[Smoking as a risk factor for COPD and prognosis after smoking cessation]

Cigarette smoking is the major risk factor for chronic obstructive pulmonary disease (COPD). Smokers have higher death rates for COPD and they also have a higher prevalence of lung function abnormalities. Smoking is associated with a greater annual rate of decline in forced expiratory volume in one second (FEV1). Smoking cessation results in an attenuation of the excessive rates of lung function loss. Patients who stop smoking are likely to survive longer than those who continue to smoke. Smoking cessation is the most important intervention in COPD.