Long-term exposure to lung irritants that damage the lungs and the airways usually is the cause of COPD.
In the United States, the most common irritant that causes COPD is cigarette smoke. Pipe, cigar, and other types of tobacco smoke also can cause COPD, especially if the smoke is inhaled.
Breathing in secondhand smoke, air pollution, or chemical fumes or dust from the environment or workplace also can contribute to COPD. (Secondhand smoke is smoke in the air from other people smoking.)
Rarely, a genetic condition called alpha-1 antitrypsin deficiency may play a role in causing COPD. People who have this condition have low levels of alpha-1 antitrypsin (AAT)—a protein made in the liver.
Having a low level of the AAT protein can lead to lung damage and COPD if you're exposed to smoke or other lung irritants. If you have this condition and smoke, COPD can worsen very quickly.
Although uncommon, some people who have asthma can develop COPD. Asthma is a chronic (long-term) lung disease that inflames and narrows the airways. Treatment usually can reverse the inflammation and narrowing. However, if not, COPD can develop.
The NHLBI "Grand Opportunity" Exome Sequencing Project
Clinical trials are research studies that explore whether a medical strategy, treatment, or device is safe and effective for humans. To find clinical trials that are currently underway for COPD, visit www.clinicaltrials.gov.
November 21, 2012
CDC and NIH survey provides first report of state-level COPD prevalence
The age-adjusted prevalence of chronic obstructive pulmonary disease (COPD) varies considerably within the United States, from less than 4 percent of the population in Washington and Minnesota to more than 9 percent in Alabama and Kentucky. These state-level rates are among the COPD data available for the first time as part of the newly released 2011 Behavioral Risk Factor Surveillance System (BRFSS) survey.

If you have COPD or think you might be at risk, you can take steps to make breathing easier and live a longer and more active life. Get a simple breathing test and talk with your doctor or health care provider about treatment options.
The NHLBI developed the national COPD Learn More Breathe Better® campaign to increase awareness of COPD. The campaign aims to help people with COPD and those at risk get diagnosed early, understand their treatment options, and live better with the disease.
Learn more about key campaign events, activities, and resources.
The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.