Table 7.
Associations Between Prenatal Exposure to Air Pollution and Prevalence of Active Asthma at Age 7 (Parental Recall) in the DNBC of 22,084 Children Born in Denmark, 1998–2003 With Increasing Level of Adjustment for Confounders a
| Pollutant | Model 1 OR (95%CI) |
Model 2 OR (95%CI) |
Model 3 OR (95%CI) |
Model 4 OR (95%CI) |
Model 5 OR (95%CI) |
|---|---|---|---|---|---|
| PM2.5 | 0.86 (0.68–1.08) | 0.88 (0.70–1.11) | 0.90 (0.71–1.13) | 0.81 (0.63–1.04) | 0.93 (0.70–1.23) |
| PM10 | 0.88 (0.61–1.26) | 0.88 (0.61–1.27) | 0.94 (0.65–1.36) | 0.85 (0.57–1.28) | 0.89 (0.60–1.34) |
| NO2 | 0.95 (0.87–1.04) | 0.96 (0.88–1.06) | 0.97 (0.88–1.06) | 0.92 (0.83–1.02) | 0.97 (0.86–1.09) |
| NOx | 0.96 (0.90–1.03) | 0.97 (0.90–1.04) | 0.97 (0.90–1.04) | 0.95 (0.87–1.02) | 0.97 (0.90–1.05) |
| EC | 0.93 (0.78–1.10) | 0.94 (0.79–1.12) | 0.96 (0.81–1.14) | 0.90 (0.74–1.09) | 0.96 (0.79–1.17) |
| OC | 0.85 (0.68–1.07) | 0.90 (0.71–1.14) | 0.98 (0.76–1.26) | 0.88 (0.66–1.16) | 1.02 (0.75–1.38) |
| SO2 | 1.03 (0.95–1.13) | 1.02 (0.93–1.12) | 1.01 (0.91–1.11) | 1.00 (0.97–1.03) | 1.00 (0.89–1.12) |
| O3 | 1.00 (0.97–1.03) | 1.00 (0.97–1.03) | 1.01 (0.98–1.04) | 1.05 (0.94–1.17) | 1.00 (0.97–1.04) |
| SO42- | 0.82 (0.60–1.11) | 0.85 (0.63–1.16) | 0.82 (0.60–1.12) | 0.73 (0.53–1.02) | 0.88 (0.60–1.30) |
| NO3- | 0.69 (0.34–1.38) | 0.72 (0.36–1.45) | 0.67 (0.33–1.36) | 0.57 (0.27–1.20) | 0.85 (0.37–1.96) |
| NH4+ | 0.82 (0.56–1.20) | 0.83 (0.56–1.22) | 0.85 (0.58–1.25) | 0.79 (0.53–1.19) | 0.91 (0.60–1.39) |
| SOA | 1.17 (0.62–2.22) | 1.21 (0.64–2.30) | 0.76 (0.34–1.70) | 0.68 (0.29–1.58) | 0.90 (0.37–2.16) |
| Sea salt | 1.35 (0.89–2.04) | 1.26 (0.83–1.91) | 1.40 (0.90–2.18) | 1.66 (1.04–2.65) | 1.31 (0.75–2.29) |
a Odds ratios (OR) and the 95% CIs from logistic regression models with GEE for fixed increments (μg/m3) of the time-weighted average exposures to ambient air pollutants for the full prenatal period of 5 for PM2.5, 10 for PM10, 10 for NO2, 20 for NOx, 1 for EC, 1 for OC, 1 for SO2, 10 for O3, 1 for SO42-, 5 for NO3-, 1 for NH4+, 1 for SOA, and 1 for sea salt with increasing degrees of adjustment. Asthma refers to active asthma at age 7 and the models for all included (N = 22.084, n = 978).
Model 1: Adjusted for sex and birth year. Model 2: Further adjusted for maternal education, income, and parity. Model 3: Further adjusted for season of birth and maternal smoking during pregnancy. Model 4: Further adjusted for maternal and paternal asthma, pets during pregnancy, house size at birth, breastfeeding, daycare, mold, dampness, ETS, and presence of gas stove, presence of wood stove, and candlelight burning in the home at age 11. Model 5: Further adjusted for municipality.