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Table 3 Associations (multivariable a adjusted incidence RRs) between cigarette smoking and risk of subtypes of head-neck cancer; Netherlands Cohort Study (NLCS), 1986 - 2003

From: Alcohol consumption, cigarette smoking and the risk of subtypes of head-neck cancer: results from the Netherlands Cohort Study

  

Subcohort

Head-neck cancer cases

   

Overall

Subtypes

    

OCCb

OHPCb

LCb

 
 

Categorical median

Person time at risk (years)

No. of cases

RR (95% CI)

No. of cases

RR (95% CI)

No. of cases

RR (95% CI)

No. of cases

RR (95% CI)

Pfor heterogeneity

Cigarette smoking status

           

Never smokers

 

25051

44

1 (reference)

29

1 (reference)

6

1 (reference)

9

1 (reference)

0.97

Former smokers

 

22644

110

1.44 (0.97-2.14)

24

0.70 (0.37-1.33)

22

2.68 (1.00-7.14)i

64

2.63 (1.26-5.47)

 

Current smokers

 

16657

241

4.49 (3.11-6.48)

57

2.11 (1.23-3.62)

55

8.53 (3.38-21.55)

126

8.07 (3.94-16.54)

 

P for trendc

   

<0.001

 

0.001

 

<0.001

 

<0.001

 

P for interaction with sexd

   

0.25

 

0.08

 

0.44

 

0.46

 

Cigarette smoking status, additionally adjusted for frequency and duration of cigarette smoking e

Never smokers

 

25051

44

1 (reference)

29

1 (reference)

6

1 (reference)

9

1 (reference)

0.97

Former smokers

 

22644

110

1.64 (1.08-2.49)

24

0.79 (0.40-1.58)

22

3.03 (1.09-8.45)

64

2.87 (1.34-6.13)

 

Current smokers

 

16657

241

3.51 (2.36-5.23)

57

1.91 (1.06-3.42)

55

7.49 (2.87-19.54)

126

5.26 (2.45-11.28)

 

P for trend

   

<0.001

 

0.03

 

<0.001

 

<0.001

 

Frequency of cigarette smoking ( N /day) f

Never smokers

0

25051

44

1 (reference)

29

1 (reference)

6

1 (reference)

9

1 (reference)

0.99

>0 to <20

10

24787

155

1.30 (0.84-2.01)

38

0.63 (0.30-1.32)

30

2.08 (0.73-5.94)

85

2.32 (1.07-5.04)

 

≥20

20

14514

196

2.23 (1.45-3.44)

43

1.06 (0.52-2.16)

47

4.67 (1.64-13.34)

105

3.75 (1.73-8.14)

 

P for trend

   

<0.001

 

0.33

 

<0.001

 

<0.001

 

Continuous, 10 cigarettes/day increments

 

64352

395

1.25 (1.13-1.38)

110

1.20 (1.00-1.44)j

83

1.42 (1.20-1.69)

199

1.21 (1.08-1.36)

0.71

Duration of cigarette smoking (years) g

Never smokers

0

25051

44

1 (reference)

29

1 (reference)

6

1 (reference)

9

1 (reference)

<0.001

>0 to <20

13

7433

20

1.00 (0.56-1.77)

4

0.38 (0.13-1.17)

5

2.11 (0.59-7.51)

11

1.88 (0.75-4.69)

 

20 to <40

30

18999

105

1.44 (0.95-2.21)

30

0.80 (0.41-1.59)

25

2.74 (0.98-7.68)

50

2.35 (1.09-5.06)

 

≥40

43

12868

226

2.45 (1.49-4.02)

47

0.98 (0.39-2.46)

47

3.89 (1.22-12.40)

129

4.81 (2.11-11.00)

 

P for trend

   

<0.001

 

0.87

 

0.02

 

<0.001

 

Continuous, 10 years increments

 

64352

395

1.28 (1.14-1.42)

110

1.03 (0.85-1.24)

83

1.36 (1.09-1.70)

199

1.49 (1.25-1.78)

0.25

Pack-years of cigarette smoking h

Never smokers

0

25051

44

1 (reference)

29

1 (reference)

6

1 (reference)

9

1 (reference)

1.00

>0 to <20

9

20832

96

1.16 (0.77-1.76)

24

0.58 (0.30-1.14)

20

2.12 (0.77-5.80)

51

2.07 (0.97-4.41)

 

20 to <40

28

12732

132

1.65 (1.04- 2.60)

32

0.84 (0.39-1.83)

26

2.87 (0.94-8.79)

73

2.93 (1.33-6.48)

 

≥40

48

5736

123

2.82 (1.76-4.50)

25

1.28 (0.58-2.82)

31

6.49 (2.11-19.95)

66

4.79 (2.15-10.64)

 

P for trend

   

<0.001

 

0.07

 

<0.001

 

<0.001

 

Continuous, 10 pack-years increments

 

64352

395

1.18 (1.11-1.25)

110

1.16 (1.04-1.28)

83

1.24 (1.12-1.36)

199

1.16 (1.09-1.24)

0.77

Cigarette smoking cessation i

Never smokers

25

25051

44

1 (reference)

29

1 (reference)

6

1 (reference)

9

1 (reference)

<0.001

Stopped ≥20 years

14

6953

24

1.25 (0.72-2.19)

5

0.63 (0.22-1.81)

6

3.35 (0.97-11.55)

13

1.92 (0.79-4.70)

 

Stopped 10 to <20 years

5

7717

36

1.49 (0.91-2.43)

8

0.78 (0.32-1.86)

8

3.29 (1.04-10.39)

20

2.45 (1.07-5.61)k

 

Stopped >0 to <10 years

0

7918

50

1.73 (1.09-2.76)

11

0.84 (0.39-1.83)

8

2.48 (0.77-7.93)

31

3.45 (1.56-7.62)

 

Current smokers

 

16657

241

4.26 (2.93-6.20)

57

2.03 (1.16-3.56)

55

8.10 (3.14-20.87)

126

7.53 (3.65-15.51)

 

P for trend

   

<0.001

 

0.004

 

<0.001

 

<0.001

 
  1. aAll analyses were adjusted for age (years), sex, and alcohol consumption (g ethanol/day; continuous).
  2. bOCC: oral cavity cancer; OHPC: oro-/hypopharyngeal cancer; LC: laryngeal cancer.
  3. cTests for dose-response trends were assessed by fitting ordinal variables as continuous terms in the Cox proportional hazards model.
  4. d P Value for interaction between sex and cigarette smoking status, based on cross-product terms in the Cox proportional hazards model and Wald test.
  5. eAdditionally adjusted for frequency (N/day; continuous; centered) and duration of cigarette smoking (years; continuous; centered).
  6. fAnalyses of cigarette smoking frequency were additionally adjusted for current cigarette smoking and duration of cigarette smoking (years; continuous; centered).
  7. gAnalyses of cigarette smoking duration were additionally adjusted for current cigarette smoking and frequency of cigarette smoking (N/day; continuous; centered).
  8. hAnalyses of cigarette smoking pack-years were additionally adjusted for current cigarette smoking.
  9. iCigarette smoking cessation was additionally adjusted for the no. of cigarette pack-years (continuous; centered).
  10. j P < 0.05.
  11. kProportional hazards assumption was possibly violated for the exposure variable, and there was a statistically significant interaction with time.