What is Chronic Obstructive Pulmonary Disease (COPD)?

July 10, 2024
Avatar for Jyoti Kinghorn, PhDJyoti Kinghorn, PhD
COPD is a lung disease

Chronic obstructive pulmonary disease, or COPD, is a chronic lung disease that causes breathing problems due to restrictions in airflow through the lungs. In COPD, the capacity of the lungs to filter air is reduced by cellular damage or deposition of too much phlegm in the airways. The disease is characterized by difficulty breathing, cough, phlegm, wheezing, and fatigue.

COPD generally emerges after the age of 40 and gets worse with age. In addition to a general loss of productivity caused by frequent breathlessness, the disease affects health by making the lungs more susceptible to infections and cancer. COPD is also associated with heart problems, weakness in bones and muscles, and mood disorders such as depression and anxiety.

COPD is the third biggest cause of death around the globe, being responsible for 6% of global deaths, exceeded only by ischemic heart disease (16%) and stroke (11%).

Types of COPD

Two common types of COPD are emphysema and chronic bronchitis. Patients with COPD often suffer from both emphysema and chronic bronchitis, though the severity of each may vary from patient to patient.

What is emphysema?

Emphysema is a type of COPD that affects the air sacs (alveoli) in the lungs. In this condition, the walls between the alveoli get degraded and broken. As a result, numerous alveoli fuse into fewer ones. This reduces the surface area of the lungs in contact with the air. The capacity of the lungs to push out all the carbon dioxide is also reduced.

What is chronic bronchitis?

In this condition, the lining of the airways in the lungs is constantly inflamed causing swelling and mucus generation. A constant cough tries to clear the airways of mucus.

Causes of COPD

Tobacco smoke

The most common cause of damage to alveoli seen in emphysema and irritation of airways seen in chronic bronchitis is cigarette smoking. Each puff of tobacco smoke contains particulate matter which can deposit deep in the airways of the lungs, and thousands of chemicals hundreds of which are harmful to health. Some of these can cause irritations that cause or worsen COPD.

In developed countries, 70% of the cases of COPD can be attributed to tobacco smoking.

Pollutants in the air

A constant presence of pollutants in the air can irritate the airways and cause or exacerbate COPD. In low- and middle-income countries (LMIC), high levels of indoor and outdoor pollutants can exceed or add to the damage to the lungs caused by cigarette smoking. According to WHO, almost 90% of deaths that occur due to COPD before the age of 70 occur in LMIC. Tobacco smoke only accounts for 30-40% of cases of COPD in these areas.

Common sources of pollution include:

  • Dust
  • Fumes from industrial or vehicular emissions
  • Fumes from burning substances for cooking such as wood, other plant materials, and animal dung

Premature birth and early childhood events

Factors that prevent optimal lung growth in babies and young children can cause COPD later in life. Since lungs may not have fully developed in children born prematurely, premature birth is a risk factor for developing COPD later. Similarly, if a baby or child has too many respiratory infections, that could prevent their lungs from developing well and make them susceptible to COPD later. Children who have asthma in childhood are also at an increased risk of developing COPD.

Genetic predisposition


About 1% of people who have COPD have a mutation in a gene that encodes alpha-1 antitrypsin (AAT), a metabolite that protects the lungs. Deficiency of AAT makes lungs more susceptible to developing COPD.

How to manage COPD?

COPD is not curable, but the condition can be managed by medications and making lifestyle changes.

  • Access medical care. Talk to your doctor if you feel that you are having breathing issues or a constant cough. If your doctor determines that you have COPD, they may prescribe medications that can help heal some of the inflammation such as steroids. Inhaler medications can further help open the airways and make breathing easier.
  • Avoid respiratory irritants.
    Quit smoking. Cigarette smoke releases particular matter and thousands of chemicals into the lungs, many of which can irritate the airways. When trying to quit smoking, you can find support and access free help from the CDC. CDC’s quitlines offer free coaching and resources to help individuals quit smoking.
    Watch out for air quality outdoors. Avoid going outside on days when the air quality is poor. When making travel plans, take into account the air quality of the areas you may be visiting, and have medications ready in case you suffer a flare.
  • Keep indoor air clean. Avoid sources of indoor air pollution. Use exhaust fans while cooking, and check indoor air quality by using an air quality monitor.
  • Avoid respiratory infections. Get your annual flu vaccine, any relevant COVID-19 boosters, and pneumonia and RSV vaccines (if applicable) to avoid respiratory infections. Wash your hands often and avoid touching your nose and eyes when you are out during colder months when many common cold viruses circulate.
  • Stay physically active. Get regular exercise to improve your lung health. Exercise strengthens chest muscles, improves breathing, avoids shortness of breath, and reduces the risk of COPD flare-ups.

The information provided in our blog posts is for informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this blog.

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