Title: Risk Factors for Cancer - Cancer - Merck Manuals Consumer Version
Headings: Risk Factors for Cancer
Risk Factors for Cancer
Family history
Genes and chromosomes
Age
Environmental factors
Geography
Diet
Drugs and medical treatments
Table
Some Carcinogens
Infections
Inflammatory disorders
Drugs Mentioned In This Article
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Content: These cancers result from suppressor gene mutations that are either inherited or that occur during fetal development. However, most other cancers are more common in adults, particularly in older people. In the United States, more than 60% of cancers occur in people older than 65. The increased cancer rate is probably due to a combination of increased and prolonged exposure to carcinogens and weakening of the body’s immune system. Environmental factors
Numerous environmental factors increase the risk of developing cancer. Tobacco smoke contains carcinogens that substantially increase the risk of developing cancers of the lungs, mouth, throat, esophagus, kidneys, and bladder. Pollutants in the air or water, such as asbestos, industrial waste, or cigarette smoke, can increase the cancer risk. Many chemicals are known to cause cancer, and many others are suspected of doing so. For example, asbestos exposure may cause lung cancer and mesothelioma (cancer of the pleura). Exposure to pesticides is associated with a higher risk of some types of cancer (for example, leukemia and non-Hodgkin lymphoma ).