For the sake of this discussion, smoking includes cigarettes, cigars, and pipes. According to the Surgeon General's office, smokers who quit before age 50 have only one-half the risk of dying in the next 15 years than those who continue to smoke. Regardless of age, anyone who quits smoking lives longer than those who continue. Quitting substantially decreases the risk of lung, oral, larynx, esophageal, pancreatic, bladder, and cervical cancer. At the same time, quitting smoking can lead to significant reduction in one's risk of many other major diseases.
Oral cancer develops much more frequently in users of smokeless tobacco products than in non-users.
The Environmental Protection Agency says that secondhand smoke is a human carcinogen. At least four chemicals in secondhand smoke are known to cause cancer in humans, and ten others are classified by the EPA as probable human carcinogens. Every year, thousands of non-smoking adults in the US die of lung cancers resulting from secondhand smoke, and thousands more die of heart disease caused by secondhand smoke. There is no doubt. Environmental Risk Factors Environmental factors are commonly misunderstood, perhaps because the degree of risk depends on the concentration of the cancer causing agent or the amount of a person's exposure.