Research has shown that environment can play a big part in colon cancer development. Where you live, who's around you, your occupation, and even when you work may all influence your risk of developing colon cancer.
Where You Live
Studies indicate that colon cancer rates are lowest in Kuwait, India, and Romania and highest in America, Switzerland, and Canada. But, it isn't clear how much environmental factors impact that risk as opposed to other factors, like culture and cancer screening.
Radiation exposure also influences colon cancer risk. According to the U.S. Department of Health and Human Services, colon cancer has been caused by doses of about 1,000 millisieverts (mSv). About 80% of our radiation exposure comes from natural, unavoidable sources. The good news is it's pretty difficult to rack up 1,000 mSv from the environment. (Learn more about radiation exposure and colon cancer risk.)
Who's Around You
You're probably already aware that exposure to cigarette smoke doesn't exactly do wonders for your health. The U.S. Surgeon General has declared that involuntary exposure to second-hand smoke causes premature death and disease in children, as well as in adults who don't smoke. We know that smoking increases colon cancer risk, but scientists aren't sure if inhaling second-hand smoke can cause colon cancer.
Your Occupation
Some studies indicate that asbestos workers are at increased risk for colon cancer; others indicate they aren't. After assessing 120 studies of asbestos exposure and cancers of the throat and digestive tract, the Institute of Medicine determined that the evidence was suggestive but insufficient to infer a link. In English: seems like asbestos exposure might cause colorectal cancer, but they can't say for sure. (Learn more about asbestos exposure and colon cancer risk.)
When You Work
Research published in the Journal of the National Cancer Institute determined that working the night shift increased colon cancer risk. They explained that it may have something to do with lack of exposure to natural light. The results haven't been duplicated though, so it's hard to say if working the night shift really can increase your risk of developing colon cancer.
Bottom Line
The impact of environment on colon cancer risk isn't very clear. But, you can use what exists to make informed health decisions. For example, if you're an American asbestos employee who works the late shift and lives in a house of smokers, well, you might want to make colon cancer screening a priority. Few people will actually fit that description, but you get the idea. If you think you're in an environment that may increase your risk of developing colon cancer, please talk to your doctor about it.
Sources:
Colorectal Cancer Prevention and Treatment. National Foundation for Cancer Research. 23 Jun. 2006 [http://www2.nfcr.org/site/PageServer?pagename=cancers_colorectal].
Detailed Guide: Colon and Rectum Cancer: What Are the Risk Factors for Colorectal Cancer? American Cancer Society. 7 Mar. 2006. 23 Jun. 2006 [http://www.cancer.org/docroot/CRI/content/CRI_2_4_2X_What_are_the_risk_factors_for_colon_and_rectum_cancer.asp].
Institute of Medicine of the National Academies. Asbestos Exposure Linked to Cancer of the Larynx; Evidence About Links to Cancer of the Digestive Tract is Less Clear. 6 Jun. 2006. 10 Jun. 2006 [http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=11665].
Overview: Colon and Rectum Cancer: What Causes Colorectal Cancer? American Cancer Society. 15 Mar. 2006. 23 Jun. 2006 [http://www.cancer.org/docroot/CRI/content/CRI_2_2_2X_What_causes_colorectal_cancer.asp?sitearea=].
Schernhammer, E. and Laden, F. "Night-Shift Work and Risk of Colorectal Cancer in the Nurses' Health Study." Journal of the National Cancer Institute 95.11 (Jun. 2003): 825-828. 26 Aug. 2006 [http://jncicancerspectrum.oxfordjournals.org/cgi/content/full/jnci;95/11/825].
The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General. U.S. Department of Health and Human Services. 27 Jun. 2006. 28 Jun. 2006 [http://www.surgeongeneral.gov/library/secondhandsmoke].
U.S. Surgeon General Releases Report on the Effects of Secondhand Smoke. NCI Cancer Bulletin. 27 Jun. 2006. 28 Jun. 2006 [http://www.cancer.gov/ncicancerbulletin/NCI_Cancer_Bulletin_062706/page10].
