Table 4.
Odds ratios (95% confidence intervals) of higher blood pressure category on admission to labor/delivery by volatile organic compoundsa
| Exposure by hypertensive status | Time (hours) | ||||
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | |
| Normotensive | |||||
| Benzene | 1.001 (0.973–1.030) | 1.009 (0.981–1.038) | 1.006 (0.978–1.035) | 0.997 (0.970–1.026) | 0.995 (0.967–1.023) |
| 1,3-butadiene | 1.013 (0.985–1.043) | 1.018 (0.990–1.047) | 1.038 (1.010–1.067) | 1.051 (1.022–1.081) | 1.058 (1.028–1.089) |
| Ethylbenzene | 0.997 (0.968–1.028) | 1.001 (0.971–1.032) | 0.999 (0.969–1.030) | 0.999 (0.969–1.030) | 0.986 (0.956–1.016) |
| Cyclohexane | 1.008 (0.977–1.040) | 1.016 (0.985–1.048) | 1.013 (0.982–1.045) | 1.016 (0.985–1.048) | 1.015 (0.984–1.047) |
| Methyl-tertiary-butyl ether | 0.983 (0.956–1.010) | 0.992 (0.965–1.019) | 0.997 (0.971–1.025) | 0.994 (0.968–1.022) | 0.980 (0.953–1.007) |
| N-hexane | 1.000 (0.972–1.029) | 1.010 (0.982–1.039) | 1.007 (0.979–1.036) | 1.011 (0.983–1.040) | 0.994 (0.966–1.023) |
| Ethyl-methyl ketone | 0.979 (0.951–1.008) | 1.001 (0.972–1.030) | 0.999 (0.970–1.028) | 0.995 (0.967–1.025) | 0.988 (0.959–1.017) |
| M-xylene | 0.996 (0.966–1.027) | 1.009 (0.979–1.040) | 1.005 (0.975–1.036) | 1.002 (0.972–1.033) | 1.001 (0.971–1.032) |
| O-xylene | 0.993 (0.962–1.024) | 0.985 (0.955–1.017) | 1.000 (0.969–1.032) | 1.007 (0.976–1.039) | 0.998 (0.968–1.030) |
| P-xylene | 0.996 (0.966–1.026) | 1.008 (0.978–1.039) | 1.003 (0.973–1.033) | 1.000 (0.970–1.030) | 0.983 (0.954–1.014) |
| Propene | 1.000 (0.974–1.027) | 1.014 (0.988–1.041) | 1.036 (1.009–1.064) | 1.047 (1.020–1.075) | 1.039 (1.012–1.067) |
| Sesquiterpene | 0.971 (0.948–0.995) | 0.979 (0.955–1.003) | 0.992 (0.968–1.017) | 0.992 (0.969–1.016) | 0.992 (0.968–1.016) |
| Styrene | 0.986 (0.958–1.016) | 1.000 (0.972–1.029) | 1.017 (0.989–1.046) | 1.031 (1.002–1.061) | 1.035 (1.005–1.066) |
| Toluene | 0.988 (0.958–1.019) | 0.982 (0.952–1.013) | 0.995 (0.964–1.026) | 1.004 (0.973–1.035) | 1.004 (0.973–1.036) |
| Gestational hypertension | |||||
| Benzene | 1.153 (0.992–1.340) | 1.183 (1.014–1.379)* | 1.216 (1.045–1.415)* | 1.190 (1.025–1.383)* | 1.203 (1.037–1.394)* |
| 1,3-butadiene | 0.960 (0.837–1.101) | 0.991 (0.861–1.140) | 1.008 (0.874–1.162) | 1.010 (0.875–1.165) | 1.077 (0.932–1.244) |
| Ethylbenzene | 1.163 (0.989–1.369) | 1.119 (0.951–1.318) | 1.103 (0.935–1.300) | 1.141 (0.972–1.340) | 1.143 (0.974–1.342) |
