, 4-group study of health status measures and biomarkers in subjects who smoke and are switched to either a tobacco-heating cigarette, snus, or a tobacco-burning cigarette, with a non-treatment group of never-smokers. Primary Objectives: * Evaluate select biomarkers of tobacco exposure and biomarkers of harm from subjects who smoke and who are switched to a tobacco-heating cigarette, snus, or a tobacco-burning cigarette. * Evaluate ability of a tobacco-heating cigarette and snus to modify patient-reported Chronic Obstructive Pulmonary Disease (COPD)-related health status in subjects who smoke and are switched to either a tobacco-heating cigarette or snus relative to a control group (a tobacco-burning ultra-low machine yield \[ULMY\]) cigarette. * Assess subject compliance. Secondary Objectives: * Measure amount and repeatability of smoke components yielded from the cigarettes (yield in use) and determine relative uptake of selected smoke components. * Evaluate the ability of a tobacco-heating cigarette and snus to modify general health status as measured by self-administered health questionnaires in subjects who smoke and are switched to either a tobacco-heating cigarette or snus relative to a control group (a tobacco-burning ULMY cigarette). * Compare health status measures in smokers who are switched to a tobacco-heating cigarette to smokers who are switched to snus. * Compare baseline data from all tobacco-using groups to baseline data from the never-smoking (non-treatment) group.