What are major cancer risk factors?
What are major cancer risk factors?

Heredity and environment are major risk factors in the development of cancer. According to the National Cancer Institute, specific risk factors within these larger categories include:

  • Tobacco use. Research consistently links exposure to tobacco products (through smoking, chewing and second-hand smoke) to certain types of cancer and other potentially fatal diseases. These include lung cancer and cardiovascular disease. Marijuana may be even more damaging than tobacco.
  • High-fat diet. Scientists believe there is a connection between diets high in certain types of fats and colorectal cancers.
  • Obesity. Research indicates that obesity (high body fat levels) increases a person’s likelihood of developing several types of cancer.
  • Ultraviolet radiation. Prolonged exposure to sunlight, tanning beds and sunlamps increases the chances of developing several types of skin cancer, including melanoma.
  • Alcohol. High alcohol intake, especially with smoking, likely increases the risk for certain cancers.
  • Ionizing radiation. Lung cancer and leukemia, among others, may be caused in part by exposure to X-rays and radioactive substances. Certain occupations result in exposure to potentially cancer-causing agents such as asbestos and certain dyes.
  • Chemicals, metals, pesticides. Many commonly used pesticides and household cleaning products contain chemicals shown to cause cancer in laboratory animals.
  • Hormone replacement therapy (HRT). Research points to a link between HRT and breast cancer in women.
  • Diethylstilbestrol (DES). DES is a synthetic form of estrogen, a female hormone. It was prescribed between 1938 and 1971 to help women with certain complications of pregnancy. In 1971, DES was linked to an uncommon cancer (called clear cell adenocarcinoma) in a small number of daughters of women who had used DES during pregnancy. The overall risk of an exposed daughter to develop this type of cancer is estimated to be approximately 1/1000 (0.1 percent).
  • Close relatives with certain types of cancer. Some types of cancer tend to “run in families,” suggesting a genetically increased risk.
  • Infections such as HIV or human papilloma virus (HPV) may be related to certain types of cancers.

To learn more:

Cancer Causes and Risk Factors
(National Cancer Institute)
This list of cancer causes and risk factors leads to written discussions about specific issues. The list includes foods, genetics, hormones, smoking, workplace and environment, and other topics. Each discussion includes research results which can be hard to understand.
Smokeless Tobacco
Links to sites which have been reviewed by librarians at the National Library of Medicine.

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Written by: Nancy C. McKeehan, M.S.L.S.
Reviewed by: Jeffrey G. Schultze, M.D.
Last Modified: Tuesday August 25, 2015 10:27 AM