| Cyclohexane | 1.164 (0.986–1.375) | 1.140 (0.966–1.345) | 1.176 (0.996–1.387) | 1.198 (1.015–1.415) | 1.132 (0.961–1.332) |
| Methyl-tertiary-butyl ether | 1.144 (0.992–1.320)* | 1.221 (1.059–1.409)* | 1.259 (1.092–1.451)* | 1.186 (1.031–1.366)* | 1.154 (1.003–1.328)* |
| N-hexane | 1.266 (1.088–1.472)* | 1.252 (1.076–1.456)* | 1.270 (1.092–1.476)* | 1.275 (1.097–1.481)* | 1.218 (1.048–1.416)* |
| Ethyl-methyl ketone | 1.055 (0.901–1.236) | 1.080 (0.921–1.266) | 1.096 (0.936–1.284) | 1.093 (0.933–1.280) | 1.080 (0.924–1.262) |
| M-xylene | 1.132 (0.961–1.332) | 1.203 (1.019–1.422)* | 1.190 (1.010–1.402)* | 1.235 (1.048–1.456)* | 1.229 (1.046–1.443)* |
| O-xylene | 1.184 (1.001–1.402)* | 1.183 (0.997–1.404)* | 1.179 (0.995–1.398) | 1.178 (0.995–1.395) | 1.198 (1.015–1.413)* |
| P-xylene | 1.085 (0.920–1.279) | 1.110 (0.942–1.307) | 1.144 (0.971–1.347) | 1.153 (0.981–1.355) | 1.098 (0.935–1.288) |
| Propene | 1.203 (1.048–1.382)* | 1.222 (1.06–1.408)* | 1.211 (1.049–1.397)* | 1.255 (1.085–1.452)* | 1.242 (1.073–1.437)* |
| Sesquiterpene | 1.017 (0.888–1.165) | 0.992 (0.866–1.136) | 1.044 (0.913–1.195) | 1.092 (0.954–1.249) | 1.010 (0.881–1.156) |
| Styrene | 1.008 (0.878–1.158) | 1.044 (0.907–1.203) | 1.062 (0.922–1.224) | 1.026 (0.890–1.182) | 1.054 (0.914–1.214) |
| Toluene | 1.174 (0.992–1.390) | 1.171 (0.988–1.387)* | 1.219 (1.028–1.444)* | 1.213 (1.027–1.431)* | 1.209 (1.025–1.426)* |
| Preeclampsia | |||||
| Benzene | 1.162 (1.046–1.291)* | 1.179 (1.061–1.309)* | 1.194 (1.074–1.327)* | 1.160 (1.043–1.289)* | 1.115 (1.003–1.238)* |
| 1,3-butadiene | 0.946 (0.842–1.063) | 0.936 (0.831–1.056) | 0.947 (0.836–1.073) | 0.992 (0.874–1.127) | 0.966 (0.849–1.100) |
| Ethylbenzene | 1.110 (0.998–1.234) | 1.101 (0.990–1.224) | 1.078 (0.970–1.199) | 1.053 (0.947–1.171) | 1.029 (0.925–1.144) |
| Cyclohexane | 1.104 (0.992–1.228) | 1.129 (1.014–1.256) | 1.145 (1.029–1.274)* | 1.129 (1.015–1.256) | 1.096 (0.985–1.219) |
| Methyl-tertiary-butyl ether | 1.084 (0.976–1.205) | 1.107 (0.997–1.230)* | 1.110 (0.999–1.234) | 1.074 (0.966–1.193) | 1.028 (0.925–1.142) |
| N-hexane | 1.265 (1.138–1.406)* | 1.236 (1.112–1.375)* | 1.180 (1.060–1.312)* | 1.193 (1.073–1.326)* | 1.142 (1.027–1.270)* |
| Ethyl-methyl ketone | 1.070 (0.962–1.191) | 1.104 (0.993–1.229) | 1.067 (0.959–1.187) | 1.039 (0.934–1.156) | 1.030 (0.926–1.146) |
| M-xylene | 1.117 (1.004–1.242)* | 1.128 (1.014–1.255)* | 1.106 (0.995–1.231) | 1.042 (0.937–1.159) | 1.006 (0.905–1.119) |
