Chronic Effects of Cigarette Smoke on the Respiratory Tract

Cigarette smoking is a major cause of death and disease in the United States and worldwide. It is associated with approximately 90% of lung cancer cases and elevates the risk of chronic obstructive pulmonary disease (COPD); both diseases are leading causes of death worldwide. Cigarette smoke contains over 7000 chemicals and more than 70 known carcinogens and toxicants. While smoking causes the majority of lung cancer and COPD cases, only 15% of smokers get lung cancer, and only 20% of smokers develop COPD. This suggests that the susceptibility of developing these conditions is determined by many factors, including genetics. Interestingly, smokers with COPD have an elevated risk of developing lung cancer. Electronic nicotine delivery systems (ENDS) have been on the market since 2006 and are considered a product of reduced harm. The impact of their chronic use is unknown, but studies suggest that they may contribute to lung cancer and COPD risk.