Excess weight risk factor in some cancers in U.S., according to CDC report

After struggling for years to lose weight, Elaine Nealious finally got her insurance company to approve gastric bypass surgery at University Hospital last August and has since dropped more than 100 pounds. While Nealious’ decision and determination have always been about improving her health and quality of life, that it might also reduce her risk of cancer is an added bonus.


“Cancer is prevalent on both sides of my family,” said Nealious, 52. “That is just more confirmation that what I did a year ago was for life for me.”

Being overweight or obese is a risk factor in 13 cancers that made up 40 percent of cancers in the U.S. in 2014, the Centers for Disease Control and Prevention reported Tuesday in its monthly Vital Signs report. It is involved in two out of three cancer cases in people ages 50-74, according to the report. There have been well-known associations between excess weight and an increased risk of heart disease, stroke and diabetes, said Dr. Anne Schuchat, principal deputy director of the CDC.

“But more than half of Americans are not aware that excess weight can increase the risk of many cancers,” she said.

The toll is worse in women, with 55 percent of cancers having a link to excess weight versus 24 percent in men. Cancers associated with excess weight, excluding colorectal cancer, increased seven percent between 2005 and 2014, while those not associated with excess weight declined 13 percent.

The study did not specifically look at the mechanism by which overweight or obesity increases that risk, but endocrine changes associated with excess weight are linked to some cancers and the resulting inflammation is “extremely important” in increasing that risk, said Dr. Lisa Richardson of the CDC Division of Cancer Prevention and Control.

Researchers at Georgia Cancer Center at Augusta University have different views on whether those inflammatory links can be used to prevent cancer. Dr. Satya Ande has studied the role of obesity in liver cancer and has looked at whether certain genes are more likely to promote that cancer or not in a mouse model of obesity. While obesity is well-known to increase the risk of liver cancer, it is probably not just one mechanism, he said. The excess fat creates a low-grade inflammation that can cause a lot of chemical messengers known as cytokines to be released.

“And most of the cytokines have the ability to promote cancer,” Ande said. “There is no one silver bullet. They all work together.”

But his colleague Dr. Ahmed Chadli disagrees. He has long worked on a molecule important in cancer cell proliferation and recently discovered it also has a role in fat accumulation. “We have this molecule that is very important for cancer, but at the same time, is very important for the accumulation of the white fat” associated with obesity, Chadli said. “We think of it as this molecule that makes this link between the accumulation of fat and the promotion of cancer.” He is currently seeking a grant to continue exploring this link.

Whether losing weight also reduces the risk for these cancers is not yet clear from the scientific evidence, Schuchat said.

“We do know that even modest weight loss can help when it comes to lowering the risk of other chronic diseases, like diabetes and heart disease,” she said. Richardson points to a study published earlier this year from the Women’s Health Initiative that found postmenopausal women who lost weight, particularly those who had been obese, had a lower risk of endometrial cancer. The literature has shown calorie restriction suppresses tumor growth and weight loss does significantly reduce inflammation, Ande said.

Weighing as much as 300 pounds before her surgery took its toll on Nealious, an office specialist at Augusta University.

“Before, I could get through what I was doing, but once I made it home, all I could do was collapse in a chair because I would be so physically tired because of the excess weight,” she said. She struggled at times to do even simple things like tie her own shoes. But now she feels “reborn” after all her weight loss, with much better sleep and better quality of life overall.

“Just that energy, being able to get up and go, is an amazing thing, it is a wonderful thing,” Nealious said. “It’s not about the size, it is about the health for me.”

Pancreatic cancer has already claimed her grandfather, and breast cancer has killed a couple of her nieces and a couple of cousins, she said. Her family has been through enough, Nealious said.

“Losing two nieces not even a year apart, it’s a tough thing,” she said. “Cancer wreaks havoc on people.”