Table 1 Characteristics of participants by groups at 6 months follow-up visit

Sex

0.92

 Boys (%)

42.6

42.2

38.5

41.4

 Girls (%)

57.4

57.8

61.5

58.6

Age

 11 years (%)

1.6

1.8

2.6

0.8

0.50

 12 years (%)

23.0

32.1

31.6

38.3

 13 years (%)

48.4

45.9

42.7

39.8

 14 years (%)

27.0

20.2

23.1

21.1

School grade

 7th (%)

45.9

51.4

51.3

47.7

0.81

 8th (%)

54.1

48.6

48.7

52.3

Residence status

 With both parents (%)

88.5

89.0

77.8

80.5

0.10

 With one parent and step parent (%)

0.8

0.9

6.0

2.3

 With one parent only (%)

5.7

6.4

10.3

6.3

 With relatives (%)

4.1

3.7

4.3

8.6

 Others (%)

0.8

0

1.7

2.3