Table 2 Odds ratios for breast cancer associated with smoking variables stratified by SULT1A1 genotype

Never active

86

159

1 (ref)

88

209

1 (ref)

Ever active

112

215

0.92 (0.63–1.34)

133

301

1.01 (0.73–1.42)

Never active/passive^{c, d}

20

56

1 (ref)

19

57

1 (ref)

Former active

44

94

1.23 (0.64–2.36)

59

157

1.11 (0.60–2.06)

Current active

68

121

1.44 (0.76–2.71)

74

144

1.51 (0.82–2.78)

Average cigarettes per day^{c, e}

>0–9

42

106

1.06 (0.55–2.03)

52

154

0.99 (0.54–1.84)

10–19

56

73

2.12 (1.10–4.07)

60

99

1.75 (0.94–3.25)

20+

14

34

1.05 (0.45–2.46)

20

48

1.09 (0.51–2.32)

Duration of smoking^{c, d}

1–15 years

36

80

1.19 (0.61–2.34)

46

145

0.97 (0.52–1.82)

16+ years

76

135

1.44 (0.77–2.69)

87

156

1.62 (0.89–2.95)

Age at first cigarette^{c, d}

9–15 years

21

47

1.09 (0.51–2.35)

20

63

0.84 (0.40–1.79)

16–18 years

56

109

1.33 (0.70–2.52)

70

145

1.42 (0.77–2.62)

19+ years

35

59

1.51 (0.75–3.05)

43

93

1.42 (0.74–2.72)

Pack-years^{c, e}

>0–10

59

129

1.22 (0.65–2.27)

76

191

1.15 (0.64–2.07)

11+

53

84

1.77 (0.91–3.42)

56

110

1.43 (0.77–2.67)

Passive smoking^f

No

20

57

1 (ref)

19

57

1 (ref)

Yes

66

102

1.69 (0.89–3.21)

69

152

1.40 (0.74–2.64)

Duration of passive exposure in adulthood^{f, g, h}

1–13 years

29

40

1.91 (0.91–4.00)

33

70

1.47 (0.72–2.98)

14+ years

32

47

1.66 (0.79–3.48)

29

61

1.47 (0.70–3.10)

Cumulative lifetime exposure (in hours/day-years)^{f, g, i}

1–55

22

49

1.13 (0.52–2.38)

37

76

1.76 (0.89–3.50)

56+

43

52

2.12 (1.06–4.25)

32

71

1.39 (0.68–2.83)