Colorectal Cancer: Risk Factors


Risk factors for colorectal cancer include:

Age Over 50

Colorectal cancer is more likely to occur as people get older. More than 90% of people with this disease are diagnosed after age 50. The average age at diagnosis is 72.


African-Americans have the highest rates of sporadic (non-hereditary) colorectal cancer in the United States and colon cancer is a leading cause of cancer-related deaths among African-Americans. African-American women are more likely to die from colorectal cancer than women from any other racial group, and African-American men are even more likely to die from colorectal cancer than African-American women.

Diet and Supplements

A diet rich in fruits and vegetables and low in red meat may help reduce the risk of colon cancer. Studies have also found that people who take folic acid and calcium supplements have a lower risk of colorectal cancer.


Recent studies have shown that smokers are more likely to die from colorectal cancer than nonsmokers.

Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)

Some studies suggest that aspirin and other NSAIDs may reduce the development of polyps in people with a history of colorectal cancer or polyps. However, regular use of NSAIDs may result in major side effects, including bleeding of the stomach lining and blood clots leading to stroke or heart attack. Taking aspirin or other NSAIDs cannot be substituted for regular colorectal cancer screening.

Personal History of Cancer

People with a personal history of cancer are more likely to develop colon cancer. Colorectal cancer is more likely to develop in women who have had cancer of the ovary or uterus.

Physical inactivity and obesity: People who lead an inactive lifestyle (no regular exercise and a lot of sitting) and people who are overweight may have increased risk of colorectal cancer.

Family History of Cancer

Colorectal cancer is more likely to develop in a person whose parents, siblings or children have had colorectal cancer, particularly if the family member developed colorectal cancer before age 60. Members of families with certain uncommon inherited conditions, such as familial adenomatous polyposis (FAP) or hereditary nonpolyposis colorectal cancer (HNPCC), also have a significant increased risk of colorectal cancer. Relatives of women with uterine cancer may also be at higher risk.

Inflammatory Bowel Disease (IBD)

People with IBD, such as ulcerative colitis or Crohn’s disease, may develop chronic inflammation of the large intestine, which increases the risk of colon cancer. IDB is not the same as irritable bowel syndrome.

Adenomatous Polyps (Adenomas)

Polyps are not cancer, but some types of polyps called adenomas are most likely to develop into colorectal cancer. Polyps can often be completely removed using a tool during colonoscopy, a test in which a doctor looks through a lighted tube into the colon after the patient has been sedated. Polyp removal can prevent colon cancer. People who have had adenomas have a greater risk of additional polyps and of colon cancer, so they should have follow-up screening tests regularly.