5 Common Causes of COPD

1. Smoking. Cigarette smoke is by the far the most common reason people get COPD. You can also get it from tobacco products, like cigar and pipe smoke, especially if you breathe in the smoke.
2. Secondhand smoke. Even if you don't smoke yourself, you can get COPD from living with a smoker and breathing in the smoke.
3. Pollution and fumes. You can get COPD from air pollution. Breathing in chemical fumes, dust, or toxic substances at work can also cause it.
4. Your genes. About 2 to 3 in 100 people with COPD have a defect in their DNA, the code that tells your body how to work properly. This defect is called alpha-1 antitrypsin deficiency or AAT deficiency. Your lungs don't have enough of a protein needed to protect them from damage. This can lead to severe COPD. If you or a family member had serious lung problems -- especially at a young age -- ask your doctor about testing for AAT deficiency. 
5. Asthma. It's not common, but asthma can lead to COPD. If you don't treat your asthma, over time you can get lifetime damage.