An individual has about a one in 20 lifetime risk of developing colon cancer. Only about three percent of colon cancers occur in persons under age 40. In the United States, both incidence and mortality rates have begun to decline. This decline may reflect better nutrition, and possibly removal of polyps from the colon before they have had a chance to turn into cancer. Well-established risk factors for colon cancer are high dietary fat intake and heredity.
Animal fat has the highest association with colon cancer.
About 15 percent of all colon cancer patients have a family history of colon cancer in a first-degree relative. Low dietary fiber is also associated with a higher risk of colon cancer. A sedentary lifestyle and obesity are both correlated with an increased risk of colon cancer. Diets that are high in fruits and vegetables are associated with a lower colon cancer risk. Interestingly, removal of the gallbladder is associated with a small increase in colon cancer in females.