Chronic obstructive pulmonary disease (COPD) is a lung disease that limits how much air you’re able to breathe in and out of your lungs. According to the Centers for Disease Control and Prevention (CDC), there are nearly 15.7 million Americans living with COPD.1 However, many more are living with lung or breathing problems (low pulmonary function) and haven’t been diagnosed with COPD yet.
In this article, we’ll cover the causes and risk factors of COPD, what symptoms to look out for, and how this disease is diagnosed. By better understanding your individual risk and potential for complications, you can get take extra steps to prevent or treat your COPD.
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What Causes COPD?
COPD is a progressive lung disease, which means that once it develops, it continues to worsen over time. People with healthy lungs are able to breathe in plenty of air, which travels down the bronchial tubes deep into the lungs. There, the tube splits into thousands of small, thin tubes known as bronchioles. At the end of each bronchiole, there are tiny, stretchy air sacs called alveoli that allow oxygen to enter the bloodstream.2
Healthy lungs have around 300 million alveoli inside them that stretch as you breathe in, moving oxygen into the bloodstream. When you breathe out, the alveoli shrink and push carbon dioxide out of your lungs in your breath.3
People with COPD have damaged, inflamed, or narrowed airways that block airflow into the lungs. COPD can affect the lungs by:4
- Damaging alveoli so they lose their stretch
- Causing inflammation and thickening that narrows the airways
- Destroying the walls between alveoli so they can’t move oxygen into the bloodstream
The biggest cause of COPD is exposure to tobacco smoke. In fact, smoking is responsible for around 75 percent of all COPD cases. The chemicals released by tobacco are harmful to the lungs and cause irritation, inflammation, and damage. They also make it harder for your body to fight infections. Air pollution or exposure to smoke, chemicals, or dust from work or home is responsible for another 10 to 20 percent of COPD cases.5
When you breathe in something that irritates your lungs, they create a thick, sticky fluid called mucus to trap it. Mucus helps stop you from getting sick when you breathe in bacteria or viruses, but it can also block your airways if you make too much.6 People who smoke tobacco typically make extra mucus and develop a “smoker’s cough” to try to clear it out of their lungs. Many people with COPD who smoke have extra mucus that clogs their airways, making it hard to breathe.
Types of COPD
There are two types of COPD — emphysema and chronic bronchitis.7
Emphysema causes your alveoli to break, and they lose the ability to move oxygen into your bloodstream. Instead of having many tiny air sacs as you’d find in healthy lungs, you have several broken alveoli next to each other that form large air pockets. This can trap air in your lungs, making your chest puff out or appear barrel-shaped (barrel-chested). Over time, the surface area of your lungs shrinks, making it harder for you to breathe in and out deeply.3
The second type of COPD is chronic bronchitis, or long-term inflammation of the bronchi in the lungs. Most people develop the acute form of bronchitis after a cold or respiratory infection. It typically lasts a few weeks and gets better on its own. However, chronic bronchitis symptoms never really go away. There may be periods where they’re better or worse than usual, but chronic bronchitis can’t be cured.8,9
Controllable Risk Factors Associated with COPD
There are many factors that play into your risk of developing COPD. Some of these are in your control, while others aren’t. The biggest risk factors — like smoking tobacco and exposure to smoke, chemicals, and dust — can be controlled. By quitting smoking and taking steps to avoid these irritants, you can lower your risk of COPD.4
We know that quitting smoking is easier said than done, but you can work with your doctor, family, and friends to find what works best for you. The CDC offers free resources, coaching, and plans to help you take control of your health and live better with COPD.
Uncontrollable Risk Factors Associated with COPD
On the other hand, some risk factors are simply out of your control. For example, the older you are, the higher your risk of developing COPD. Symptoms typically start in people who are 40 years or older, but they’re most common in people aged 65 years or older.1
Studies show that women are more likely to develop and pass away from COPD. It’s the fourth-leading cause of death in women, behind heart disease, cancer, and stroke.10 Researchers think it’s because women tend to be diagnosed later than men — this means their COPD has damaged their lungs more, and treatments are less likely to work. Women are also more likely to be affected by the chemicals in tobacco smoke compared to men.1,4
Your genetics and family history of health conditions also play a big role in your overall health and risk of COPD. A genetic condition known as alpha-1 antitrypsin (AAT) deficiency raises your risk of lung diseases and COPD.11 A healthy person makes the AAT protein in their liver, which helps protect their lungs from smoke, dust, chemicals, and other irritants. People with AAT deficiency have a changed or mutated AAT gene that can’t properly make the protein, putting them at risk of COPD and diseases.
