Studies n | Mean OR (95% CI)# | ||
Single-pollutant model | Two-pollutant model | ||
Bronchitis | |||
In studies with SO2 data | 3 | 1.17 (0.93–1.48) | 0.81 (0.44–1.51)¶ |
In studies with NO2data | 3 | 1.35 (0.96–1.91) | 1.49 (0.85–2.61) |
Phlegm | |||
In studies with SO2 data | 2 | 1.23 (0.81–1.89)¶ | 1.24 (0.80–1.94)¶ |
In studies with NO2data | 2 | 1.55 (1.11–2.18) | 1.55 (1.01–2.38) |
Nocturnal cough | |||
In studies with SO2 data | 2 | 1.41 (0.68–2.93)¶ | 1.43 (0.61–3.36)¶ |
In studies with NO2data | 3 | 1.14 (0.68–1.91)¶ | 0.79 (0.53–1.19) |
Morning cough | |||
In studies with SO2 data | 5 | 1.25 (0.93–1.67)¶ | 1.24 (0.90–1.70)¶ |
In studies with NO2data | 3 | 1.42 (1.04–1.92) | 1.36 (0.87–2.13) |
Hay fever | |||
In studies with SO2 data | 5 | 1.13 (0.98–1.31) | 1.19 (1.01–1.40) |
In studies with NO2data | 4 | 1.22 (0.84–1.78)¶ | 1.18 (0.70–1.97) |
Itchy rash | |||
In studies with SO2 data | 3 | 1.05(0.93–1.19) | 1.13 (0.97–1.33) |
In studies with NO2data | 3 | 1.18 (0.94–1.50) | 0.91 (0.48–1.71)¶ |
Allergy to pets | |||
In studies with SO2 data | 3 | 1.31 (0.90–1.90)¶ | 1.16 (0.88–1.52) |
In studies with NO2data | 3 | 1.25 (0.92–1.70) | 0.87 (0.42–1.80)¶ |
Combined effect estimates calculated from country-specific estimates using random effects model. #: adjusted for age, sex, maternal education, paternal education, household crowding, current parental smoking, mother smoking during pregnancy, gas cooking, unvented gas/oil/kerosene heater, mould, nationality, birth order, and “ever had a pet” and expressed per 10-μg·m−3 increase in PM10;¶: evidence of between study heterogeneity (p<0.10).