Extended Data Table 1.
Blood-based* biomarkers of aging validated in cross-population studies.
| Biomarker | Type | Assay | Variable selection method |
Biomarker components | |
|---|---|---|---|---|---|
| Panel | “Phenotypic aging”11 | Blood biomarkers | Blood biochemistry and hematology | Penalized Cox regression model, 42 variables | 9 blood measures |
| “Agglomerative algorithm”12 | Blood biomarkers | Blood biochemistry and hematology | Hierarchical clustering, 40 variables | 19 blood measures | |
| BloodAge 13 | Blood biomarkers | Blood biochemistry and hematology | Deep Neural Networks | 45 blood measures | |
| Omic | DNAmRS 14 | Epigenetics | DNAm microarray | EWAS on mortality, ∼450K CpGs | Weighted DNAm levels at 10 CpGs |
| PhenoAge11 | Epigenetics | DNAm microarray | EN regression model with 20169 CpGs | Weighted DNAm levels at 513 CpGs | |
| GrimAge 15 | Epigenetics | DNAm microarray | EN Cox regression model with ∼450K CpGs | Weighted DNAm levels at 1030 CpGs | |
| GrimAge2 16 | Epigenetics | DNAm microarray | EN Cox regression model of time-to-death, 1030 CpGs | Weighted DNAm levels at 1030 CpGs | |
| DunedinPACE 17 | Epigenetics | DNAm microarray | EN regression model on 81239 CpGs with high test-retest reliability | Weighted DNAm levels at 173 CpGs | |
| bAge 18 | Epigenetics | DNAm microarray | EN Cox regression model of time-to-death, ~ 370K CpGs | 35 EpiScores based on weighted DNAm levels | |
| MetaboHealth score 19 | Metabolomic | Nuclear magnetic resonance | Stepwise Cox proportional hazards model, 226 variables | Concentration of 14 metabolites | |
| MetaboAge score 20 | Metabolomic | Nuclear magnetic resonance | Linear model trained on chronological age, 56 variables | Concentration of 56 metabolites | |
| M-metabo-score 21 | Metabolomic | Liquid chromatography-mass spectrometry | Cox proportional hazards model, 470 variables | Concentration of 17 metabolites | |
| “Proteomic signature” 22 | Proteomic | SOMAscan 1.3K | Cox proportional hazard model, 1301 variables | Concentration of 76 proteins | |
| Integrative | “Integrative biomarker” 23 | Clinical + Epigenetics | clinical measurements and DNAm microarray | EWAS and Elastic-coxph | 12 clinical measurements and DNAm levels at 76 CpGs |
Biomarker selection: Biomarkers were selected based on the following criteria 1) we reviewed biomarkers compiled by Justice et al. 14 10, Rutledge et al.24, and Kudryashova et al.25 which, to the best of our knowledge, collectively provide the most comprehensive list of blood-based and omic biomarkers of aging in the geroscience field; 2) we consulted a recent systematic ranking and scoring of biomarkers of aging performed by Hartmann et al. in 2021 to select the most cited biomarkers 26; and 3) we queried the literature using search terms [“epigenetic”, “metabolomic”, “proteomic”, “transcriptomic”], [“mortality”, “death”], and [“validation”] to identify additional omic biomarkers that have been validated in cohort studies. Genomic biomarkers of aging (e.g., genetic variants) were not included in this work, as we focused on biomarkers potentially responsive to interventions. All included biomarkers/studies met the following inclusion criteria: 1) studies that propose new ways to quantify biological aging (predicting aging outcomes better than chronological age 27); 2) biomarkers measured entirely or primarily in blood; 3) biomarkers that are applicable to the general population and not specific to certain subpopulations with specific diseases; 4) biomarkers that underwent validation in an independent cohort (cross-population validation) with at least 10 years of follow-up data on aging outcomes, including mortality (e.g., time to death); and 5) biomarkers whose predictive performance is reported in terms of hazard ratio (HR). As these strict inclusion criteria resulted in omission of numerous studies and biomarkers (see Extended Data Table 3 below for examples).
Abbreviations: SBP: Systolic blood pressure; FEV1: forced expiratory volume at 1 second; FVC: forced vital capacity; CRP: C-reactive protein; ALP: Alkaline phosphatase; WBC: White blood cell count, CN: Creatinine; ALB: Albumin; EWAS: epigenome-wide association studies; EN: Elastic Net; 10F CV: 10 fold cross validation; RFU: relative fluorescence units