Respiratory disorders related to smoking tobacco

Respiratory disorders are among the most frequent causes of death and severe disability from the steadily worsening global pandemic of smoking tobacco. Two disorders stand out: lung cancer and chronic obstructive pulmonary disease (COPD). First, lung cancer caused 1.59 million deaths worldwide in 2012, more than the next two top cancer causes combined (liver and stomach). Tobacco smoke induces pathologic changes in the bronchial epithelium that often progress to fatal invasive lung cancer. For the first time, the recent US National Lung Screening Trial reported a significant (20%) reduction in lung cancer mortality in current or previous heavy smokers detected by low-dose, spiral computed tomography. Second, dramatic advances in understanding COPD include the recognition that it is a complex, multisystem disease that involves many organs-not just the lungs. COPD results from an inflammatory process leading to narrowing and scarring of small airways and destruction of lung parenchyma causing emphysema. Tobacco smoke remains the most important risk factor for COPD globally, but occupational and environmental exposures play increasing roles. Tobacco smoke is also the principal cause of certain interstitial lung diseases and worsens others. Both prenatal and postnatal tobacco exposure contribute to impairment in lung growth and development, and increase the risk of acquiring infectious pneumonias and tuberculosis.