Table 2

Details of US studies considered.
First author, year of publication	Location	Study Period^a	Sex	Age	Population	Further details of study design	Endpoints^b

Experimental studies

Grasser 1997 [21]	North Carolina	10 days	M+F	18 to 47	214 soldiers	4 ST users with oral leukoplakia advised to stop	ML
Payne 1998 [22]	Nebraska, Iowa	7 days	M	Mean 25	16 snuff users with oral lesions at habitual sites only	Site of snuff placement changed	ML
Martin 1999 [23]	Texas	6 weeks	M	17 to 34	3051 air force trainees	119 ST users with oral leukoplakia ordered to stop	ML

Prospective studies

Beck 1995 [24]	North Carolina	1988 to 1991	M+F	65+	818 dentate adults (50% black, 50% white)	Selected from Piedmont study. Reexamined at 18 and 36 months	PD, OP
Dietrich 2007 [25]	National	1986 to 2002	M	40–75	43112 health professionals dentate and cancer free at baseline	Data on tooth loss recorded every 2 years	DC

Case-control studies

Fisher 2005A [26]	West Virginia	2001 to 2002	M+F	18+	90 cases of oral leukoplakia, 78 controls with periapical cysts and no oral leukoplakia	Subjects identified from biopsy of hyperkeratosis	ML

Cross-sectional studies of populations unselected by ST use

Greer 1983 [27]	Colorado	Not given	M+F	14 to 19	1119 high school students	-	ML, PD, DC
Poulson 1984 [28]	Colorado	Not given	M+F	14 to 19 Mean 16.7	445 high school students	-	ML, PD, DC
Offenbacher 1985 [29]	Georgia	Not given	M	10 to 17 Mean 13.8	565 grammar and high school students	-	ML, PD, DC
Wolfe 1987 [30]	New Mexico	Not given	M+F	14 to 19 Mean 16.0	226 Native American children at boarding school	-	ML, PD
Cummings 1989 [31]	New York	1985	M	22 to 44 Mean 29	25 baseball players and coaches	-	ML, PD
Creath 1988 [32]	Alabama	Not given	M	11 to 18	995 adolescent football players	-	ML, PD
Stewart 1989 [33]	Florida	Not given	M	10 to 18	114 middle and high school students	5588 M+F interviewed, 182 examined orally, no results for 68F	ML
Ernster 1990 [34]^c	Arizona	1988	M+F	20 to 29 (77%)	1109 professional baseball players	-	ML, PD, DC
Greene 1992 [35]	Arizona	1989 to 1990	M	20 to 29 (76%)	894 professional baseball players	-	ML
Sinusas 1992 [36]	Pennsylvania	1990	M	17 to 58 Mean 25	206 baseball players and managers	-	ML, PD, DC
Daughety 1994 [37]	Iowa	Not given	M	16 to 17	821 11th and 12th grade school students	-	ML
Robertson 1997 [38]	Arizona	1988 to 1990	M	20 to 29 (77%)	1846 professional baseball players	Includes subjects in Ernster 1990 [34] and Greene 1992 [35]	ML, PD, DC
Tomar 1997 [39]^d	National	1986 to 1987	M+F	12 to 17	17027 school students	NIDR National Survey of Oral Health	ML
Tomar 1999 [40]	National	1988 to 1994	M+F	18+	14087 dentate adults	Third National Health and Nutrition Examination Survey (NHANES III)	DC
Riley 2004 [41]	Florida	1993 to 2000	M+F	45+	873 adults	Reinterviews occurred over a 48 month period but analyses are all cross-sectional	OP
Shulman 2004 [42]	National	1988 to 1994	M+F	18+	17235 adults	NHANES III, but different endpoints from Tomar 1999 [40]	ML
Fisher 2005B [43]	National	1988 to 1994	M+F	18+	12932 adults	NHANES III, but different endpoints from Tomar 1999 [40] and Shulman 2004 [42]	PD
Sinusas 2006 [44]	Pennsylvania	1991 to 2000	M	Mean 26	190 to 259 baseball players and coaches examined each year	Men attending spring training. Some men may attend on multiple occasions	ML

Cross-sectional studies of populations selected by ST use and/or presence of oral lesions

Smith 1970 [45]	Tennessee	Not given	M+F	Mean 55	15000 long-term snuff users	-	ML
Christen 1979 [46]	Texas	Not given	M	18 to 22 Mean 20	14 college athletes who used ST	-	ML, PD
Kaugars 1992 [47]	Virginia	Not given	M	14 to 77 Mean 29	347 ST users recruited by advertising^e	-	ML
Little 1992 [48]	Oregon, Washington	Not given	M	15 to 77	245 ST users in Kaiser Permanente Dental Care Program	Also 223 age-matched non ST users	ML
Roberts 1997 [49]	Indiana	1994 to 1995	M+F	Not given	22 snuff users and 19 non users	Oral lesions not recorded in non users	ML

^aLength of follow-up period for experimental studies, period of follow-up for prospective studies, and time study conducted otherwise ^bDC = dental caries, ML = mucosal lesion, OP = oral pain, PD = periodontal or gingival diseases ^cSimilar results are reported by Grady et al [83], Robertson et al [84] and Daniels et al [85] ^dResults from this study are also reported by Kleinman et al [86] ^eAn additional group of 91 non users of ST with no oral lesions provides no useful information and has been ignored
Kallischnigg et al. BMC Oral Health 2008 8:13 doi:10.1186/1472-6831-8-13