| Clinical characteristics | MZ twins | DZ twins | p Value* |
| Pairs | 57 | 52 | |
| Subjects | 114 | 104 | |
| Female subjects (%) | 54 | 60 | 0.67 |
| Straight/wavy/tortuous arteries (%) | 32/52/16 | 41/49/10 | 0.17† |
| Smokers (%) | 39 | 47 | 0.35 |
| Pack years (smokers only) | 8.27 (6.04) | 10.79 (7.96) | 0.12 |
| Age (years) | 35.1 (7.5) | 35.1 (7.1) | 0.96 |
| Diastolic blood pressure (mm Hg) | 70.3 (9.4) | 70.7 (7.9) | 0.78 |
| Systolic blood pressure (mm Hg) | 115.3 (12.7) | 117.7 (11.5) | 0.24 |
| Mean arterial blood pressure (mm Hg) | 85.3 (10.0) | 86.3 (8.6) | 0.50 |
| Body mass index (kg/m2) | 23.5 (3.5) | 23.9 (3.6) | 0.50 |
| Fasting blood glucose (mM)‡ | 4.88 (0.48) | 4.88 (0.41) | 0.99 |
| Total cholesterol (mM)‡ | 5.24 (1.00) | 5.54 (1.04) | 0.08 |
Values are given as mean (SD), except pairs and subjects, which are given in actual numbers. Gender, smokers and tortuosity are given in per cent.
*Robust t test (adjusted for clustering).
†Chi-square test.
‡Whole capillary blood samples