Characteristics of the study participants (n=556)
| n (%)/mean (SD) | |
| Sex, n (%) | |
| Female | 288 (51.80) |
| Male | 268 (48.20) |
| Age, mean (SD), years | 5.46 (0.70) |
| District, n (%) | |
| Hong Kong Island | 254 (45.68) |
| Yuen Long | 302 (54.32) |
| Number of EDs the family owned, mean (SD) | |
| Television | 1.45 (0.73) |
| Computer | 1.96 (0.93) |
| Tablet computer | 0.55 (0.59) |
| Smartphone | 1.31 (0.91) |
| Game console | 0.51 (0.72) |
| Portable game console | 0.58 (0.78) |
| Placement of ED in child’s bedroom, n (%) | |
| Any | 164 (29.50) |
| Television | 99 (17.81) |
| Computer | 114 (20.50) |
| Game console | 16 (2.88) |
| Parental restriction of ED use, n (%) | |
| All EDs | 398 (71.58) |
| Television | 447 (80.40) |
| Desktop/laptop computer | 462 (83.09) |
| Game console | 451 (81.12) |
| Parent–child interaction score, mean (SD) (range: 0–3) | |
| Recreation-based | 1.86 (0.61) |
| Learning-based | 2.04 (0.66) |
| Sleep duration, mean (SD), hours | 9.41 (1.04) |
| School readiness, mean (SD) | |
| CEDI total score (range: 0–50) | 43.55 (5.57) |
| CEDI physical well-being (range: 0–10) | 8.99 (1.06) |
| CEDI social competence (range: 0–10) | 8.40 (1.68) |
| CEDI emotional maturity (range: 0–10) | 8.35 (1.29) |
| CEDI language and cognitive skills (range: 0–10) | 9.29 (1.22) |
| CEDI communication and general knowledge (range: 0–10) | 8.53 (1.87) |
CEDI is a teacher-reported assessment for school readiness.
Median (IQR) of the continuous variables were presented in online supplementary table 1.
CEDI, Chinese Early Development Instrument; ED, electronic device.