Table 3.
The results of forward, backward, stepwise and adjusted risk prediction by logistic regression.
| WHO reference | China reference | ||||||
|---|---|---|---|---|---|---|---|
| Variables | OR | 95% CI | P | Variables | OR | 95% CI | P |
| FORWARD REGRESSION | |||||||
| Education | 0.44 | 0.23–0.84 | 0.013 | Education | 0.49 | 0.25–0.95 | 0.033 |
| Rain | 1.14 | 1.05–1.25 | 0.003 | Humidity | 1.24 | 1.05–1.48 | 0.013 |
| Altitude | 1.24 | 1.02–1.51 | 0.033 | Altitude | 1.22 | 1.01–1.48 | 0.042 |
| BACKWARD REGRESSION | |||||||
| Humidity | 1.34 | 1.14–1.57 | <0.001 | Humidity | 1.24 | 1.05–1.48 | 0.013 |
| Altitude | 1.25 | 1.03–1.52 | 0.025 | Education | 0.49 | 0.25–0.95 | 0.033 |
| Education | 0.40 | 0.21–0.78 | 0.007 | Altitude | 1.22 | 1.01–1.48 | 0.042 |
| STEPWISE REGRESSION | |||||||
| Humidity | 1.34 | 1.14–1.57 | <0.001 | Humidity | 1.24 | 1.05–1.48 | 0.013 |
| Altitude | 1.25 | 1.03–1.52 | 0.025 | Education | 0.49 | 0.25–0.95 | 0.033 |
| Education | 0.40 | 0.21–0.78 | 0.007 | Altitude | 1.22 | 1.01–1.48 | 0.042 |
| MULTIVARIABLE ADJUSTED | |||||||
| Education | 0.40 | 0.22–0.74 | 0.003 | Education | 0.42 | 0.22–0.77 | 0.006 |
| Humidity | 1.26 | 1.03–1.54 | 0.024 | Humidity | 1.26 | 1.02–1.55 | 0.029 |
| Altitude | 1.61 | 1.20–2.17 | 0.002 | Altitude | 1.54 | 1.15–2.05 | 0.004 |
WHO, World Health Organization; OR, odds ratio; 95% CI, 95% confidence interval. P-values were calculated by logistic regression.
We do some conversion of data when we running logistic regression analysis, the details as follows: altitude/250, humidity/3, sunshine/200, temperature/3, rain/100, wind speed/5.
In multivariable adjusted model, risk prediction of each adjusted factor was calculated by adjusting for the other factors (sex, sunshine, wind speed, temperature).