{
 "approved_by_author": "\u231b",
 "citation": "Sehgal, R., Markov, Y., Qin, C., et al. (2025). Systems Age: a single blood methylation test to quantify aging heterogeneity across 11 physiological systems. Nature Aging, 5, 1880\u20131896.",
 "citations": 41,
 "citations_date": "2026-07-05",
 "clock_name": "systemsage",
 "data_type": "DNA methylation",
 "doi": "https://doi.org/10.1038/s43587-025-00958-3",
 "journal": "Nature Aging",
 "last_author": "Morgan Levine",
 "model_type": "PCA + elastic net regression",
 "n_features": 125175,
 "notes": "Composite Systems Age integrates the 11 mortality-associated physiological-system scores plus a DNAm chronological-age prediction through PCA and Cox elastic-net regression, then rescales the result to an age-like value.",
 "platform": [
  "Illumina 450K",
  "Illumina EPIC"
 ],
 "population": "older adults",
 "predicts": [
  "multisystem biological age"
 ],
 "reference_values": true,
 "research_only": true,
 "species": "Homo sapiens",
 "tissue": [
  "whole blood"
 ],
 "training_target": [
  "mortality"
 ],
 "unit": [
  "years"
 ],
 "version": "0.5.0",
 "year": 2025
}