Table 2.
Relative risksa of PPD (EPDS ≥ 13) at 1 and 6 months postpartum (N = 509).
| Variable | Level/unit | PPD, 1 month RR (95% CI) | P | PPD, 6 months RR (95% CI) | P |
|---|---|---|---|---|---|
| PM2.5 in pregnancy | 5-μg/m3 change | 0.85 (0.61, 1.19) | 0.35 | 1.59 (1.11, 2.28) | 0.01 |
| Maternal age at enrollment | 1-yr change | 0.96 (0.93, 1.00) | 0.04 | 0.99 (0.96, 1.02) | 0.51 |
| Tobacco exposure in pregnancy | Yes | 0.78 (0.53, 1.15) | 0.22 | 1.03 (0.71, 1.49) | 0.88 |
| Maternal education | < High School | Ref. | - | Ref. | - |
| High School | 0.95 (0.63, 1.44) | 0.82 | 0.85 (0.56, 1.28) | 0.42 | |
| > High School | 0.61 (0.36, 1.02) | 0.06 | 0.57 (0.34, 0.93) | 0.03 | |
| Birth season | Dry/cold | Ref. | - | Ref. | - |
| Dry/warm | 1.72 (1.07, 2.76) | 0.03 | 1.17 (0.71, 1.95) | 0.54 | |
| Rainy | 1.18 (0.76, 1.81) | 0.46 | 1.00 (0.66, 1.53) | 0.99 | |
| Gestational age | 1-week change | 0.95 (0.83, 1.08) | 0.42 | 0.87 (0.78, 0.98) | 0.02 |
| Pregnancy NLE score | 1-event change | 1.21 (1.13, 1.30) | 9 × 10−8 | 1.21 (1.12, 1.31) | 1 × 10−6 |
a
Estimated from modified Poisson regression models with robust error variance, adjusted for all variables listed in table.