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Researchers have developed a simple urine-based test that can estimate how fast a person is aging—without the need for blood draws. In a study published in NPJ Aging, a team led by researchers in Japan described a new “aging clock” built from microRNAs (miRNAs) found in extracellular vesicles in urine. These tiny RNA molecules change predictably with age, allowing scientists to estimate a person’s chronological age and identify whether their biology appears to be aging faster or slower than expected.
The researchers analysed urine samples from more than 6,300 people in Japan who were undergoing routine cancer screening. Using machine learning, they trained a model to predict age based on patterns of urinary miRNAs. The resulting clock was surprisingly accurate, estimating age within about four to five years on average across multiple independent test groups. The difference between predicted age and actual age—called age acceleration—was used as an indirect indicator of biological aging rather than a direct diagnostic measure.
Many of the most important miRNAs identified by the model are already well known in aging research. These include so-called “geromiRs” linked to cellular senescence, inflammation, and age-related tissue changes. Pathway analyses showed strong connections to biological processes involved in aging, such as bone remodelling and immune cell regulation. Among common health conditions examined, type 2 diabetes stood out as being associated with faster biological aging in middle-aged and older adults.
While the urine-based clock is not yet ready for clinical diagnosis, the authors emphasize its potential as a scalable, non-invasive tool for aging research and population health studies. Compared with DNA methylation clocks, it is slightly less precise, but it matches or exceeds the performance of many blood-based RNA aging clocks. With further validation, urinary miRNA clocks could help track aging, assess lifestyle or therapeutic interventions, and reduce reliance on invasive testing.
