Obesity has long been associated with an increased risk for certain types of cancer. Now, recent research from the National Institute on Aging, in Bethesda, MD, reveals new information about just what types of fat are most likely to cause cancer – and who should be most worried.
In a study published in the journal Applied Physiology, Nutrition, and Metabolism, researchers became the first to use direct radiographic imaging of adipose (fat) tissue in order to analyze the relationship between levels of body fat and cancer.
Previous studies often used body mass index (BMI), or waist circumference, to analyze the relationship between adiposity and cancer, but study author Dr. Rachel Murphy said that these methods are often an inaccurate way to measure body fat. For example, a person who is shorter and very muscular may weigh enough that their BMI would categorize them as overweight or obese – despite the fact that they actually have very little body fat.
“Radiographic imaging is a lot more precise than waist circumference or BMI…and is the gold standard of body composition analysis,” Murphy, a researcher at the National Institute on Aging, told FoxNews.com. “…These images allow people to differentiate precise amounts of muscle and adipose tissue.”
For the study, researchers analyzed radiographic imaging of body fat in 2,519 older adults who were involved in the Health, Aging, and Body Composition Study – a prospective, population-based study supported by the National Institute on Aging.
All study participants underwent imaging to measure for total body fat, body fat within the abdomen and thigh, subcutaneous fat and visceral fat – or fat around the internal organs. Researchers then tracked the individuals for 13 years, in order to monitor for any incidences of cancer.
Overall, researchers found that both men and women with greater body fat had an increased risk of developing cancer, regardless of their BMI. In fact, researchers found that high body fat held an increased risk for many types of cancers – even beyond those categorized as obesity-related by the National Cancer Institute.
Most notably, Murphy and her colleagues discovered that men with elevated levels of visceral fat had a particularly high risk of cancer, compared to men with low levels of visceral fat. According to the study, men with this type of fat had a threefold greater risk of developing certain types of cancers – including those of the esophagus, pancreas, colon and rectum, kidney, thyroid, and gallbladder.
“In men, visceral adipose tissue is quite strongly related to the obesity-related cancers,” Murphy said. “Even in models adjusted for body mass index, that risk remains.”
Murphy said that her research points out the importance of maintaining a healthy diet and body weight in order to reduce the risk of cancer. In the future, she hopes to expand her study of obesity and cancer risk in order to assess lifetime risks associated with weight.
“I think it’s important to analyze changes over time to understand how weight fluctuations can impact risk, and if there are cumulative effects,” Murphy said.