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Table 3 Secondhand smoke exposure at work and breast cancer among non-smoking cases and controls from Delaware

From: Case-control study of tobacco smoke exposure and breast cancer risk in Delaware

Secondhand smoke exposure at worka

cases

controls

odds ratiob

95% confidence Intervalb

 

n

%

n

%

  

Never employed or

      

not exposed at work

60

48.4

69

43.4

1.00

Reference

Any secondhand smoke exposure at work

64

51.6

90

56.6

0.80

0.49–1.32

Number of years employed at a job with secondhand smoke exposure

      

   < 10

27

21.8

48

30.1

0.66

0.35–1.23

   10–19

24

19.4

27

17.0

1.02

0.52–2.00

   20–45

13

10.5

15

9.4

0.86

0.35– 2.07

Number of years employed at a job with light secondhand smoke exposure

      

   < 10

17

13.7

27

17.0

0.96

0.46–1.97

   ≥ 10

13

10.5

13

8.2

1.14

0.47– 2.78

Number of years employed at a job with moderate secondhand smoke exposure

      

   < 10

11

8.9

16

10.1

0.70

0.29– 1.68

   ≥ 10

17

13.7

22

13.8

1.01

0.49– 2.09

Number of years employed at a job with heavy secondhand smoke exposure

      

   < 10

5

4.0

8

5.0

1.02

0.31– 3.37

   ≥ 10

7

5.6

7

4.4

1.07

0.35– 3.30

  1. a 2 non-smoking controls were missing data on exposure to smoke at work
  2. b Adjusted for age, menopausal status, body mass index (<25, 25–29, 30+), age at menarche (<12 vs. 12+), age at first live birth (nulliparous, <30, 30+), oral contraceptive use (ever vs. never), other hormone use (ever vs. never), family history of breast cancer (yes vs. no), alcohol consumption (ever drank 12 drinks in lifetime vs. had 12 drinks in lifetime but never had 1+ drink per month for 6+ months vs. ever had 1+ drink per month for 6+ months); data for adjustment factors was missing for 4 cases and 3 controls