Table 1. Demographic Characteristics of the Study Samples.
| No./total No. (%) | |||
|---|---|---|---|
| Invited families (n = 506) | Study sample (n = 437) | EEG subsample (n = 150) | |
| Sex | |||
| Male | 269/506 (53.2) | 227/437 (51.9) | 81/150 (54.0) |
| Female | 237/506 (46.8) | 210/437 (48.1) | 69/150 (46.0) |
| Smoke exposure during pregnancy | 77/500 (15.4) | 84/435 (19.3) | 27/146 (18.5) |
| Monthly household income, SGD (US$) | |||
| <2000 (1478) | 116/493 (23.5) | 95/424 (22.4) | 31/138 (22.5) |
| 2000-3999 (1478-2955) | 119/493 (24.1) | 106/424 (25.0) | 34/138 (24.6) |
| 4000-5999 (2956-4433) | 124/493 (25.2) | 109/424 (25.7) | 35/138 (26.1) |
| ≥6000 (4434) | 134/493 (27.2) | 114/424 (26.9) | 37/138 (26.8) |
| Maternal education level | |||
| High school and below | 149/500 (29.8) | 138/431 (32.0) | 47/146 (32.2) |
| Diplomas/certificates | 177/500 (35.4) | 166/431 (38.5) | 57/146 (39.0) |
| University and above | 174/500 (34.8) | 127/431 (29.5) | 42/146 (28.8) |
| Ethnicity | |||
| Chinese | 285/506 (56.3) | 250/437 (57.2) | 76/150 (50.7) |
| Malay | 144/506 (28.5) | 122/437 (27.9) | 51/150 (34.0) |
| Indian | 77/506 (15.2) | 65/437 (14.9) | 23/150 (15.3) |
| Maternal age at delivery, mean (SD), y | 31.25 (5.11) | 31.42 (5.11) | 31.26 (5.28) |
| Screen time, mean (SD), h/d | 2.01 (1.85) | 2.12 (1.94) | 2.34 (1.87) |
| Birth weight, mean (SD), kg | 3.12 (0.43) | 3.17 (0.39) | 3.15 (0.40) |
| Gestational age, median (IQR), wk | 38.86 (38.00-39.71) | 38.93 (38.00-39.71) | 38.78 (38.14-39.50) |
Abbreviations: EEG, electroencephalography; SGD, Singapore dollars.