They found an unmistakable trend of cancer in people whose epigenetic, or biological age, is greater than their chronological age.
Biological age is determined by how well your body functions, and is influenced by a wide variety of physical and emotional factors. For example, if you are overweight, suffer chronic stress or just look old, that can increase your biological age.
When your biological age is greater than your actual age, researchers say, you are at a greater risk of developing cancer. The bigger the difference between the two ages, the higher your risk of dying of cancer.
Early cancer warning
"This could become a new early warning sign of cancer," senior author Dr. Lifang Hou said in a release. "The discrepancy between the two ages appears to be a promising tool that could be used to develop an early detection blood test for cancer."
Hou is chief of cancer epidemiology and prevention in preventive medicine at the Northwestern University Feinberg School of Medicine and co-leader of the cancer prevention program at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University.
"People who are healthy have a very small difference between their epigenetic/biological age and chronological age," Hou said. "People who develop cancer have a large difference and people who die from cancer have a difference even larger than that. Our evidence showed a clear trend."
For every year the biological age is greater than the actual age, the researchers found a 6% increased risk of getting cancer within three years and a 17% increased risk of dying from cancer within five years.
Difference of three years could be lethal
People in the study who got cancer had a biological age of about six months greater than their chronological age. Those who will die of cancer are about 2.2 years older, the study found.
Hou says a person's epigenetic age is calculated using an algorithm measuring 71 blood DNA methylation markers. These markers are subject to change by factors such as a person's environment, including environmental chemicals, obesity, exercise, and diet.
There isn't a commercially available test, but the subject is the focus of study by academic researchers, including a team at Northwestern. There are a number of online tests that may be subject to varying degrees of accuracy, like this one. They may be useful to give you an idea of where you fall on the biological age spectrum.
Hou says a highly accurate test would use DNA methylation, where a cluster of molecules attaches to a gene and makes the gene more or less receptive to biochemical signals from the body.
A first
The Northwestern researchers say that their study is the first to link the difference between biological and chronological age with both cancer development and cancer death using multiple blood samples. They say the multiple samples, which showed changing biological age, allowed for more accurate measurements of cancer risk.
Last summer InsideTracker, which operates the InnerAge platform that offers a biological age test, reported most Americans are actually older than their biological age.
The company's survey found 60% of users are an average of 3.13 years older in real terms than their chronological age, yet most were clueless about this fact.