Table 3.
Adjusted odds ratio and 95% confident interval (95% CI) for each window of exposure to air pollutants (CO, SO2, NO2, and PM10) for term small for gestational age (SGA) and preterm birth (PTB).
| Windows and quartiles of exposures |
CO
|
SO2
|
NO2
|
PM10
|
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| N | Adjusteda | Trend-adjustedb | N | Adjusteda | Trend-adjustedb | N | Adjusteda | Trend-adjustedb | N | Adjusteda | Trend-adjustedb | |||
| Term SGA | 1st month | 2nd | 51,545 | 1.17 (1.06–1.29) | 1.11 (1.00–1.24) | 103,576 | 0.98 (0.92–1.04) | 0.96 (0.90–1.03) | 70,918 | 1.06 (0.99–1.14) | 1.07 (0.99–1.14) | 23,929 | 1.06 (0.91–1.24) | 1.07 (0.92–1.25) |
| 3rd | 1.07 (0.97–1.18) | 1.00 (0.89–1.12) | 1.03 (0.97–1.10) | 1.00 (0.94–1.07) | 1.06 (0.98–1.14) | 1.06 (0.98–1.14) | 0.99 (0.84–1.16) | 1.01 (0.85–1.20) | ||||||
| 4th | 1.20 (1.09–1.33) | 1.14 (1.02–1.27) | 1.11 (1.04–1.18) | 1.04 (0.97–1.13) | 1.10 (1.01–1.19) | 1.11 (1.03–1.21) | 1.15 (0.98–1.36) | 1.16 (0.98–1.38) | ||||||
| Last month | 2nd | 56,916 | 1.06 (0.97–1.17) | 1.00 (0.90–1.11) | 111,480 | 1.03 (0.97–1.09) | 1.01 (0.95–1.07) | 77,264 | 1.00 (0.93–1.07) | 1.00 (0.93–1.07) | 25,905 | 0.99 (0.85–1.15) | 1.00 (0.86–1.17) | |
| 3rd | 1.10 (1.00–1.20) | 1.02 (0.91–1.13) | 0.98 (0.92–1.04) | 0.94 (0.88–1.01) | 1.00 (0.93–1.07) | 1.00 (0.93–1.07) | 1.07 (0.92–1.25) | 1.09 (0.93–1.28) | ||||||
| 4th | 1.05 (0.96–1.16) | 0.98 (0.88–1.09) | 1.07 (1.00–1.14) | 0.98 (0.91–1.05) | 0.93 (0.86–1.01) | 0.95 (0.88–1.03) | 1.08 (0.92–1.26) | 1.07 (0.91–1.26) | ||||||
| 1st trimester | 2nd | 52,254 | 1.15 (1.04–1.27) | 1.11 (0.98–1.25) | 104,362 | 1.04 (0.98–1.11) | 1.02 (0.96–1.09) | 71,449 | 1.02 (0.95–1.10) | 1.03 (0.96–1.11) | 24,096 | 1.02 (0.87–1.19) | 1.06 (0.90–1.25) | |
| 3rd | 1.17 (1.06–1.29) | 1.10 (0.98–1.24) | 1.04 (0.97–1.11) | 1.01 (0.94–1.09) | 1.04 (0.95–1.12) | 1.05 (0.97–1.14) | 1.01 (0.86–1.20) | 1.06 (0.89–1.27) | ||||||
| 4th | 1.16 (1.04–1.28) | 1.10 (0.97–1.25) | 1.15 (1.08–1.23) | 1.09 (1.00–1.18) | 1.02 (0.93–1.12) | 1.06 (0.97–1.16) | 1.11 (0.94–1.32) | 1.14 (0.95–1.36) | ||||||
| 2nd trimester | 2nd | 53,805 | 1.07 (0.97–1.18) | 1.01 (0.90–1.13) | 107,681 | 1.00 (0.94–1.06) | 0.98 (0.92–1.05) | 74,384 | 0.98 (0.91–1.05) | 0.98 (0.91–1.06) | 24,248 | 1.16 (0.99–1.37) | 1.23 (1.04–1.45) | |
