Table 4 The combined effects of dietary antioxidant intake and environmental tobacco smoke on the risk for asthma

Vitamin A

ETS

High

No

6/148(3.90)

1.00

19/131(12.67)

1.00

Low

No

14/309(4.33)

1.59

(0.54

4.67)

0.40

24/290(7.64)

0.80

(0.39

1.64)

0.55

High

Yes

6/89(6.32)

2.01

(0.61

6.64)

0.25

11/86(11.34)

0.98

(0.44

2.21)

0.96

Low

Yes

17/62(9.50)

4.43

(1.51

12.96)

<0.01

31/152(16.94)

2.23

(1.10

4.54)

0.03

Retinol

ETS

High

No

5/149(3.25)

1.00

20/134(12.99)

1.00

Low

No

15/308(4.64)

2.67

(0.85

8.34)

0.09

23/287(7.42)

0.73

(0.36

1.49)

0.39

High

Yes

8/83(8.79)

4.37

(1.30

14.63)

0.02

19/74(20.43)

2.16

(1.05

4.43)

0.04

Low

Yes

15/168(8.20)

5.15

(1.63

16.25)

0.01

23/164(12.30)

1.29

(0.63

2.66)

0.49

Carotene

ETS

High

No

7/144(4.64)

1.00

18/127(12.41)

1.00

Low

No

13/313(3.99)

0.88

(0.31

2.48)

0.81

25/294(7.84)

0.72

(0.36

1.46)

0.37

High

Yes

8/90(8.16)

2.03

(0.69

6.00)

0.20

13/86(13.13)

1.16

(0.53

2.54)

0.71

Low

Yes

15/161(8.52)

2.45

(0.87

6.85)

0.09

29/152(16.02)

1.84

(0.90

3.73)

0.09

Vitamin C

ETS

High

No

7/153(4.38)

1.00

21/133(13.64)

1.00

Low

No

13/304(4.10)

1.09

(0.38

3.15)

0.87

22/288(7.10)

0.58

(0.28

1.18)

0.13

High

Yes

9/90(9.09)

2.65

(0.92

7.64)

0.07

14/86(14.00)

1.13

(0.53

2.40)

0.75

Low

Yes

14/161(8.00)

2.61

(0.90

7.59)

0.08

28/152(15.56)

1.55

(0.76

3.13)

0.23

Vitamin E

ETS

High

No

9/166(5.14)

1.00

23/145(13.69)

1.00

Low

No

11/291(3.64)

0.78

(0.26

2.31)

0.65

20/276(6.76)

0.56

(0.26

1.21)

0.14

High

Yes

11/84(11.58)

3.32

(1.25

8.80)

0.02

18/81(18.18)

1.67

(0.83

3.36)

0.15

Low

Yes

12/167(6.70)

1.58

(0.54

4.64)

0.41

24/157(13.26)

1.22

(0.57

2.58)

0.61