A risk factor is any factor that is associated with increasing someone’s chances of developing a certain condition, such as cancer. Some risk factors are modifiable, such as lifestyle or environmental risk factors, and others cannot be modified, such as inherited factors or whether someone in the family has had cancer.
Having one or more risk factors does not mean you will develop cancer. Many people have at least one risk factor but will never develop cancer, while others with cancer may have had no known risk factors. Even if a person with cancer has a risk factor, it is usually hard to know how much that risk factor contributed to the development of their disease.
Bowel cancer risk factors
Both men and women are at risk of developing bowel cancer. The risk is greater if you:
- are aged 50 years and over – your risk increases with age
- have had an inflammatory bowel disease, such as Crohn's disease or ulcerative colitis
- have previously had special types of polyps, called adenomas, in the bowel
- have a significant family history of bowel cancer or polyps.
Other risk factors include:
- Excess body fat and physical inactivity
- High intake of particular foods (such as processed meat)
- High alcohol consumption
- Some gene mutations.
Anyone, including younger people, with concerns about their risk of developing bowel cancer should talk to their doctor.
Healthy lifestyle and risk reduction
The following modifiable lifestyle factors can reduce your risk of developing bowel cancer.
Cancer Australia recommends not smoking and avoiding exposure to second-hand smoke to reduce cancer risk.
Overweight and obesity
Cancer Australia recommends achieving and maintaining a healthy body weight within a BMI range of 18.5 to 25 kg/m2 to reduce cancer risk and a waist circumference below 94 cm for men and below 80 cm for women.
Cancer Australia recommends aiming for at least 30 minutes of moderate-intensity physical activity every day and limiting sedentary habits, such as watching television, to reduce cancer risk.
Cancer Australia recommends consuming adequate dietary fibre, including unprocessed cereals (grains) and pulses (legumes), and aiming for five servings of vegetables and two servings of fruit per day. Cancer Australia recommends limiting intake of red meat to less than 500 g per week and avoiding processed meat to reduce cancer risk. Cancer Australia recommends limiting intake of salt and processed foods with added salt to reduce cancer risk.
The lifetime risk of harm from drinking alcohol increases with the amount consumed2. For healthy men and women, drinking no more than two standard drinks on any day reduces the lifetime risk of harm from alcohol-related disease or injury.
On the basis of international evidence specific to cancer3, it is recommended that if alcoholic drinks are consumed, women further limit alcohol consumption to one standard drink, to reduce cancer risk.
Find out more:
- Lifestyle and risk reduction
- Check Your Cancer Risk - online tool
- Position Statement on Lifestyle risk factors and the primary prevention of cancer
- Australian Cancer Network Colorectal Cancer Guidelines Revision Committee (2005). Guidelines for the prevention, early detection and management of colorectal cancer. Sydney: The Cancer Council Australia and Australian Cancer Network.
- National Health and Medical Research Council. Australian Guidelines to Reduce Health Risks from Drinking Alcohol. Canberra: NHMRC, 2009.
- World Cancer Research Fund / American Institute for Cancer Research. Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective. Washington, DC: AICR, 2007.
- National Cancer Institute (2014). Colon cancer treatment (PDQ®) http://cancer.gov/cancertopics/pdq/treatment/colon/Patient.