| O-xylene | 1.058 (0.951–1.176) | 1.042 (0.936–1.159) | 1.026 (0.922–1.141) | 1.013 (0.911–1.127) | 0.980 (0.881–1.089) |
| P-xylene | 1.101 (0.990–1.224) | 1.125 (1.012–1.251)* | 1.088 (0.979–1.211) | 1.043 (0.938–1.159) | 0.992 (0.892–1.103) |
| Propene | 1.019 (0.914–1.136) | 1.017 (0.911–1.135) | 1.079 (0.965–1.206) | 1.096 (0.979–1.227) | 1.027 (0.916–1.15) |
| Sesquiterpene | 1.130 (1.010–1.264)* | 1.125 (1.005–1.258)* | 1.122 (1.002–1.256)* | 1.066 (0.953–1.192) | 1.112 (0.996–1.242) |
| Styrene | 0.980 (0.871–1.103) | 0.939 (0.832–1.059) | 0.996 (0.879–1.128) | 1.022 (0.899–1.161) | 1.033 (0.908–1.176) |
| Toluene | 1.057 (0.950–1.176) | 1.047 (0.941–1.165) | 1.050 (0.944–1.168) | 1.021 (0.918–1.135) | 0.998 (0.898–1.109) |
| Chronic hypertension | |||||
| Benzene | 0.890 (0.743–1.065) | 0.957 (0.799–1.147) | 0.975 (0.811–1.171) | 0.996 (0.829–1.197) | 1.041 (0.868–1.249) |
| 1,3-butadiene | 1.022 (0.862–1.213) | 0.946 (0.800–1.119) | 0.972 (0.823–1.149) | 0.954 (0.806–1.129) | 0.903 (0.763–1.068) |
| Ethylbenzene | 0.911 (0.760–1.093) | 0.917 (0.765–1.099) | 0.922 (0.767–1.109) | 1.060 (0.883–1.273) | 1.070 (0.893–1.282) |
| Cyclohexane | 0.885 (0.741–1.057) | 0.931 (0.777–1.115) | 0.919 (0.767–1.102) | 0.947 (0.791–1.133) | 1.011 (0.847–1.207) |
| Methyl-tertiary-butyl ether | 0.961 (0.810–1.140) | 0.972 (0.820–1.153) | 1.024 (0.864–1.213) | 0.976 (0.824–1.155) | 1.101 (0.929–1.304) |
| N-hexane | 0.852 (0.714–1.017) | 0.908 (0.760–1.085) | 0.889 (0.743–1.063) | 1.007 (0.844–1.202) | 1.036 (0.868–1.237) |
| Ethyl-methyl ketone | 0.967 (0.808–1.158) | 0.853 (0.712–1.023) | 0.879 (0.735–1.052) | 1.004 (0.842–1.198) | 0.973 (0.816–1.160) |
| M-xylene | 0.905 (0.755–1.084) | 0.904 (0.755–1.082) | 0.956 (0.797–1.149) | 0.986 (0.821–1.183) | 1.054 (0.880–1.261) |
| O-xylene | 0.946 (0.788–1.137) | 0.983 (0.819–1.181) | 1.032 (0.858–1.241) | 1.094 (0.911–1.313) | 1.057 (0.878–1.272) |
| P-xylene | 0.915 (0.765–1.095) | 0.942 (0.787–1.127) | 0.934 (0.777–1.123) | 1.052 (0.876–1.264) | 1.092 (0.911–1.308) |
| Propene | 0.953 (0.800–1.135) | 0.919 (0.771–1.096) | 0.913 (0.766–1.088) | 0.941 (0.789–1.123) | 1.038 (0.871–1.237) |
| Sesquiterpene | 0.891 (0.747–1.062) | 0.957 (0.804–1.141) | 1.050 (0.881–1.253) | 0.968 (0.814–1.152) | 0.978 (0.821–1.166) |
| Styrene | 1.000 (0.845–1.184) | 0.989 (0.836–1.169) | 0.921 (0.779–1.088) | 0.853 (0.722–1.008) | 0.892 (0.755–1.053) |
