Table 1.
Demographic and clinical characteristics of all twins and across terciles of the Impact of Events Scale
| Variable | Total (n = 3,740) | Impact of Events Scale Scores | ||
|---|---|---|---|---|
| Tercile 1a(n = 1,154) | Tercile 2 (n = 1,186) | Tercile 3 (n = 1,153) | ||
| Monozygotic (%) | 56 | 55 | 57 | 57 |
| Age, mean (SD) | 33.0 (14.8) | 34.3 (15.7) | 32.5 (15.0) | 32.1 (13.7) |
| Femalesb (%) | 61 | 51 | 61 | 71 |
| White (%) | 87 | 87 | 88 | 86 |
| Marriedb (%) | 33 | 37 | 32 | 28 |
| Education | ||||
| Less than college (%) | 43 | 43 | 42 | 45 |
| College (%) | 46 | 45 | 47 | 47 |
| Graduate schoolb (%) | 11 | 13 | 12 | 8 |
| Body mass index, mean (SD) | 24.7 (5.0) | 24.9 (5.0) | 24.5 (5.0) | 24.7 (5.2) |
| CWPb (%) | 7 | 4 | 8 | 10 |
| PTSDb (%) | 3.8 | 1.3 | 2.3 | 8.4 |
| Depressionb (%) | 20 | 9 | 18 | 34 |
a
Impact of Event Scale score tercile ranges: tercile 1 = 0–6; tercile 2 = 7–24; tercile 3 = 25+;
b
Ptrend < 0.01