A new study from the Stanford University School of Medicine have found that they are able to categorize individuals into different classes based on how they age.
“We know already there are a handful of nice molecular and clinical markers, such as high cholesterol, that are more common in older populations,” said Michael Snyder, Ph.D., professor and chair of genetics. “But we want to know more about aging than what can be learned from population averages. What happens to an individual as they age? No one has ever looked at the same person in detail over time.”
Snyder and his team profiled a group of 43 healthy men and women between the ages of 34 and 68. They then took extensive measurements of their molecular biology at least five times over two years.
The team ultimately determined that people generally age along certain biological four main pathways in the body: metabolic, immune, hepatic (liver) and nephrotic (kidney).
For instance, people who are metabolic agers, may be at a higher risk for diabetes or show signs of elevated hemoglobin A1c, a measure of blood-sugar levels, as they grow older, according to the study.
However, people with an immune ageotype might generate higher levels of inflammatory markers or be more prone to immune-related diseases as they age. But these ageotypes are not mutually exclusive. A metabolic ager could also be an immune ager, for example, according to Medical Xpress.
The study took several varieties of biological samples to track levels of certain microbes and biological molecules, such as proteins, metabolites and lipids, in participants over two years, monitoring how the levels changed over time.
“Our study captures a much more comprehensive view of how we age by studying a broad range of molecules and taking multiple samples across years from each participant,” Snyder said. “We’re able to see clear patterns of how individuals experience aging on a molecular level, and there’s quite a bit of difference.”
“The ageotype is more than a label; it can help individuals zero in on health-risk factors and find the areas in which they’re most likely to encounter problems down the line,” Snyder said. “Most importantly, our study shows that it’s possible to change the way you age for the better. We’re starting to understand how that happens with behavior, but we’ll need more participants and more measurements over time to fully flesh it out.”
Snyder pointed out that just because an individual falls along one of the ageotypes, that doesn’t mean that is that end-all, be-all of the matter, It’s just the type that is most pronounced.
The study also looked at differences in aging between healthy participants and participants who are insulin-resistant, or cannot properly process sugar. “The differences in aging between healthy and insulin-resistant folks is something that’s never been looked at before,” Snyder said. “Overall, we found there were about 10 molecules that significantly differed between insulin-sensitive and insulin-resistant folks as they aged.” Many of those markers were involved in immune function and inflammation, according to Medical Xpress.
One of the most exciting things the study found was that not everyone in the study showed an increase in ageotype markers over time. For some people, their markers decreased, at least for a short period, when they changed their behavior. the overall rate at which they aged actually declined, and in some cases aging markers decreased.
Snyder said there were individuals who made lifestyle changes to slow their aging rate. In other cases, exactly why rates of aging markers waned was unclear. For some people, there were no obvious behavioral changes, yet the team still saw a decreased rate of aging along their ageotype pathways. There was also a handful of people that maintained a slower-than-average aging rate throughout the entire study, but why or how remains a mystery.
A paper describing the study will be published Jan. 13 in Nature Medicine. Snyder is the senior author. Stanford postdoctoral scholar Sara Ahadi, Ph.D., and bioinformaticist Wenyu Zhou, Ph.D., share lead authorship.