Gastric cancer and salt preference: a population-based cohort study in Korea 1 3

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1 Gastric cancer and salt preference: a population-based cohort study in Korea 1 3 Jeongseon Kim, Sohee Park, and Byung-Ho Nam ABSTRACT Background: Although the incidence of gastric cancer is declining, it remains the most common cancer in Korea. There have been discrepancies in epidemiologic studies regarding a causal relation between highly salted food and the risk of gastric cancer. Objective: The aim of this study was to assess the effect of salt preference on the incidence of gastric cancer in Korean adults through a population-based, prospective cohort study. Design: Participants were Korean government employees, school faculty members, and their unemployed dependents, aged y, who underwent health examinations between 1996 and In 2003, information on the gastric cancer incidence in these participants was obtained during the 6 7-y follow-up period. The final data analysis included 2,248,129 study subjects. The hazard ratio (HR) and 95% CI of the HR were estimated by using the Cox proportional hazards regression model. Results: The age-standardized incidence rates per 100,000 personyears for the overall total population, men only, and women only were 97.64, , and 52.90, respectively. The Cox proportional hazards regression model, with adjustment for possible confounding factors, showed evidence of an increased risk of gastric cancer with salt preference. The HRs were 1.10 (95% CI: 1.04, 1.16) and 1.10 (95% CI: 1.03, 1.17) for the overall total population and men only, respectively. Conclusion: The current findings suggest that salt preference has a marginal positive association with a risk of gastric cancer. Am J Clin Nutr 2010;91: INTRODUCTION Gastric cancer is the second leading cause of cancer death globally (1). Statistics have shown that both the incidence and mortality rates of gastric cancer are steadily declining worldwide. Despite the recent declining incidence rate, the absolute number of cases is predicted to increase up to the year 2050 (2). In South Korea, gastric cancer remains the most common cancer, with an age-standardized incidence rate of 67.3 and 28.1 cases per 100,000 person-years for men and women, respectively, according to the 2005 national cancer statistics (3). Although salt is regarded as an indispensible food additive to improve the taste of food, it has been hypothesized since the 1960s that salty food is related to the cause of cancer (4). Many case-control, ecologic, and experimental studies showed that highly salted food may be a risk factor for the development of gastric cancer (5). A recent meta-analysis (4) of case-control data showed an 18% increased risk per gram of sodium per day. However, in nearly all prospective cohort studies (6 10), no association was shown, and unequivocal evidence remains scarce. Thus, epidemiologic studies failed to detect a causal relation between highly salted food and a risk of gastric cancer. Because there are discrepancies between the results of case-control and cohort studies that explored the association between salt and gastric cancer cause, a large population-based, prospective cohort study was conducted to assess the effect of salt preference on the risk of gastric cancer in Korean adults. SUBJECTS AND METHODS Study population The participants were Korean government employees, school faculty members, and their unemployed dependents, aged y, who underwent a health examination between 1996 and Because gastric cancer is the most common cancer in Korea, and it is especially the leading cancer affecting men aged y (3), young subjects aged,40 y were also included in this study. The examination was conducted by the Korean Health Insurance Corporation, a major institution for a nationwide health insurance system in Korea. This study was analyzed by using data obtained during regular medical checkups and from the cancer registry. Because this study involved routinely collected medical data, participant consent was not required. Incident cancer cases were identified from the Korean Central Registry, and the collected data included the time of diagnosis and type of cancer. The study was approved by the institutional review board of the National Center (institutional review board no. NCCNCS09-305). Of the 5,657,474 individuals screened, those who provided incomplete information on their cancer history, dietary habits, body mass index (BMI; in kg/m 2 ), alcohol consumption and smoking habits, physical activity, and family history of cancer were excluded. Those who had already had cancer (13,622 men and From the Epidemiology Branch (JK) and the Biostatistics Branch (SP and B-HN), Division of Epidemiology and Management, National Center Research Institute, Goyang-si, Gyeonggi-do, South Korea. 2 Supported by The National Center, Korea (grant ). 3 Address correspondence to B-H Nam, Biostatistics Branch, Division of Epidemiology and Management, National Center Research Institute, 111 Junbalsan-ro, Ilsandong-gu, Goyang-si, Gyeonggido, , South Korea. byunghonam@ncc.re.kr. Received September 24, Accepted for publication January 31, First published online March 10, 2010; doi: /ajcn Am J Clin Nutr 2010;91: Printed in USA. Ó 2010 American Society for Nutrition 1289

