Table 1. Demographics and Characteristics of the Twin Sample.
| Total sample | MZ | DZ | p-values | |
| N | 284 | 158 | 126 | |
| Age M (SD) yrs | 69.82 (4.76) | 69.92 (4.97) | 69.69 (4.51) | 0.79 |
| Age Min/Max yrs | 65/85 | 65/83 | 65/85 | - |
| Sex - Female, N | 188 | 100 | 88 | 0.39 |
| Right-handed, N | 254 | 140 | 114 | 0.87 |
| Current smokers, N | 82 | 50 | 32 | 0.40 |
| Diabetic, N | 32 | 21 | 11 | 0.23 |
| Alcohol consumption>1 drink per day, N | 66 | 43 | 23 | 0.20 |
| Cholesterol (mmol/L) mean (SD) | 5.20 (1.05) | 5.10 (1.04) | 5.33 (1.06) | 0.58 |
| Systolic mean (SD) | 138.17 (18.15) | 137.84 (18.92) | 138.57 (17.21) | 0.79 |
| Diastolic mean (SD) | 80.77 (10.35) | 79.77 (9.95) | 82.00 (10.75) | 0.14 |
| Total white matter lesions (mm3) | 6688.04 (7997.89) | 6513.22 (7977.05) | 6907.26 (8050.41) | 0.12 |
Notes: MZ – monozygotic twins; DZ- Dizygotic twins; M –mean; SD – standard deviation.