Causes and risk factors for early-onset colorectal cancer
- genetic condition Inherited physical problems, such as Lynch syndrome and familial adenomatous polyposis (which can result in hundreds of polyps in the colon), increase the likelihood of developing colorectal cancer, especially at a young age.
The World Colon Cancer Society estimates that 16 to 25 percent of early-onset cases are associated with genetic syndromes, whereas only up to 10 percent of common colorectal cases are associated with genetics.
- Racial and ethnic background In the United States, American Indians and Alaska Natives have the highest rates of colorectal cancer, followed by black men and women. Eastern European Jews (Ashkenazi Jews) are also at increased risk compared to other ethnic groups. About 6 percent have certain genetic mutations that double their risk of developing colorectal cancer.
- Other health-related issues Certain health-related conditions may contribute to the risk of colorectal cancer, including a family history of colorectal cancer, a personal history of radiation to the abdominal or pelvic area, a personal history of inflammatory bowel disease (Crohn’s disease or ulcerative colitis), and a history of cholecystectomy (cholecystectomy).
- toxins in the environment Researchers are studying whether exposure to chemicals may play a role in colorectal cancer. Exposure to chemicals (such as air and water pollution, chemicals in soil and food, and the use of pesticides) can damage the DNA of intestinal cells and cause cancer-causing mutations.
Modifiable risk factors
According to two research studies, one-third to one-half of early-onset colorectal cancer cases are attributable to modifiable risk factors, including:
obesity Early-onset colorectal cancer is associated with obesity, but the exact mechanisms are still not fully understood. Excess fat is associated with inflammation and can increase your chances of developing cancer. Obesity is also associated with insulin resistance, diabetes, increased production of the hormone leptin, and gut hormonal imbalances, all of which are linked to increased cancer risk.
unhealthy eating habits Colorectal cancer is associated with eating red meat (such as beef, pork, lamb, and liver) and processed meat (such as hot dogs and some lunch meats). Research has also found that sugary drinks may be to blame.
lack of exercise Research has well established that physical inactivity and sedentary behavior are risk factors for colorectal cancer. Lack of exercise can lead to weight gain, insulin resistance, and inflammation.
smoking A study of more than 700 adults under 55 with colorectal cancer found that former smokers had a 139 percent higher risk of developing colorectal cancer than nonsmokers in the same age group. For people who currently smoke, the risk is 150% greater.
alcohol use Moderate to heavy alcohol consumption is a known risk factor for colorectal cancer. Consuming alcohol can damage the intestinal lining, allowing bacteria and toxins to invade other tissues in the body. A scientific study of more than 8,000 colorectal cancer patients aged 20 to 49 found an increased risk associated with alcohol consumption. Compared to non-drinkers, those who drank one to two drinks a week had a 7% higher risk. Those who drank three to four drinks a week had a 14% higher risk, and those who drank five or more had a 27% higher risk.
