Table 5.
Associations of PM10 and NO2 exposure with the risks of adverse birth outcomes [OR (95% CI)].
| Air pollution exposure | n | Preterm birth (< 37 weeks) (n = 7,045) | n | Low birth weight (< 2,500 g) (n = 7,003) | n | SGA at birth (< 5%) (n = 6,997) | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM10 | ||||||||||||
| First quartile | 78 | Reference | 74 | Reference | 73 | Reference | ||||||
| Second quartile | 75 | 0.96 (0.70, 1.33) | 66 | 0.76 (0.49, 1.20) | 78 | 1.05 (0.75, 1.47) | ||||||
| Third quartile | 106 | 1.40 (1.03, 1.89)* | 93 | 0.89 (0.58, 1.34) | 98 | 1.38 (1.00, 1.90)* | ||||||
| Fourth quartile | 105 | 1.32 (0.96, 1.79)# | 90 | 0.91 (0.60, 1.40) | 97 | 1.23 (0.89, 1.70) | ||||||
| Trend test (per 1-µg/m3 increase) | 1.03 (1.00, 1.07) | 1.00 (0.95, 1.05) | 1.03 (0.99, 1.07) | |||||||||
| p-Value for trend | 0.07 | 0.93 | 0.13 | |||||||||
| NO2 | ||||||||||||
| First quartile | 79 | Reference | 75 | Reference | 70 | Reference | ||||||
| Second quartile | 92 | 1.10 (0.81, 1.51) | 71 | 0.84 (0.54, 1.31) | 73 | 0.93 (0.66, 1.31) | ||||||
| Third quartile | 95 | 1.09 (0.79, 1.49) | 88 | 0.86 (0.55, 1.33) | 101 | 1.25 (0.90, 1.73) | ||||||
| Fourth quartile | 99 | 1.10 (0.77, 1.57) | 89 | 0.95 (0.58, 1.55) | 102 | 1.35 (0.94, 1.94) | ||||||
| Trend test (per 1-µg/m3 increase) | 1.01 (0.98, 1.04) | 1.00 (0.95, 1.04) | 1.03 (0.99, 1.06) | |||||||||
| p-Value for trend | 0.43 | 0.87 | 0.11 | |||||||||
| Values are ORs (95% CI) and reflect the risk for adverse birth outcomes for each quartile of air pollution exposure during pregnancy (from conception until delivery) compared with the reference group (lowest quartile). Cutoff values for categorization are < 27.8, 27.8–30.0, 30.0–32.9, > 32.9 μg/m3 for PM10 exposure and < 37.2, 37.2–39.6, 39.6–42.2, > 42.2 μg/m3 for NO2 exposure. Models are adjusted for maternal age, body mass index, height, parity, ethnicity, education, folic acid supplementation use, smoking, alcohol consumption, noise exposure, and paternal height. Models with preterm birth and low birth weight are additionally adjusted for fetal sex, and models with low birth weight are additionally adjusted for gestational age at birth. *p < 0.05. #p < 0.10. | ||||||||||||