157812
Causes AECB can be caused by : Although the condition of a patient with chronic bronchitis can become exacerbated by many other factors as well , the scope is generally restricted to the ones that cause the symptoms below .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 None