2 1290 KIM ET AL women) were excluded from further data analysis. A total of 2,248,129 study subjects were included in the final data analysis. Information on health-related behavior was collected by using a self-administered questionnaire during the health examination. Questions on dietary habits, a main variable of interest, pertained to the following: meal regularity (regular, medium, and irregular), salt preference (not salty, medium, and salty), diet preference (vegetables preferred, animal products and vegetables preferred, and animal products preferred), and frequency of meat consumption (1, 2 3, and 4 times/wk). Other questions on health-related behaviors included questions on personal history of cancer, family history of cancer, alcohol intake [none, light (,51.8 g/wk), medium ( g/wk), and heavy ( g/wk)], smoking (never, ex-smoker,,0.5 pack/d, between 0.5 and 1 pack/d, and.1 pack/d), and physical activity [none, low (active 4 times/wk for,30 min/time or 1 time/wk for 30 min/time), moderate (active 2 4 times/wk for 30 min/time or 5 times/wk for,30 min/time), high (active 5 times/wk for 30 min/time)]. Weight and height were measured during the health examination. Participants were categorized into 4 groups on the basis of their BMI:,18.5, , , and incidence We identified study subjects who were diagnosed with cancer up to 2003 through data linkage with the Korea National Incidence Database of the Korea Central Registry (11). Codes C00 C99 in the International Classification of Diseases, 10th edition (12), were used to identify the cancers, and C16 was used for gastric cancer. Statistical analyses Age-standardized incidence rates were calculated by weighting the rate of a standardized population from each age group by using the World Health Organization world standard population: agestandardized incidence rate = R [(crude incidence rate for each age group) (world standard population size for each age group)/ total world standard population size] (13). A Mantel-Haenszel chisquare test was administered to compare strata in terms of age, BMI, alcohol intake, smoking habits, physical activity, and family history of cancer. The hazard ratio (HR) and 95% CI of the HR were estimated by using the Cox proportional hazards regression model. The proportionality assumption of the model was tested, and adjustments were made for age, sex, BMI, smoking habits, alcohol consumption, physical activity, and family history of cancer. All analyses were performed with the SAS statistical package (9.1.3; SAS Institute, Cary, NC), and P, 0.05 was considered significant. RESULTS The data from 2,248,129 study subjects (1,420,981 men and 827,148 women) were analyzed to assess the association between a risk of gastric cancer and dietary habits. The distribution of general characteristics is shown in Table 1. The categories belonging most to healthy subjects were age y (34.7%), BMI (41.8%), consuming little alcohol (52.6%), not smoking (48.1%), not engaging in physical activity (57.2%), and not having a family history of cancer (88.1%) in the overall total group. In comparison, y was the age range for most of the subjects with gastric cancer (34.5% in the overall total group, 36.1% in men only, and 30.2% in women only). During the 7-y follow-up, gastric cancer occurred in 9620 men and 2773 women. There were significant differences in the distribution of age, BMI, smoking, physical activity, and family history of cancer between subjects who had cancer and subjects who did not have it in the overall total group. In men, factors that were shown to be significant were age, BMI, alcohol intake, smoking, and family history of cancer. In women, age, BMI, alcohol intake, smoking habits, and family history of cancer were significant factors. In the overall total, men only, and women only groups, those with cancer tended to be older and were less likely to have a history of smoking compared with subjects without cancer. In addition, more female cancer subjects than healthy subjects had a BMI. 25, and those with cancer compared with those without cancer had more family history of cancer in the overall total and men only groups. The age-standardized incidence rates per 100,000 personyears for the overall total (97.64), men only (136.03), and women only (52.90) groups are listed in Table 2. An association was shown between a risk of gastric cancer and dietary habits. There was evidence of an increased risk of gastric cancer with a preference for salty food. The estimated HRs were 1.10 (95% CI: 1.04, 1.16) and 1.10 (95% CI: 1.03, 1.17) for the overall total and men only groups, respectively. Other variables related to dietary habits, such as meal regularity, meal preference, and frequency of meat consumption were not significant. DISCUSSION To our knowledge, this is the first prospective cohort study to evaluate an association between a dietary factor, especially salt, and a risk of gastric cancer in South Korea. In this populationbased, prospective study of Korean men and women, we compared the age-standardized incidence rate for gastric cancer with that of nationwide data from the cancer registry (14) and confirmed similar figures between the 2 rates (97.64, , and per 100,000 person-years in this study compared with 92.72, , and per 100,000 person-years in the nationwide data for the overall total population, men only, and women only, respectively). We also observed an increased risk of gastric cancer with salt preference. According to the summary table in the second World Research Fund report (4), salt is a probable risk factor for gastric cancer. In general, most case-control studies showed positive associations between a risk of gastric cancer and sodium intake (15 18) and a preference for salty foods (19 23). However, some case-control studies showed no association between a risk of gastric cancer and sodium intake (24 26) and a preference for salty foods (27 30). Moreover, cohort studies (6 10, 31) that reported results on the relation between salt intake and a risk of gastric cancer, which are limited and less consistent, showed no clear association between the 2. Even the only cohort study (31) to measure sodium intake showed no difference between those with and without cancer in terms of an association between salt intake and gastric cancer. However, a large, prospective, cohort study in Japan (32) showed that high salt intake was significantly associated with an increased risk of gastric cancer in men but not in women. The findings of the Netherlands cohort study (33) suggested that the dietary salt intake was weakly but positively associated with a risk of gastric cancer.

