Table 3

Study details and effect estimates.

Study

First author, year of publication

Method of exposure assessment

Cancer site

Adjustment factorsa

Exposure (period)

Sex

Cases/Controlsb

OR/RRc(95% CI)


1

Broders

1920 [74]

NS

Lip

Smoking

Chewing (NS)

M+F

537/500

2.05 (1.48–2.83)de

None

Snuff (NS)

M+F

537/500

1.76 (0.12–26.2)ef

None

Smokeless (NS)

M+F

537/500

2.05 (1.48–2.83)efg

2

Moore

1953 [57]

Interview

Buccal mucosa, gum, floor of mouth

None

Smokeless (20+ years)

M

112/38

3.00 (1.37–6.54)f

3

Wynder

1957 [58]

Interview

Lip, floor of mouth, gum, buccal mucosa, tongue, palate, tonsil, pharynx

Smokingh

Chewing (ever)

M

525/186

2.00 (1.16–3.47)ef

4

Peacock

1960 [93]

Interview

Buccal mucosa, alveolar ridge, floor of mouth

Age, ins.

Smokeless (20+ years)

M

25/191

3.06 (1.08–8.63)di

F

20/172

2.00 (0.66–6.01)di

5

Vogler

1962 [62]

Interview or questionnaire

Lip, buccal mucosa, tongue, palate, gingiva, floor of mouth, minor salivary glandsk

None

Chewing (ever)

M

14/402

7.38 (4.31–12.62)dij

Snuff (ever)

F

75/826

38.28 (21.49–68.15)dei

6

Vincent

1963 [94]

Interview

Oral cavity, pharynx

None

Snuff (NS)

M

66/100

4.22 (1.41–12.63)fi

7

Martinez

1969 [95]

Interview

Mouth and pharynx

Smokingl

Chewing (last 20 years)

M

18/81

2.29 (0.62–8.48)fim

F

16/79

0.34 (0.04–2.79)fim

8

Keller

1970 [75]

Hospital records

Lip

Smoking

Smokeless (NS)

M

258/207

3.63 (1.02–12.95)d

9

Browne

1977 [96]

Interview, proxy interview

Buccal mucosa, upper alveolus and hard palate, lower alveolus, floor of mouth, pillar of fauces, soft palate, unspecified or multiple

None

Chewing (NS)

M+F

75/150

0.67 (0.27–1.66)f

10

Williams

1977 [97]

Interview

Lip, tongue, salivary glands, gum, mouth, pharynx

None

Smokeless (ever)

M

190/1788

0.91 (0.53–1.56)fgi

F

79/3188

1.54 (0.37–6.42)fgi

11

Wynder

1977 [98]

Interview

Oral cavity

None

Chewing (ever)

M

591/2560

1.15 (0.85–1.55)f

Snuff (ever)

M

591/2560

0.62 (0.32–1.22)f

Smokeless (ever)

M

591/2560

1.02 (0.78–1.34)fgn

12

Westbrook

1980 [63]

Hospital records

Buccal mucosa, gum

None

Snuff (ever)

F

55/55

540.0 (60.97–4782.82)f

13

Winn

1981 [13]

Interview, proxy interview

Mouth and pharynx

Smoking, race

Snuff (ever)

F

232/410

2.67 (1.83–3.90)d

14

Wynder

1983 [99]

Interview

Oral and pharyngeal

None

Chewing (ever)

M

414/414

1.00 (0.62–1.61)ef

Snuff (ever)

M

414/414

0.42 (0.11–1.65)f

Smokeless (ever)

M

414/414

0.90 (0.57–1.41)efgn

15

Stockwell

1986 [65]

Medical records

Lip, tongue, salivary glands, gum, floor of mouth, other parts of mouth, pharynx

None

Smokeless (ever)

M+F

1462/8285

2.02 (1.01–4.02)fi

16

Blot

1988 [100]

Interview, proxy interview

Oral and pharyngeal

None

Smokeless (ever)

M

762/837

0.85 (0.57–1.26)ef

F

352/431

3.44 (1.09–10.91)ef

17

Spitz

1988 [101]

Questionnaire

Larynx, tongue, orohypopharynx, oral cavityo

None

Chewing (ever)

M+F

185/185

1.00 (0.54–1.85)f

NS

Snuff (ever)

M+F

185/185

3.40 (1.00–10.90)p

None

Smokeless (ever)

M+F

185/185

1.05 (0.57–1.91)fg

18

Franco

1989 [102]

Interview

Oral cavity, tongue, gum, floor of mouth

None

Smokeless (ever)

M+F

232/464

1.40 (0.59–3.33)f

19

Blomqvist

1991 [103]

Questionnaire

Lower lip

Smokingl

Snuff (ever)

M+F

14/10

0.67 (0.08–5.75)f

20

Maden

1992 [104]

Interview

Lip, tongue, gum, floor of mouth, oropharynx, other parts of mouth

Age

Smokeless (ever)

M

131/136

4.50 (1.50–14.30)p

21

Sterling

1992 [67]

Interview (controls), proxy interview (cases)

Oral and pharyngeal

Smoking, sex, race, age, alc, occ.

