Table 1. . Demographic information of the sample.
| Demographic categories | African–Americans | χ2/t-test | European–Americans | χ2/t-test | ||
|---|---|---|---|---|---|---|
| AD cases (n = 28) | Controls (n = 28) | AD cases (n = 32) | Controls (n = 32) | |||
| Sex, males | 12 (42.9%) | 12 (42.9%) | χ2 = 1.00, p = 1.000 | 16 (50.0%) | 16 (50.0%) | χ2 = 1.00, p = 1.000 |
| Age, year (mean ± SD) | 39 ± 13 | 39 ± 12 | t = -0.11, p = 0.915 | 40 ± 12 | 46 ± 16 | t = 0.99, p = 0.324 |
| RIN (mean ± SD) | 6.7 ± 1.7 | 6.3 ± 1.8 | t = -0.86, p = 0.392 | 7.2 ± 1.2 | 6.7 ± 1.6 | t = -1.34, p = 0.186 |
| Co-morbid substance use disorders: | ||||||
| – Cocaine dependence | 11 (39.3%) | 0 (0%) | – | 23 (71.9%) | 0 (0%) | – |
| – Opioid dependence | 4 (14.3%) | 0 (0%) | – | 17 (53.1%) | 0 (0%) | – |
| – Nicotine dependence | 12 (42.9%) | 0 (0%) | – | 21 (65.6%) | 0 (0%) | – |
| – Marijuana dependence | 20 (71.4%) | 0 (0%) | – | 11 (34.4%) | 0 (0%) | – |
| – Sedative dependence | 1 (3.6%) | 0 (0%) | – | 8 (25.0%) | 0 (0%) | – |
| – Stimulant dependence | 1 (3.6%) | 0 (0%) | – | 4 (12.5%) | 0 (0%) | – |
AD: Alcohol dependence; RIN: RNA integrity number; SD: Standard deviation.