Table 1 Characteristics of Participants

  Non-low (comfortable, somewhat comfortable, normal, somewhat difficult)

1119

(95.72)

1095

(96.65)

  Low (difficult)

50

(4.28)

38

(3.35)

  Both biological parents

964

(82.46)

928

(81.91)

  Single parent or stepfamily

205

(17.54)

205

(18.09)

 Family members’ smoking status (mother, father, or others)

  None

565

(48.33)

527

(46.51)

  Yes (≥1 person)

604

(51.67)

606

(53.49)

 BMI

18.92

(2.63)

19.19

(2.57)

 BMI z-score (WHO standard)

−0.17

(0.68)

−0.18

(0.63)

   < −2 SD

53

(4.53)

36

(3.18)

   ≥ −2 SD and < −1 SD

215

(18.39)

220

(19.42)

   ≥ −1 SD and < +1 SD

793

(67.84)

797

(70.34)

   ≥ +1 SD and < +2 SD

94

(8.04)

67

(5.91)

   ≥ +2 SD

14

(1.20)

13

(1.15)

  7th

396

(33.88)

387

(34.16)

  8th

382

(32.68)

361

(31.86)

  9th

391

(33.45)

385

(33.98)

  No (eat breakfast daily)

1032

(88.28)

963

(85.00)

  Yes (skip breakfast ≥ 1 time per week)

137

(11.72)

170

(15.00)

   < 1 time per week

959

(82.04)

961

(84.82)

   ≥ 1 time per week

210

(17.96)

172

(15.18)

  Physical

850

(72.71)

575

(50.75)

  Non-physical

77

(6.59)

322

(28.42)

  No participation

242

(20.70)

236

(20.83)

  Yes

398

(34.05)

466

(41.13)

  No

771

(65.95)

667

(58.87)

   ≥ 6 h 30 min per day (Q2–Q5)

955

(81.69)

826

(72.90)

   < 6 h 30 min per day (Q1)

214

(18.31)

307

(27.10)

  Good (excellent, good, fair)

1084

(92.73)

1033

(91.17)

  Not good (somewhat poor or poor)

85

(7.27)

100

(8.83)

 Smoking status

  No

1,126

(96.32)

1107

(97.71)

  Yes

43

(3.68)

26

(2.29)