Review of salt consumption and stomach cancer risk: Epidemiological and biological evidence

Table 1 Summary of 45 case-control studies that evaluated the association between salt consumption and stomach cancer risk

Author and year	No. of cases	No. of controls	Factors evaluated	Exposure levels and OR (95% CI)1
SALT AND SODIUM INTAKE
Modan et al, 1974: Israel[23]	166	429	Salt	No association
Risch et al, 1985: Canada[24]	246	246	Salt	No association
You et al, 1988: China[25]	564	1131	Salt (per capita household)	≤ 13 kg/yr, ≤ 19 kg/yr, ≤ 20 kg/yr, > 20 kg/yr
				1.0, 1.2, 1.1, 1.1 (0.8-1.4); NS
Negri et al, 1990: Italy[26]	526	1223	Salt	Low, intermediate, salty
				1.0, 1.3, 1.2 (0.8-1.7); NS
Wu-Willians et al, 1990: USA[27]	137 male	137	Add salt	Rarely, often, always
				1.0, 1.4, 1.2 (Na); NS
Nazario et al, 1993: Puerto Rico[28]	136	151	Salt	≤ 6.979 g/wk; 6.98-18.66 g/wk; 18.67-43.26 g/wk; ≥ 43.27g/wk
				1.0, 2.9, 4.5, 5.0 (2.1-12.0); P < 0.05
Ramón et al, 1993: Spain[29]	117	234	Salt	Quartiles 1 through 4
				1.0, 1.2, 1.8, 2.1 (1.2-7.1); P for trend < 0.01
Lee et al, 1995: Korea[30]	213	213	Salt	Tertile 3 vs 1
				3.7 (1.1-12.5); P < 0.05
La Vecchia c et al, 1997: Italy[31]	746	2053	Salt	Low, intermediate or high
				1.0, 1.5 (1.0-2.2); P < 0.05
Ye et al, 1998: China[32]	272	544	Salt	0.25 kg/m; > 0.25 kg/m
				1.0, 1.3 (1.0-1.6); NS
López-Carrillo et al, 1999: Mexico[33]	220	752	Salt	Never, sometimes (adding salt after tasting the food)
				Positive association; P < 0.05
Liu et al, 2001: China[34]	189	189	Heavy salt	Low to high half
				1.0, 2.0 (1.3-3.2); P < 0.05
Machida-Montani et al, 2004: Japan[35]	122	235	Salt	Tertiles 1 through 3
				1.0, 1.3, 1.5 (0.6-3.7); N
Qiu et al, 2004: China[36]	103	133	Salt	Positive association; P < 0.05
La Vecchia et al, 1987: Italy[37]	206	474	Table salt	Tertile 3 vs 1
				1.5 (Na); NS
Tuyns et al, 1988: Belgium[38]	293	2851	Table salt	Never, sometimes, always
				1.0, 1.0, 1.8 (1.2-2.8); P < 0.05
Buiatti et al, 1989: Italy[39]	1016	1159	Table salt	Seldom, always
				1.5 (1.3-1.9); NS
Coggon et al, 1989: England[40]	95	190	Table salt	Low to high half
				1.0, 6.2 (2.0-18.9); P < 0.05
Boeing et al, 1991: Germany[41]	143	579	Table salt	No association
Boeing et al, 1991: Poland[42]	741	741	Table salt	Low to high half
				1.0, 1.6 (1.2-2.3); P < 0.05
Graham et al, 1990: USA[43]			Sodium intake	≤ 73.2 g/mo; 73.2-98.8 g/mo; ≤ 98.9-127.3 g/mo; > 127.3 g/mo
	186 male	181		1.0, 1.8, 2.6, 3.1 (1.7-5.8); P for trend = 0.001
				≤ 66.9; 67.0-88.5; > 88.5
	107 female	104		1.0, 1.8, 4.7 (2.3-9.6); P for trend = 0.0001
Harrison et al, 1997: USA[44]		132	Sodium intake	Low to high half
	60 intestinal			1.0, 1.3 (0.8-1.9); NS
	31 diffuse			1.0, 1.4 (0.9-2.1); NS
SALTY FOODS
Salted fish
Haenszel et al, 1972: Japan[45]	220	440	Salted/dried fish	None, use both, 2 times/mo; 3-5 times/mo; 6 times/mo
				1.0, 2.0, 1.5, 2.5, 2.6 (Na); P < 0.05
Haenszel et al, 1976: Japan[46]	783	1566	Salted/dried fish	None; < 4 times/mo; 4-9 times/mo; ≥ 10 times/mo
				1.0, 1.1, 1.1, 1.2 (Na); NS
Tajima et al, 1985: Japan[47]	93	186	Salted/dried fish	Low to high half
				1.0, 2.6 (Na); P < 0.01
You et al, 1988: China[25]	564	1131	Sated fish	≤ 0.5 kg/yr, ≤ 1 kg/yr, > 1 kg/yr
				1.0, 1.0, 1.4 (0.8-1.5); NS
Buiatti et al, 1989: Italy[39]	1016	1159	Salted/dried fish	Tertile 3 vs 1
				1.4 (Na); P for trend = 0.001
Kato et al, 1990: Japan[48]				< 2-3 times/wk; ≥ 2-3 times/wk
	289 male	1247	Salted/dried fish	1.0, 1.2 (0.9-1.7); NS
			Salted fish gut, cod roe	1.0, 1.5 (1.1-2.1); P < 0.05
	138 female	1767	Salted/dried fish	1.0, 0.7 (0.5-1.0); NS
			Salted fish gut, cod roe	1.0, 0.5 (0.3-1.0); NS
González et al, 1991: Spain[49]	354	354	Salted fish	Low to high half
