Dietary factors and stomach cancer: a case-control study in Korea

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

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 30-80 y, who underwent health examinations between 1996 and 1997. 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 person-years for the overall total population, men only, and women only were 97.64, 136.03, 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.

Fresh and pickled vegetable consumption and gastric cancer in Japanese and Korean populations: a meta-analysis of observational studies

It is widely known that vegetable consumption contributes to reducing the risk of gastric cancer (GC). However, the incidence rates of GC remain high in both Japanese and Korean populations, even though they have a high consumption of total vegetables. This may be due to the fact that Japanese and Koreans mainly consume processed vegetables, such as cooked, salted, or pickled vegetables, rather than fresh vegetables. To determine whether the intakes of fresh and pickled vegetables have different effects on the risk of GC in Japanese and Korean populations, we carried out a meta-analysis of published epidemiological reports. Eight studies on the consumption of fresh vegetables and 14 studies on the consumption of pickled vegetables related to GC risk were included in this meta-analysis. Four studies exploring differences in GC risk in men and women were considered separately. We observed that a high intake of fresh vegetables was significantly associated with a decreased risk of GC (overall summary OR = 0.62, 95% CI = 0.46-0.85) but that a high intake of pickled vegetables was significantly associated with an increased risk of GC (overall summary OR = 1.28, 95% CI = 1.06-1.53). The results of this meta-analysis provide evidence that a high intake of pickled vegetables may increase GC risk and suggest that a high consumption of fresh vegetables, rather than a large total amount of vegetables including pickled vegetables, is important to reduce GC risk.

Atrophic gastritis and the risk of incident colorectal cancer

Previous studies evaluating whether risk factors for gastric cancer are also associated with colorectal cancer (CRC) have shown inconsistent results. We prospectively examined the association of atrophic gastritis, a pre-malignant condition for gastric cancer and long-term sequelae common to many exposure factors, and the risk of incident CRC.

METHODS

A total of 20,928 Finnish male smokers, aged 50-69, who were participants in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC) had serum pepsinogen I (SPGI) levels measured. Participants with low SPGI levels (< 25 microg/l; n = 1,665) were invited for gastroscopy. Of these, 1,059 (63.6%) participants underwent gastroscopy and atrophic gastritis was histologically confirmed in 1,006 (95.0%) participants. We used Cox proportional hazards regression to evaluate the risk of incident CRC.

RESULTS

During a mean follow-up of 11.3 years (236,258 person-years), 425 incident CRCs were diagnosed. The incidence rates were 1.82, 1.48, and 1.82 per 1,000 person-years of follow-up for participants with normal SPGI (> or =25 microg/l), low SPGI, and histologically confirmed atrophic gastritis, respectively. Compared to subjects with normal SPGI, there was no increased risk of CRC among subjects with low SPGI (Adjusted Hazard Ratio (HR) = 0.71; 95% CI: 0.47-1.05) and among those with histologically confirmed atrophic gastritis (Adjusted HR = 0.86; 95% CI: 0.55-1.34).

CONCLUSION

Atrophic gastritis is not associated with an increased risk of colorectal cancer among male smokers.

The role of diet and other environmental factors in the causation of gastric cancer in Iran--a population based study

Despite a declining trend in the incidence of gastric cancer (GC), it is still a major global public health concern of the 21st century. The rates of GC reported from Ardabil Province, Iran, are among the highest in the world. To investigate risk factors for GC in Ardabil, we undertook a population-based case-control study. The study aimed to recruit all Ardabil residents newly diagnosed with GC in the time period of 2004-2005, and 2 controls per case. Participants were interviewed using a structured questionnaire. Ten milliliters of blood was collected for blood grouping and investigating the presence of IgG antibodies against Helicobacter pylori. During the study period, 217 people with GC and 394 controls were recruited. In multivariate analysis, diet and Helicobacter pylori infection (OR = 2.41; 95% CI: 1.35-4.32) were found to be the factors that were most strongly related to GC. High intake of Allium vegetables (OR = 0.35) and fruit, especially citrus fruit (OR = 0.31) and consumption of fresh fish (OR = 0.37) were significantly protective. On the other hand, consumption of red meat (OR = 3.40) and dairy products (OR = 2.28) were positively associated with the risk of GC. People who had a preference for higher salt intake (OR = 3.10) and drinking strong and hot tea (OR = 2.64 and 2.85, respectively) were at higher risk. In conclusion, Helicobacter pylori infection as measured by serum IgG as well as the consumption of red meat and dairy products increases the risk of GC in Ardabil, while the intake of fresh fruit and fresh fish decrease the risk.

