Table 2.
Subgroup analyses of association of asthma with humidity and precipitation.
| Subgroup | Numbers of studies | Pooled OR (95% CI) | Heterogeneity | P of Egger's test |
|---|---|---|---|---|
| Humidity | 18 | 1.0489 (1.0061; 1.0935) | I2 = 99.933%, P < 0.001 | 0.9037 |
| Age | ||||
| <18 years | 8 | 1.0898 (1.0290; 1.1541) | I2 = 99.892%, P < 0.001 | 0.6147 |
| ≥18 years | 5 | 1.0010 (1.0003; 1.0017) | I2 = 44.445%, P = 0.13 | 0.2730 |
| Development level | ||||
| Developing countries or regions | 9 | 1.0927 (1.0220; 1.1684) | I2 = 99.968%, P < 0.001 | 0.8497 |
| Developed countries or regions | 9 | 1.0126 (0.9651; 1.0625) | I2 = 93.271%, P < 0.01 | 0.7507 |
| Latitude level | ||||
| Low latitude | 4 | 1.0600 (0.9921; 1.1325) | I2 = 96.897%, P < 0.01 | 0.4156 |
| Middle latitude | 8 | 1.0138 (0.9868; 1.0416) | I2 = 94.227%, P < 0.01 | 0.2982 |
| High latitude | 3 | 1.1298 (0.9502; 1.3433) | I2 = 66.149%, P = 0.05 | 0.8935 |
| Precipitation | 8 | 0.9991 (0.9987; 0.9995) | I2 = 33.588%, P = 0.16 | 0.0849 |
| Age | ||||
| <18 years | 4 | 1.0002 (0.9969; 1.0034) | I2 = 61.246%, P = 0.05 | 0.2852 |
| ≥18 years | 5 | 0.9991 (0.9987; 0.9995) | I2 = 12.918%, P = 0.33 | 0.5438 |
| Development level | ||||
| Developing countries or regions | 4 | 0.9991 (0.9987; 0.9995) | I2 = 28.794%, P = 0.24 | 0.3127 |
| Developed countries or regions | 4 | 1.0013 (0.9895; 1.0132) | I2 = 51.607%, P = 0.10 | 0.1530 |
| Latitude level | ||||
| Low latitude | 3 | 1.0005 (0.9990; 1.0021) | I2 = 0%, P = 0.77 | 0.4967 |
| Middle latitude | 5 | 0.9990 (0.9986; 0.9994) | I2 = 36.901%, P = 0.18 | 0.2632 |
Statistically significant results are in bold.