Every organ in our body ages at a different pace. Researchers now say around 18% of healthy adults above the age of 50 face accelerated aging in at least one of their organs.

A study, led by researchers from Stanford Medicine, suggests that with a simple blood test, it might be possible to detect accelerated aging of an organ that elevates disease risk and mortality.

"We can estimate the biological age of an organ in an apparently healthy person. That, in turn, predicts a person's risk for disease related to that organ," said the study's senior author, Tony Wyss-Coray.

"Numerous studies have come up with single numbers representing individuals' biological age — the age implied by a sophisticated array of biomarkers — as opposed to their chronical age, the actual numbers of years that have passed since their birth," Wyss-Coray said.

However, the team took a step further by identifying the biological age of each of the 11 key organs and organ systems – heart, fat, lung, immune system, kidney, liver, muscle, pancreas, brain, vasculature, and intestine.

"When we compared each of these organs' biological age for each individual with its counterparts among a large group of people without obvious severe diseases, we found that 18.4% of those age 50 or older had at least one organ aging significantly more rapidly than the average," Wyss-Coray said.

The study evaluated 5,678 participants. The results showed that only 1 in 60 participants had two organs aging at an accelerated rate. Accelerated aging of two organs raises the mortality risk by 6.5 times.

"Using commercially available technologies and an algorithm of their own design, the researchers assessed the levels of thousands of proteins in people's blood, determined that nearly 1,000 of those proteins originated within one or another single organ, and tied aberrant levels of those proteins to corresponding organs' accelerated aging and susceptibility to disease and mortality," the researchers explained.

The research team estimated an "age gap" for each organ. Age gap refers to the difference between an organ's actual age and the age estimated based on the algorithm's organ-specific-protein-driven calculations. The identified age gaps, except that of intestine, were significantly associated with future risk of death from all causes.

Having an accelerated aging organ raises the mortality risk from 15% to 50% over the next 15 years, researchers said. The mortality risk depends on the organ that was affected.

While accelerated heart aging elevated heart failure risk by 2.5 times, brain aging raised the risk of cognitive decline by 1.8 times.

Researchers say if verified in a larger population, it could help predict organ failure and disease risk even before symptoms appear.

"If we can reproduce this finding in 50,000 or 100,000 individuals, it will mean that by monitoring the health of individual organs in apparently healthy people, we might be able to find organs that are undergoing accelerated aging in people's bodies, and we might be able to treat people before they get sick," Wyss-Coray said.

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