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Table 3 Frequencies, Odds Ratios and 95% Confidence Intervals for Birth Defects According to Average Monthly PCE Exposure during Year First Trimester Ended

From: Modeled exposure to tetrachloroethylene-contaminated drinking water and the occurrence of birth defects: a case-control study from Massachusetts and Rhode Island

 

Number of Cases

Number of Controls

Crude Odds Ratio (95% CI)

Multivariablea Odds Ratio (95% CI)

All Central Nervous System Defects (N = 268)

 Any Exposure

183

523

1.0 (0.8–1.4)

1.1 (0.8–1.6)

 No Exposure

85

248

1.0 (−-----)

 

Exposure Categorized by 1980 Action Level

  > 1.136 g (>40μg/L)

13

32

1.2 (0.6–2.4)

1.2 (0.6–2.4)

  > 0- < =1.136 g

170

491

1.0 (0.7–1.4)

1.1 (0.8–1.6)

 0 (Referent)

85

248

1.0 (−-----)

 

P value for trend

   

0.64

All Neural Tube Defects (N = 151)

 Any Exposure

100

523

0.9 (0.6–1.3)

1.1 (0.8–1.7)

 No Exposure

51

248

1.0 (−-----)

 

Exposure Categorized by 1980 Action Level

  > 1.136 g (>40μg/L)

11

32

1.7 (0.8–3.5)

1.5 (0.7–3.1)

  > 0- < =1.136 g

89

491

0.9 (0.6–1.3)

1.1 (0.7–1.7)

 0 (Referent)

51

248

1.0 (−-----)

 

P value for trend

   

0.33

Anencephaly (N = 82)

 Any Exposure

54

523

0.9 (0.6–1.5)

1.1 (0.7–1.9)

 No Exposure

28

248

1.0 (−-----)

 

Exposure Categorized by 1980 Action Level

  > 1.136 g (>40μg/L)

5

32

1.4 (0.5–3.8)

1.1 (0.4–3.1)

  > 0- < =1.136 g

49

491

0.9 (0.5–1.4)

1.1 (0.6–1.9)

 0 (Referent)

28

248

1.0 (−-----)

 

P value for trend

   

0.86

Spina bifida with and without hydrocephalus (N = 69)

 Any Exposure

46

523

0.9 (0.6–1.6)

1.2 (0.7–2.2)

 No Exposure

23

248

1.0 (−-----)

 

Exposure Categorized by 1980 Action Level

  > 1.136 g (>40μg/L)

6

32

2.0 (0.8–5.3)

2.0 (0.8–5.4)

  > 0- < =1.136 g

40

491

0.9 (0.5–1.5)

1.1 (0.6–2.1)

 0 (Referent)

23

248

1.0 (−-----)

 

P value for trend

   

0.16

Other CNS Defects (N = 117)

 Any Exposure

83

523

1.2 (0.8–1.8)

1.1 (0.7–1.8)

 No Exposure

34

248

1.0 (−------)

 

Exposure Categorized by 1980 Action Level

  > 1.136 g (>40μg/L)

2

32

------b

------b

  > 0- < =1.136 g

81

491

1.2 (0.8–1.8)

1.2 (0.7–1.9)

 0 (Referent)

34

248

1.0 (−-----)

 

P value for trend

   

N/A

All Oral Clefts (N = 112)

 Any Exposure

81

523

1.2 (0.8–1.9)

1.7 (1.0–2.8)

 No Exposure

31

248

1.0 (−-----)

 

Exposure Categorized by 1980 Action Level

  > 1.136 g (> 40μg/L)

6

32

1.5 (0.6–3.9)

2.2 (0.8–6.0)

  > 0- < =1.136 g

75

491

1.2 (0.8–1.9)

1.7 (1.0–2.8)

 0 (Referent)

31

248

1.0 (−-----)

 

P value for trend

   

0.13

Cleft Lip with or without Cleft Palate (N = 59)

 Any Exposure

44

523

1.4 (0.8–2.5)

2.1 (1.1–4.0

 No Exposure

15

248

1.0 (−-----)

 

Exposure Categorized by 1980 Action Level

  > 1.136 g (>40μg/L)

5

32

2.6 (0.9–7.6)

3.8 (1.2–12.3)

  > 0- < =1.136 g

39

491

1.3 (0.7–2.4)

1.9 (1.0–3.8)

 0 (Referent)

15

248

1.0 (−-----)

 

P value for trend

   

0.02

Cleft Palate Alone (N = 53)

 Any Exposure

37

523

1.1 (0.6–2.0)

1.4 (0.7–2.7)

 No Exposure

16

248

1.0 (−-----)

 

Exposure Categorized by 1980 Action Level

  > 1.136 g (>40μg/L)

1

32

------b

------b

  > 0- < =1.136 g

36

491

1.1 (0.6–2.1)

1.4 (0.7–2.8)

 0 (Referent)

16

248

1.0 (−-----)

 

P value for trend

   

N/A

Hypospadias (N = 94)c

 Any Exposure

58

266

0.9 (0.5–1.4)

1.3 (0.8–2.2)

 No Exposure

36

142

1.0 (−-----)

 

Exposure Categorized by 1980 Action Level

  > 1.136 g (>40μg/L)

3

11

1.1 (0.3–4.1)

2.1 (0.5–8.3)

  > 0- < =1.136 g

55

255

0.9 (0.5–1.4)

1.3 (0.8–2.2)

 0 (Referent)

36

142

1.0 (−-----)

 

P value for trend

   

0.31

  1. aAll adjusted analyses control for state of birth, delivery year. In addition, maternal alcohol use during pregnancy is controlled in the oral cleft analysis and maternal race is controlled in the hypospadias analysis
  2. bNot calculated
  3. cAnalysis includes only male cases and controls
  4. N/A not applicable