Smokeless (100+ times)

M+F

6976/NS

1.04 (0.41–2.68)q

Sex, race, age

Snuff (ever)

M+F

6976/NS

2.42 (1.28–4.59)p

22

Zahm

1992 [72]

Questionnaire

Buccal cavity, pharynx

Age, time

Smokeless (ever)

M

129/248046

4.11 (2.90–5.84)r

23

Mashberg

1993 [68]

Interview

Oral cavity, oropharynx

Smoking, age, race, alc.

Snuff (ever)

M

359/2280

0.80 (0.40–1.90)p

Chewing (ever)

M

359/2280

1.00 (0.70–1.40)p

Smokeless (ever)

M

359/2280

0.96 (0.70–1.33)nq

24

Perry

1993s

NS

Oral

Smoking, age, sex, race, alc, occ.

Smokeless (100+ times)

M+F

133/678

1.43 (0.64–3.21)q

25

Kabat

1994 [59]

Interview

Tongue, floor of mouth, gums, gingiva, buccal mucosa, palate, retromolar area, tonsil and other pharynx

Smokingl

Snuff (ever)

M+F

195/918

4.79 (1.19–19.30)f

Smoking

Chewing (ever)

M

1097/2075

1.11 (0.81–1.53)de

26

Bundgaard

1995 [105]

Questionnaire

Retromolar area, buccal mucosa, floor of mouth, hard palate, upper alveolus, lower alveolus, tongue

None

Chewing (ever)

M+F

161/400

1.44 (0.59–3.51)d

27

Lewin

1998 [64]

Interview

Oral and pharyngeal

Smoking, age, area, alc.

Snuff (ever)

M

266/641

0.98 (0.63–1.50)r

28

Muscat

1998 [106]

Interview

Major salivary gland

None

Chewing (ever)

M+F

128/114

0.89 (0.18–4.49)d

Smokeless (ever)

M+F

128/114

1.19 (0.26–5.45)dgn

29

Schildt

1998 [73]

Questionnaire from next-of-kin for deceased cases/controls

Lip, tongue, gum, mouth

Smoking, alc.

Snuff (ever)

M+F

354/354

0.80 (0.50–1.30)p

None

Chewing (ever)

M+F

354/354

0.60 (0.20–2.00)p

Smokeless (ever)

M+F

354/354

0.87 (0.61–1.25)fgn

30

Schwartz

1998 [69]

Interview

Tongue, gum, floor of mouth, tonsils, oropharynx, other parts of mouth

Smoking, age, alc, sex

Smokeless (ever)

M

165/302

1.00 (0.40–2.30)p

31

Boffetta

2005 [82]

Questionnaire

Oral and pharyngeal

Smoking, age

Snuff (ever)

M

34/10136

1.10 (0.50–2.41)p

32

Henley

2005 [66]

Questionnaire

Oral and pharyngeal

Smokingl, age, race, educ., alc, exer, asp, bmi, diet, occt.

Smokeless (current)

M (CPS-I)

13/77407

2.02 (0.53–7.74)p

Smokeless (ever)

M (CPS-II)

46/114809

0.90 (0.12–6.71)p


a alc = alcohol consumption, asp = aspirin, bmi = body mass index, educ = education, exer = exercise, ins = insurance status, occ = occupation

b At risk population for cohort studies

c OR = odds ratio (case-control studies), RR = relative risk (cohort studies)

d Estimated from multiple independent 2 × 2 tables using fixed-effect meta-analysis

e Numbers of exposed and unexposed cases and controls estimated from proportions exposed given numerically

f Estimated from 2 × 2 table

g Numbers of exposed cases and controls combined over levels of exposure

h Analysis based on smokers only (only one SLT user was a non-smoker)

i Numbers of cases combined over cancer types specified

j Numbers of exposed and unexposed cases and controls estimated from proportions exposed given graphically

k Due to the joint reporting of pharynx and larynx cases, both sites excluded from analysis

l Analysis based on non-smokers only

m Note that in Table 13 of source chewing only data for mouth cancer wrongly given under pipe only

n Calculated assuming no-one chewed tobacco and used snuff

o Larynx cases cannot be sorted out due to incomplete reporting

p As reported by the authors

q Estimated from non-independent relative risks by level of exposure using method of Fry and Lee

r Estimated from non-independent relative risks for cancer types using method of Fry and Lee

s Attributable oral cancer risk due to smokeless tobacco use based on a case-control study at Sinai Hospital in Detroit; unpublished

t Occupation only adjusted for in CPS-II

Weitkunat et al. BMC Public Health 2007 7:334   doi:10.1186/1471-2458-7-334

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