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The American Cancer Society lists the following risk factors for CRC:1

  • Age: CRC is more likely to occur as people get older. More than 90% of people with this disease are diagnosed after age 50.
  • Personal history of colorectal polyps: A person who has had an adenomatous polyp is at an increase risk for colorectal cancer.
  • Family history of CRC: Close relatives (parents, brothers, sisters, or children) of a person with a history of CRC are more likely to develop this disease, especially if the relative had the cancer at a young age.
  • Personal history of CRC: A person who has already had the disease may develop CRC a second time.
  • Ulcerative Colitis or Crohn's Disease: A person who has had a condition that causes inflammation of the colon for many years is at increased risk of developing CRC.
  • Diet: Studies suggest that diets high in saturated fat (especially animal fat) and low in fiber may increase the risk of CRC.
  • Cigarette smoking: A person who smokes cigarettes may be at increased risk of developing polyps and CRC.

The American Cancer Society further augments this list of risk factors with the following information1

  • In total, people over the age of 50 account for 91% of new CRC cases, and 94% of CRC deaths. For individuals between the ages of 60 and 79, the incidence rate is greater than 50% higher than for those below the age of 40.
  • Ethnicity and race play a factor. African American men and women have a higher risk.
  • Being overweight and/or obese increases the risk of CRC even when physical activity is taken into consideration.
  • Additionally, CRC has been linked to alcohol consumption (4+ drinks per week).
  • To help avoid developing CRC, the American Cancer Society recommends people eat a varied diet, with an emphasis on plant sources, and to limit foods high in saturated fats.

1Colorectal Cancer Facts & Figures, Special Edition 2005, the American Cancer Society.