Table 5.
Selected variables using training data shown to be associated with dental calculus, evaluated 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 | ||||
| Gender | Female | 1 | ||
| Male | 1.32 (1.13, 1.54) | < 0.01 | ||
| hukou | Rural | 1 | ||
| Urban | 0.69 (0.59 0.82) | < 0.01 | ||
| Family size | One child | 1 | ||
| More than one child | 1.34 (1.12, 1.59) | < 0.01 | ||
| Father’s educational level | Middle school or lower a | 1 | ||
| More than middle schoolb | 0.46 (0.39 0.54) | < 0.01 | ||
| Mother’s educational level | Middle school or lower a | 1 | ||
| More than middle schoolb | 0.65 (0.59 0.82) | < 0.01 | ||
| Brushing frequency (times/day) | Never | 1 | ||
| Sometimes | 1.76 (1.21, 2.54) | < 0.01 | ||
| One | 1.04 (0.771.42) | 0.79 | ||
| ≥Twice | 0.57 (0.42 0.78) | < 0.01 | ||
| Dental floss use | Never | 1 | ||
| Yes | 0.66 (0.48 0.90) | 0.01 | ||
| Sugar-containing soft drink/Pop/ milk/yogurt/tea/coffee/water | ≤1/week | 1 | ||
| > 1/week | 1.30 (1.11 1.53) | < 0.01 | ||
| Dental visit (last year) | No | 1 | ||
| Yes | 1.15 (0.96 1.39) | 0.14 | ||
|
Frequency of dental curricula (last semester) |
0 | 1 | ||
| ≥1 | 0.85 (0.67, 1.07) | 0.16 | ||
| Random effect | ||||
| Contextual level variance (SEc) | 0.065 (0.42) | 0.12 (0.07) | 0.11 | |
| AICd | 4277.8 | 3985.3 | ||
| Average intercept | 0.715 | 1.06365 | ||
| VPCe | 0.01438 | 0.022693 | ||
Abbreviations: aMiddle school or lower: ≤9 years; bMore than middle school: >9 years; cSE standard error, dAIC Akaike Information Criteria, eVPC variance partitioning coefficient