One of the most common lung disorders in adults is chronic obstructive pulmonary disease (COPD), a term used to include chronic bronchitis and emphysema. Obstruction due to airway inflammation and excess mucus occurs in the airways of the lung (called bronchi and bronchioles), leading to decreased air flow. This ultimately results in decreased amounts of oxygen delivered to the body's tissues. In emphysema, there is also destruction of the alveoli (tiny sacs where oxygen and carbon dioxide exchange takes place). Emphysema and chronic bronchitis may both be present in an individual at the same time. COPD is one of the leading causes of death in developed nations and affects both men and women. Smoking is the cause of COPD in most cases and accounts for 80% to 90% of COPD-related deaths. The June 16, 2010, issue of JAMA includes an article about treatment of COPD. This Patient Page is based on one previously published in the November 26, 2008, issue of JAMA.