This photomicrograph shows a bronchus with increased numbers of chronic inflammatory cells in the submucosa. Chronic bronchitis does not have characteristic pathologic findings, but is defined clinically as a persistent productive cough for at least three consecutive months in at least two consecutive years. Most patients are smokers. Often, there are features of emphysema as well. Since chronic bronchitis and emphysema often overlap, the term 'chronic obstructive pulmonary disease' (COPD) can be applied.

Most cases of COPD are the consequence of smoking. The lung damage is cumulative and permanent and not reversible. Hence, reduction in numbers of smokers can reduce the health consequences and costs. Worldwide, a third of tobacco produced and consumed, and a third of all smokers, reside in China. The economics of cigarette production and consumption need to be modified to dissuade persons from smoking, or the economics of decreased population health will be unacceptable. (