Table 1 Demographic variables of the participants
From: Association of peripheral BDNF level with cognition, attention and behavior in preschool children
|  | Boys (n = 13) | Girls (n = 15) | Total (n = 28) |
|---|---|---|---|
Age range | 5.11–6.80 | 5.10–7.00 | 5.10–7.00 |
Age mean (SD) | 6.12 (0.55) | 6.19 (0.66) | 6.16 (0.60) |
Maternal age at pregnancy | 29.54 (2.30) | 29.73 (3.70) | 29.65 (3.07) |
Birth weight | 3.23 (0.56) | 3.04 (0.49) | 3.13 (0.52) |
Paternal education (n, %) | |||
 12 years | 3 (23.1) | 3 (20.0) | 6 (21.4) |
 13–16 years | 8 (61.5) | 12 (80.0) | 20 (71.4) |
 Above 16 years | 2 (15.4) | 0 | 2 (7.2) |
Maternal education (n, %) | |||
 12 years | 2 (15.4) | 2 (13.3) | 4 (14.3) |
 13–16 years | 8 (61.5) | 13 (86.7) | 21 (75.0) |
 Above 16 years | 3 (23.1) | 0 | 3 (10.7) |
Income (n, %) | |||
 1–3 million/month | 3 (23.1) | 4 (26.7) | 7 (25.0) |
 3–5 million/month | 8 (61.5) | 9 (60.0) | 17 (60.7) |
 Above 5 million/month | 2 (15.4) | 2 (13.3) | 4 (14.3) |
Indirect smoking | |||
 Yes (n, %) | 8 (61.5) | 9 (60.0) | 17 (60.7) |
Serum BDNF level mean (SD) (pg/ml) | |||
 Age 5–6 | 24,063.33 (10463.72) | 21,680.00 (6081.51) | 22,871.67 (8253.99) |
 Age 6–7 | 19,562.14 (4843.85) | 24,938.33 (10309.37) | 22,586.25 (8582.34) |
Plasma BDNF level mean (SD) (pg/ml) | |||
 Age 5–6 | 2546.08 (1971.05) | 2827.75 (1725.49) | 2686.92 (1772.26) |
 Age 6–7 | 2728.82 (1605.08) | 3205.25 (1682.22) | 2996.81 (1612.25) |