3 SALT PREFERENCE AND GASTRIC CANCER 1291 TABLE 1 General characteristics of study participants Total (n = 2,248,129) Men (n = 1,420,981) Women (n = 827,148) Category (n = 2,235,736) (n = 12,393) P 1 (n = 1,411,361) (n = 9620) P 1 (n = 824,375) (n = 2773) P 1 Age group [n (%)],0.001,0.001, y 648,035 (29.0) 981 (7.9) 498,608 (35.3) 803 (8.4) 149,427 (18.1) 178 (6.4) y 775,071 (34.7) 2624 (21.2) 461,649 (32.7) 2062 (21.4) 313,422 (38.0) 562 (20.3) y 505,770 (22.6) 4281 (34.5) 300,175 (21.3) 3471 (36.1) 205,595 (24.9) 810 (29.2) y 238,477 (10.7) 3388 (27.3) 120,299 (8.5) 2551 (26.5) 118,178 (14.3) 837 (30.2) y 68,383 (3.1) 1119 (9.0) 30,630 (2.2) 733 (7.6) 37,753 (4.6) 386 (13.9) BMI [n (%)],0.001, ,18.5 kg/m 2 67,087 (3.0) 486 (3.9) 34,181 (2.4) 364 (3.8) 32,906 (4.0) 122 (4.4) kg/m 2 934,787 (41.8) 5367 (43.3) 577,299 (40.9) 4259 (44.3) 357,488 (43.4) 1108 (40.0) kg/m 2 601,443 (26.9) 3250 (26.2) 400,566 (28.4) 2562 (26.6) 200,877 (24.4) 688 (24.9).25.0 kg/m 2 630,667 (28.2) 3284 (26.5) 398,395 (28.3) 2433 (25.3) 232,272 (28.2) 851 (30.7) Alcohol intake [n (%)] , None 541,491 (37.5) 2822 (37.1) 148,323 (15.8) 1425 (24.2) 393,168 (78.2) 1397 (81.4) Light 758,847 (52.6) 4161 (54.7) 650,160 (69.1) 3843 (65.2) 108,687 (21.6) 318 (18.5) Moderate 85,178 (5.9) 350 (4.6) 84,419 (9.0) 348 (5.9) 759 (0.2) 2 (0.1) Heavy 57,774 (4.0) 281 (3.7) 57,399 (6.1) 281 (4.8) 375 (0.1) 0 (0.0) Smoking amount [n (%)], ,0.001 Never 919,681 (48.1) 3943 (36.0) 380,771 (28.4) 2252 (25.0) 538,910 (94.2) 1691 (87.4) Ex-smoker 207,047 (10.8) 1573 (14.4) 199,474 (14.9) 1524 (16.9) 7573 (1.3) 49 (2.5),0.5 pack currently 144,387 (7.5) 1152 (10.5) 129,472 (9.7) 1026 (11.4) 14,915 (2.6) 126 (6.5) pack currently 463,932 (24.2) 3085 (28.2) 455,142 (33.9) 3034 (33.7) 8790 (1.5) 51 (2.6).1 pack currently 178,875 (9.4) 1188 (10.9) 176,844 (13.2) 1170 (13.0) 2031 (0.4) 18 (0.9) Physical activity [n (%)] 3, None 1211,413 (57.2) 6353 (55.1) 655,493 (47.9) 4503 (49.7) 555,920 (74.1) 1850 (75.1) Low 272,088 (12.8) 1568 (13.6) 219,071 (16.0) 1407 (15.5) 53,017 (7.1) 161 (6.5) Moderate 505,201 (23.8) 2656 (23.0) 402,741 (29.4) 2343 (25.8) 102,460 (13.7) 313 (12.7) High 130,560 (6.2) 955 (8.3) 91,698 (6.7) 815 (9.0) 38,862 (5.2) 140 (5.7) Family history of cancer [n (%)],0.001, No 1,969,150 (88.1) 10,751 (86.8) 1,250,552 (88.6) 8369 (87.0) 718,598 (87.2) 2382 (85.9) Yes 266,586 (11.9) 1642 (13.3) 160,809 (11.4) 1251 (13.0) 105,777 (12.8) 391 (14.1) 1 The Mantel-Haenzel chi-square test was used for comparison between strata in age, BMI, alcohol intake, smoking amount, physical activity, and family history of cancer. 2 None, light (,51.8 g/wk), medium ( g/wk), and heavy ( g/wk). 