Table 1 Relationships between myopia at baseline and other variables.

Residency area

Sub-urban

4537

93.93%

293

6.07%

1 (Reference)

Urban

1096

90.43%

116

9.57%

1.64 (1.31, 2.05)

p < 0.001

Age (years)

6

1874

97.10%

56

2.90%

1 (Reference)

7

2747

92.09%

236

7.91%

2.87 (2.14, 3.87)

p < 0.001

8

1012

89.64%

117

10.36%

3.87 (2.79, 5.37)

p < 0.001

Gender

Male

2964

92.45%

242

7.55%

1 (Reference)

Female

2668

94.11%

167

5.89%

0.77 (0.63, 0.94)

p = 0.01

0

2443

96.29%

94

3.71%

1 (Reference)

Myopic parent

1

1883

91.90%

166

8.10%

2.29 (1.77, 2.97)

p < 0.001

2

1025

88.59%

132

11.41%

3.35 (2.54, 4.40)

p < 0.001

Parent education level

Lower than undergrad

3481

94.00%

222

6.00%

1 (Reference)

Undergrad

1855

92.15%

158

7.85%

1.34 (1.08, 1.65)

p = 0.007

Postgrad

225

90.36%

24

9.64%

1.67 (1.07, 2.60)

p = 0.02

Usual wake-up time

Before 6:30 a.m.

1749

94.54%

101

5.46%

1 (Reference)

p = 0.24

6:30 to 6:59 a.m.

2437

93.69%

164

6.31%

1.17 (0.90, 1.50)

7 a.m. and after

1445

90.94%

144

9.06%

1.73 (1.33, 2.25)

p < 0.001

Usual bedtime

Before 9 p.m.

1178

94.85%

64

5.15%

1 (Reference)

9 to 9:29 p.m.

2894

93.26%

209

6.74%

1.33 (1.00, 1.77)

p = 0.05

9:30 p.m. and after

1552

91.94%

136

8.06%

1.61 (1.19, 2.19)

p = 0.002

Sleep duration (h)

< 9.5

2315

92.90%

177

7.10%

1 (Reference)

≥ 9.5 and < 10

1846

93.37%

131

6.63%

0.93 (0.71, 1.17)

p = 0.53

 ≥ 10

1463

93.54%

101

6.46%

0.90 (0.70, 1.16)

p = 0.43

Reading time weekly total (h)

16.25 ± 6.91

16.51 ± 7.43

1.01 (0.99, 1.02)

p = 0.45

Screen time weekly total (h)

9.49 ± 0.54

9.47 ± 0.51

0.98 (0.95, 1.01)

p = 0.16

Outdoor time weekly total (h)

7.26 ± 3.86

6.63 ± 3.83

0.96 (0.93, 0.98)

p = 0.002