Table 2.
The twin pair, phenotypic and cross-twin cross-trait correlations (95% CI) for the Horvath and Levine epigenetic clocks. The correlations are adjusted for sex, smoking, birth year and sample origin (country).
| Pooled sample of SATSA and LSADT |
|||||
|---|---|---|---|---|---|
| Baseline | Follow-up | CTCT r | Phenotypic r | ||
| Horvath clock | MZ | 0·54 (0·29, 0·79) | 0·55 (0·35, 0·75) | 0·37 (0·18, 0·53) | 0·52 |
| DZ | 0·31 (0·12, 0·51) | 0·19 (−0·04, 0·42) | 0·25 (0·08, 0·41) | (0·41, 0·63) | |
| Levine clock | MZ | 0·41 (0·07, 0·75) | 0·38 (0·10, 0·67) | 0·44 (0·23, 0·65) | 0·36 |
| DZ | 0·10 (−0·11, 0·31) | 0·19 (−0·03, 0·41) | 0·11 (−0·05, 0·27) | (0·24, 0·49) | |
Note. Phenotypic correlation represents the cross-time correlation for the trait in the sample. The CTCT correlation is the within-pair correlation between the twin A's clock value at time 1 and twin B's clock value at time 2 and vice versa.
Abbreviations: CI, confidence interval; CTCT, cross-twin cross-trait; MZ, monozygotic; DZ, dizygotic.