Table 1.
Characteristics and DNA methylation twin pair correlations of the sample
| Study | Country | Twins | Number of twins (number of females) | Mean age (SD), range | Twin pair correlations of the 353,681 sites |
|||
|---|---|---|---|---|---|---|---|---|
| 25th percentile | Median | Mean | 75th percentile | |||||
| PETS | Australia | MZ | 46 (24) | 0 (0), 0-0 | -0.21 | -0.04 | -0.01 | 0.16 |
| DZ | 44 (21) | 0 (0), 0-0 | -0.19 | -0.05 | -0.04 | 0.10 | ||
| BSGS | Australia | MZ | 134 (62) | 13.8 (1.9), 12-18 | -0.03 | 0.09 | 0.14 | 0.27 |
| DZ | 222 (107) | 13.2 (2.0), 10-24 | -0.01 | 0.06 | 0.08 | 0.16 | ||
| E-Risk | UK | MZ | 852 (414) | 18 (0), 18-18 | -0.12 | 0.21 | 0.26 | 0.37 |
| DZ | 612 (300) | 18 (0), 18-18 | 0.09 | 0.17 | 0.20 | 0.28 | ||
| DTR young adults | Denmark | MZ | 146 (66) | 33.1 (2.0), 30-37 | 0.10 | 0.24 | 0.26 | 0.39 |
| NTR | The Netherlands | MZ | 1,538 (1082) | 36.1 (12.4), 18-78 | 0.05 | 0.12 | 0.20 | 0.32 |
| DZ | 848 (511) | 33.9 (10.5), 17-79 | 0.01 | 0.06 | 0.09 | 0.15 | ||
| AMDTSS | Australia | MZ | 132 (132) | 55.6 (8.4), 43-72 | -0.06 | 0.05 | 0.08 | 0.19 |
| DZ | 132 (132) | 57.0 (7.2), 43-74 | -0.09 | -0.001 | 0.001 | 0.09 | ||
| MuTHER | UK | MZ | 186 (186) | 61.0 (9.3), 44-85 | 0.01 | 0.12 | 0.14 | 0.26 |
| DZ | 306 (306) | 57.4 (9.3), 39-83 | -0.01 | 0.06 | 0.07 | 0.14 | ||
| DTR old adults | Denmark | MZ | 154 (78) | 63.2 (4.1), 57-74 | 0.06 | 0.18 | 0.20 | 0.31 |
| OATS | Australia | MZ | 216 (136) | 71.2 (6.0), 65-90 | -0.004 | 0.09 | 0.12 | 0.22 |
| LSADT 1997 | Denmark | MZ | 36 (22) | 76.3 (2.0), 73-82 | -0.13 | 0.07 | 0.08 | 0.28 |
| DZ | 50 (40) | 76.2 (1.6), 74-80 | -0.10 | 0.05 | 0.05 | 0.20 | ||
| LSADT 2007 | Denmark | MZ | 36 (22) | 86.2 (2.0), 83-92 | -0.12 | 0.07 | 0.08 | 0.27 |
| DZ | 50 (40) | 86.1 (1.6), 84-90 | -0.09 | 0.05 | 0.05 | 0.20 | ||
PETS – Peri/postnatal Epigenetic Twins Study; BSGS – Brisbane System Genetics Study; E-Risk – Environmental Risk Longitudinal Twin Study; DTR – Danish Twin Registry, with participants of two age groups: younger and older adults; NTR – Netherlands Twin Register; AMDTSS – Australian Mammographic Density Twins and Sisters Study; MuTHER – Multiple Tissue Human Expression Resource Study; OATS – Older Australian Twins Study; LSADT – Longitudinal Study of Aging Danish Twins, with samples collected in years 1997 and 2007, respectively; MZ – monozygotic; DZ – dizygotic; SD – standard deviation.