Table 19

Bladder 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

Norway cohorts: Boffetta et al. 2005 [26]

Snuff

Current

Any

M

1

40

0.72 (0.52–1.06)

age, smok

Former

2

30

0.98 (0.66–1.47)

Ever

3

69

0.83 (0.62–1.11)

Case-control studies

Lockwood 1961 [43]

ST

Current

Never

M

4

2

0.35 (0.07–1.77)^f

none

Wynder et al. 1963 [46]

Chew

Ever

Any

M

5

33

1.42 (0.82–2.47)^f

none

Snuff

6

6

0.66 (0.23–1.88)^f

ST

7

39

1.21 (0.74–1.98)^g

Dunham et al. 1968 [48]

ST

Ever

Never

M

8

4

2.57 (0.52–12.54)^f

race

F

9

3

0.58 (0.14–2.45)^f

Cole et al. 1971 [51]

Chew

Ever

Any

M

10

46

no association^h

age

Snuff

11

3

no associationⁱ

Williams and Horm 1977 [55]

ST

Ever

Any

M

12

29

1.67 (1.09–2.55)^f

age, race, smok

F

13

1

0.82 (0.11–6.02)^f

none

Wynder and Stellman 1977 [56]

Chew

Ever

Any

M

14

47

0.87 (0.63–1.21)^f

none

Snuff

15

11

0.69 (0.36–1.31)^f

ST

16

58

0.82 (0.61–1.10)^g

Howe et al. 1980 [58]

Chew

Ever

Any

M

17

NA

0.90 (0.50–1.60)

age, smok

Mommsen and Aagaard 1983 [62]

Chew

Ever

Any

M

18

39

1.70 (1.00–2.90)

age, res

Hartge et al. 1985 [66]

Chew

Ever

Never^j

M

19

40

1.02 (0.67–1.54)

age, race, res, smok^j

Snuff

20

11

0.77 (0.38–1.56)

ST

21

51

1.14 (0.80–1.61)^g

none

Kabat et al. 1986 [69]

Snuff

Ever

Never

F

22

3

10.40 (1.07–101.46)

none

Slattery et al. 1988 [77]

Chew

Ever

Any

M

23

20

0.76 (0.42–1.39)

smok^k

Never

24

1

0.36 (0.05–2.82)^l

none

Snuff

Ever

Any

25

16

0.92 (0.47–1.82)

smok^k

Never

26

2

2.74 (0.45–16.69)^m

none

ST

Ever

Any

27

36

0.82 (0.52–1.29)^g

smok^k

Never

28

3

0.86 (0.24–3.07)^g

none

Burch et al. 1989 [79]

Chew

Ever

Any

M

29

26

0.60 (0.34–1.06)

age, res, smok

Snuff

30

9

0.47 (0.21–1.07)

ST

31

35

0.54 (0.34–0.87)^g

^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 20, and 'Cases' is the number of cases in ST users as defined. NA = not available.

^e Abbreviations used: res = area of residence, smok = smoking.

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

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

^h Age-adjusted expected number of cases who chewed tobacco was given as 42.3 versus 46 observed.

ⁱ Age-adjusted expected number of cases who used snuff was given as 2.9 versus 3 observed.

^j Estimates were for never cigarette smokers adjusted for other tobacco use.

^k Adjusted for age started to smoke; results adjusted for smoking group, pack years or years stopped are similar.

^l The source paper gave 2.78 (0.38–20.20) which is incorrect based on the numbers in the 2 × 2 table.

^m The source paper gave 2.73 (0.48–15.57) which is incorrect based on the numbers in the 2 × 2 table.

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