TABLE 1.
Descriptive statistics of the study variables by zygosity among young adult (n = 570) and older (n = 470) twin individuals.
| Young Adult (21–25 yr) | Older (55–72 yr) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| MZ Twins (n = 326) | DZ Twins (n = 244) | MZ Twins (n = 294) | DZ Twins (n = 176) | |||||||
| Mean (SD) | n | Mean (SD) | n | Pa | Mean (SD) | n | Mean (SD) | n | Pa | |
| Women, n (%) | 208 (63.8) | 142 (58.2) | 0.174 | 188 (63.9) | 94 (53.4) | 0.024 | ||||
| Chronological age, yr | 22.4 (0.7) | 326 | 22.4 (0.7) | 244 | 0.672 | 62.0 (4.1) | 294 | 62.9 (4.3) | 176 | 0.036 |
| DNAm age, yr | 25.0 (3.5) | 326 | 24.4 (3.4) | 244 | 0.057 | 60.2 (6.2) | 294 | 62.1 (7.6) | 176 | 0.004 |
| DNAm PhenoAge, yr | 15.0 (4.6) | 326 | 15.3 (4.8) | 244 | 0.496 | 54.7 (6.5) | 294 | 56.0 (8.1) | 176 | 0.045 |
| DNAm GrimAge, yr | 28.6 (2.9) | 326 | 28.6 (3.4) | 244 | 0.843 | 59.8 (5.3) | 294 | 60.8 (5.5) | 176 | 0.061 |
| Body mass index, kg·m−2 | 23.1 (3.8) | 326 | 23.7 (4.2) | 244 | 0.028 | 27.1 (4.7) | 294 | 27.2 (4.8) | 176 | 0.727 |
| Education, yr | 16.7 (3.5) | 325 | 16.6 (3.6) | 244 | 0.429 | 11.9 (3.8) | 252 | 11.4 (3.5) | 96 | 0.266 |
| Smoking status | 325 | 244 | 292 | 176 | ||||||
| Never smokers, n (%) | 182 (56.0) | 116 (47.5) | 148 (50.8) | 88 (50.0) | ||||||
| Former smokers, n (%) | 37 (11.4) | 30 (12.3) | 97 (33.3) | 63 (35.8) | ||||||
| Current smokers, n (%) | 106 (32.6) | 98 (40.2) | 0.121 | 47 (15.9) | 25 (14.2) | 0.787 | ||||
| Alcohol use, g·d−1 | 12.4 (16.7) | 326 | 13.4 (16.7) | 244 | 0.460 | 6.9 (11.2) | 278 | 8.8 (11.6) | 158 | 0.080 |
| LTPA | ||||||||||
| Sport index | 2.9 (0.8) | 251 | 3.0 (0.8) | 233 | 0.358 | 3.2 (0.9) | 241 | 3.1 (0.8) | 156 | 0.421 |
| Nonsport leisure index | 2.9 (0.6) | 253 | 3.1 (0.6) | 234 | 0.023 | 2.9 (0.7) | 241 | 2.8 (0.7) | 156 | 0.715 |
| OPA | ||||||||||
| Work index | 2.7 (0.6) | 256 | 2.8 (0.6) | 234 | 0.315 | 2.4 (1.0) | 234 | 2.3 (1.0) | 150 | 0.935 |
| Out of working life | 322 | 243 | 241 | 156 | ||||||
| Retired or unemployed, n (%) | 49 (15.2) | 26 (10.7) | 105 (43.6) | 76 (50) | 0.209 | |||||
aP value for the difference between the groups from independent-samples t-test or χ2 test.