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. Author manuscript; available in PMC: 2015 Jun 18.
Published in final edited form as: Occup Environ Med. 2012 Jul 17;69(9):628–635. doi: 10.1136/oemed-2011-100536

Table 1.

Selected demographic, lifestyle, and occupational exposure characteristics of mothers of infants with simple, isolated congenital heart defects and control infants, National Birth Defects Prevention Study, 1997–2002

Congenital heart defect cases (n=2047) Controls (n=2951) P-Value*
N % N %

Maternal age at delivery (years)
 <20 150 7.3 241 8.2 0.25
 20–24 446 21.8 637 21.6
 25–29 543 26.5 787 26.7
 30–34 570 27.8 848 28.7
 ≥35 338 16.5 438 14.8
Maternal education
 Less than high school 219 10.7 295 10.0 0.08
 High school 549 26.8 730 24.7
 More than high school 1276 62.3 1921 65.1
 Missing 3 0.1 5 0.2
Maternal race-ethnicity
 Non-Hispanic White 1341 65.5 1910 64.7 0.48
 Non-Hispanic Black 278 13.6 374 12.7
 Hispanic 330 16.1 520 17.6
 Other 97 4.7 140 4.7
 Missing 1 0.0 7 0.2
Maternal smoking during periconceptional period
 Yes 458 22.4 606 20.5 0.12
 No 1589 77.6 2345 79.5
 Missing 0 0.0 0 0.0
Maternal folic acid intake during periconceptional period
 Yes 1792 87.5 2587 87.7 0.63
 No 205 10.0 310 10.5
 Missing 50 2.4 54 1.8
Periconceptional occupational exposure from expert consensus-based approach
 Any solvent 96 4.7 110 3.7 0.09
  Chlorinated solvents 88 4.3 101 3.4 0.11
  Stoddard solvent 31 1.5 37 1.3 0.44
Periconceptional occupational exposure from literature-based approach
 Any solvent 194 9.5 240 8.1 0.10
  Aromatic solvents 50 2.4 61 2.1 0.35
   Benzene 16 0.8 16 0.5 0.28
   Toluene 45 2.2 59 2.0 0.59
   Xylene 47 2.3 60 2.0 0.50
  Chlorinated solvents 156 7.6 203 6.9 0.30
   Carbon tetrachloride 5 0.2 8 0.3 0.87
   Chloroform 58 2.8 83 2.8 0.91
   Methylene chloride 137 6.7 177 6.0 0.30
   Perchloroethylene 82 4.0 108 3.7 0.49
   Trichloroethane 138 6.7 175 5.9 0.23
   Trichloroethylene 69 3.4 94 3.2 0.67
   Stoddard solvent 67 3.3 79 2.7 0.21
*

P-value for Chi-Square test of association

Periconceptional defined as one month before conception through the end of the first trimester.