Estimated ORs (95% CIs) and variance components for individual characteristics and respiratory symptoms in three samples
| Individual variables | Primary school pupils | Secondary school pupils | Parents | |||
| Symptoms in general | Symptoms in relation to school | Symptoms in general | Symptoms in relation to school | Symptoms in general | Symptoms in relation to school | |
| Age | 1.05 (1.01 to 1.10) | 1.08 (1.00 to 1.15) | 1.19 (1.08 to 1.32) | 1.34 (1.16 to 1.54) | 1.00 (0.94 to 1.06) | 0.99 (0.89 to 1.09) |
| Female gender | 1.21 (1.09 to 1.34) | 1.09 (0.93 to 1.29) | 1.34 (1.11 to 1.61) | 1.18 (0.90 to 1.55) | 1.10 (0.90 to 1.35) | 1.17 (0.84 to 1.62) |
| Smoking | 1.22 (1.08 to 1.37) | 1.31 (1.09 to 1.57) | 1.12 (0.91 to 1.37) | 1.31 (0.98 to 1.75) | 1.59 (1.24 to 2.05) | 1.51 (1.02 to 2.25) |
| Asthma | 1.54 (1.26 to 1.88) | 1.67 (1.27 to 2.22) | 2.35 (1.71 to 3.21) | 2.61 (1.75 to 3.90) | 2.28 (1.58 to 3.30) | 2.87 (1.69 to 4.85) |
| Hay fever | 1.50 (1.29 to 1.73) | 1.55 (1.25 to 1.93) | 1.64 (1.33 to 2.03) | 1.75 (1.29 to 2.37) | 1.74 (1.37 to 2.22) | 1.86 (1.28 to 2.72) |
| Atopic dermatitis | 1.49 (1.26 to 1.74) | 1.41 (1.10 to 1.81) | 1.45 (1.13 to 1.87) | 1.43 (1.00 to 2.05) | 1.14 (0.90 to 1.45) | 0.79 (0.53 to 1.19) |
| Swedish-speaking school (school level) | 0.95 (0.78 to 1.16) | 1.23 (0.90 to 1.67) | 1.27 (0.90 to 1.80) | 1.30 (0.67 to 2.50) | 1.31 (0.88 to 1.95) | 1.12 (0.54 to 2.32) |
| Variance between schools, σ2u | 0.024 | 0.071 | 0.055 | 0.266 | 0.103 | 0.470 |
| PCV | 1% | 5% | 31% | 9% | 11% | 3% |
| ICC | 0.007 | 0.021 | 0.017 | 0.075 | 0.030 | 0.125 |
| MOR | 1.16 | 1.29 | 1.25 | 1.64 | 1.36 | 1.93 |
The estimates highlighted in bold are statistically significant at p<0.05.
*Proportional change of variance (PCV) was calculated as (σ2u of the model including only random intercept − σ2u of the model including individual characteristics)/σ2u of the model including only random intercept.
ICC, intraclass correlation; MOR, median OR.