Over 12 million people have been diagnosed with COPD--and about 12 million more don't know they have it. This lung disease, which makes breathing difficult, is usally caused by smoking. If you’ve been diagnosed with COPD, it’s important to understand what kind of lifestyle changes you should make and to learn strategies to help you cope with living with the disease. Though COPD can’t be cured, it can be effectively treated to reduce symptoms and improve your quality of life.