3 None, low (active 4 times/wk for,30 min/time or 1 time/wk for 30 min/time), moderate (active 2 4 times/wk for 30 min/time or 5 times/wk for,30 min/time), and high (active 5 times/wk for 30 min/time). Several mechanisms of gastric carcinogenesis induced by a high-salt diet were discussed in the literature (34 36), although there has been no conclusive evidence reported to date. Salt was hypothesized to act as an irritant that leads to mucosal damage in the stomach, leading to excessive cell replication, an event well known to increase cancer risk because it potentiates the action of carcinogens and poses the possibility of an increased rate of endogenous mutations. Further, damage to the stomach mucosa increases the susceptibility of the mucosal cells to carcinogens from foods, and its repair is associated with inflammatory changes (33, 34). An excessively salty diet induced atrophy in experimental animals and was associated with atrophic changes in the human gastric mucosa (35, 36). It was postulated that the continuous consumption of high doses of salt would result in early atrophic gastritis, thereby increasing the risk of developing gastric cancer at a later time (37). The strength of the current study includes its prospective cohort design and its large sample size. However, one of the limitations of this study is the lack of information on Helicobacter pylori infection. Because several studies showed an interaction between salt and H. pylori infection (38), there is a chance that the mucosal cell proliferation in the antrum is positively related to the salt intake in H. pylori positive subjects. Information from previous studies includes the percentage of infected people in the study population (38); different results for the association between salt preference and the risk of gastric cancer may be explained by different infection rates. However, we have no information on the H. pylori infection status of our subjects. A second limitation of this study is that salt intake was not measured; instead, we recorded salt preference, which was self-evaluated in a questionnaire, and therefore, the data may be too subjective to assess absolute salinity. Although a study (39) showed that salt-taste perceptions and preferences are unrelated to sodium consumption among healthy older adults, several studies (40, 41) indicated that either the frequency of consumption of or the amount of salty food may be associated with the preference for a salty taste. A third limitation is that we were unable to control for other potential confounders such as income and occupation. Confounding factors that were taken into consideration included age, smoking, alcohol consumption, physical activity, and a family history of cancer.

