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The Link Between Colorectal Cancer and Obesity

In 2000, President Clinton Declared March as National Colorectal Cancer Awareness Month. Did you know colorectal cancer (cancers of the colon and/or rectum) is the third most common cancer — excluding skin cancers — found in both men and women in the U.S.? About one in 20 people will develop colorectal cancer in his or her lifetime.

There are many health and lifestyle factors that can increase one’s risk of developing cancer, and obesity is one of them. According to The National Cancer Institute, obesity is associated with increased risks of several types of cancer, including colorectal cancer.

According to a review on studies about obesity and colorectal cancer, people who are obese are slightly (about 30 percent) more likely to develop colorectal cancer than normal-weight people. A higher BMI is associated with increased risks of colon and rectal cancers in both men and in women, but the increases are higher in men than in women.

Recently, researchers at Thomas Jefferson University examined the link between colorectal cancer and obesity and published their findings in Cancer Research. The scientists’ findings suggest that the culprit for the link is excess calories.

“These findings came as a surprise — we and many other researchers worldwide have been trying to disentangle obesity from development of colorectal cancer,” says the study’s senior author, Scott Waldman, M.D. Ph.D., Chair of Pharmacology & Experimental Therapeutics at Sidney Kimmel Medical College of Thomas Jefferson University. “Calories sit in the middle of these two conditions, but the question of what they were doing has been one of the most perplexing and provocative questions in cancer research. Now we finally have a big clue as to the origin of colorectal cancer in obese individuals and perhaps in other people as well,” says Dr. Waldman.

Other risk factors of colorectal cancer

According to the American Cancer Society, in addition to obesity, some of the other risk factors for colorectal cancer include:

  • Physical inactivity
  • Diet that is high in red meats or processed meats
  • Cooking meats at high heat (frying, broiling, grilling)
  • Smoking
  • Heavy alcohol use
  • Age (risk increases with age)
  • Personal history of polyps or colorectal cancer
  • History of inflammatory bowel disease (IBD)
  • Family history of colorectal cancer
  • Racial and ethnic background (people who are African American or Ashkenazi are at higher risk)
  • Type 2 diabetes
  • Some hereditary syndromes

The big danger with colorectal cancer is that many people will not experience symptoms in the early stages of the disease. It’s often not until the cancer grows and develops that symptoms appear. Possible symptoms for colorectal cancer include:

  • Change in bowel habits
  • Constant feeling of needing to have a bowel movement, even after doing so
  • Blood in the stool, dark stools, rectal bleeding
  • Cramping or stomach pain
  • Weakness or tiredness
  • Unexplained weight loss
  • Low red blood cell count

Although most of these symptoms can have another causes unrelated to colorectal cancer, if you do experience any of these symptoms, you should see your doctor.

The exact cause of most colorectal cancers not be fully known, but changing high-risk lifestyle factors, such as diet and exercise, weight loss and getting regular cancer screenings can help prevent you from developing colorectal cancer.

By Nick Nicholson, MD

About the Author

One of the most experienced weight loss surgeons in the country — Dr. Nick Nicholson — along with a full staff of surgeons, nurses and other experienced clinicians, help patients reverse obesity with LAP-BAND, Gastric Bypass, Sleeve Gastrectomy, Gastric Balloon and Revisions.

Copyright 2016 WFAA


Related: BMI Calculator for Men, Women & Kids

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