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Table 6 Intensity of maternal residential exposure index for selected chlorinated solvents and spina bifida in offspring

From: Maternal residential proximity to chlorinated solvent emissions and birth defects in offspring: a case–control study

Type of chlorinated solvent Intensity of exposure risk valuea Spina bifida cases Controls Adjusted odds ratiob 95% confidence interval p- value for trend
n % n %
Carbon tetrachloride 0.00 1269 96.6 237857 98.1 1.00 Referent 0.059
0.01-189.30 18 1.4 1531 0.6 2.08 1.29, 3.37
189.31-2342.12 14 1.1 1531 0.6 1.53 0.89, 2.64
>2342.12 12 0.9 1506 0.6 1.19 0.66, 2.14
Chloroform 0.00 1276 97.2 238440 98.4 1.00 Referent 0.027
0.01-42.27 14 1.1 1331 0.5 1.74 1.02, 2.99
42.28-1490.26 9 0.7 1331 0.5 1.23 0.63, 2.40
>1490.26 14 1.1 1323 0.5 1.66 0.94, 2.91
1,1-dichloroethane 0.00 1294 98.6 240578 99.2 1.00 Referent 0.046
0.01-0.53 8 0.6 618 0.3 2.18 1.07, 4.43
0.54-6.59 4 0.3 613 0.3 0.94 0.35, 2.53
>6.59 7 0.5 616 0.3 2.14 1.00, 4.57
1,2-dichloroethane 0.00 1248 95.0 235788 97.3 1.00 Referent < 0.0001
0.01-5.85 17 1.3 2197 0.9 1.24 0.76, 2.05
5.86-221.92 24 1.8 2215 0.9 1.83 1.20, 2.78
>221.92 24 1.8 2225 0.9 1.85 1.21, 2.84
1,2-dichloroethylene 0.00 1293 98.5 240399 99.2 1.00 Referent 0.065
0.01-0.48 6 0.5 676 0.3 1.51 0.67, 3.41
0.49-7.59 8 0.6 677 0.3 1.79 0.88, 3.63
>7.59 6 0.5 673 0.3 1.49 0.66, 3.36
Ethyl chloride 0.00 1263 96.2 237154 97.8 1.00 Referent 0.003
0.01-12.11 17 1.3 1761 0.7 1.71 1.04, 2.81
12.12-98.74 12 0.9 1764 0.7 1.17 0.65, 2.08
>98.74 21 1.6 1746 0.7 1.87 1.19, 2.92
Methyl chloroform 0.00 1256 95.7 237131 97.8 1.00 Referent 0.002
0.01-5.02 21 1.6 1751 0.7 1.67 1.07, 2.61
5.03-198.09 12 0.9 1778 0.7 1.08 0.60, 1.92
>198.09 24 1.8 1765 0.7 1.90 1.23, 2.94
Tetrachloroethane 0.00 1293 98.5 240470 99.2 1.00 Referent 0.033
0.01-0.18 7 0.5 653 0.3 1.88 0.88, 4.01
0.19-1.69 7 0.5 653 0.3 1.83 0.86, 3.92
>1.69 6 0.5 649 0.3 1.62 0.72, 3.66
1,1,2-trichloroethane 0.00 1283 97.7 239864 98.9 1.00 Referent 0.026
0.01-0.45 15 1.1 853 0.4 3.01 1.77, 5.10
0.46-1.78 8 0.6 855 0.4 1.46 0.72, 2.96
>1.78 7 0.5 853 0.4 1.40 0.66, 2.98
1,2,3-trichloropropane 0.00 1282 97.6 239578 98.8 1.00 Referent < 0.0001
  0.01-16.45 8 0.6 950 0.4 1.31 0.65, 2.68  
  16.46-132.51 8 0.6 947 0.4 1.42 0.70, 2.88  
  >132.51 15 1.1 950 0.4 2.62 1.55, 4.46  
  1. aExposure risk value based on maternal residential proximity to source(s) of air emissions and estimated pounds of chemical emitted annually.
  2. bAdjusted for birth year and maternal race/ethnicity, age, education, and public health region.