What Causes COPD
Over time, exposure to irritants that damage your lungs and airways can cause chronic obstructive pulmonary disease (COPD), which includes chronic bronchitis and emphysema. The main cause of COPD is smoking, but nonsmokers can get COPD too.
About 85 to 90 percent of all COPD cases are caused by cigarette smoking. When a cigarette burns, it creates more than 7,000 chemicals, many of which are harmful. The toxins in cigarette smoke weaken your lungs' defense against infections, narrow air passages, cause swelling in air tubes and destroy air sacs—all contributing factors for COPD.
What you breathe every day at work, home and outside can play a role in developing COPD. Long-term exposure to air pollution, secondhand smoke and dust, fumes and chemicals (which are often work-related) can cause COPD.
A small number of people have a rare form of COPD called alpha-1 deficiency-related emphysema. This form of COPD is caused by a genetic (inherited) condition that affects the body's ability to produce a protein (Alpha-1) that protects the lungs.
Reviewed and approved by the American Lung Association Scientific and Medical Editorial Review Panel. Last reviewed December 23, 2017.
Page Last Updated: July 11, 2019
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