Causes of COPD

Chronic obstructive pulmonary disease (COPD) happens when our airways and lungs become damaged and inflamed. It makes the airways narrower, leading to breathing difficulties. The damage is usually caused by long-term exposure to irritants in the air. There’s sadly no cure, but COPD can be treated so that people can live well with the condition.  

What is the main cause of COPD?

While not the only cause of COPD, up to three-quarters of people who have COPD currently smoke or used to smoke. Cigarette smoke contains harmful chemicals that damage the lining of our airways. Smoking other types of tobacco – pipes, cigars, water pipes – and marijuana also puts you at a higher risk of developing COPD. There is little research on the damage that vaping can cause, but most doctors would also recommend avoiding it.

Some research suggests that breathing in other people’s cigarette smoke – called passive smoking – can also increase or contribute to your risk of COPD. Your risk of COPD increases with how often you smoke and for how many years you’ve been smoking.

However, not all smokers will develop COPD, and there are many other factors that cause the disease.  

Cigarrete smoking can cause COPD

Close up of womans hand with cigarette in the street.

What else causes COPD?

Whether or not a person develops COPD in their lifetime is influenced by a complex mix of their environment and genetic make-up. Although smoking is the main cause, not all smokers develop the condition. Indeed, fewer than half of all heavy smokers go on to have COPD.

Furthermore, people who have never smoked can still develop COPD. We don’t know for certain why non-smokers can get COPD, but it appears the risks are higher as you get older, if you have asthma, are a woman, or have a lower social and educational background. There’s recent evidence that suggests if your airways are naturally small for your lung size (called ‘dysanapsis’) you’re also at increased risk of COPD, even if you’ve never smoked.

Air pollution

Household air pollution affects nearly three billion people globally. Burning fuel on open fires for cooking and heating in poorly ventilated homes can be one of the main causes. This may put people, particularly women, in many developing countries at greater risk of COPD.

We know that poor air quality in towns and cities can be harmful to our lungs, especially for people who already have heart or respiratory conditions. However, it’s not clear how that affects our chances of developing COPD, as more research is needed.

Fumes and dust in the workplace

Nearly 15% of the global impact of COPD is caused by workplace exposure. Some occupational dust and chemicals may cause COPD, especially if you breathe them in, including:

  • Cadmium dust and fumes
  • Grain and flour dust
  • Silica dust
  • Welding fuels
  • Isocyanates
  • Coal dust.

Genetics

If you have a rare genetic condition called alpha-1-antitrypsin deficiency (AATD), you’re more likely to develop COPD. Alpha-1-antitrypsin is a chemical normally produced in the liver that protects our lungs from harmful substances and infections. People with AATD lack alpha-1-antitrypsin, and this can be the cause of COPD. You also might have COPD at a younger age and your COPD might progress more rapidly, especially if you smoke.

About one in 100 people with COPD have AATD. If you’ve been diagnosed with AATD, it’s not certain you’ll go on to develop COPD as well but there is a higher chance. If you smoke, it’s even more important to stop. Ask your doctor what other health and lifestyle measures you can take.  

What are the early warning signs for COPD?

The early signs of COPD are:

  • Increasing breathlessness
  • A chesty cough that produces phlegm and won’t go away
  • Wheezing
  • Frequent chest infections.

Your symptoms might flare up for a short period, particularly in the winter. If you’re experiencing these symptoms persistently, especially if you’re over 35 years old and you smoke or used to smoke, see your family doctor for medical advice. If you want to find out more about COPD, its causes, and its relationship with other conditions, such as asthma, read our guide here.

Sources

BLF 2020. Alpha-1-antitrypsin deficiency.

BLF 2020. What health problems can alpha-1-antitrypsin deficiency cause?

GOLD 2020. Global strategy for the diagnosis, management and prevention of chronic obstructive pulmonary disease. 2020 report.

Lamprecht B, McBurnie MA, Vollmer WM, et al. COPD in never smokers: results from the population-based burden of obstructive lung disease study. Chest. 2011;139(4):752-763. doi:10.1378/chest.10-1253

NHS 2019. Causes. Chronic obstructive pulmonary disease (COPD).

NHS 2019. Symptoms. Chronic obstructive pulmonary disease (COPD).

NIH 2020. Lung development may explain why some non-smokers get COPD and some heavy smokers do not. News release.

Mayo Clinic Staff 2020. COPD. Symptoms & causes.

Ruvuna L, Sood A. Epidemiology of Chronic Obstructive Pulmonary Disease. Clin Chest Med. 2020 Sep;41(3):315-327.

Smith BM, Kirby M, Hoffman EA, et al. Association of dysanapsis with chronic obstructive pulmonary disease among older adults. JAMA 2020; 323: 2268-2280.

US NLM. 2021. COPD. US National Library of Medicine.