Table 3

Oropharyngeal cancer; individual effect (relative risk/odds ratio) estimates

ST use

RR/OR

Source^a

Type^b

Exposure^c

Smoking

Sex

Id.

Cases^d

Estimate (95%CI)

Adjustment factors^e

Cohort studies

US Veterans: Zahm et al. 1992 [17]

ST

Ever

Any

M^f

1

129

4.11 (2.90–5.84)^g

age, time

CPS-I: Henley et al. 2005 [23]

ST

Current

Never

M

2

4

2.02 (0.53–7.74)

age, alc, asp, bmi, diet, edu, exer, occ, race

CPS-II: Henley et al. 2005 [23]

ST

Current

Never

M

3

1

0.90 (0.12–6.71)

age, alc, asp, bmi, diet, edu, exer, occ, race

Norway Cohorts: Boffetta et al. 2005 [26]

Snuff

Current

Any

M

4

6

1.13 (0.45–2.83)

age, smok

Former

5

3

1.04 (0.31–3.50)

Ever

6

9

1.10 (0.50–2.41)

Swedish construction workers: Luo et al. 2007 [32]

Snuff

Ever

Any

M

7

NA

0.70 (0.50–0.90)

age, bmi, smok

Current

Never

8

9

0.90 (0.40–1.80)

age, bmi

Former

9

1

0.70 (0.10–5.00)

Ever

10

10

0.80 (0.40–1.70)

Uppsala County: Roosaar et al. 2008 [35]

Snuff

Ever

Any

M

11

11

3.10 (1.50–6.60)

age, alc, res, smok, time

Never

12

5

2.30 (0.70–8.30)

age, alc, res, time

Case-control studies

Broders 1920 [37]

Chew

Use

Any

M+F

13

128

2.05 (1.48–2.83)^g

smok

Snuff

14

2

1.76 (0.12–26.52)^g

none

ST

15

130

2.05 (1.48–2.83)^g

Moore et al. 1953 [39]

ST

Use

Any

M

16

65

3.00 (1.37–6.54)^g

none

Wynder et al. 1957 [40]

Chew

Ever

Any

M

17

NA

no association^h

none

Wynder and Bross 1957 [41]

Chew

Ever

Any

M

18

91

2.00 (1.16–3.47)^g

smok

Peacock et al. 1960 [42]

ST

Use

Any

M

19

14

3.06 (1.08–8.63)^g

age, ins

F

20

11

2.00 (0.66–6.01)^g

Vogler et al. 1962 [36]

Chew

Ever

Any

M

21

46

7.38 (4.31–12.62)^g

none

Snuff

F

22

54

38.28 (21.49–68.15)^g

Vincent and Marchetta 1963 [45]

Snuff

Use

Any

M

23

12

4.22 (1.41–12.63)^g

none

Martinez et al. 1969 [49]

Chew

Use

Any

M

24

4

2.29 (0.62–8.48)^g

none

F

25

1

0.34 (0.04–2.79)^g

Keller 1970 [50]

ST

Use

Any

M

26

11

3.63 (1.02–12.95)^g

smok

Never

27

4

3.04 (0.62–14.99)^g

Browne et al. 1977 [54]

Chew

Use

Any

M+F

28

7

0.67 (0.27–1.66)^g

none

Williams and Horm 1977 [55]

ST

Ever

Any

M

29

16

0.91 (0.53–1.56)^g

none

F

30

2

1.54 (0.37–6.42)^g

Wynder and Stellman 1977 [56]

Chew

Ever

Any

M

31

10

0.62 (0.32–1.21)^g

none

Snuff

32

61

1.15 (0.85–1.55)^g

ST

33

71

1.02 (0.78–1.34)ⁱ

Westbrook et al. 1980 [59]

Snuff

Ever

Any

F

34

50

540.00 (60.97–4782.82)^g

none

Winn et al. 1981 [61]

Snuff

Ever

Any

F

35

107

2.67 (1.83–3.90)^g

race, smok

Wynder et al. 1983 [63]

Chew

Ever

Any

M

36

37

1.00 (0.62–1.61)^g

none

Snuff

37

12

0.42 (0.11–1.65)^g

ST

38

49

0.90 (0.57–1.41)ⁱ

Stockwell and Lyman 1986 [70]

ST

Ever

Any

M+F

39

11

2.02 (1.01–4.02)^g

none

Young et al. 1986 [71]

ST

Ever

Any

M

40

NA

no association

none

Blot et al. 1988 [74]

ST

Ever

Any

M

41

46

0.85 (0.57–1.26)^g

none

F

42

11

3.44 (1.09–10.91)^g

Never

F

43

6

6.20 (1.90–19.80)

age, race, res, resp

Spitz et al. 1988 [78]

