Table 2.
Crude and adjusted odds ratios quantifying the relation between categorized z-scores for PM10 measurements and spontaneous and induced preterm delivery.
| Crude odds ratio (95% CI) | Adjusted* odds ratio (95% CI) | Wald P | |
|---|---|---|---|
| Spontaneous delivery | |||
| Categorized z-scores for proportion > 55 μg PM10/m3 | |||
| <0 | 1.9 (1.2–3.1) | 2 (1.2–3.1) | P = 0.005 |
| [0—1] | Ref | Ref | |
| >1 SD | 5.5 (3.4–9.0) | 5.4 (3.2–8.9) | P < 0.001 |
| Categorized z-scores for mean PM10/m3 | |||
| <−1 SD | 1.6 (1–2.6) | 1.7 (1–2.7) | P = 0.04 |
| [−1 SD—0] | 1 (0.7–1.6) | 1 (0.7–1.6) | P = 0.8 |
| [0—1 SD] | Ref | Ref | |
| >1 SD | 2.1 (1.4–3.3) | 2 (1.3–3.2) | P = 0.002 |
| Induced delivery | |||
| Categorized z-scores for proportion > 55 μg PM10/m3 | |||
| <0 | 2.6 (1.6–4.2) | 2.7 (1.6–4.5) | P < 0.001 |
| [0—1] | Ref | Ref | |
| >1 SD | 6.4 (3.8–10.7) | 6.8 (3.9–11.9) | P < 0.001 |
| Categorized z-scores for mean PM10/m3 | |||
| <−1 SD | 1.9 (1.2–3.2) | 2.1 (1.3–3.6) | P = 0.005 |
| [−1 SD—0] | 1.5 (0.9–2.2) | 1.8 (1.1–2.9) | P = 0.01 |
| [0—1 SD] | Ref | Ref | |
| >1 SD | 3.2 (2.1–5.1) | 3.7 (2.3–6.0) | P < 0.001 |
*Multiple logistic regression model with presence or absence of preterm delivery (<37 weeks) adjusting for gravidity, parity, age, preeclampsia, trimester of first consultation, and prenatal interview.