Most scientists agree that these things affect the risk of colon cancer. Some may apply to you, but others may not.
The risk of colon cancer goes up with age. Most cases are diagnosed in people over the age of 50. The average age the disease is found is 73.
Tall people have a higher risk of colon cancer. Researchers don’t know exactly why, but it may be related to the fact that tall people grow more. Some of the same hormones and other factors that make people grow may also increase the chance that dividing cells become abnormal and turn cancerous.
People who maintain a healthy weight have a lower risk of colon cancer. One reason may be that fat tissue affects different hormone levels in the body. Too much fat tissue can lead to higher hormone levels and increase the risk of cancer.
People who maintain a healthy weight also have a lower risk of kidney cancer, heart disease, pancreatic cancer, diabetes and stroke, and women have a lower risk of breast cancer and uterine cancer.
People who are physically active for at least 30 minutes a day have a lower risk of colon cancer, possibly because physical activity affects hormone levels and other growth factors in the body.
Being physically active is one of the best ways to help maintain a healthy weight. Physically active people also have a lower risk of breast cancer, heart disease, diabetes and stroke. Even just 30 minutes of moderate activity (like walking) daily can decrease your risk of disease.
People who eat less than three servings of red meat per week have a lower risk of colon cancer. Avoiding processed meats, like hot dogs, ham and salami, may be especially good. One possible explanation is that cooked and processed meat may contain chemicals that can cause cells to become cancerous.
Red meat includes beef, pork, veal and lamb. One serving is 4 ounces, about the size of a deck of cards.
People who drink more than one drink of alcohol per day have a higher risk of colon cancer. (A drink is a can of beer, a glass of wine or a shot of hard liquor.) There are many possible reasons for this. For example, alcohol may cause abnormal cell changes in the body that can lead to cancer. Alcohol can also decrease levels of folate (folic acid) in the body. Folate is a B-vitamin that helps keep cells from becoming cancerous.
Men and women who limit alcohol consumption also have a lower risk of high blood pressure and stroke. In addition, women have a lower risk of breast cancer.
However, drinking a moderate amount (not more than one drink a day for women or two drinks a day for men) has benefits, too. People who drink a moderate amount have a lower risk of heart disease and diabetes.
People who take a multivitamin with folate (folic acid) every day have a lower risk of colon cancer. Folate is a B-vitamin that can help protect cells from abnormal changes that lead to cancer. Multivitamins with folate are an important source of this vitamin. Folate is also found in different fruits, vegetables, grains, nuts and legumes.
Folate doesn't just protect against colon cancer. People who take a multivitamin with folate can have a lower risk of heart disease and stroke. And it lowers the risk of birth defects when taken by women before or during the early stages of pregnancy.
People who don’t get enough calcium have a higher chance of developing colon cancer. Calcium is a mineral that is important for healthy bones, muscles and the nervous system. Calcium can also help protect against abnormal growths in the colon (polyps) and colon cancer.
Calcium in the diet comes from different sources, like dairy foods, some leafy green vegetables (such as broccoli and collards) and fortified foods. Vitamin supplements also provide calcium. Research suggests that about 700 milligrams a day helps lower the risk of colon cancer, and more is not necessarily better. People who don’t eat dairy products and other calcium-rich foods may want to take a calcium supplement.
People who have higher levels of vitamin D in their blood have a lower risk of colon cancer. Vitamin D helps protect the cells in the colon against changes that can lead to cancer. People can get vitamin D through sunlight and through their diets. Some people get vitamin D by taking vitamins. Good food sources include dairy products, breakfast cereals that are fortified with vitamin D and fatty fish like salmon and tuna.
Vitamin D is also important for bone health and can help prevent osteoporosis (bone loss).
Birth Control Pills
Women who take birth control pills for at least five years have a lower risk of colon cancer. The longer a woman takes the pill, the more she lowers her risk. One possible explanation is that birth control pills lower levels of certain digestive chemicals in the body. High levels of these chemicals may cause cells in the colon to become cancerous.
Birth control pills can have positive and negative effects on a woman's health. If taken for at least five years, birth control pills can lower a woman's risk of colon cancer, uterine cancer and ovarian cancer. However, while she's taking them, they raise a woman's risk of breast cancer, heart attack and stroke. For some women, they can also cause side effects like nausea and vomiting.
Smoking and taking birth control pills can be a deadly combination. Together, they greatly increase the risk of a heart attack, stroke and other clotting problems. All women who smoke should quit as soon as possible.
Postmenopausal hormones are medications that help ease the symptoms of menopause, like hot flashes and vaginal dryness. They contain hormones that are similar to the female reproductive hormones estrogen and progesterone, which the body stops making in large quantities after menopause.
Women who take postmenopausal hormones for at least five years have a lower risk of colon cancer. Although scientists aren't sure why, it may be that postmenopausal hormones lower the levels of certain chemicals needed for digestion. High levels of these chemicals may cause cells in the colon to become cancerous.
Postmenopausal hormones can have both positive and negative effects on a woman's health. These hormones may cause abnormal growth of cells, increasing the risk of breast cancer, but different hormones affect risk differently. The combination of estrogen plus progesterone seems to increase breast cancer risk more that estrogen alone, but estrogen alone increases the risk of uterine cancer. In contrast, postmenopausal hormones may lower a woman’s risk of colon cancer and osteoporosis (bone loss). Postmenopausal hormones were once thought to lower the risk of heart attack, but it is now unclear exactly how they affect the risk of heart disease.
People who take aspirin regularly for more than 15 years have a lower risk of colon cancer. One possible explanation is that aspirin prevents abnormal growths (polyps) by blocking the production of certain chemicals in the body.
Aspirin has both risks and benefits. It can lower the risk of colon cancer and heart attack, but it can raise the risk of stroke. Aspirin is also sometimes linked to bleeding in the stomach, intestine and brain. Talk to a doctor about aspirin's risks and benefits before taking it regularly.
Inflammatory Bowel Disease
Inflammatory bowel disease (IBD) is caused by abnormal changes in the digestive tract. The two main types are Crohn's disease and ulcerative colitis.
People who have inflammatory bowel disease for 10 or more years have a higher risk of colon cancer. This is probably because IBD causes cells in the colon to grow and divide too quickly. If DNA damage occurs during this process, it may lead to colon cancer.
People who have a close relative (mother, father, brother or sister) with colon cancer have a higher risk of the disease. This is because some colon cancer is linked to mutations (changes) in the genetic structure (DNA) of the body's cells that can be passed from generation to generation.
People with a family history of colon cancer may need to get screening tests for the disease earlier and more often than most people. Click here for more on family history and colon cancer screening.
People who get screened regularly for colon cancer have a lower risk of the disease. Screening tests can prevent colon cancer by finding polyps (abnormal growths) before they have a chance to grow and spread.
Click here for more information on colon cancer screening.
To assess your risk for colon cancer and get tips for reducing that risk, visit the Your Disease Risk website.