| Environmental factor | B | S.E | Wals | Odd Ratio (95% CI) | P-value |
| Land use type |
|
| 47.15 |
| 0.00 |
| Woodland | −3.39 | 0.51 | 44.52 | 0.03 (0.01 - 0.09) | 0.00 |
| Grassland | −2.49 | 0.49 | 25.71 | 0.08 (0.03 - 0.22) | 0.00 |
| Residential area | - | - | - | 1.00 | - |
| Soil type |
|
| 18.39 |
| 0.01 |
| Neritic yellow laterite | 2.61 | 1.02 | 6.60 | 13.65 (1.86 - 100.21) | 0.01 |
| Granite yellow laterite | 3.20 | 0.92 | 12.18 | 24.40 (4.06 - 146.74) | 0.00 |
| Granite yellow red soil | 3.38 | 0.93 | 13.12 | 29.26 (4.71 - 181.83) | 0.00 |
| Sand shale yellow red soil | 5.28 | 1.43 | 13.71 | 196.76 (12.01 - 3224.32) | 0.00 |
| Paddy soil | - | - | - | 1.00 | - |
| Distance to highway | −0.01 | 0.00 | 10.94 | 0.99 (0.99 - 1.00) | 0.00 |
| Air pressure | −0.10 | 0.04 | 5.92 | 0.91 (0.84 - 0.98) | 0.02 |
| Relative humidity | −0.13 | 0.04 | 11.47 | 0.877 (0.81 - 0.95) | 0.00 |