Table 1 Characteristics of the study participants (N = 106,320)

Total

106,320

104,142(98.0)

2,178(2.0)

Sex

< 0.001

 Male

55,167(51.9)

54,423(52.3)

744(34.2)

 Female

51,153(48.1)

49,719(46.8)

1,434(65.8)

Age

15.1 ± 1,75

Class

0.004

 Middle school

57,611(54.2)

56,350(54.1)

1,261(57.9)

 High school

48,709(45.8)

47,792(45.9)

917(42.1)

Body mass index (kg/m²)

0.023

 Underweight (BMI < 5th percentile)

5,330(5.0)

5,195(5.0)

135(6.2)

 Normalweight (5th percentile ≤ BMI < 85th percentile)

85,019(80.0)

83,283(80.0)

1,736(79.7)

 Overweight (BMI ≥ 85th percentile)

15,971(15.0)

15,664(15.0)

307(14.1)

Subjective body weight perception

< 0.001

 Perceived underweight

26,691(25.1)

26,191(25.2)

500(23.0)

 Perceived normalweight

38,808(36.5)

38,094(36.6)

714(32.8)

 Perceived overweight

40,821(38.4)

39,857(38.3)

964(44.3)

Smoking status

< 0.001

 Smokers

10,463(9.8)

9,925(9.5)

538(24.7)

 Non-smoker

95,857(90.2)

94,217(90.5)

1,640(75.3)

Alcohol Consumption

< 0.001

 Drinker

34,952(32.9)

33,794(32.5)

1,158(53.2)

 Non-drinkers

71,368(67.1)

70,348(67.6)

1,020(46.8)

Drug use

< 0.001

 Yes

715(0.7)

606(0.6)

109(5.0)

 No

105,605(99.3)

103,536(99.4)

2,069(95.0)

Depressive symptom

< 0.001

 Yes

27,438(25.8)

25,671(24.7)

1,767(81.1)

 No

78,882(74.2)

78,471(75.4)

411(18.9)

Educational level of father

< 0.001

 Less than middle school

1,146(1.1)

1,084(1.5)

62(4.0)

 High school

17,442(16.4)

17,073(26.9)

369(28.4)

 College and higher

44,502(41.9)

43,657(71.5)

845(67.6)

Educational level of mother

< 0.001

 Less than middle school

892(0.8)

848(1.2)

44(2.9)

 High school

20,578(19.4)

20,136(30.6)

442(32.4)

 College and higher

43,832(41.2)

42,980(68.3)

852(64.8)