Table 2 Adjusted* hazards ratios and 95% confidence intervals for associations between cigarette smoking and hepatocellular carcinoma and intrahepatic cholangiocarcinoma incidence, Liver Cancer Pooling Project

From: Tobacco, alcohol use and risk of hepatocellular carcinoma and intrahepatic cholangiocarcinoma: The Liver Cancer Pooling Project

Cigarette smoking

 

Hepatocellular carcinoma

Intrahepatic cholangiocarcinoma

 

Non-case, N

Case, N

HR

95% CI

Case, N

HR

95% CI

Smoking status

Never smoker

591,378

360

1.00

 

124

1.00

 

Former smoker

507,215

588

1.24

(1.08−1.43)

177

1.32

(1.03–1.68)

Current smoker

209,556

242

1.86

(1.57–2.20)

60

1.47

(1.07–2.02)

Smoking cessation, years

Never smoker

573,113

358

  

122

  

>2–10

112,879

123

1.47

(1.19–1.82)

43

1.68

(1.17–2.42)

>10–20

257,299

383

1.18

(1.00–1.38)

100

1.16

(0.86–1.55)

>20–30**

58,229

39

1.21

(0.85–1.71)

27

1.42

(0.90–2.25)

>30

46,028

31

1.09

(0.74–1.61)

   

p for trend***

   

0.003

  

0.5

Smoking intensity (No./day)

Never smoker

591,381

360

1.00

 

124

1.00

 

≤10

218,375

170

1.16

(0.96–1.40)

50

1.00

(0.72–1.40)

>10–15

123,753

197

1.44

(1.19–1.73)

46

1.19

(0.83–1.71)

>15–25

173,570

196

1.46

(1.21–1.74)

55

1.39

(1.00–1.93)

>25

150,311

240

1.55

(1.30–1.84)

74

1.86

(1.37–2.53)

p for trend***

   

0.02

  

0.02

Duration of smoking, years

Never smoker

373,171

133

1.00

 

54

1.00

 

≤12

91,080

32

1.03

(0.70–1.53)

16

1.42

(0.80–2.51)

>12–22

84,642

50

1.46

(1.04–2.04)

14

1.24

(0.68–2.27)

>22–34

86,851

53

1.32

(0.95–1.84)

15

1.18

(0.66–2.12)

>34

85,951

67

1.50

(1.10–2.03)

30

2.01

(1.26–3.20)

p for trend***

   

0.03

  

0.2

Pack-years

Never smoker

394,092

139

1.00

 

57

1.00

 

≤7

99,635

35

1.06

(0.73–1.55)

17

1.25

(0.72–2.17)

>7–17

77,516

34

1.14

(0.78–1.67)

15

1.47

(0.82–2.62)

>17–34

88,416

75

1.90

(1.42–2.55)

20

1.57

(0.93–2.65)

>34

89,506

75

1.47

(1.08–1.98)

30

2.04

(1.28–3.27)

p for trend***

   

0.7

  

0.06

  1. CI confidence interval, HR hazard ratio. *Adjusted for: sex, age (continuous), race (white, black, Asian/Pacific Islander, American Indian/Alaskan Native, other), cohort (AARP, AHS, USRT, BCDDP, PLCO, WHS, PHS, HPFS, CPS-II, NYU, IWHS, BWHS, WHI, NHS), BMI (continuous), diabetes (yes/no), alcohol (non-drinker, and >0–<0.5, 0.5–<1, 1–<3, 3–<5, 5–<7, ≥7 drinks/day), and education (less than HS, HS, some college/vocational, college degree, post-college)
  2. **Highest category considered for ICC. This corresponds to >20 years since quitting smoking
  3. ***p-value for trend of continuous variable, excluding the referent group
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