Définition
The Horvath clock is an epigenetic biological age calculator developed by Steve Horvath in 2013. It measures DNA methylation at hundreds of CpG sites and estimates biological age with accuracy comparable to chronological age itself — making it one of the most important tools in longevity science.
Published in Genome Biology in 2013, the original Horvath clock analyzed methylation levels at 353 CpG sites across the genome to produce a biological age estimate that correlates with chronological age at r ≈ 0.96 across nearly every human tissue. The clock works on saliva, blood, skin, or brain tissue — making it unusually portable across sample types.
The significance isn't accuracy per se, but deviation. Epigenetic age acceleration (biological age greater than chronological age) predicts all-cause mortality, cancer incidence, cognitive decline, and frailty independent of chronological age. A 5-year acceleration on the Horvath clock is roughly equivalent to a doubling of mortality risk. Conversely, epigenetic age deceleration is associated with longevity.
Subsequent clocks have been developed for specific use cases. PhenoAge (2018) uses clinical markers and is more predictive of disease onset. GrimAge (2019) incorporates DNA methylation proxies for plasma proteins and smoking history — it is currently the most predictive clock for mortality. DunedinPACE measures the rate of biological aging per chronological year, which is more responsive to short-term interventions.
Interventions that slow or reverse epigenetic age in humans include Mediterranean-style diet, regular aerobic exercise, adequate sleep, stress management, and some supplementation protocols. The TRIIM and CALERIE trials have both shown modest but measurable epigenetic age reversal in humans. Commercial tests (TruAge, Elysium Index) are now widely accessible for tracking biological age over time.
Termes associés
Ava Longevity · Built on the Ava Method · MMXXV