From: Systematic review of the relation between smokeless tobacco and cancer in Europe and North America
 | ST use |  |  | RR/OR | ||||
---|---|---|---|---|---|---|---|---|
Sourcea | Typeb | Exposurec | Smoking | Sex | Id. | Casesd | Estimate (95%CI)e | Adjustment factorsf |
Cohort studies | Â | Â | Â | Â | Â | Â | Â | Â |
Lutheran Brotherhood: Zheng et al. 1993 [13] | ST | Ever | Any | M | 1 | 16 | 1.70 (0.90–3.10) | age, alc, smok |
US Veterans: Winn et al. 1982 [19] | ST | Ever | Never | Mg | 2 | NA | 1.65 (NA) | age |
Norway cohorts: Boffetta et al. 2005 [26] | Snuff | Current | Any | M | 3 | 27 | 1.60 (1.00–2.55) | age, smok |
 |  | Former |  |  | 4 | 18 | 1.80 (1.04–3.09) |  |
 |  | Ever |  |  | 5 | 45 | 1.67 (1.12–2.50) |  |
 |  | Ever | Never |  | 6 | 3 | 0.85 (0.24–3.07) | age |
Swedish construction workers: Luo et al. 2007 [32] | Snuff | Ever | Any | M | 7 | NA | 0.90 (0.70–1.20) | age, bmi, smok |
 |  | Current | Never |  | 8 | 18 | 2.10 (1.20–3.60) | age, bmi |
 |  | Former |  |  | 9 | 2 | 1.40 (0.40–5.90) |  |
 |  | Ever |  |  | 10 | 20 | 2.00 (1.20–3.30) |  |
Case-control studies | Â | Â | Â | Â | Â | Â | Â | Â |
Williams and Horm 1977[55] | ST | Ever | Any | M | 11 | 3 | 0.29 (0.09–0.92)h | age, race, smok |
Falk et al. 1988 [75] | Chew | Use | Any | M+F | 12 | NA | no association | none |
 | Snuff |  |  |  | 13 | NA | no association |  |
Farrow and Davis 1990 [82] | Chew | Ever | Any | M | 14 | NA | 0.80 (NA) | edu, race |
Ghadirian et al. 1991[84] | Chew | Use | Any | M+F | 15 | NA | no association | none |
Muscat et al. 1997 [101] | Chew | Ever | Neveri | M | 16 | 6 | 2.82 (0.85–9.39)j | none |
 | Snuff |  | Any |  | 17 | 2 | 1.32 (0.22–7.93) |  |
Alguacil and Silverman 2004 [111] | ST | Ever | Neverk | M+F | 18 | 5 | 1.10 (0.40–3.10) | age, race, res, sex, smokk |
Hassan et al. 2007 [114] | Chew | Ever | Any | M+F | 19 | 34 | 0.70 (0.40–1.10) | age, alc, diab, edu, mar, race, res, sex, smok |
 |  |  | Never |  | 20 | 10 | 0.60 (0.30–1.40) | age, alc, diab, edu, mar, race, res, sex |
 | Snuff | Ever | Any |  | 21 | 18 | 0.60 (0.30–1.10) | age, alc, diab, edu, mar, race, res, sex, smok |
 |  |  | Never |  | 22 | 4 | 0.50 (0.10–1.50) | age, alc, diab, edu, mar, race, res, sex |
 | ST | Ever | Any |  | 23 | 52 | 0.65 (0.43–0.97)l | age, alc, diab, edu, mar, race, res, sex, smok |
 |  |  | Never |  | 24 | 14 | 0.57 (0.29–1.11)l | age, alc, diab, edu, mar, race, res, sex |