Table 4.
Selected variables using training data shown to be associated with gingival bleeding by multi-level logistic regression analyses (n = 3394)
| Variables | Categories | Null model | Model with individual and contextual variables | |
|---|---|---|---|---|
| OR (95% CI) | p | |||
| Fixed effect | ||||
| Individual level | ||||
| hukou | 1 | |||
| Rural | 0.61 (0.52, 0.72) | < 0.01 | ||
| Family size | Urban | 1 | ||
| One child | 1.41 (1.19, 1.68) | < 0.01 | ||
| Father’s educational level | More than one child | 1 | ||
| Middle school or lower a | 0.53 (0.45, 0.63) | < 0.01 | ||
| Mother’s educational level | More than middle schoolb | 1 | ||
| 0.71 (0.59, 0.86) | < 0.01 | |||
| Brushing frequency (times/day) | 1 | |||
| 2.03 (1.46, 2.82) | < 0.01 | |||
| 0.93 (0.70, 1.23) | 0. 60 | |||
| 0.35 (0.26, 0.48) | < 0.01 | |||
| Dental floss use | 1 | |||
| 0.58 (0.41, 0.83) | < 0.01 | |||
| Sugar-containing soft drink/Pop/ milk/yogurt/tea/coffee/water | 1 | |||
| 2.11 (1.80, 2.49) | < 0.01 | |||
| Dental visit (previous year) | 1 | |||
| 1.44 (1.19, 1.74) | < 0.01 | |||
| Random effect | ||||
| Contextual level variance (SEc) | 0.20 (0.12) | 0.13 (0.08) | 0.10 | |
| AICd | 4562.8 | 4051.4 | ||
| Average intercept | −0.173 | −0.02246 | ||
| VPCe | 0.0469 | 0.031252 | ||
Abbreviations: aMiddle school or lower, ≤9 years; bMore than middle school, > 9 years; cSE standard error, dAIC Akaike Information Criteria, eVPC variance partitioning coefficient attributable to the second level (regions)