A ticking time bomb may be hiding inside your body—and a new, simple blood test could reveal whether you’re at risk.
Scientists have discovered that specific organs in the human body can age prematurely, up to 15 years faster than the rest. This accelerated aging increases the chances of developing diseases such as heart failure and Alzheimer’s within a few years.
“The major advance from our study is that we show that we can now measure the biological age of your organs with a blood test,” Hamilton Se-Hwee Oh, co-lead author and a student in the graduate program in Stem Cell and Regenerative Medicine at Stanford University, told The Epoch Times.
The findings could inspire a personalized approach to medicine that targets high-risk organs before they trigger systemic deterioration.
‘Old’ Vital Organs Increase Disease Risk
One in 5 people harbor these risky “old organs,” according to the new study published in December 2023 in Nature. Major organs can age at different rates from the body as a whole, and these prematurely aged organs are associated with significantly greater disease risk.
Researchers made this discovery by first identifying organ-specific proteins in blood samples. They then trained a machine learning algorithm to correlate protein levels with organ age.
Levels substantially different from those of similarly aged people predicted health problems were on the horizon.
The study examined 11 major organs, concluding that all are susceptible to accelerated aging. Twenty percent of the more than 5,600 participants had at least one rapidly aging organ, and almost 2 percent had more than one.
People with accelerated heart aging had 2.5 times the risk of heart failure. Those with older brains were nearly twice as likely to experience cognitive decline over five years. Accelerated brain and vascular aging predicted Alzheimer’s progression as accurately as existing biomarkers.
The study also found that extreme kidney aging correlated strongly with hypertension and diabetes. Older heart scores indicated a higher risk of atrial fibrillation and heart attack. Only the intestine appeared to lack a correlation between accelerated aging and all-cause mortality over 15 years.
Factors Linked to Accelerated Organ Aging
The study identified factors tied to accelerated organ aging, especially in the heart and brain, Mr. Oh said.
High Troponin Levels
Regarding the heart, people with “older” hearts had higher cardiac troponin levels. This protein indicates heart failure but also rises in seemingly healthy people as they age.
Mr. Oh said that the health care system as we know it is more like “sick care.”
“So you come into the doctor’s office; you either have heart failure or you don’t, and we measure this protein,” he said. “But maybe what we should be doing is monitoring the level of this protein and many other proteins throughout the healthy aging process.”
Tracking the protein over time could reveal accumulating damage and future heart failure risk.
Neuronal Connection, Not Number, Matters
The brain has long been considered inaccessible behind the blood-brain barrier, which blocks toxins from entering and affecting cognitive function. However, the study found that numerous proteins actually pass from the brain into the bloodstream.
These proteins originate in synapse neurons, which enable cognitive function and reflect brain aging. Analyzing blood levels could, therefore, reveal coming cognitive impairment risks, Mr. Oh said.
One such protein is neurofilament, which is part of the neuron structure. Conventional thinking is that changes in neurofilament signal neuron death. However, the study uncovered a different mechanism that mattered more: deteriorating connections between neurons.
“So even if you have fewer neurons, let’s say, in your brain—as long as they’re making stable connections with the other neurons,” Mr. Oh said, “maybe you can keep your cognitive functioning.”
Biological Versus Chronological Age
Chronological age merely tracks years lived. But biological age—measured via blood proteins—reveals underlying organ health, Mr. Oh said.
People of the same age can differ drastically in biological aging. This new blood test characterizes biological age across bodily systems. Although two 50-year-olds may have similar skin aging, for example, one may have a much older brain, Mr. Oh said.
“This, of course, has huge implications for which patients are at risk for which diseases so we can help monitor them in a clinical trial design,” he said. “No one has really looked at aging from this lens of the whole body as a connection of multiple and crucial organ systems.”
However, with a little more than 5,600 participants, the study has limitations. Mr. Oh’s team is now assessing UK Biobank data from 50,000 people to address this.