Table 1 Distribution of socio-demographic characteristics and oral health-related behaviors in children aged 12 years in China in 2005 and 2015 surveys

Level-1 (individual) indicators

Sex

Male

6330

51.26

13840

49.75

20170

50.21

Female

6020

48.74

13978

50.25

19998

49.79

Ethnicity

Han

10963

88.77

24333

87.47

35296

87.87

Other

1387

11.23

3485

12.53

4872

12.13

Location of residence *

Urban

5987

48.48

11522

41.42

17509

43.59

Rural

6363

51.52

16296

58.58

22659

56.41

Only child *

Yes

5585

45.26

10009

35.99

15594

38.84

No

6755

54.74

17805

64.01

24560

61.16

Parental highest education attainment *

Junior high school or below

1721

13.94

3306

11.88

5027

12.52

High school

7935

64.27

16421

59.03

24356

60.64

Tertiary or bachelor degree or above

2169

17.57

5335

19.18

7504

18.68

Unknown or orphan

521

4.22

2756

9.91

3277

8.16

Toothbrushing frequency

Twice or more per day

3500

28.35

8879

31.93

12379

30.83

Once a day or less

8846

71.65

18933

68.07

27779

69.17

Use of dental floss *

No or do not know

11436

92.73

25146

90.41

36582

91.12

Yes

897

7.27

2666

9.59

3563

8.88

Frequency of toothache within the past 12 months *

Often

406

3.3

826

2.97

1232

3.07

Occasionally

5318

43.17

14518

52.19

19836

49.42

Never

4509

36.6

9226

33.17

13735

34.22

Can't remember

2086

16.93

3245

11.67

5331

13.28

Time of last dental visit *

Within 6 months

1235

10.01

3645

13.1

4880

12.15

Within 6 to 12 months

1301

10.55

3704

13.32

5005

12.47

More than 12 months

3946

31.99

7432

26.72

11378

28.34

Never

5853

47.45

13035

46.86

18888

47.04

Dental fluorosis

Yes

2264

18.37

5751

20.92

8015

20.13

No

10060

81.63

21741

79.08

31801

79.87

Frequency of sweet snack intake *

Occasionally/ never

2853

23.1

7296

26.23

10149

25.27

Less than 2 times per week

4500

36.44

10946

39.35

15446

38.46

2 to 6 times per week

1924

15.58

5178

18.61

7102

17.68

More than 6 times per week

3071

24.87

4398

15.81

7469

18.6

Level-2 (province) indicators

Economic development

GDP per capita, quartile 1

2876

23.29

7270

26.13

10146

25.26

GDP per capita, quartile 2

2935

23.77

6093

21.9

9028

22.48

GDP per capita, quartile 3

3350

27.13

7093

25.5

10443

26

GDP per capita, quartile 4

3189

25.82

7362

26.46

10551

26.27

Region

North China

1970

15.95

4473

16.08

6443

16.04

Northeast China

1184

9.59

2584

9.29

3768

9.38

East China

2916

23.61

6536

23.5

9452

23.53

Middlesouth (Central) China

2694

21.81

5188

18.65

7882

19.62

Southwest China

1549

12.54

4562

16.4

6111

15.21

Northwest China

2037

16.49

4475

16.09

6512

16.21