Table 4.

Prevalence of oral mucosal lesions in relation to snuff use evidence from Scandinavia

Study	Location	Summary of main results
Experimental studies
Larsson 1991 [1]	Sweden	Of 29 users with degree 2 to 4 lesions, the lesion disappeared in 20 who quit snuff or changed to portion-bags and changed placement of the quid, reduced in 7 who changed to portion-bags and reduced their exposure, and remained in 2 who modified their habits only slightly.
Andersson 1995 [2]	Sweden	100% lesion prevalence initially in 24 users of ordinary snuff and in 18 users of low nicotine snuff. After 2 weeks, severity was non-significantly lower in habitual users of low nicotine brand. After a further 10 weeks, switching to the low nicotine brand was associated with a reduction in lesion severity (p < 0.01), despite an increased intake of 2.5 g/day.
Andersson 2003 [3]	Sweden	The 20 users of brand A (0.8% nicotine, pH 8.6) had a severity distribution of 0/0/16/4 for degrees 1/2/3/4 respectively. Switching to brand B (0.8% nicotine, pH 8.0) for 12 weeks, reduced the severity to 0/7/13/0, and switching to brand C (0.4–0.5% nicotine, pH 8.0) reduced it further to 2/11/7/0.
Prospective studies
Roosaar 2006 [4]	Sweden	Of 176 users with grade 1–4 lesions in 1973–1974 who were re-examined in 1993–1995, the lesion had disappeared in 62/66 = 94% of those who stopped, and remained in 108/110 = 98% of whose who continued (p < 0.001). Grade 3 and 4 lesions were less common in those who switched to portion-bag snuff, 6/42 = 14%, than in those who continued with loose snus, 20/68 = 29% (0.05 < p < 0.1).
Case-control studies
Rosenquist 2005 [5]	Sweden	100% lesion prevalence in 31 population controls who currently used snuff. Lesion severity was significantly associated with hours/day consumed (p = 0.01), but not with daily consumption (p = 0.07), or duration of use (p = 0.8).
Cross-sectional studies of populations unselected by ST use
Jungell 1985 [7]	Finland	63.6% lesion prevalence in 33 snuff users examined. Of the 12 with no lesions, 8 had quit snuff and 4 started snuff in the previous 3 weeks.
Salonen 1990 [8]	Sweden	92 lesions in 58 snuff only users, 29 in 23 mixed smokers and snuff users, 5 in 235 smokers and 0 in 602 with no tobacco habit (frequencies of subjects with lesion not given).
Cross-sectional studies of populations selected by ST use and/or presence of lesions
Pindborg 1963 [13]	Denmark	100% lesion prevalence in 12 long-term snuff users (lesion prevalence probable inclusion criterion).
Roed-Peterson 1973 [14]	Denmark	Among 450 selected patients with oral leukoplakia, the 32 who used snuff experienced fewer symptoms than the other 418 patients.
Axéll 1976 [15]	Sweden	Among 108 selected snuff users with oral lesions, severity increased with consumption (hours/day or grams/day) of snuff.
Hirsch 1982 [16]	Sweden	100% lesion prevalence in 50 habitual snuff users (lesion prevalence probable inclusion criterion). Severity increased with consumption (hours/day or grams/day) of snuff, and also with duration of use.
Frithiof 1983 [17]	Sweden	Among 21 snuff users referred for treatment due to oral lesions, those who quit following advice to do so had marked lesion improvement in two weeks.
Andersson 1989 [18]	Sweden	100% lesion prevalence in 252 snuff users. Severity was significantly less in 68 users of portion-bag snuff than in 184 users of loose snuff. Severity was also clearly associated with consumption (hours/day or grams/day), though less clearly with duration of use.
Andersson 1994 [19]	Sweden	100% lesion prevalence in 45 snuff users. Severity was less in 23 users of portion-bag snuff than in 22 users of loose snuff.
Rolandsson 2005 [20]	Sweden	Lesion prevalence 87.5% in 40 snuff users and 0.0% in 40 non-users (p < 0.001). Prevalence and severity increased with hours/day of snuff and was lower in users of portion-bag snuff.