Biological-Age Clocks

MRI-based brain age is a biological-age estimate derived from structural or functional brain imaging features—including cortical thickness, white-matter integrity, grey-matter…

CausAge is an epigenetic-age clock introduced by Ying, Gladyshev and colleagues (preprint 2022; Nature Aging 2024) that attempts to address a fundamental limitation of…

DamAge and AdaptAge are causality-aware epigenetic clocks developed by Kejun Ying and colleagues in the Gladyshev lab at Harvard / Brigham and Women's Hospital (Nature Aging,…

The DNAm Skin & Blood clock, published by Horvath and colleagues in 2018, is an epigenetic age estimator based on 391 CpG sites selected from methylation arrays applied to skin…

DNAmTL is an epigenetic estimator of telomere length derived from the methylation levels of 140 CpG sites in blood DNA, trained via elastic net regression against…

DunedinPACE (Pace of Aging Calculated from the Epigenome) is an epigenetic clock published in 2022 by Belsky and colleagues that estimates the rate of biological ageing rather…

Epigenetic age is a biological-age estimate derived from DNA-methylation patterns at selected CpG sites, computed by algorithms known as epigenetic clocks (e.g. Horvath, Hannum,…

GlycanAge is a biological-age estimate derived from the N-glycan composition of immunoglobulin G (IgG), measured in blood plasma by high-throughput capillary electrophoresis or…

GrimAge is a second-generation epigenetic clock introduced by Lu et al. (2019, with Steve Horvath as senior author). Instead of predicting chronological age, it is trained on…

The Hannum clock is a blood-based epigenetic age estimator published by Gregory Hannum and colleagues in 2013. It uses DNA methylation levels at 71 CpG sites, derived from…

The Horvath clock is a multi-tissue epigenetic age estimator published by Steve Horvath in 2013. It uses DNA methylation levels at 353 CpG sites to predict chronological age…

iAge is an inflammatory-age metric introduced by Sayed and colleagues (2021, Stanford) that uses a deep-learning model trained on a panel of 50 circulating cytokines and…

The Klemera-Doubal method (KDM) is a statistical algorithm that estimates biological age from clinical biomarkers by minimizing the sum of squared distances between m regression…

Leukocyte telomere length (LTL) is the average length of repetitive TTAGGG sequences capping chromosome ends in white blood cells, measured in kilobases (kb), used as a proxy for…

OMICmAge is a DNA-methylation-based biological age clock that incorporates information from the proteome, metabolome, and routine clinical laboratory data into a single…

PCGrimAge applies the same principal-component denoising framework introduced by Higgins-Chen et al. (2022) to the GrimAge methylation features, producing a more technically…

PCPhenoAge is a technically refined variant of DNAm PhenoAge introduced by Higgins-Chen and colleagues (2022) that applies principal-component (PC) regression to the underlying…

PhenoAge is a composite biological-age measure developed by Levine and colleagues in 2018. The original blood-based version combines nine clinical biomarkers including albumin,…

ProAge and related proteomic-age clocks estimate biological age from the concentrations of hundreds to thousands of plasma or serum proteins measured by aptamer-based (SomaScan)…

RetinaAge is a biological-age clock derived from fundus photographs of the retina, using deep-learning models trained to predict chronological age from the vascular and neural…

SystemsAge is a multi-organ biological-age framework introduced by Tian and colleagues (2023, Nature Medicine) that uses longitudinal brain MRI and physiological/biomarker…