Asthma and Other Lung Diseases

Chronic lung diseases affect the airways and other parts of the lungs. Chronic means they are ongoing. Many people with asthma have other lung diseases. These diseases may overlap because they have risk factors in common. For example, you could be exposed to something in early childhood or adulthood and that could cause more than 1 lung disease.^1,2

Common lung diseases include:^1,2

• Asthma
• Chronic obstructive pulmonary disease (COPD)
• Bronchiectasis
• Lung cancer

Reducing exposures can lower the risk of asthma and other lung diseases. Talk to your doctor about ways to lower your risk of lung disease.¹

What does asthma have in common with other lung diseases?

Asthma is linked to many other lung diseases. Lung diseases often have similar or overlapping causes. Premature birth and exposures during childhood can have long-term effects on the lungs. This is because lung development starts before birth and continues into early adulthood.^1-3

Environmental exposures and other factors affect lung growth and function. And that increases the risk for asthma, COPD, and other lung diseases. Some of these risk factors include:^1,3

• Indoor and outdoor pollution
• Being born premature
• Having certain infections or being exposed to allergens as an infant or child
• Smoking or being exposed to secondhand smoke

Some exposures are easier to change than others. In some cases, lifestyle changes can reduce harmful exposures. For example, reducing allergen exposure can improve lung function. In other cases, we need larger efforts to improve community health. For example, improving indoor and outdoor quality requires changing laws and policies.¹

How does asthma overlap with other lung diseases?

Understanding how asthma overlaps with other lung diseases can help you get the right diagnosis and treatment.

Asthma and COPD

COPD is a common lung disease that causes airflow obstruction. The main types of COPD are emphysema and chronic bronchitis. The most common risk factor for COPD is cigarette smoking.⁴

Asthma and COPD are different lung conditions. But they have similar symptoms and features. Many people with asthma or COPD also have the other condition. This is called asthma-COPD overlap syndrome (ACOS). ACOS occurs in about 25 percent of people with COPD and 10 to 30 percent of people with asthma.^5-7

ACOS typically happens to people over 40 who have:⁵

• Difficulty breathing, especially after activity
• Partially reversible airflow obstruction
• History of allergies
• History of tobacco smoking
• History of asthma before age 40

We do not know why asthma and COPD often occur together. They may both be caused by the same risk factors or exposures. Separate risk factors may also drive each disease. So the causes of ACOS probably vary from person to person.⁵

Doctors will use your symptom history and test how your lungs work (perform lung function tests) to diagnose ACOS. Your doctor will probably recommend lifestyle changes and drugs to treat your asthma. These might include:⁶

• Avoiding smoking
• Getting vaccinated
• Avoiding allergens and controlling seasonal allergies
• Taking inhaled corticosteroids, long-acting beta-agonists, or biologic drugs

Asthma and bronchiectasis

Bronchiectasis is a lung condition that damages airways and causes them to widen. This makes it hard to clear mucus from the lungs. It also increases the risk of infections. Coughing with mucus is the main symptom. Cystic fibrosis is the most common cause of bronchiectasis in the United States.⁸

Asthma and bronchiectasis are different lung conditions. Between 3 and 8 percent of people with bronchiectasis also have asthma. Severe asthma can be a cause of bronchiectasis. Treatment involves medicine for asthma and airway infections.^9,10

Another condition has symptoms of both asthma and bronchiectasis. It is called allergic bronchopulmonary aspergillosis (ABPA). ABPA happens most often to people who have asthma or cystic fibrosis after they are exposed to mold. Treatment involves corticosteroid and antifungal drugs.^8-10

Asthma and lung cancer

Lung cancer is one of the most common types of cancer. Airway inflammation may cause problems that lead to lung cancer. Partly controlled asthma may increase the risk of lung cancer. Well-controlled asthma does not seem linked to lung cancer.^11-13

Different studies disagree on the link between asthma and lung cancer. Certain things make it harder to find clear links. For example:^11-13

• Smoking is a common cause of lung cancer. Smoking is also more common among people with asthma.
• People with asthma may visit the doctor more, so they may be more likely to get screened for lung cancer.
• Drugs used to treat asthma may impact the risk of lung cancer.
• People with asthma may avoid exposures that increase the risk of lung cancer.

We need more research to understand if asthma is a risk factor for lung cancer.