| 3rd | 1.10 (1.00–1.21) | 1.01 (0.90–1.14) | 0.97 (0.91–1.03) | 0.94 (0.88–1.01) | 0.97 (0.90–1.06) | 0.99 (0.91–1.08) | 1.17 (0.99–1.38) | 1.22 (1.02–1.45) | ||||||
| 4th | 1.10 (0.99–1.23) | 1.02 (0.90–1.15) | 1.12 (1.05–1.20) | 1.05 (0.96–1.14) | 0.96 (0.88–1.05) | 1.01 (0.92–1.11) | 1.04 (0.88–1.23) | 1.05 (0.87–1.26) | ||||||
| 3rd trimester | 2nd | 51,607 | 1.08 (0.98–1.19) | 1.00 (0.90–1.11) | 112,609 | 1.07 (1.01–1.13) | 1.04 (0.98–1.11) | 82,359 | 0.93 (0.87–1.00) | 0.94 (0.88–1.01) | 24,193 | 1.03 (0.88–1.22) | 1.05 (0.89–1.25) | |
| 3rd | 1.05 (0.95–1.15) | 0.96 (0.86–1.07) | 1.02 (0.95–1.08) | 0.98 (0.92–1.05) | 0.98 (0.91–1.06) | 0.99 (0.92–1.07) | 1.20 (1.02–1.42) | 1.25 (1.05–1.49) | ||||||
| 4th | 1.06 (0.96–1.17) | 0.97 (0.87–1.09) | 1.12 (1.05–1.20) | 1.03 (0.96–1.12) | 0.98 (0.90–1.06) | 1.01 (0.93–1.09) | 1.22 (1.04–1.44) | 1.22 (1.03–1.46) | ||||||
| PTB | 1st month | 2nd | 59,876 | 0.90 (0.84–0.97) | 0.96 (0.88–1.04) | 121,870 | 1.00 (0.96–1.05) | 0.99 (0.94–1.04) | 84,760 | 1.03 (0.97–1.08) | 1.03 (0.97–1.09) | 23,929 | 0.99 (0.87–1.12) | 0.97 (0.86–1.10) |
| 3rd | 0.92 (0.86–0.99) | 0.98 (0.90–1.07) | 1.00 (0.95–1.05) | 0.97 (0.93–1.02) | 1.03 (0.97–1.09) | 1.03 (0.97–1.09) | 1.10 (0.97–1.24) | 1.07 (0.94–1.22) | ||||||
| 4th | 0.89 (0.83–0.97) | 0.95 (0.87–1.03) | 1.03 (0.98–1.09) | 0.98 (0.92–1.04) | 1.00 (0.95–1.07) | 1.02 (0.96–1.08) | 1.06 (0.93–1.20) | 1.05 (0.92–1.20) | ||||||
| Last month | 2nd | 66,001 | 0.97 (0.91–1.04) | 1.04 (0.96–1.13) | 111,480 | 1.08 (1.03–1.13) | 1.08 (1.03–1.13) | 92,315 | 0.98 (0.93–1.04) | 0.98 (0.93–1.03) | 28,406 | 0.98 (0.87–1.10) | 0.96 (0.85–1.08) | |
| 3rd | 0.89 (0.83–0.96) | 0.96 (0.89–1.04) | 1.11 (1.05–1.16) | 1.11 (1.05–1.16) | 0.99 (0.94–1.05) | 0.99 (0.94–1.05) | 0.91 (0.80–1.02) | 0.88 (0.78–1.00) | ||||||
| 4th | 0.96 (0.89–1.04) | 1.04 (0.95–1.13) | 1.07 (1.02–1.13) | 1.07 (1.01–1.14) | 0.98 (0.92–1.04) | 0.98 (0.92–1.04) | 0.95 (0.84–1.07) | 0.95 (0.84–1.08) | ||||||
Note: N = numbers of mothers who had pollutant exposures by exposure windows; term SGA models do not include infant sex.
a
Adjusted for infant sex, maternal race, age groups, education levels, tobacco use, prenatal care, birth seasons and site of residency.
b
Adjusted for variables above and birth periods.