The early stages of COPD are often unrecognized in part because many individuals discount symptoms such as breathlessness, chronic cough, and bringing up phlegm as a normal part of getting older or an unexpected consequence of cigarette smoking. 

Some people whose breathlessness is very severe may avoid seeking treatment because learning they have COPD is frightening. The most common cause of COPD is cigarette smoking. For people who smoke, the most effective strategy to prevent COPD is to quit smoking.