| Toluene | 1.006 (0.837–1.208) | 1.012 (0.843–1.216) | 1.037 (0.862–1.248) | 1.084 (0.904–1.301) | 1.062 (0.884–1.275) |
| Superimposed preeclampsia | |||||
| Benzene | 0.778 (0.547–1.105) | 0.793 (0.554–1.135) | 0.870 (0.606–1.249) | 0.928 (0.652–1.321) | 0.910 (0.640–1.292) |
| 1,3-butadiene | 0.765 (0.553–1.057) | 0.767 (0.551–1.067) | 0.809 (0.580–1.129) | 0.797 (0.569–1.115) | 0.702 (0.504–0.979)* |
| Ethylbenzene | 0.748 (0.527–1.061) | 0.774 (0.544–1.100) | 0.793 (0.558–1.128) | 0.887 (0.629–1.253) | 0.909 (0.646–1.280) |
| Cyclohexane | 0.774 (0.545–1.099) | 0.867 (0.612–1.227) | 0.814 (0.571–1.160) | 0.886 (0.630–1.248) | 0.891 (0.634–1.253) |
| Methyl-tertiary-butyl ether | 0.960 (0.692–1.333) | 1.077 (0.775–1.497) | 1.126 (0.809–1.567) | 1.285 (0.928–1.779) | 1.250 (0.901–1.734) |
| N-hexane | 0.794 (0.561–1.123) | 0.759 (0.535–1.076) | 0.731 (0.513–1.043) | 0.895 (0.632–1.266) | 0.849 (0.603–1.195) |
| Ethyl-methyl ketone | 0.812 (0.573–1.150) | 0.858 (0.608–1.212) | 0.847 (0.598–1.200) | 0.868 (0.618–1.218) | 0.916 (0.657–1.276) |
| M-xylene | 0.719 (0.507–1.017) | 0.775 (0.544–1.105) | 0.889 (0.618–1.280) | 0.898 (0.634–1.272) | 0.854 (0.603–1.208) |
| O-xylene | 0.716 (0.501–1.024) | 0.770 (0.539–1.098) | 0.850 (0.590–1.224) | 0.992 (0.694–1.417) | 0.986 (0.693–1.403) |
| P-xylene | 0.762 (0.537–1.081) | 0.820 (0.578–1.163) | 0.871 (0.613–1.238) | 0.892 (0.634–1.255) | 0.870 (0.618–1.224) |
| Propene | 0.914 (0.655–1.275) | 1.026 (0.732–1.438) | 0.903 (0.634–1.287) | 0.797 (0.562–1.130) | 0.916 (0.652–1.286) |
| Sesquiterpene | 0.655 (0.467–0.918) | 0.727 (0.514–1.027) | 0.734 (0.515–1.046) | 0.795 (0.563–1.123) | 0.926 (0.658–1.304) |
| Styrene | 0.872 (0.629–1.209) | 0.830 (0.596–1.155) | 0.764 (0.549–1.062) | 0.763 (0.547–1.065) | 0.694 (0.498–0.967)* |
| Toluene | 0.745 (0.520–1.066) | 0.738 (0.516–1.055) | 0.860 (0.599–1.236) | 0.944 (0.661–1.350) | 1.013 (0.713–1.440) |
aOrdinal logistic regression with linear function of air pollutant, hypertensive disorder, and their interaction and results clustered within woman estimated the effect of high air toxics exposure (≥75th percentile in parts per billion), adjusted for site, maternal age, race/ethnicity, insurance, smoking during pregnancy, and time of day.
*Interaction term is significant (P < 0.05), suggesting that the response is different than in the normotensive women. Estimates that are statistically significant are given in bold.