Causes and Risk Factors of Chronic Bronchitis

Chronic bronchitis refers to inflammation and irritation of the bronchial tubes, which carry air to and from your lungs. It's a type of chronic obstructive pulmonary disease (COPD). Chronic bronchitis causes excess mucus production which can cause breathing problems when it builds up.

It is usually the result of prolonged exposure to irritants that can damage your lungs. Smoking is the leading cause of chronic bronchitis, but other factors may increase a person's risk of developing this condition, such as environmental factors and workplace exposure to harmful substances.

Rarely, a genetic condition called alpha-1 antitrypsin deficiency can play a role in causing chronic bronchitis.

man smoking a cigarette outside

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Common Causes

The most common, and also the most preventable, cause of chronic bronchitis is cigarette smoking. Increasingly, the use of electronic cigarettes and marijuana smoking are being linked to chronic bronchitis too.

Unlike some toxins you may be exposed to for short periods, cigarette smoke is inhaled throughout the day—sometimes dozens of times per day—and contains more than 7,000 known harmful chemicals that can damage the tissue in your lungs and cause irritation.

An estimated 85% to 90% of all COPD cases are linked to cigarette smoking.

Outside of smoking, there are other ways that toxins can reach your lungs and lead to chronic bronchitis. These include air pollution and chemicals used in the workplace.

Aerosolized paints, pesticides, fuels, and fertilizers are some of the chemicals that can increase your risk of chronic bronchitis. Some jobs that have been linked to a higher risk of chronic bronchitis and COPD include:

  • Coal miners
  • Hard rock miners
  • Tunnel workers
  • Concrete manufacturers and laborers
  • Livestock farmers
  • Farmers who use pesticides

Familial patterns have been noticed as well, but many times these cases are a result of sharing the same environment, especially air pollution and secondhand smoke.

Genetics

Chronic bronchitis has also been linked to genetics and family history. One study found that 55% of chronic bronchitis cases in twins were not linked to environmental factors.

Other studies point to genetic variations, specifically in the alpha-1 gene. Alpha-1 is a protein that helps protect the lungs, and people who are deficient in this gene have been found to be at a higher risk of developing chronic bronchitis.

Your gender and ethnic background may also play a role. Hereditary cases of chronic bronchitis were found to be more common in women, and women overall have a higher chance of developing chronic bronchitis whether they smoke or not. Non-Hispanic whites are also more likely to develop the condition than other ethnic groups.

Lifestyle Risk Factors

The risk for developing chronic bronchitis is linked to lifestyle choices, including:

  • Smoking: Up to 75% of people who have chronic bronchitis smoke or used to smoke.
  • Long-term exposure to other lung irritants: These include secondhand smoke, air pollution, and chemical fumes and dusts from the environment or workplace.
  • A history of childhood respiratory infection

Summary

You can greatly lower your risk of chronic bronchitis by quitting smoking and avoiding exposure to substances that are harmful to your lungs. In rare cases a genetic deficiency can cause this condition. You may also be more likely to have chronic bronchitis if you have a family history of the disease.

A Word From Verywell

While there are some genetic and environmental causes of chronic bronchitis that can be difficult to avoid, the condition is most often caused by personal choices like smoking and being exposed to irritants that can harm your lungs.

You can therefore take steps to reduce your risk of developing chronic bronchitis by choosing not to smoke, quitting smoking, and protecting yourself from harmful dust and chemicals. If you work in an environment that's prone to exposure, wear protective equipment to keep yourself safe on the job.

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5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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