Table 1. Descriptive summary of MZ and DZ twins in Swedish and Danish twin samples, stratified by sex.
| Sample |
Swedish |
Danish |
|||
|---|---|---|---|---|---|
| Males | Females | Males | Females | ||
| Number of paired twins Number of single twins | MZ | 6524 2335 | 9270 2131 | 11 006 59 | 11 110 59 |
| DZ | 7440 3757 | 9770 3421 | 19 538 130 | 17 640 113 | |
| Opposite-sex | 17 078 6880 | 34 900 848 | |||
| Total | 50 082 18 524 | 94 194 1209 | |||
| Age, mean (s.d.) | MZ | 54.9 (17.9) | 55.0 (18.7) | 58.3 (16.8) | 59.5 (18.3) |
| DZ | 60.3 (16.8) | 61.3 (18.0) | 60.5 (16.1) | 63.0 (17.7) | |
| Opposite-sex | 59.2 (16.5) | 58.6 (15.7) | |||
| Total | 58.5 (17.6) | 60.0 (16.8) | |||
| Prevalence of T2DM (%)a | MZ | 5.5 | 4.2 | 4.1 | 3.3 |
| DZ | 6.9 | 5.2 | 4.7 | 4.2 | |
| Opposite-sex | 5.8 | 3.1 | |||
| Prevalence of depression (%)a | MZ | 3.7 | 5.8 | 2.8 | 4.7 |
| DZ | 3.7 | 5.7 | 3.2 | 5.7 | |
| Opposite-sex | 4.9 | 3.8 | |||
| Proband wise concordance rate for T2DM (Number of concordant pair, discordant pair) | MZ | 0.42 (69, 190) | 0.43 (75, 195) | 0.37 (83, 287) | 0.33 (60, 247) |
| DZ | 0.20 (49, 398) | 0.23 (53, 350) | 0.14 (64, 764) | 0.18 (66, 605) | |
| Opposite-sex | 0.18 (91, 813) | 0.13 (66, 886) | |||
| Proband wise concordance rate for depression (Number of concordant pair, discordant pair) | MZ | 0.21 (22,174) | 0.22 (57, 399) | 0.19 (29, 243) | 0.23 (59, 400) |
| DZ | 0.06 (8, 249) | 0.05 (13, 489) | 0.05 (16, 591) | 0.16 (77, 837) | |
| Opposite-sex | 0.09 (37, 706) | 0.09 (61, 1170) | |||
Abbreviations: DZ, dizygotic twins; MZ, monozygotic twins; T2DM, type 2 diabetes.
a
In the genetic modelling, the thresholds and other estimates apply to the sample at mean age. For example, with the effect of age being estimated at −0.03 for males in the Swedish Twin Registry, T2DM prevalence rates will be 1.3% at age 40 and 9.0% at age 70.