Around 20 percent of people with COPD also have asthma, an inflammatory lung disease that causes your airways to swell and narrow.4 When you breathe in allergens or substances you’re allergic to (like pollen or dust mites), your airways start to close and make it hard to breathe.12 While asthma doesn’t cause lung damage like COPD, it makes your airways more sensitive to irritating substances like tobacco smoke and chemicals.13
Symptoms of COPD
The symptoms of COPD depend on which type you have. If you notice any of the following symptoms of emphysema or chronic bronchitis, talk to your doctor or pulmonologist (a doctor who specializes in lung diseases). They can order more tests and make a final diagnosis to get you the treatment you need.
Symptoms of Ephysema
Most people living with emphysema don’t know they have it until they start experiencing symptoms. Shortness of breath and fatigue or tiredness are often the first noticeable symptoms, which typically don’t start until 50 percent or more of their lung tissue has been destroyed.3 Other symptoms of emphysema include:
- Smoker’s cough
- Squeezing or tightness in your chest
- Feeling like you can’t get enough air, especially with movement or light exercise
- Heart problems
- Weight loss
- Making and coughing up green or yellow mucus (known as a productive cough)
- Anxiety and/or depression
Symptoms of Chronic Bronchitis
Many symptoms of chronic bronchitis overlap with symptoms of emphysema. According to the American Lung Association, people with chronic bronchitis can be diagnosed if they’ve had a productive cough for at least three months many times in at least the last two years.8 You may also hear a squeak or whistling sound when you breathe. In more severe cases, some people with chronic bronchitis also have swollen feet, ankles, and/or legs.9
How Is COPD Diagnosed?
COPD is diagnosed using your medical history, a physical exam, imaging tests, and lung function tests. Your doctor or pulmonologist will start by taking your medical history.14,15 They’ll ask you questions about:
- Your family history of COPD, asthma, and other lung diseases
- Your smoking history
- What you do for a living
- Your overall health
- If your symptoms get worse when you’re walking up the stairs or exercising
- If you’re experiencing shortness of breath or have been coughing a lot
- If your cough is dry or if you’re coughing up mucus
During your physical exam, your doctor or pulmonologist will listen to your heart and lungs and check your blood pressure and heart rate. They’ll also check your body for any signs of swelling in your feet, ankles, or legs, or to see if you’re barrel-chested from extra air trapped in your body.
Your doctor or pulmonologist may order imaging tests to take a closer look at your lungs. A chest X-ray or computed tomography (CT) scan can help them see how much damage has occurred. A chest X-ray may not always pick up on emphysema, so your doctor or pulmonologist may use a CT scan to take detailed images.16 These imaging tests are also used to rule out other conditions that may be causing your symptoms.
Finally, lung function tests may be done to measure how well your lungs are working. The most commonly used test is spirometry.15 It measures how much air you’re able to push out of your lungs.17 Other examples of lung function tests include:
- Fractional exhaled nitric oxide (FeNO) test: Measures how much nitric oxide you breathe out; this chemical is used to diagnose inflammation in your lungs.
- Arterial blood gas test: Measures the levels of carbon dioxide and oxygen in your bloodstream.
- Peak expiratory flow (PEF) test: Measures how fast you can push air out of your lungs during spirometry.
Complications of COPD
Lung damage caused by inflammation and harsh chemicals makes it harder for your lungs to work well. If you’re living with COPD, you’re more likely to have health complications such as:18
- Lung infections: Your lungs have a harder time fighting off bacteria and viruses, so you’re more likely to get sick with pneumonia, the common cold, or the flu. Infections also make it harder for you to breathe and can make your COPD symptoms worse.
- Lung cancer: Chronic inflammation in your lungs increases your chances of lung cancer.
- Heart problems: Doctors and researchers aren’t quite sure why, but you’re at a higher risk of developing heart disease or having a heart attack when living with COPD.
- Pulmonary hypertension: People with COPD are more likely to have high blood pressure affecting their lungs’ arteries.
- Depression: COPD symptoms negatively affect your quality of life and stop you from doing the things you love, which can contribute to depression.
Resources for Living with COPD
Millions of Americans are living with COPD and have found ways to get connected with others who understand. The American Lung Association, CDC, and other patient organizations provide resources for people with COPD.