Chronic obstructive pulmonary disease (COPD) happens when the lungs and airways become damaged and inflamed.

It's usually associated with long-term exposure to harmful substances such as cigarette smoke. Things that can increase your risk of developing COPD are discussed in this section.

Smoking

Smoking is the main cause of COPD and is thought to be responsible for around 9 in every 10 cases. The harmful chemicals in smoke can damage the lining of the lungs and airways. Stopping smoking can help prevent COPD from getting worse.

Some research also suggests that being exposed to other people's cigarette smoke (passive smoking) may increase your risk of COPD.

Fumes and dust at work

Exposure to certain types of dust and chemicals at work may damage the lungs and increase your risk of COPD. Substances that have been linked to COPD include:

• cadmium dust and fumes
• grain and flour dust
• silica dust
• welding fumes
• isocyanates
• coal dust

The risk of COPD is even higher if you breathe in dust or fumes in the workplace and you smoke.

Air pollution

Exposure to air pollution over a long period can affect how well the lungs work and some research suggests it could increase your risk of COPD. But the link between air pollution and COPD is not conclusive and research is continuing.

Genetics

You're more likely to develop COPD if you smoke and have a close relative with the condition, which suggests some people's genes might make them more vulnerable to the condition.

People with alpha-1-antitrypsin deficiency can go on to develop COPD. Alpha-1-antitrypsin is a substance that protects your lungs. Without it, the lungs are more vulnerable to damage.

People who have an alpha-1-antitrypsin deficiency usually develop COPD at a younger age – particularly if they smoke.

Chronic obstructive pulmonary disease (COPD) makes breathing increasingly more difficult. But it develops slowly over many years and you may not be aware you have it at first. Most people with COPD do not have any noticeable symptoms until they reach their late 40s or 50s.

Symptoms

Common symptoms of COPD include:

• shortness of breath – this may only happen when exercising at first, and you may sometimes wake up at night feeling breathless
• a persistent chesty cough with phlegm that does not go away
• frequent chest infections
• persistent wheezing

The symptoms will usually get gradually worse over time and make daily activities increasingly difficult, although treatment can help slow the progression.

Sometimes there may be periods when your symptoms get suddenly worse – known as a flare-up or exacerbation. It's common to have a few flare-ups a year, particularly during the winter.

Other symptoms

Less common symptoms of COPD include:

• weight loss
• tiredness
• swollen ankles from a build-up of fluid (oedema)
• chest pain and coughing up blood – although these are usually signs of another condition, such as a chest infection or possibly lung cancer

These additional symptoms only tend to happen when COPD reaches an advanced stage.