				1.0, 1.5 (0.9-2.6); NS
Palli et al, 1992: Italy[50]		1159	Salted/dried fish	Tertile 3 vs 1
	68 cardia			1.7 (0.9-3.1); NS
	855 others			1.5 (1.2-1.8); NS
Hansson et al, 1993: Sweden[51]	338	669	Salted fish	None, ≤ 0.9 times/mo; ≤ 3 times/mo; ≤ 7 times/mo; ≤ 11 times/mo
				1.0, 1.0, 0.9, 0.9, 1.3 (0.8-2.1); NS (adolescence)
				None, ≤ 0.9 times/mo; ≤ 3 times/mo; ≤ 7 times/mo
				1.0, 1.0, 0.8, 0.8 (0.5-1.3); NS (20 yr prior to interview)
Kim et al, 2002: Korea[52]	136	136	Salted fish	Tertiles 1 through 3
				1.0, 0.8, 0.8 (0.4-1.6); NS
Cai et al, 2003: China[53]	381	222	Salty fish	< times/mo, < 3 times/wk, ≥ 3 times/wk
				1.0, 1.0, 5.5 (1.4-19.5); NS
Strumylaite et al, 2006: Lithuania[54]	379	1137	Salted fish	Almost do not use, 1-3 times/mo
				1.0, 0.7 (0.5-0.9); P for trend = 0.002
Salted vegetable
You et al, 1988: China[25]	564	1131	Sated vegetables	< daily, daily
				1.0, 1.1 (0.7-1.8); NS
Ye et al, 1998: China[32]	272	544	Salted vegetables	< 2 kg/yr; > 2 kg/yr
				1.0, 1.4 (1.1-1.8); P < 0.05
Kim et al, 2002: Korea[52]	136	136	Salted vegetables	Tertiles 1 through 3
				1.0, 0.9, 1.5 (0.8-2.9); NS
Xibin et al, 2002: China[55]	210	630		Low to high half
			Pickled or salted vegetables	1.0, 4.0 (1.6-9.8); P < 0.05
			Preference for a high salt vegetables	1.0, 2.6 (1.6-4.3); P < 0.05
Cai et al, 2003: China[53]	381	222	Pickled vegetables	< times/M, < 3 times/w, ≥ 3 times/wk
				1.0, 1.3, 1.8 (1.0-3.0); P for trend = 0.038
Strumylaite et al, 2006: Lithuania[54]	379	1137	Pickled vegetables with salt and oil	Almost do not use, 1-3 times/mo, ≥ 1-2 times/wk
			Pickled vegetables with salt and vinegar	1.0, 0.6, 0.8 (0.6-2.1); NS
			Salted mushrooms	Almost do not use, 1-3 times/mo, ≥ 1-2 times/wk
				1.0,0.7, 0.8 (0.6-1.0); NS
				1-3 times/mo, ≥ 1-2 times/wk
				1.0, 1.6 (1.1-2.4); NS
Salted snacks
Boeing et al, 1991: Germany[41]	143	579	Pretzels, salty snacks	Tertiles 1 through 3
				1.0, 0.7, 1.5 (1.0-2.2); NS
Ward et al, 1999: Mexico[56]	220	752	Salty snacks	Never, ≤ 2, > 2 times/mo
				1.0, 1.3, 1.8 (1.2-2.8); P for trend = 0.008
Chen et al, 2002: Nebraska[57]	124	449	Salty snacks	Quartiles 1 through 4
				1.0, 1.4, 1.2, 0.7 (0.3-1.6);NS
Salted foods in general
Hu et al, 1988: China[58]	241	241	Salted and fermented soya paste	< 2 kg/yr; > 2 kg/yr
				1.0, 1.5 (1.0-2.2); NS
Kono et al, 1988: Japan[59]	139	2852	Salty foods	None or 1-3 times/mo; 1-3 times/mo; once/do more
				1.0, 0.8, 1.4 (Na): NS
Demirer et al, 1990: Turkey[60]	100	100	Salted foods	Less than once or twice/wk; once or twice/wk vs
				1.0, 3.8 (2.1-6.9); P < 0.001
Hoshiyama et al,1992: Japan[61]	294	294 (general population)	Salty foods	No, moderate, yes
		202 (hospital control)		1.0, 1.7, 2.3 (1.5-3.4); P < 0.01
				1.0, 1.3, 1.1 (0.7-1.9); NS
Ramón et al, 1993: Spain[29]	117	234	Pickled foods	Quartiles 1 through 4
				1.0, 1.2, 2.1, 3.7 (Na); P for trend < 0.01
Ji et al, 1998: China[62]	1124	1451	Salted foods	Occasionally, sometimes, frequently
				1.0, 1.4, 1.7 (1.3-2.4); P for trend = 0.001
Lee et al, 1995: Korea[30]	213	213	Salted side dishes	Tertile 3 vs 1
				4.5 (2.5-8.0); P < 0.05
Ye et al, 1998: China[32]	272	544	Salted fermented sea foods	< 1.5 kg/yr; > 1.5 kg/yr
				1.0, 1.6 (1.2-2.0); P < 0.01
Kim et al, 2002: Korea[52]	136	136	Salty foods	Tertiles 1 through 3
				1.0, 1.1, 0.9 (0.4-1.8); NS
De Stefani et al, 2004: Uruguay[63]	240	960	Salted meat	Tertiles 1 through 3 1.0, 1.3, 2.0 (1.4-2.9); P for trend = 0.0003
Campos et al, 2006: Colombia[64]	368	431	Salting meals before tasting	No, yes
				1.0, 3.5 (1.6-7.3); P for trend = 0.001
Strumylaite et al, 2006: Lithuania[54]	379	1137	Salted meat	Almost do not use, 1-3 times/mo, ≥ 1-2 times/wk
				1.0, 1.5, 3.0 (2.2-4.0); P for trend < 0.001

