Table 2.
Results of multiple level models.
| Group | Null Model | Base Model | Full Model |
|---|---|---|---|
| OR (95% CI) | OR (95% CI) | OR (95% CI) | |
| Grade | |||
| 1–2 | 1.00 | ||
| 3–4 | 1.23 (0.52, 2.89) | ||
| 5- | 0.41 (0.18, 0.94)* | ||
| Universities types | |||
| High level | 1.00 | 1.00 | |
| Middle level | 0.93 (0.31, 2.74) | 0.40 (0.15, 1.08) | |
| Low level | 3.28 (1.46, 5.35)** | 2.22 (1.04, 3.57)* | |
| City population (million) | |||
| <1 | 1.00 | 1.00 | |
| 1–3,999 | 0.83 (0.29, 2.33) | 1.22 (0.24, 4.16) | |
| 4 and over | 0.34 (0.16, 0.76)** | 0.16 (0.06, 0.42)** | |
| Air pollution | |||
| <15 | 1.00 | ||
| 15–25 | 1.18 (0.28, 3.33) | ||
| ≥25 | 6.67 (2.56, 16.7)** | ||
| Fixed parameters | −0.5592 (0.1821)** | 0.7542 (0.2883) | 0.8745 (0.3441) |
| Random parameters between universities | 1.6355 (0.3425)** | 1.5988 (0.6547)** | 1.4998 (0.7847)** |
| Random parameters between universities cities | 1.6514 (0.3352)** | 1.6124 (0.6628)** | 1.5083 (0.7946)** |
*
P <0.05,
**
P <0.01.