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Table 4 Odds ratio of breast cancer risk associated with serum levels of PCBs

From: Serum levels of environmental pollutants is a risk factor for breast cancer in Inuit: a case control study

 

Unadjusted

Adjusted

 

Continuous

(μg/kg lipid)

Continuous

(μg/kg lipid)

1st Tertile

2nd Tertile

3rd Tertile

∑PCB (OR (95% CI))

1.00

1.00 (1.00; 1.00)

1.00 (reference)

1.93 (0.84; 4.43)

2.50 (1.11; 5.63)

 n (cases/controls)

76/84

76/84

14/28

27/28

35/28

p-value

0.008

0.008

 

0.122

0.027

∑PCB Grp1 (OR (95% CI))

1.00

1.00 (1.00; 1.01)

1.00 (reference)

1.35 (0.60; 3.06)

2.12 (0.97; 4.16)

 n (cases/controls)

76/84

76/84

17/28

23/28

36/28

p-value

0.006

0.006

 

0.468

0.059

∑PCB Grp2 (OR (95% CI))

1.00

1.00 (1.00; 1.00)

1.00 (reference)

2.28 (1.01; 5.18)

2.14 (0.94; 4.88)

 n (cases/controls)

76/84

76/84

14/28

32/28

30/28

p-value

0.029

0.029

 

0.048

0.069

∑PCB Grp3 (OR (95% CI))

1.00

1.00 (1.00; 1.00)

1.00 (reference)

1.63 (0.72; 3.67)

2.13 (0.96; 4.69)

 n (cases/controls)

76/84

76/84

16/28

26/28

34/28

p-value

0.006

0.006

 

0.242

0.062

∑DL-PCB (OR (95% CI))

1.00

1.00 (1.00; 1.01)

1.00 (reference)

1.10 (0.50; 2.41)

1.52 (0.71; 3.26)

 n (cases/controls)

76/84

76/84

21/28

23/28

32/28

p-value

0.057

0.057

 

0.821

0.277

PCB99 (OR (95% CI))

1.01

1.01 (1.00; 1.01)

1.00 (reference)

2.85 (1.25; 6.47)

2.00 (0.86; 4.67)

 n (cases/controls)

76/84

76/84

13/28

37/28

26/28

p-value

0.039

0.039

 

0.013

0.109

PCB101 (OR (95% CI))

1.00

1.00 (0.96; 1.05)

1.00 (reference)

1.73 (0.80; 3.71)

1.26 (0.56; 2.81)

 n (cases/controls)

76/84

76/84

19/28

34/28

23/27

p-value

0.902

0.902

 

0.161

0.580

PCB105 (OR (95% CI))

1.01

1.01 (0.99; 1.04)

1.00 (reference)

1.11 (0.51; 2.41)

1.54 (0.71; 3.33)

 n (cases/controls)

76/84

76/84

21/28

25/30

30/26

p-value

0.217

0.217

 

0.790

0.274

PCB118 (OR (95% CI))

1.01

1.01 (1.00; 1.01)

1.00 (reference)

0.83 (0.37; 1.84)

1.48 (0.70; 3.11)

 n (cases/controls)

76/84

76/84

23/28

19/28

34/28

p-value

0.026

0.026

 

0.641

0.304

PCB138 (OR (95% CI))

1.00

1.00 (1.00; 1.00)

1.00 (reference)

2.83 (1.22; 6.57)

2.50 (1.07; 5.85)

 n (cases/controls)

76/84

76/84

12/28

34/28

30/28

p-value

0.048

0.048

 

0.015

0.035

PCB153 (OR (95% CI))

1.00

1.00 (1.00; 1.00)

1.00 (reference)

2.15 (0.93; 4.99)

2.69 (1.18; 6.14)

 n (cases/controls)

76/84

76/84

13/28

28/28

35/28

p-value

0.005

0.005

 

0.074

0.019

PCB156 (OR (95% CI))

1.00

1.00 (1.00; 1.01)

1.00 (reference)

1.69 (0.75; 3.80)

2.06 (0.93; 4.56)

 n (cases/controls)

76/84

76/84

16/28

27/28

33/28

p-value

0.250

0.250

 

0.206

0.074

PCB170 (OR (95% CI))

1.00

1.00 (1.00; 1.01)

1.00 (reference)

2.00 (0.87; 4.58)

2.43 (1.08; 5.48)

 n (cases/controls)

76/84

76/84

14/28

28/28

34/28

p-value

0.022

0.022

 

0.101

0.033

PCB180 (OR (95% CI))

1.00

1.00 (1.00; 1.00)

1.00 (reference)

0.93 (0.41; 2.08)

1.65 (0.78; 3.47)

 n (cases/controls)

76/84

76/84

22/29

19/27

35/28

p-value

0.012

0.012

 

0.855

0.189

PCB183 (OR (95% CI))

1.02

1.02 (1.00; 1.03)

1.00 (reference)

2.46 (1.07; 5.65)

2.39 (1.04; 5.49)

 n (cases/controls)

76/84

76/84

13/28

32/28

31/28

p-value

0.013

0.013

 

0.034

0.041

PCB187 (OR (95% CI))

1.00

1.00 (1.00; 1.01)

1.00 (reference)

1.56 (0.69; 3.54)

2.19 (0.99; 4.82)

 n (cases/controls)

76/84

76/84

16/28

25/28

35/28

p-value

0.005

0.005

 

0.285

0.052

  1. n: number of observations per group; OR: odds ratio; 95% CI: 95% confidence interval; Unadjusted analysis: Only OR, and not 95% CI, were reported for unadjusted data; Adjusted: adjusted for confounders identified by change in estimate, following confounders were considered age, BMI, cotinine levels, parity, and breastfeeding; Bold text: significant finding, OR significantly different from 1; ∑PCB: PCB 99, 101, 105, 118, 128, 138, 153, 156, 170, 180, 183, 187; ∑PCB group 1 (estrogenic PCBs): PCB 101, 187; ∑PCB group 2 (anti-estrogenic and dioxin-like PCBs): PCB 105, 118, 128, 138, 156, 170; ∑PCB group 3 (CYP1A1 and CYP2B inducing PCBs): PCB 99, 153, 180, 183; ∑DL-PCBs (dioxin-like PCBs): PCB 105, 118, 156