[Chronic respiratory diseases from tobacco use].

Cigarette smoke exerts significant deleterious effects on both lung structures and function. Tobacco alone is the most important risk factor for the development of chronic obstructive lung disease (COLD). The responsibility of smoking for the occurrence of COLD has been demonstrated by epidemiological studies and anatomicopathological findings. Smoking-related lesions initially involve the small airways and remain silent for a long time. There are still uncertainties concerning the mechanisms through which some smokers develop clinical COLD. The clinical diagnosis of COLD rests on the demonstration of dyspnoea by meticulous questioning. Only respiratory function tests can assert the presence of bronchial obstruction. These tests also are necessary to evaluate the severity of the disease, determine its prognosis and follow up its course. In clinical practice the early diagnosis of COLD rests on repeated measurements of FEV1 in smokers.