Table 13.
Estimated ORs and 95% CIs for PTB and LBW Attributable to Maternal Exposure to Pollutants During Entire Pregnancy for 6,787 Cases and Controls Who Did Not Relocate During Pregnancy in the Nested Case-Control Study (Wuhan, China; August 19, 2010–June 9, 2013)a
| Pollutant | Model 1b | Model 2c | Model 3d | Model 4e |
|---|---|---|---|---|
| OR (95% CI) | OR (95% CI) | OR (95% CI) | OR (95% CI) | |
| PTB | ||||
| PM2.5 | 1.10 (0.98, 1.23) | 1.11 (0.98, 1.26) | 1.12 (0.99, 1.27) | 1.14 (1.01, 1.29) |
| PM10 | 1.11 (1.00, 1.23) | 1.16 (1.00, 1.35) | 1.17 (1.01, 1.36) | 1.19 (1.02, 1.38) |
| SO2 | 1.03 (0.92, 1.14) | 0.95 (0.84, 1.09) | 0.93 (0.82, 1.07) | 0.95 (0.84, 1.08) |
| NO2 | 1.09 (0.98, 1.21) | 1.07 (0.94, 1.22) | 1.07 (0.94, 1.21) | 1.07 (0.94, 1.22) |
| CO | 1.13 (1.01, 1.25) | 1.17 (1.01, 1.36) | 1.20 (1.03, 1.40) | 1.20 (1.04, 1.40) |
| O3 | 1.06 (0.95, 1.17) | 1.21 (1.04, 1.39) | 1.21 (1.04, 1.40) | 1.21 (1.05, 1.40) |
| LBW | ||||
| PM2.5 | 1.11 (0.98, 1.27) | 1.13 (0.98, 1.30) | 1.14 (0.98, 1.31) | 1.14 (0.99, 1.31) |
| PM10 | 1.01 (0.90, 1.14) | 1.03 (0.87, 1.21) | 1.03 (0.87, 1.22) | 1.05 (0.89, 1.24) |
| SO2 | 0.99 (0.88, 1.12) | 0.95 (0.82, 1.10) | 0.94 (0.81, 1.09) | 0.93 (0.78, 1.11) |
| NO2 | 1.03 (0.91, 1.16) | 1.02 (0.88, 1.18) | 1.00 (0.87, 1.16) | 1.01 (0.88, 1.17) |
| CO | 1.02 (0.90, 1.15) | 1.06 (0.89, 1.27) | 1.07 (0.89, 1.28) | 1.07 (0.90, 1.28) |
| O3 | 1.07 (0.95, 1.20) | 1.12 (0.95, 1.32) | 1.13 (0.96, 1.34) | 1.12 (0.96, 1.32) |
a The cut points were values close to medians of pollutants. Specifically for PTB they were 63.7 μg/m3 for PM2.5, 96.6 μg/m3 for PM10, 34.9 μg/m3 for SO2, 58.8 μg/m3 for NO2, 987.5 μg/m3 for CO, and 70.8 μg/m3 for O3; and for LBW they were 63.5 μg/m3 for PM2.5, 99.1 μg/m3 for PM10, 34.9 μg/m3 for SO2, 58.9 μg/m3 for NO2, 1010.8 μg/m3 for CO, and 72.3 μg/m3 for O3.
b ORs were estimated as the increase in the crude odds.
c Adjusted for covariates from the delivery data, including maternal age, maternal educational attainment, maternal occupation, gravidity, parity, infant sex, season of conception, and temperature at conception.
d Adjusted for covariates from the delivery data plus additional covariates from the survey, including total household income, SHS exposure, depression during pregnancy, and vaginal bleeding during pregnancy.
e Two-phase models that adjusted for covariates from both the delivery data and survey data in model 3.