Association of climatic factors with the 12 month period prevalence rates (in %) of symptoms of allergic rhinoconjunctivitis in children; results of the multilevel linear regression analyses
| Worldwide* | Western Europe | |||
|---|---|---|---|---|
| 13–14 years RC† (95% CI) | 6–7 years RC† (95% CI) | 13–14 years RC† (95% CI) | 6–7 years RC† (95% CI) | |
| *Adjusted for GNP. | ||||
| †Regression coefficient with 95% confidence interval. | ||||
| ‡All centres had ⩾1 month with mean relative humidity indoors below 50%. | ||||
| Latitude (degree) | −0.09 (−0.18 to −0.01) | −0.05 (−0.11 to 0.00) | 0.13 (−0.06 to 0.33) | 0.00 (−0.12 to 0.11) |
| Altitude (100 m) | −0.02 (−0.30 to 0.25) | −0.05 (−0.26 to 0.16) | −0.38 (−0.97 to 0.20) | −0.19 (−0.53 to 0.14) |
| Outdoor temperature | ||||
| Mean annual temperature (°C) | 0.21 (0.03 to 0.39) | 0.11 (−0.02 to 0.25) | 0.01 (−0.36 to 0.39) | −0.05 (−0.22 to 0.12) |
| Annual variation in mean temperature (°C) | −0.12 (−1.25 to 1.01) | −0.20 (−1.03 to 0.63) | −2.87 (−5.81 to 0.06) | −2.23 (−3.85 to −0.60) |
| Lowest monthly mean temperature (°C) | 0.06 (−0.04 to 0.17) | 0.04 (−0.04 to 0.12) | 0.12 (−0.15 to 0.39) | 0.07 (−0.09 to 0.24) |
| Mean temperature of ⩾1 month below 0°C | −0.84 (−3.55 to 1.87) | −1.04 (−3.16 to 1.09) | −1.39 (−5.60 to 2.82) | 0.45 (−1.16 to 2.06) |
| Outdoor relative humidity | ||||
| Mean annual relative humidity (%) | −0.10 (−0.19 to −0.01) | −0.03 (−0.09 to 0.03) | 0.12 (−0.06 to 0.30) | 0.06 (−0.03 to 0.16) |
| Annual variation in mean relative humidity (%) | 0.15 (−0.72 to 1.02) | −0.13 (−0.64 to 0.39) | −0.60 (−1.82 to 0.62) | −0.62 (−1.33 to 0.09) |
| Lowest monthly mean relative humidity (%) | −0.05 (−0.10 to 0.01) | −0.01 (−0.04 to 0.03) | 0.06 (−0.04 to 0.15) | 0.06 (0.01 to 0.11) |
| Mean relative humidity of ⩾1 month below 50% | 1.52 (−0.65 to 3.68) | 0.65 (−0.61 to 1.92) | −2.54 (−6.34 to 1.27) | −1.86 (−3.69 to −0.04) |
| Indoor relative humidity at 20°C | ||||
| Mean annual relative humidity (%) | 0.03 (−0.02 to 0.07) | 0.01 (−0.02 to 0.03) | 0.07 (−0.09 to 0.24) | 0.03 (−0.05 to 0.12) |
| Annual variation in mean relative humidity (%) | 0.13 (−0.29 to 0.55) | 0.10 (−0.13 to 0.33) | −0.61 (−1.64 to 0.42) | −0.21 (−0.71 to 0.29) |
| Lowest monthly mean relative humidity (%) | 0.04 (−0.01 to 0.08) | 0.01 (−0.02 to 0.03) | 0.18 (0.01 to 0.36) | 0.06 (−0.03 to 0.16) |
| Mean relative humidity of ⩾1 month below 50% | −0.77 (−3.06 to 1.52) | 0.20 (−1.20 to 1.60) | ‡ | ‡ |