¹OR, Odds ratio; CI: Confidence interval; Na: No association.

Table 2 Summary of 11 cohort studies that evaluated the association between salt consumption and stomach cancer risk

Author and yr	Size of cohort	No. of cases	Length of follow-up (yr)	Factors evaluated	Exposure levels and RR (95% CI)1
Salt
Nomura et al, 1990: USA[65]	7990 male	150	4	Table salt/shoyu	Never-seldom, after tasting, always
					1.0, 1.4, 1.0 (0.6-1.6); NS
van den Brandt et al, 2003: Netherlands[66]	120 852	282	6.3	Dietary salt	Quintiles 1 through 5
					1.0, 1.5, 1.0, 1.5, 1.2 (0.8-1.8); NS
				Table salt	Never, seldom, sometimes, often/very often
					1.0, 1.1, 0.7, 0.9 (0.6-1.4); NS
Tsugane et al, 2004: Japan[67]			12	Salt	Quintiles 1 through 5
	18 684	358			Male: 1.0, 1.7, 2.0, 2.3, 2.2 (1.5-3.4); P for trend < 0.001
	20 381	128			Female:1.0, 0.9, 1.0, 0.6, 1.3 (0.8-2.3); NS
Shikata et al, 2006: Japan[68]	2476	93	14	Dietary salt	< 10.0, 10.0-12.9, 13.0-15.9, ≤ 16.0 1.0, 2.1, 1.9, 2.7 (1.4-5.2); P for trend = 0.01
Sjödahl et al, 2008: Sweden[69]	73 133	313	18	Dietary salt	Low to high half
					1.0, 1.0 (0.7-1.4); NS
Salty foods
Kneller et al, 1991: USA[70]	17 633 male	75	20	Salted fish	Never, < 1, ≥ 1 1.0, 1.0, 1.9 (1.0-3.6); NS
Galanis et al, 1998: USA[71]	11 907	108	14.8 (average)	Dried or salted fish	None, 1 or more times/wk
				High-salt foods	1.0, 1.0 (0.6-1.7); NS
					None, 1-3 times/wk, 4 or more times/wk
					1.0, 1.0, 1.1, (0.7-1.8); NS
Ngoan et al, 2002: Japan[72]	13 000	116	10	Salted food	Low, median, high
					1.0, 1.0, 1.4 (0.6-3.2); NS
Kim et al, 2004: Japan[73]		400	10	Salted food	Quartiles 1 through 4
	20 300			(traditional type)	Male:1.0, 2.0, 2.5, 2.9 (1.8-4.7); P for trend < 0.0001
	21 812				Female: 1.0, 1.7, 1.3, 2.4 (1.3-4.4); P for trend = 0.007
Tokui et al, 2005: Japan[74]	110 792		12	Preference for salty food	No, a little, somewhat, much, very much
		574			Male: 1.0, 0.9, 1.1, 1.1, 1.4 (0.7-2.8); NS
		285			Female: 1.0, 1.6, 1.8, 1.5, 1.9 (0.6-5.8); NS
				Dried or salty fish	None, 1-2/mo, 1-2/wk, 3-4/wk, 1+/d
		574			Male: 1.0, 0.9, 0.9, 0.9, 1.1 (0.7-1.8); NS
		285			Female:1.0, 0.6, 0.7, 0.7, 0.9 (0.5-1.6); NS
Kurosawa et al, 2006: Japan[75]	8035	76	11	Salted food	Low, intermediate, high
					1.0, 4.0, 5.4 (1.8-16.3); P for trend < 0.01

¹RR: Relative risk.