Table 1.
Characteristics of study participants
| Variable | Flow FISH | qPCR |
|---|---|---|
| N (%) | N (%) | |
| Total | 144 | 635 |
| Sex | ||
| Male | 90 (63%) | 425 (67%) |
| Female | 54 (38%) | 210 (33%) |
| Race | ||
| White | 110 (77%) | 478 (75%) |
| African American | 6 (4%) | 40 (6%) |
| Other | 26 (18%) | 93 (15%) |
| Missing | 2 (0.5%) | 24 (4%) |
| Median (range) | Median (range) | |
| Age | 36.9 (20–53.2) | 33.8 (19.1–61.1) |
| , | ||
| Flow FISH (kb)1 | 7.0 (3.7–11.2) | 7.0 (3.7–11.2) |
| qPCR (z-score)2 | − 0.03 (− 2.3 to 4.3) | − 0.17 (− 2.3 to 4.9) |
| Epigenetic age clocks2,3 | ||
| GrimAge clock | 33.9 (19.8–50.2) | 35.9 (19.8–63.6) |
| PhenoAge clock | 16.2 (− 10.7 to 42.8) | 21.1 (− 10.7 to 53.9) |
| Hannum clock | 23.1 (1.4–46) | 24.6 (− 1.2 to 49.6) |
| SkinBlood clock | 32.9 (11.9–54.8) | 30.9 (11.6–60.7) |
| DNAmAge clock | 31.6 (13.2–50.1) | 31.6 (6.2–58.6) |
| Age acceleration residual (AAR) measures | ||
| AAR GrimAge | − 0.5 (− 10.0 to 15.5) | − 4.2 (− 10.0 to 7.4) |
| AAR PhenoAge | − 0.3 (− 31.5 to 30.5) | − 7.9 (− 31.5 to 10.7) |
| AAR Hannum | 0.02 (− 23.1 to 21.7) | − 3.7 (− 18.1 to 10.35) |
| AAR SkinBlood | 0.3 (− 10.3 to 20.7) | 0.09 (− 8.6 to 9.1) |
| AAR DNAmAge | − 1.03 (− 9.1 to 10.7) | 0.5 (− 21.6 to 19.6) |
| IEAA4 | 0.2 (− 7.9 to 12.9) | 0.2 (− 19.8 to 20.5) |
| EEAA4 | − 8.3 (− 25.7 to 12.4) | 1.3 (− 25.7 to 28.2) |
Flow FISH fluorescence in situ hybridization (FISH) with flow cytometry, qPCR quantitative polymerase chain reaction, DNAm DNA methylation, AAR age acceleration residual, IEAA intrinsic epigenetic age acceleration, EEAA extrinsic epigenetic age acceleration
1Cryopreserved PBMC samples were used, and reported values are from total lymphocytes
2DNA was extracted from peripheral blood mononuclear cells (PBMCs; n = 219) or frozen whole blood (n = 416)
3Epigenetic clocks were developed using penalized regression to select CpG sites that produce the most accurate estimate of chronological age only (for DNAmAge, Hannum, and SkinBlood clocks), or to predict mortality risk from a combination of phenotypic indicators, including chronological age and blood chemistries (PhenoAge), or selected blood proteins and smoking history, controlling for chronological age (GrimAge)
4Calculated from DNAmAge clock