What is COPD?What are the main signs and symptoms of COPD?How is COPD diagnosed?What are some of the main medical treatments for COPD?Have any supplements been studied for COPD?How could diet affect COPD?Are there any other treatments for COPD?What causes COPD?What is the prevalence of COPD?Are any supplements effective for COPD?Are any particular foods helpful for COPD?How does environment affect COPD?