Smoking, which is considered to be the main source of lung irritation leading to chronic bronchitis
	Air pollution
	Working conditions, such as in the coal mining industry or manufacturing plants which produce irritating gases
	Infections of the lungs which, if the attacks of acute bronchitis are repeated often enough, will lead on to chronic bronchitis
	Living conditions may also be important as a contributing factor. A cold damp climate can be associated with chronic bronchitis
	An inherited weakness of the lungs which appears to be the most important factor in association with all of the other conditions mentioned

Males tend to suffer from chronic bronchitis more than females. However, with the increase in the number of young females now smoking, the numbers are now evening out between the sexes.

Complications of chronic bronchitis include repeated acute chest infections and emphysema which is a destruction of lung tissue resulting in poor oxygen transfer to the blood and difficulty in breathing. This is often seen in heavy smokers.

As smoking is the commonest cause of chronic bronchitis, lung cancer is the most worrying complication. People suffering from chronic bronchitis should have regular lung x-rays, and should be on the lookout for any change in the nature of their cough and particularly for the presence of blood stained sputum.

Treatment consists of first of all avoiding the contributing factors, particularly smoking. Acute lung infection should be treated with antibiotics. Long term antibiotic treatment, particularly in the winter months, may be necessary and will have to be supervised by your doctor. He can also check the air flow in your lungs and determine the extent of the lung deterioration.