4 1292 KIM ET AL TABLE 2 Association between risk of gastric cancer and dietary habits 1 Age-standardized incidence rate 2 Crude HR Multivariate HR (95% CI) 3 (95% CI) 3 n n Total (n = 2,248,129) Regular 1,279, Medium 732, (0.85, 0.91) 1.04 (1.00, 1.08) Irregular 223, (0.73, 0.84) 1.04 (0.97, 1.11) Not salty 1,443, Medium 356, (0.98, 1.08) 1.03 (0.98, 1.08) Salty 436, (1.15, 1.26) 1.10 (1.04, 1.16) Mostly vegetables 568, Animal products and vegetables 1,511, (0.93, 1.01) 0.97 (0.93, 1.02) Animal products preferred 155, (1.02, 1.18) 1.01 (0.94, 1.09) 1 time/wk 1,112, times/wk 991, (0.92, 0.99) 0.96 (0.93, 1.00) 4 times/wk 132, (1.21, 1.39) 0.99 (0.93, 1.07) Total 2,235,736 12, Men (n = 1,420,981) Regular 814, Medium 471, (0.82, 0.89) 1.05 (0.99, 1.10) Irregular 124, (0.73, 0.85) 1.05 (0.97, 1.13) Not salty 884, Medium 225, (0.94, 1.05) 1.03 (0.97, 1.09) Salty 300, (1.09, 1.20) 1.10 (1.03, 1.17) Mostly vegetables 287, Animal products and vegetables 1,005, (0.87, 0.96) 0.97 (0.92, 1.02) Animal products preferred 118, (0.90, 1.06) 1.00 (0.92, 1.08) 1 time/wk 649, times/wk 686, (0.85, 0.92) 0.96 (0.92, 1.00) 4 times/wk 75, (1.25, 1.46) 0.96 (0.88, 1.04) Total 1,411, Women (n = 827,148) Regular 464, Medium 261, (0.88, 1.04) 0.99 (0.91, 1.07) Irregular 98, (0.82, 1.04) 1.00 (0.89, 1.13) Not salty 558, Medium 130, (0.99, 1.22) 0.99 (0.89, 1.09) Salty 135, (1.08, 1.31) 1.07 (0.94, 1.21) Mostly vegetables 281, Animal products and vegetables 506, (0.75, 0.87) 0.96 (0.88, 1.03) Animal products 36, (0.71, 1.03) 1.04 (0.86, 1.26) 1 time/wk 462, times/wk 304, (0.84, 0.99) 0.96 (0.89, 1.04) 4 times/wk 56, (1.00, 1.33) 1.05 (0.91, 1.21) Total 824, HR, hazard ratio. 2 Defined as: R[(crude incidence rate for each age group) (world standard population size for each age group)/total world standard population size]. 3 Estimated by using the Cox proportional hazards regression model. The proportionality assumption of the model was tested, and adjustments were made for age, sex, BMI, smoking habits, alcohol consumption, physical activity, and family history of cancer.

5 SALT PREFERENCE AND GASTRIC CANCER 1293 In conclusion, a weak but positive association was shown between salt preference and a risk of gastric cancer. Although the mechanisms by which salt is involved in gastric carcinogenesis remain unclear, restricting salt intake is thought to be beneficial for preventing gastric cancer. The authors responsibilities were as follows JK: contributed to the analysis and interpretation of the data and the writing of the manuscript; SP: contributed to the interpretation of data and critical revision of the manuscript; and B-HN: contributed to obtaining funding and provided important advice in preparing the manuscript. None of the authors had potential conflicts of interest to disclose. REFERENCES 1. Parkin DM, Bray F, Ferlay J, Pisani P. Global cancer statistics, CA J Clin 2005;55: Forman D, Burley VJ. Gastric cancer: global pattern of the disease and an overview of environmental risk factors. Best Pract Res Clin Gastroenterol 2006;20: Jung KW, Won YJ, Park S, et al. statistics in Korea: incidence, mortality and survival in J Korean Med Sci 2009;24: World Resarch Fund/American Institute for Research. Food, nutrition, physical activity, and the prevention of cancer: a global perspective. 2nd ed. Washington, DC: World Research Fund/ American Institute for Research, Kurosawa M, Kikuchi S, Xu J, Inaba Y. Highly salted food and mountain herbs elevate the risk for stomach cancer death in a rural area of Japan. J Gastroenterol Hepatol 2006;21: Ikeda M, Yoshimoto K, Yoshimura T, Kono S, Kato H, Kuratsune M. A cohort study on the possible association between broiled fish intake and cancer. Gann 1983;74: Nomura A, Grove JS, Stemmermann GN, Severson RK. A prospective study of stomach cancer and its relation to diet, cigarettes, and alcohol consumption. Res 1990;50: Kneller RW, McLaughlin JK, Bjelke E, et al. A cohort study of stomach cancer in a high-risk American population. 