Chew

Ever

Any

M+F

44

23

1.00 (0.54–1.85)^g

none

Snuff

45

9

3.40 (1.00–10.90)

ST

46

25

1.05 (0.57–1.91)^g

Franco et al. 1989 [80]

ST

Use

Any

M+F

47

9

1.40 (0.59–3.33)^g

none

Blomqvist et al. 1991 [83]

Snuff

Ever

Never

M+F

48

2

0.67 (0.08–5.75)^g

none

Maden et al. 1992 [85]

ST

Ever

Any

M

49

19

4.50 (1.50–14.30)

age

Marshall et al. 1992 [86]

Chew

Use

Any

M

50

NA

no significant association

none

Sterling et al. 1992 [89]

ST

Ever

Any

M+F

51

28^g

1.04 (0.41–2.68)^g

age, alc, occ, race, sex, smok

Snuff

Ever

Any

M+F

52

NA

2.42 (1.28–4.59)

age, race, sex

Mashberg et al. 1993 [90]

Chew

Ever

Any

M^f

53

NA

1.00 (0.70–1.40)

age, alc, race, smok

Snuff

54

NA

0.80 (0.40–1.90)

ST

55

52

0.96 (0.70–1.33)ⁱ

Perry et al. 1993^j

ST

Use

Any

M+F

56

10

1.43 (0.64–3.21)^g

age, alc, occ, race, sex, smok

Spitz et al. 1993 [92]

Chew

Use

Any

M+F

57

NA

1.20 (not significant)

none

Kabat et al. 1994 [97]

Chew

Ever

Any

M

58

67

1.11 (0.81–1.53)^g

smok

Snuff

Ever

Never

M+F

59

4

4.79 (1.19–19.30)^g

none

Bundgaard et al. 1995 [98]

Chew

Ever

Any

M+F

60

8

1.44 (0.59–3.51)^g

none

Lewin et al. 1998 [102]

Snuff

Current

Any

M

61

18

0.84 (0.47–1.50)^g

age, alc, res, smok

Former

62

22

1.28 (0.70–2.35)^g

Ever

63

40

0.98 (0.63–1.50)^g

Muscat et al. 1998 [103]

Chew

Ever

Any

M+F

64

3

0.89 (0.18–4.49)^g

none

ST

65

4

1.19 (0.26–5.45)ⁱ

Schildt et al. 1998 [104]

Chew

Use

Any

M+F

66

5

0.60 (0.20–2.00)

age, sex, res

Snuff

Current

67

39

0.70 (0.40–1.10)

Former

68

28

1.50 (0.80–2.90)

Ever

69

67

0.80 (0.50–1.30)

age, alc, sex, smok, res

Current

Never

70

19

0.70 (0.40–1.20)

age, sex, res

Former

71

9

1.80 (0.90–3.50)

Ever

72

28

1.01 (0.64–1.57)^g

ST

Ever

Any

73

72

0.87 (0.61–1.25)ⁱ

none

Schwartz et al. 1998 [105]

ST

Ever

Any

M

74

NA

1.00 (0.40–2.30)

age, alc, smok

Rosenquist et al. 2005 [113]

Snuff

Current

Any

M+F

75

13

1.10 (0.50–2.50)

alc, smok

Former

76

7

0.30 (0.10–0.90)

Ever

77

20

0.70 (0.30–1.30)

^a Fuller details of the studies are given in Tables 1 and 2.

^b ST implies smokeless tobacco unspecified, or combined snuff use or chewing.

^c Ever, former and current ST use were compared with never ST. Use indicates timing not given and comparison is with non use.

^d 'Id.' is the RR/OR identification number used in Table 4, and 'Cases' is the number of cases in ST users as defined. NA = not available.

^e Abbreviations used: alc = alcohol, asp = aspirin, bmi = body mass index, edu = education, exer = exercise, ins = insurance status, occ = occupation, res = area of residence, resp = respondent, smok = smoking.

^f The population included < 0.5% females.

^g RR/OR and/or 95% CI estimated from data provided in the source.

^h The average ridit duration of chewing did not differ significantly from the controls for any type of oral cancer.

ⁱ RR/OR and/or 95% CI estimated from data provided in the source assuming that no one both chewed and used snuff.

^j "Attributable oral cancer risk due to smokeless tobacco use based on a case-control study at Sinai Hospital in Detroit", Perry et al., unpublished. Cited by Gross et al. 1995 [91].

CI = confidence interval; ST = smokeless tobacco; OR = odds ratio; RR = relative risk.

Lee and Hamling BMC Medicine 2009 7:36   doi:10.1186/1741-7015-7-36