Causes and Risk Factors of COPD

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Although smoking is the primary cause of chronic obstructive pulmonary disease (COPD), long-term, cumulative exposure to other types of airway irritants and, to a lesser degree, genetics, can also play an important role in the development of the disease. These are also risk factors for developing COPD, along with age, socioeconomic status, and infections.

COPD causes and risk factors
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Common Causes

There are several causes that can contribute to the development of COPD.


This is by far the number one cause of COPD.

The American Lung Association estimates that 85 percent to 90 percent of COPD cases are related to cigarette smoking, whether by secondhand smoke or by past or present cigarette smoking.

However, people who have never smoked can develop COPD as well.

Occupational Exposure

Being exposed to chemicals and substances such as coal mine dust, gases, and silica in the workplace, particularly long-term, is one of the leading causes of COPD other than smoking.

Indoor and Outdoor Air Pollution

Long-term exposure to indoor air pollution, especially exposure to fumes from cooking and heating in poorly ventilated areas, is another cause, as is long-term exposure to outdoor air pollution.

Alpha-1-Antitrypsin (AAT) Deficiency

Alpha-1-antitrypsin (AAT) deficiency is an inherited disorder that's responsible for a small number of cases of COPD. It involves low levels of AAT protein, which helps protect your lungs. If you have AAT deficiency, whether or not you're exposed to smoke or other lung irritants, you can develop COPD simply because your body doesn't make enough of the protein to protect your lungs from damage.

COPD due to AAT deficiency is usually diagnosed at a younger age than COPD caused by smoking.

If you are under 45 and have been diagnosed with COPD, ask your doctor for a simple blood test to determine if your COPD is caused by AAT deficiency, as treatment options differ from standard COPD treatment.


Sometimes people with asthma develop COPD. Asthma, which involves inflammation and narrowing of your airways, is usually a reversible condition with treatment.


As mentioned, having alpha-1-antitrypsin deficiency can be both a cause of and a risk factor for COPD. Research has also shown that if you have a sibling with severe COPD and you smoke, you are much more susceptible to having airflow limitations. Other genes have been linked to decreased lung function as well, but it's unclear if any of these are actually responsible for the development of COPD.

Risk Factors

There are a number of risk factors, similar to many of the causes, that are associated with developing COPD, some of which may be in your control.

Tobacco Smoke

While the risk varies for different people, the more packs and time you smoke, the higher your risk of developing COPD tends to be. Smoking cigars, pipes, and marijuana also increases your risk, as does exposure to secondhand smoke. If you smoke and have a family history of COPD, your risk is further increased by your habit.


If you have asthma, research shows that your risk of developing COPD may be up to 12 times higher than those who don't.

Long-Term Exposure to Irritants

Long-term exposure to lung irritants such as chemicals, dust, or fumes from your workplace, secondhand smoke, or air pollution increases your risk of developing COPD. If you work with irritants, talk to your employer about protecting yourself.


Since COPD develops over the course of years, most people are at least 40 when they're diagnosed. Additionally, as you age, your airway appears to go through some of the same structural changes that are found in COPD.

Chronic Bronchitis

If you're a younger adult and you have chronic bronchitis and smoke, your chance of developing COPD is higher.

Socioeconomic Status

Having a lower socioeconomic status poses an increased risk of developing COPD, but researchers aren't exactly sure why. This could be related to poor nutrition, infections, exposure to irritants, or the effects of smoking, which is more common in lower socioeconomic statuses.


If you have a history of severe childhood respiratory infections, this may put you at a higher risk of developing COPD. Having tuberculosis is also a risk factor and sometimes occurs in addition to COPD. If you have human immunodeficiency virus (HIV), this can also speed up the development of COPD that's caused by smoking.

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Article Sources

  1. National Heart, Lung, and Blood Institute. COPD

  2. Grigsby M, Siddharthan T, Chowdhury MA, et al. Socioeconomic status and COPD among low- and middle-income countries. Int J Chron Obstruct Pulmon Dis. 2016;11:2497-2507. doi:10.2147/COPD.S111145

  3. Stocks J, Sonnappa S. Early life influences on the development of chronic obstructive pulmonary disease. Ther Adv Respir Dis. 2013;7(3):161-73. doi:10.1177/1753465813479428

Additional Reading

  • American Lung Association. What Causes COPD. Updated December 23, 2017.
  • American Lung Association. Preventing COPD. Updated December 23, 2017.
  • Global Initiative for Chronic Obstructive Lung Disease. Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary Disease: 2018 Report. Published November 20, 2017.
  • Mayo Clinic Staff. COPD: Symptoms and Causes. Mayo Clinic. Updated August 11, 2017.
  • National Heart, Lung, and Blood Institute. COPD. National Institute of Health. U.S. Department of Health and Human Services.