Excluding skin cancers, colorectal cancer, also referred to as bowel or colon cancer depending on where it originally begins, is the third most common cancer diagnosed across the United States. In fact, according to the American Cancer Society, the risk of developing colorectal cancer is about one in 24 for men and one in 25 for women in the U.S.

And although the exact cause is currently unknown, there are some factors that can potentially put someone at an increased risk of developing it, these include:

  • Genetic conditions
  • Digestive disorders
  • Obesity
  • Excessive use of alcohol
  • Smoking
  • Family history
  • Age

See also: What is the Function of the Bowel?

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What are the risk factors for bowel cancer?

A risk factor is something that can increase a person's chance of developing a certain condition or disease. Remember, having a risk factor doesn't mean you are guaranteed to contract something; some people may not have any known risk factors and still get the disease.

With that said, there are several risk factors that researchers found may increase a person's chance of developing colorectal cancer or bowel cancer.

See also: What Affects Bowel Function?

Genetic conditions

According to the NHS [1], there are two inherited conditions that may lead to bowel cancer:

  • Familial adenomatous polyposis (FAP): FAP can trigger the development of non-cancerous growths inside the bowel or colon from a young age.

  • Hereditary non-polyposis colorectal cancer (HNPCC): Also referred to as Lynch syndrome, HNPCC is a genetic mutation that can increase the risk of developing bowel cancer.

Digestive disorders

Bowel cancer is more common in those with chronic inflammation and inflammatory bowel diseases (IBD) such as Crohn’s disease or ulcerative colitis for more than 10 years. If you have IBD your doctor may recommend getting screened younger and more often.


More than 1 in 20 cancers are caused by excess weight, with bowel cancer being one of them [2]. The good news is there are small lifestyle changes that can be made to ensure you stick to a healthy weight; these can make a difference to your overall health and may help lower your chances of developing bowel cancer.

Excessive use of alcohol

Alcohol use is linked to an increased risk of bowel cancer, particularly if you drink regularly or drink large amounts. If you drink alcohol, The American Cancer Society recommends drinking no more than 2 drinks a day if you’re male and 1 drink a day if you’re female [3].


Smoking is commonly associated with lung cancer, but it also has a strong link to other cancers - bowel cancer included. If you smoke and would like to hear more about quitting, read our guide to what happens when you quit smoking.

Family history

Having a close family relative who has had bowel cancer can increase your risk of developing the condition. If you’re concerned about your family history and bowel cancer, it’s important to reach out to your family doctor to discuss further.


Your risk of contracting bowel cancer increases as you get older. In fact, according to The Centers for Disease Control and Prevention estimate that about 90% of cases occur in people who are aged 50 years or older [4].

What is the number one cause of bowel cancer?

The exact cause of bowel cancer still goes unknown but it typically begins when there is a growth on the inner lining of the colon, bowel, or rectum. These growths are perhaps better known as polyps; these can sometimes turn into cancer over a long period of time but not always.

If you are concerned about your bowel cancer risk, it's important to speak with your healthcare provider.

LetsGetChecked’s at-home Bowel Cancer Screening Test can help identify the presence of cancerous or precancerous growths in the bowel by detecting blood that is invisible to the naked eye.

You should consider getting screened if:

  • You are experiencing gastrointestinal symptoms
  • You have a history of adenomas (benign tumors)
  • You have inflammatory bowel disease* (which includes Crohn's disease and ulcerative colitis)
  • You have an inherited syndrome (e.g. Lynch syndrome/HNPCC or FAP)
  • You have type 2 diabetes
  • You have undergone radiation therapy

If you have already noted blood in the stool, or any other symptoms listed, you should talk to your physician.

See also: How Can You Screen For Bowel Cancer From Home?

Add descriptive tag

Buy an At-Home Bowel Cancer Screening Test

Our test can help identify the presence of cancerous or precancerous growths in the bowel.


  1. NHS. Bowel cancer. Online: Nhs.uk, 2019
  2. Cancer Research UK. Does obesity cause cancer? Online: Cancerresearchuk.org, 2018
  3. American Cancer Society. Colorectal Cancer Risk Factors. Online: Cancer.org, 2020
  4. Centers for Disease Control and Prevention. What Are the Risk Factors for Colorectal Cancer? Online: Cdc.gov, 2020