Table 1.
Demographic characteristics of the participants
| Demographic variables | Control | ADHD | F or x 2 | p value | |
|---|---|---|---|---|---|
| Number of participants | 249 | 195 | |||
| Age (yr) | 8.06 ± 0.93 | 7.81 ± 0.96 | 2.81 | 0.005** | |
| Sex | Male | 159 (63.9) | 137 (70.3) | 2.02 | 0.156 |
| Female | 90 (36.1) | 58 (29.7) | |||
| Paternal educational level | ≤ 12 years | 86 (34.5) | 99 (51.0) | 12.20 | < 0.000** |
| > 12 years | 163 (65.5) | 95 (49.0) | |||
| Maternal educational level | ≤ 12 years | 120 (48.2) | 116 (59.8) | 5.90 | 0.015* |
| > 12 years | 129 (51.8) | 78 (40.2) | |||
| Household income (1,000 KRW per month) | ≤ 3,000 | 93 (37.5) | 100 (52.9) | 12.70 | 0.002** |
| 3,000−4,000 | 86 (34.7) | 40 (21.2) | |||
| > 4,000 | 69 (27.8) | 49 (25.9) | |||
| Exposure to secondhand smoke | No | 169 (69.8) | 98 (52.1) | 14.09 | < 0.000** |
| Yes | 73 (30.2) | 90 (47.9) | |||
Values are presented as mean ± standard deviation or number (%).
ADHD, attention deficit/hyperactivity disorder; KRW, Korean won.
*
p < 0.05; ** p < 0.01.