• Smoking : Chronic bronchitis is more common in person above the age of 40 years who have been moderate or heavy smokers. Usually people with chronic bronchitis have a smoking history of 10 pack years (amount of smoking in a lifetime is measured in“pack years”. 10 pack year means smoking a packet of cigarette per day for ten years or 2 packets per day for 5 years or half packet per day for 20 years). The cigarette smoke ‘tar’ has a direct toxic effect on the bronchi and continued smoking can lead to irreversible airflow obstruction.   
  • Passive smoking : Even though a person may not smoke he may be at risk if he is in constant touch with a person who smokes like a family member or a friend.
  • Exposure to air pollution.
  • Climate : Exposure to damp weather, sudden changes in temperature, fog, and winter season.
  • Occupational factors : Workplace exposure to airborne organic dusts or toxic gases, especially in cotton mills mines, road tunnel workers, plastic manufacturing plants.
  • Social factors : People living in overcrowded places with unhygienic conditions and improper nutrition are at increased risk.
  • History of repeated upper airway illnesses : Frequent infections especially with streptococcal and H. influenzae may progress to chronic bronchitis.
  • History of Pneumonia in childhood.
  • Chronic bronchitis may occur as a complication to measles, whooping cough or secondary to tuberculosis, rheumatism, gout or syphilis (as in homeopathy it is believed that any disease if suppressed or not properly treated can come up again as the same disease or as a new disease).