Table 4:
Multivariable Regression Models for Categorical Exposures and Per IQR Increases in Ozone and PM2.5
| Exposure categoriesa | Cases / Controls | Model 1b | Model 2c |
|---|---|---|---|
| aOR (95% CI) | aOR (95% CI) | ||
| PM2.5 1st trimester (μg/m3) | |||
| 3.9 – <10.1 (referent) | 64/932 | 1.00 | 1.00 |
| 10.1 – <14.9 | 256/3819 | 0.98 (0.72, 1.32) | 0.93 (0.67, 1.30) |
| 14.9 – 21.8 | 65/941 | 1.06 (0.72, 1.56) | 0.99 (0.66, 1.51) |
| Per IQR increase (3.39) | -- | 1.03 (0.86, 1.23) | 1.05 (0.86, 1.28) |
| PM2.5 2nd trimester (μg/m3) | |||
| 4.2 – <10.1 (referent) | 50/923 | 1.00 | 1.00 |
| 10.1 – <14.9 | 269/3810 | 1.36 (0.98, 1.89) | 1.44 (1.01, 2.05) |
| 14.9 – 20.7 | 66/959 | 1.30 (0.85, 1.99) | 1.41 (0.89, 2.24) |
| Per IQR increase (3.34) | -- | 1.08 (0.91, 1.29) | 1.13 (0.93, 1.38) |
| PM2.5 3rd trimester (μg/m3) | |||
| 3.9 – <9.9 (referent) | 62/936 | 1.00 | 1.00 |
| 9.9 – <15.1 | 254/3763 | 0.99 (0.73, 1.35) | 0.98 (0.70, 1.37) |
| 15.1 – 24.4 | 65/951 | 1.05 (0.70, 1.58) | 1.04 (0.67, 1.61) |
| Per IQR increase (3.72) | -- | 0.98 (0.81, 1.20) | 0.96 (0.77, 1.20) |
| PM2.5 entire pregnancy (μg/m3) | |||
| 5.3 – <10.8 | 64/944 | 1.00 | 1.00 |
| 10.8 – <14.0 | 252/3800 | 0.95 (0.69, 1.30) | 0.87 (0.63, 1.21) |
| 14.0 – 18.3 | 69/948 | 1.07 (0.75, 1.53) | 0.99 (0.67, 1.46) |
| Per IQR increase (2.02) | -- | 1.01 (0.98, 1.04) | 1.01 (0.97, 1.04) |
| PM2.5 1st year of life (μg/m3) | |||
| 5.2 – <11.7 (referent) | 44/946 | 1.00 | 1.00 |
| 11.7 – <13.8 | 277/3807 | 1.67 (1.17, 2.38) | 1.84 (1.26, 2.69) |
| 13.8 – 17.5 | 64/939 | 1.40 (0.94, 2.09) | 1.54 (0.98, 2.40) |
| Per IQR increase (0.90) | -- | 1.07 (0.98, 1.17) | 1.11 (1.00, 1.23) |
| PM2.5 2nd year of life (μg/m3) | |||
| 8.7 – <11.5 (referent) | 63/991 | 1.00 | 1.00 |
| 11.5 – <13.2 | 268/3835 | 1.10 (0.82, 1.48) | 1.10 (0.81, 1.50) |
| 13.2 – 17.4 | 54/866 | 0.97 (0.61, 1.55) | 1.13 (0.67, 1.94) |
| Per IQR increase (0.87) | -- | 0.98 (0.88, 1.09) | 1.07 (0.93, 1.23) |
| PM2.5, CEI (μg/m3) | |||
| 7.2 – <11.8 (referent) | 51/982 | 1.00 | 1.00 |
| 11.8 – <13.2 | 267/3798 | 1.37 (1.00, 1.86) | 1.41 (1.02, 1.95) |
| 13.2 – 14.8 | 67/912 | 1.45 (0.98, 2.15) | 1.52 (1.00, 2.31) |
| Per IQR increase (0.94) | -- | 1.10 (0.94, 1.28) | 1.17 (0.98, 1.40) |
| Ozone 1st trimester (ppb) | |||
| 18.5 – <27.8 (referent) | 76/970 | 1.00 | 1.00 |
| 27.8 – <48.6 | 259/3825 | 0.76 (0.52, 1.10) | 0.70 (0.47, 1.04) |
| 48.6 – 65.3 | 50/897 | 0.59 (0.35, 1.00) | 0.56 (0.33, 0.96) |
| Per IQR increase (15.54) | -- | 0.87 (0.61, 1.25) | 0.87 (0.60, 1.26) |
| Ozone 2nd trimester (ppb) | |||
| 18.5 – <28.1 (referent) | 70/964 | 1.00 | 1.00 |
