Table 1.
Characteristics of the study population.
| Swedish twins, SATSA |
Danish twins, LSADT |
Pooled |
p across time | ||||
|---|---|---|---|---|---|---|---|
| Mean (SD) |
Mean (SD) |
Mean (SD) |
|||||
| Baseline | Follow-up | Baseline | Follow-up | Baseline | Follow-up | ||
| aMZ pairs | 26 (41·3) | 16 (39·0) | 42 (40·4) | ||||
| aDZ pairs | 37 (58·7) | 25 (61·0) | 62 (59·6) | ||||
| aWomen | 70 (55·6) | 58 (70·7) | 128 (61·5) | ||||
| bBirth year | 1915–1947 | 1915–1923 | 1915–1947 | ||||
| aCurrent smokers | 27 (21·4) | 16 (12·7) | 18 (22·0) | 10 (12·2) | 45 (21·6) | 26 (12·5) | |
| Age | 65·6 (8·3) | 74·1 (7·3) | 76·3 (1·8) | 86·2 (1·8) | 69·8 (8·4) | 78·9 (8·3) | |
| Horvath DNAmAge | 44·3 (6·7) | 49·2 (7·7) | 71·3 (4·8) | 79·0 (5·2) | 55·0 (14·5) | 64·4 (20·2) | <0·001 |
| Horvath clock residual | 0·10 (5·9) | 0·33 (6·9) | −0·44 (4·2) | −0·02 (4·8) | −0·11 (5·3) | 0·19 (6·2) | 0·466 |
| Levine DNAmAge | 63·6 (9·6) | 69·8 (8·3) | 66·6 (6·1) | 76·7 (7·1) | 64·8 (8·3) | 72·5 (8·7) | <0·001 |
| Levine clock residual | −0·54 (7·2) | 0·48 (6·8) | −0·40 (5·7) | 0·04 (6·9) | −0·49 (6·6) | 0·31 (6·8) | 0·146 |
Note. The DNAmAge values are years. The somewhat lower than expected mean value for the Horvath DNAmAge in SATSA is explained in the Methods. The clock residuals are derived from adjusting the Horvath and Levine DNAmAges for blood cell counts and chronological age. The p-value for the across-time difference in the pooled sample was assessed using paired samples t-test. Abbreviations: DNAmAge, DNA methylation age; DZ, dizygotic; MZ, monozygotic; SD, standard deviation.
a
Numbers are N (%).
b
Numbers are range (min-max).