Table 2 Risk variables of the case and control group

Mother education level

 Intermediate (reference)

6 (2.6%)

0.1 (0.4%)

 High school

53 (23.3%)

44 (19.4%)

0.20 (0.02–1.7)

0.144

 Diploma/bachelor

154 (67.8%)

159 (70%)

0.16 (0.01–1.35)

0.093

 Master/PhD

14 (6.2%)

23 (10.1%)

0.10 (0.01–0.93)

0.043

Father education level

 Intermediate (reference)

6 (2.6%)

6 (2.6%)

 High school

46 (20.3%)

57 (25.1%)

0.80 (0.24–2.66)

0.725

 Diploma/bachelor

115 (50.7%)

134 (59%)

0.85 (0.26–2.7)

0.796

 Master/PhD

60 (26.4%)

30 (13.2%)

2 (0.59–6.7)

0.263

Use of devices

 No (reference)

22 (9.7%)

96 (42.3%)

 Yes

205 (90.3%)

131 (57.7%)

6.82 (4.09–11.40)

 < 0.001

Onset of using electronic devices

 12–24 months

181 (88.3%)

88 (67.2%)

8.22 (1.71–39.55)

0.009

 25–36 months

22 (10.7%)

35 (26.7%)

2.51 (0.48–12.94)

0.270

 37–48 months (reference)

0.2 (1%)

0.8 (6.1%)

Possession of own device

 No (reference)

74 (36.1%)

39 (29.8%)

 Yes

131 (63.9%)

92 (70.2%)

1.33 (0.83–2.13)

0.232

Watching TV

 No (reference)

92 (40.5%)

41 (18.1%)

 Yes

135 (59.5%)

186 (81.9%)

0.32 (0.21–0.49)

 < 0.001

Onset of watching TV

 12–24 months

181 (88.3%)

88 (67.2%)

2.44 (0.25–23.78)

0.442

 25–36 months

22 (10.7%)

35 (26.7%)

1.03 (0.09–10.97)

0.980

 37–48 months (reference)

0.2 (1%)

0.8 (6.1%)

TV viewing/day (hour)

 1–2 h (reference)

53 (39.3%)

122 (65.6%)

 3–4 h

65 (48.1%)

56 (30.1%)

2.67 (1.65–4.32)

 < 0.001

 5–8 h

15 (11.1%)

0.7 (3.8%)

4.93 (1.90–12.79)

0.001

  > 8 h

0.2 (1.5%)

0.1 (0.5%)

4.60 (0.40–51.87)

0.217

Spending time with children

 Yes (reference)

217 (95.6%)

216 (95.2%)

 No

10 (4.4%)

11 (4.8%)

0.905 (0.37–2.17)

0.823

Activities per day (in hours)

 1–2 h

58 (26.7%)

78 (36.1%)

0.379 (0.21–0.67)

0.001

 3–4 h

60 (27.6%)

86 (39.8%)

0.355 (0.20–0.62)

 < 0.001

 4–6 h

46 (21.2%)

25 (11.6%)

0.937 (0.48–1.83)

0.850

  > 6 h (reference)

53 (24.4%)

27 (12.5%)