For many years medical science has been working to discover if obesity increases the risk of getting cancer. Finally, this effort seems to be paying off.
OBESITY AND CANCER
FIRST FIVE CANCERS LINKED TO OBESITY
Initially, growing evidence from numerous studies strongly linked obesity to these five cancers: adenocarcinoma (a common cancer) of the esophagus; colorectal cancer; breast cancer in post-menopausal women; and uterine and kidney cancers.
IARC STUDY ON CANCER, 2016
In June, 2016, the IARC (International Agency for Research on Cancer), part of the the World Health Organization, convened a work group to review over 1,000 studies studying the risk of developing cancer posed by obesity. They found solid evidence that obesity increases the risk for at least 13 cancers, adding another eight to the first five. These additional cancers are: gastric cardia (a cancer of the part of the stomach closest to the esophagus); liver cancer; gallbladder cancer; pancreatic cancer; thyroid cancer, ovarian cancer; meningioma (usually a benign type of brain tumor), and multiple myeloma—a blood cancer.
At a recent interview, Dr. Graham Colditz, chairman of the working group that conducted the review, said, “only smoking comes close” to obesity as a behavioral factor affecting cancer risk.
An executive summary of these findings can be found in The New England Journal of Medicine, August, 2016. (Note: This article is available to subscribers or may be purchased, but it is not yet free to the general public.)
DOES LOSING WEIGHT REDUCE CANCER RISK?
Research on this issue is limited. There is, however, some evidence that weight loss may reduce the risk of after-menopause breast cancer, and possibly some other cancers, too. This may be so because people who intentionally lose weight also reduce their levels of certain hormones that are related to cancer risk, such as insulin, estrogens, and androgens (male hormones). Losing weight can have other benefits, as well, such as lowering the risk of heart disease and diabetes.
For more information:
• well.blogs.nytimes.com - Basis for this article
• nejm.org - New England Journal of Medicine: 2003 article re: relationship between obesity and cancer.
• cancer.org - Last reviewed: 4/24/15. Last revised: 2/5/16
• publichealth.wustl.edu - Dr. Graham Colditz: public health background
• wikipedia.org - Dr. Graham Colditz: professional bio