| 28.1 – <49.2 | 252/3780 | 0.93 (0.64, 1.36) | 0.96 (0.65, 1.42) |
| 49.2 – 65.4 | 63/948 | 0.94 (0.57, 1.55) | 0.92 (0.54, 1.55) |
| Per IQR increase (15.66) | -- | 0.92 (0.62, 1.35) | 0.85 (0.56, 1.29) |
| Ozone 3rd trimester (ppb) | |||
| 17.5 – <27.6 (referent) | 62/935 | 1.00 | 1.00 |
| 27.6 – <49.7 | 246/3784 | 0.94 (0.65, 1.37) | 0.92 (0.62, 1.35) |
| 49.7 – 65.2 | 73/931 | 1.16 (0.71, 1.88) | 1.17 (0.71, 1.93) |
| Per IQR increase (16.50) | -- | 1.22 (0.82, 1.80) | 1.19 (0.80, 1.77) |
| Ozone entire pregnancy (ppb) | |||
| 23.7 – <34.3 (referent) | 62/967 | 1.00 | 1.00 |
| 34.3 – <44.6 | 259/3784 | 1.16 (0.83, 1.63) | 1.23 (0.86, 1.75) |
| 44.6 – 59.4 | 64/941 | 1.18 (0.74, 1.86) | 1.28 (0.78, 2.10) |
| Per IQR increase (7.39) | -- | 1.00 (0.99, 1.00) | 1.00 (0.99, 1.01) |
| Ozone 1st year of life (ppb) | |||
| 32.8 – <36.5 (referent) | 66/924 | 1.00 | 1.00 |
| 36.5 – <41.6 | 251/3818 | 0.94 (0.70, 1.25) | 0.95 (0.69, 1.31) |
| 41.6 – 48.5 | 68/950 | 1.04 (0.72, 1.49) | 1.19 (0.79, 1.81) |
| Per IQR increase (3.83) | -- | 1.05 (0.87, 1.27) | 1.22 (0.96, 1.54) |
| Ozone 2nd year of life (ppb) | |||
| 32.8 – <36.6 (referent) | 49/887 | 1.00 | 1.00 |
| 36.6 – <41.5 | 273/3836 | 1.41 (1.00, 1.99) | 1.42 (0.98, 2.05) |
| 41.5 – 45.4 | 63/969 | 1.28 (0.84, 1.96) | 1.29 (0.81, 2.05) |
| Per IQR increase (3.66) | -- | 1.19 (0.95, 1.48) | 1.27 (0.96, 1.69) |
| Ozone CEI (ppb) | |||
| 33.1 – <37.3 (referent) | 67/927 | 1.00 | 1.00 |
| 37.3 – <41.4 | 252/3789 | 0.95 (0.71, 1.28) | 1.02 (0.76, 1.37) |
| 41.4 – 45.6 | 66/976 | 0.99 (0.66, 1.47) | 1.16 (0.76, 1.78) |
| Per IQR increase (2.79) | -- | 1.07 (0.88, 1.29) | 1.19 (0.95, 1.49) |
CEI=Cumulative Exposure Index (pregnancy through 2nd year of life)
Sextiles with middle 2–5 categories collapsed into one group.
Model 1 adjusted for year of birth, mother’s education, birth spacing, maternal pre-pregnancy body mass index, month of conception.
Model 2 adjusted for year of birth, mother’s education, birth spacing, maternal pre-pregnancy body mass index, and month of conception, multi-window (except for CEI models), and multi-pollutant. Multi-window models: 1st trimester models adjusted for 3rd trimester average exposure; 2nd trimester models adjusted for 3rd trimester average exposure; 3rd trimester models adjusted for 1st trimester average exposure; 1st year of life models adjusted for pregnancy average exposure; 2nd year of life models adjusted for pregnancy average exposure. Multi-pollutant models: ozone models adjusted for PM2.5 average exposures for the same time period; PM2.5 models adjusted for ozone average exposure during the same time period.