A simple blood test could help predict who is likely to live longer, according to new research.
The study, led by Duke Health in collaboration with the University of Minnesota, found that small RNA molecules, known as piRNAs, can accurately predict whether older adults are likely to survive at least two more years.
As people age, it becomes increasingly difficult to determine who is on track for healthy years ahead and who may be at higher risk of serious decline.
The researchers said their work, published in the journal Aging Cell, points to a potential new tool: a minimally invasive blood test that could identify short‑term survival risk earlier and help guide interventions to promote healthy aging.
“The combination of just a few piRNAs was the strongest predictor of two-year survival in older adults—stronger than age, lifestyle habits, or any other health measures we examined,” said paper author and Duke professor Virginia Byers Kraus, in a statement. “What surprised us most was that this powerful signal came from a simple blood test.”
PiRNAs are small RNA molecules previously known for their role in regulating development, regeneration and immune function. In this study, the research team measured piRNA levels in blood samples from adults aged 71 and older. They found that lower levels of certain piRNAs were strongly associated with longer survival.
To reach their conclusions, the scientists used advanced causal artificial intelligence and machine‑learning techniques to analyze 187 clinical factors and 828 different small RNAs across more than 1,200 blood samples.
The samples came from a large North Carolina-based cohort established in an earlier Duke‑led study, with survival outcomes confirmed through national mortality records.
Statistical modeling revealed that a group of just six piRNAs could predict two‑year survival with accuracy as high as 86 percent. The findings were then validated in a second, independent group of older adults.
Participants who lived longer consistently showed lower levels of specific piRNAs, echoing patterns previously seen in simpler organisms, where reducing these molecules has been linked to longer lifespans. According to Kraus, this suggests piRNAs may play a direct role in longevity.
“We know very little about piRNAs in the blood, but what we’re seeing is that lower levels of certain specific ones is better,” Kraus said. “When these molecules are present in higher amounts, it may signal that something in the body is off‑track.”
The researchers also compared piRNAs with more familiar health indicators. For predicting short‑term survival, piRNAs outperformed age, cholesterol levels, physical activity and more than 180 other clinical measures. While lifestyle factors became more influential for longer‑term survival, piRNAs still provided important insight into underlying biology.
Next, the team plans to investigate whether lifestyle changes, medications or emerging drug classes—such as GLP‑1–based therapies—can alter piRNA levels. They also aim to compare piRNA levels in blood with those in body tissues to better understand how the molecules function.
“These small RNAs are like micromanagers in the body,” Kraus said. “We are only beginning to understand how powerful they are. This research suggests we should be able to identify short-term survival risk using a practical, minimally invasive blood test—with the ultimate goal of improving health as we age.”
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