Table 8.
Estimated Adjusted ORs and 95% CIs for PTB, LBW, and IUGR Attributable to Maternal Exposure to Pollutants During the Entire Pregnancy by Temperature at Conception in the Cohort Study (Wuhan, China; August 19, 2010–June 9, 2013)a,b,c,d
| Pollutant | Normal Temperature aOR (95% CI) |
Low Temperature aOR (95% CI) |
High Temperature aOR (95% CI) |
P Value e,f |
|---|---|---|---|---|
| PTB | ||||
| PM2.5 | 1.03 (1.02, 1.05) | 1.01 (0.85, 1.21) | 1.08 (1.03, 1.13) | < 0.01 |
| PM10 | 1.02 (1.00, 1.04) | 1.11 (1.00, 1.24) | 0.94 (0.86, 1.02) | 0.98 |
| SO2 | 0.97 (0.95, 0.98) | 1.10 (1.01, 1.18) | 0.94 (0.83, 1.06) | < 0.01 |
| NO2 | 0.98 (0.97, 1.00) | 1.00 (0.94, 1.06) | 0.95 (0.88, 1.03) | 0.43 |
| CO | 1.14 (1.09, 1.18) | 1.30 (1.08, 1.58) | 1.29 (1.10, 1.51) | 0.04 |
| O3 | 1.07 (1.04, 1.09) | 0.92 (0.83, 1.01) | 1.08 (0.89, 1.30) | < 0.01 |
| LBW | ||||
| PM2.5 | 1.01 (0.99, 1.03) | 1.12 (0.91, 1.38) | 1.03 (0.98, 1.08) | < 0.01 |
| PM10 | 1.01 (0.99, 1.03) | 1.09 (0.97, 1.23) | 0.89 (0.80, 0.98) | 0.24 |
| SO2 | 0.98 (0.96, 1.00) | 1.07 (0.98, 1.17) | 0.96 (0.83, 1.11) | 0.01 |
| NO2 | 0.98 (0.96, 1.00) | 0.99 (0.92, 1.07) | 1.02 (0.93, 1.12) | 0.69 |
| CO | 1.08 (1.03, 1.13) | 1.44 (1.15, 1.80) | 1.04 (0.87, 1.25) | 0.01 |
| O3 | 1.03 (0.99, 1.06) | 0.95 (0.85, 1.06) | 1.08 (0.87, 1.35) | < 0.01 |
| IUGR | ||||
| PM2.5 | 0.99 (0.98, 1.00) | 1.09 (0.96, 1.24) | 0.96 (0.93, 0.99) | 0.04 |
| PM10 | 0.99 (0.98, 1.01) | 1.08 (1.00, 1.16) | 0.93 (0.88, 0.98) | 0.02 |
| SO2 | 1.03 (1.02, 1.04) | 1.01 (0.95, 1.07) | 1.08 (0.98, 1.18) | 0.33 |
| NO2 | 0.99 (0.98, 1.01) | 1.00 (0.95, 1.04) | 0.97 (0.92, 1.03) | 0.48 |
| CO | 0.98 (0.95, 1.01) | 0.99 (0.87, 1.14) | 1.01 (0.91, 1.12) | 0.76 |
| O3 | 0.98 (0.96, 1.00) | 1.01 (0.94, 1.08) | 0.94 (0.83, 1.07) | 0.15 |
a ORs were estimated based on per 5-μg increase in PM2.5 and PM10, 3-μg increase in NO2 and SO2, 10-μg increase in O3, and 100-μg increase in CO.
b Adjusted for maternal age, maternal educational attainment, maternal occupation, gravidity, parity, infant sex, season of conception, and temperature at conception.
c Normal temperature ≥ 5th (3.8oC) percentile and ≤ 95th percentile (31.6oC) of daily average temperatures during the study period; low temperature < 5th percentile; and high temperature > 95th percentile.
d Temperature was defined as the daily average temperatures in the week of conception with the estimated conception day in the middle.
e Estimates were obtained for the main effects and for the pollutant × temperature interaction models.
f For the interaction term for the three temperature groups.