1991;68: Kato I, Tominaga S, Matsumoto K. A prospective study of stomach cancer among a rural Japanese population: a 6-year survey. Jpn J Res 1992;83: Galanis DJ, Kolonel LN, Lee J, Nomura A. Intakes of selected foods and beverages and the incidence of gastric cancer among the Japanese residents of Hawaii: a prospective study. Int J Epidemiol 1998;27: Shin HR, Won YJ, Jung KW, et al. Nationwide cancer incidence in Korea, ; first result using the National Incidence Database. Res Treat 2005;37: WHO. International classification of diseases and related health problems, 10th revision. Geneva, Switzerland: World Health Organization, Segi M. mortality for selected sites in 24 countries ( ). Sendai, Japan: Tohuku University of Medicine, Ministry of Health, Welfare and Family Affairs. Annual report of cancer incidence ( ) in Korea. Seoul, Korea: Ministry of Health, Welfare and Family Affairs, Graham S, Haughey B, Marshall J, et al. Diet in the epidemiology of gastric cancer. Nutr 1990;13: Nazario CM, Szklo M, Diamond E, et al. Salt and gastric cancer: a case-control study in Puerto Rico. Int J Epidemiol 1993;22: La Vecchia C, Negri E, Decarli A, D Avanzo B, Franceschi S. A case-control study of diet and gastric cancer in northern Italy. Int J 1987;40: Ramon JM, Serra L, Cerdo C, Oromi J. Dietary factors and gastric cancer risk. A case-control study in Spain. 1993;71: La Vecchia C, Negri E, Franceschi S, Decarli A. Case-control study on influence of methionine, nitrite, and salt on gastric carcinogenesis in northern Italy. Nutr 1997;27: Buiatti E, Palli D, Decarli A, et al. A case-control study of gastric cancer and diet in Italy. Int J 1989;44: You WC, Blot WJ, Chang YS, et al. Diet and high risk of stomach cancer in Shandong, China. Res 1988;48: Lee JK, Park BJ, Yoo KY, Ahn YO. Dietary factors and stomach cancer: a case-control study in Korea. Int J Epidemiol 1995;24: Hoshiyama Y, Sasaba T. A case-control study of stomach cancer and its relation to diet, cigarettes, and alcohol consumption in Saitama Prefecture, Japan. Causes Control 1992;3: Hu JF, Zhang SF, Jia EM, et al. Diet and cancer of the stomach: a case-control study in China. Int J 1988;41: Jedrychowski W, Boeing H, Popiela T, Wahrendorf J, Tobiasz- Adamczyk B, Kulig J. Dietary practices in households as risk factors for stomach cancer: a familial study in Poland. Eur J Prev 1992;1: Harrison LE, Zhang ZF, Karpeh MS, Sun M, Kurtz RC. The role of dietary factors in the intestinal and diffuse histologic subtypes of gastric adenocarcinoma: a case-control study in the U.S. 1997;80: Tuyns AJ. Sodium chloride and cancer of the digestive tract. Nutr 1983;4: Negri E, La Vecchia C, D Avanzo B, Gentile A, Boyle P, Franceschi S. and the risk of gastrointestinal cancers. Nutr 1990;14: Hansson LE, Nyren O, Bergstrom R, et al. Diet and risk of gastric cancer: a population-based case-control study in Sweden. Int J 1993;55: Kono S, Hirohata T. Nutrition and stomach cancer. Causes Control 1996;7: Chyou PH, Nomura AM, Hankin JH, Stemmermann GN. A case-cohort study of diet and stomach cancer. Res 1990;50: Tsugane S, Sasazuki S, Kobayashi M, Sasaki S. Salt and salted food intake and subsequent risk of gastric cancer among middle-aged Japanese men and women. Br J 2004;90: van den Brandt PA, Botterweck AA, Goldbohm RA. Salt intake, cured meat consumption, refrigerator use and stomach cancer incidence: a prospective cohort study (Netherlands). Causes Control 2003; 14: Correa P. Human gastric carcinogenesis: a multistep and multifactorial process First American Society Award Lecture on Epidemiology and Prevention. Res 1992;52: Kodama M, Kodama T, Suzuki H, Kondo K. Effect of rice and salty rice diets on the structure of mouse stomach. Nutr 1984;6: Correa P, Haenszel W, Cuello C, Tannenbaum S, Archer M. A model for gastric cancer epidemiology. Lancet 1975;2: Joossens JV, Hill MJ, Elliott P, et al. Dietary salt, nitrate and stomach cancer mortality in 24 countries. European Prevention (ECP) and the INTERSALT Cooperative Research Group. Int J Epidemiol 1996;25: De Koster E, Buset M, Fernandes E, Deltenre M. Helicobacter pylori: the link with gastric cancer. Eur J Prev 1994;3: Drewnowski A, Henderson SA, Driscoll A, Rolls BJ. Salt taste perceptions and preferences are unrelated to sodium consumption in healthy older adults. J Am Diet Assoc 1996;96: Kim GH, Lee HM. Frequent consumption of certain fast foods may be associated with an enhanced preference for salt taste. J Hum Nutr Diet 2009;22: Watanabe M, Kudo H, Fukuoka Y, et al. Salt taste perception and salt intake in older people. Geriatr Gerontol Int 2008;8:62 4.