Cigarette smoking is the most important cause of chronic bronchitis which rarely occurs in the non-smoker. Environmental pollution may contribute to the development of chronic bronchitis. Some smokers are resistant to the development of chronic bronchitis, but as yet there is no way of predicting which smokers will not develop chronic bronchitis. The decreased incidence of chronic bronchitis among women probably reflects the difference in smoking habits between the sexes. As these differences have diminished we are seeing an increasing incidence of chronic bronchitis in women.
Chest infections seem to occur more frequently in patients with chronic bronchitis.
Inhaled tobacco products impair the ability of the lungs to combat infections. The excessive mucus associated with chronic bronchitis is ideal for bacteria to breed. It is usually worse in the winter time and when the person has a head cold. In these early phases of chronic bronchitis, the person may lead an entirely normal life, including vigorous sports. Sensitive breathing tests, however, can indicate the beginning of irreversible damage to the lung even at this stage.