Colorectal Cancer Risk Factors

Colorectal cancer develops due to a combination of age, genetics, medical history and lifestyle factors. Having one or more risk factors does not mean you will develop colorectal cancer, but understanding these risks can help guide screening and prevention decisions. There is clear and convincing evidence that colorectal cancer screening is effective and is our most important strategy in reducing the incidence of colon and rectal cancer.

Risk Factors You Cannot Change

• Your Age 
  • Risk increases significantly with age. 
  • Most cases occur in adults over 50, but rates are rising in adults younger than 50. 
     
• Family History of Colorectal Cancer or Polyps 
  • Having a first degree relative (parent, sibling or child) with colorectal cancer or adenomatous polyps increases risk. 
  • Risk is higher if the relative was diagnosed before age 50 or if multiple relatives are affected. 
     
• Inherited Genetic Syndromes 
  About 5% of colorectal cancer cases are linked to inherited syndromes, including: 
  • Lynch syndrome (HNPCC) is the most common hereditary colorectal cancer syndrome. 
  • Familial adenomatous polyposis (FAP) causes hundreds to thousands of polyps. 
     
• Personal History of Colorectal Cancer or Polyps 
  • Previous colorectal cancer increases the chance of developing new cancers. 
  • Adenomatous polyps — especially large, numerous or dysplastic — raise risk. 
     
• Inflammatory Bowel Disease (IBD) 
  • Long standing ulcerative colitis or Crohn’s disease increases colorectal cancer risk due to chronic inflammation.
  • Inflammatory bowel syndrome (IBS), different from IBD, does not increase colorectal cancer risk. 
     
• Racial and Ethnic Background 
  • Native American, Alaska Native and African American adults have higher colorectal cancer incidence and mortality. 
  • Ashkenazi Jews have one of the highest inherited colorectal cancer risks globally. 
     
• Personal History of Abdominal or Pelvic Radiation 
  • Radiation therapy — especially in childhood — can increase colorectal cancer risk later in life. 
  • Adenomatous polyps — especially large, numerous or dysplastic — raise risk. 
     

Risk Factors You Can Change 

• Diet 
  • A high intake of red meat, processed meats and meats cooked at high temperatures increases risk. 
  • Diets low in fruits, vegetables, whole grains and vitamin D may increase risk. 
     
• Physical Inactivity 
  • Lack of regular physical activity is linked to higher colorectal cancer risk. 
  • Regular exercise helps lower risk. 
     
• Excess Body Weight
  • Being overweight or obese raises the risk of developing colorectal cancer and dying from the disease.
  • This association is especially strong in men. 
     
• Alcohol and Tobacco Use 
  • Moderate to heavy alcohol use increases colorectal cancer risk. 
  • The best practice is to avoide alcohol. If you drink, limit your drinks to one or less per day for women and two or less for men. 
  • Long-term smoking increases colorectal cancer risk and the risk of colon polyps. 
     
• Type 2 Diabetes 
  • People with type 2 diabetes have a higher colorectal cancer risk, even after accounting for shared risk factors like obesity.
  • Learn how to deter or delay your risk for type 2 diabetes
     

Emerging and Less Certain Risk Factors 

• Cholecystectomy (Gallbladder Removal) 
  • Some studies show a slightly increased risk of right-sided colon cancer, though reasons remain unclear. 
     
• Low Vitamin D Levels 
  • Low vitamin D may be associated with increased colorectal cancer risk, though research continues. 
     

How to Lower Your Risk of Colorectal Cancer

• Get Regular Screening 
  • Screening can prevent colorectal cancer by removing precancerous polyps.
  • Adults at average risk should begin screening at age 45. 
  • Those with higher risk (family history, IBD, genetic syndromes) may need earlier or more frequent screening.
  • Learn more about scheduling a colonoscopy
     
•  Adopt Healthy Lifestyle Habits
  • Eat a plant-forward diet rich in whole grains, fruits and vegetables. 
  • Limit red and processed meats.
  • Maintain a healthy weight. 
  • Exercise regularly (150 minutes moderate or 75 minutes vigorous weekly). 
  •  Avoid tobacco and limit or avoid alcohol.