Table 2.
Overview of the major twin surveys in the Danish Twin Registry
| Survey | Year of survey |
Participants | Males/Females | Monozygotic | Same-sex dizygotic |
Opposite-sex dizygotic |
Unknown/other zygocities |
Complete pairs |
|---|---|---|---|---|---|---|---|---|
| Omnibus I | 1994 | 29,433 | 14,181/15,252 | 8670 | 10,424 | 9282 | 1057 | 12,494 |
| Omnibus II | 2002 | 34,943 | 15,905/19,038 | 9123 | 12,776 | 11,913 | 1131 | 11,751 |
| LSADT | 1995 | 2401 | 859/1542 | 756 | 1391 | 224 | 30 | 480 |
| 1997 | 2172 | 773/1399 | 696 | 1339 | 129 | 8 | 487 | |
| 1999 | 2709 | 1144/1565 | 931 | 1714 | 63 | 1 | 583 | |
| 2001 | 2448 | 1090/1358 | 853 | 1562 | 33 | 0 | 525 | |
| 2003 | 1844 | 815/1029 | 651 | 1176 | 17 | 0 | 347 | |
| 2005 | 1372 | 610/762 | 490 | 872 | 10 | 0 | 236 | |
| 2007 | 121 | 35/86 | 58 | 63 | 0 | 0 | 44 | |
| MADT | 1998 | 4314 | 2198/2116 | 1471 | 1389 | 1448 | 6 | 1884 |
| 2008–2011 | 2400 | 1134/1266 | 820 | 763 | 816 | 1 | 816 | |
| MIDT | 2008–2011 | 10,276 | 4784/5492 | 1983 | 3948 | 4004 | 341 | 3035 |
| GENIMAKAR | 1998 | 1512 | 729/783 | 622 | 628 | 262 | 0 | 756 |
| 2010–2012 | 1145 | 535/610 | 504 | 444 | 197 | 0 | 513 |
Note: LSADT = Longitudinal Study of Aging Danish Twins, MADT = Middle Age Danish Twins, MIDT = Middle age Danish Twins.