From: Gingival bleeding and calculus among 12-year-old Chinese adolescents: a multilevel analysis
Level | Classification | Variable | Description and categories |
---|---|---|---|
1st Level—Individual | Intermediate SDH | Gender | Sex of individual, Female/Male |
 |  | Ethnicity | Han/Others |
 |  | hukou | Rural/Urban |
 |  | Family size | Number of Children, One child/More than one child |
 |  | Father’s educational level | Schooling of father, Middle school or lower/More than middle school |
 |  | Mother’s educational level | Schooling of parents, Middle school or lower/More than middle school |
 |  | Toothbrushing frequency | Never/Sometimes/1/≥2 |
 |  | Dental floss usage | Never/Yes (≥0) |
 |  | Candy/chocolate /cookies /cakes | ≤1/week/> 1/week |
 |  | Sugar-containing soft drink/soda/ milk/yogurt /tea/coffee/water | ≤1/week/> 1/week |
 |  | Dentist visit during past year | >  0/0 |
 |  | Frequency of dental education (previous semester) | >  0/0 |
2st Level—Contextual | Structural SDH | Regions represent different levels of urbanization | Guang’an District, Chuanshan District, Jinniu District, Da County, Yibin County and Pi County |