Mechanism of oxidative DNA damage induced by capsaicin, a principal ingredient of hot chili pepper

Although capsaicin exhibits antitumor activity, carcinogenic potential has also been reported. To clarify the mechanism for expression of potential carcinogenicity of capsaicin, we examined DNA damage induced by capsaicin in the presence of metal ion and various kinds of cytochrome P450 (CYP) using 32P-5'-end-labeled DNA fragments. Capsaicin induced Cu(II)-mediated DNA damage efficiently in the presence of CYP1A2 and partially in the presence of 2D6. CYP1A2-treated capsaicin caused double-base lesions at 5'-TG-3', 5'-GC-3' and CG of the 5'-ACG-3' sequence complementary to codon 273, a hotspot of p53 gene. DNA damage was inhibited by catalase and bathocuproine, a Cu(I) chelator, suggesting that reactive species derived from the reaction of H2O2 with Cu(I) participate in DNA damage. Formation of 8-oxo-7,8-dihydro-2'-deoxyguanosine was significantly increased by CYP1A2-treated capsaicin in the presence of Cu(II). Therefore, we conclude that Cu(II)-mediated oxidative DNA damage by CYP-treated capsaicin seems to be relevant for the expression of its carcinogenicity.

Changing prevalence of upper gastrointestinal disease in 28 893 Koreans from 1995 to 2005

OBJECTIVES

Changes in the pattern of gastrointestinal diseases in a population tend to be influenced by changes in diet and lifestyle. Shifts in gastrointestinal disease from 1995 to 2005 in Korea were evaluated, retrospectively.

METHODS

Seventeen nationwide medical centers participated in this study. The cross-sectional review of endoscopic findings in 28 893 patients included 8441 patients from 1995, 10 350 patients from 2000, and 10 102 patients from 2005.

RESULTS

The prevalence of reflux esophagitis increased from 1.8% in 1995 to 5.9% in 2000 and 9.1% in 2005 (P<0.001, the P value was only for the comparison between 1995 and 2005, the followings were as same). The prevalence of peptic ulcer diseases was 18.0% in 1995, 19.1% in 2000, and 20.2% in 2005 (P<0.001). Although no significant differences were noted in duodenal ulcers (8.4, 8.7, and 8.2%, P=0.449), gastric ulcers showed an increasing trend (9.6, 10.5, and 12.0%, P<0.001). The prevalence of gastric cancer increased from 3.4% in 1995 to 4.5% in 2000 (P<0.001), but then decreased to 2.4% in 2005 (P<0.001). The incidence of advanced gastric cancer was 2.5, 3.2, and 1.3%, respectively (P<0.001), and that of early gastric cancer remained constant with rates of 0.8%, 1.3, and 1.1%, respectively (P=0.056).

CONCLUSION

The cross-sectional review of data collected in 1995, 2000, and 2005 showed an increase in reflux esophagitis and peptic ulcer diseases. Meanwhile, the prevalence of gastric cancer increased until 2000, but decreased in 2005.

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

Stomach cancer is still the fourth most common cancer; thus, it remains an important public health burden worldwide, especially in developing countries. The remarkable geographic variations in the rates of stomach cancer indicate that dietary factors, including a range of food groups to which salt and/or nitrates have been added, may affect stomach cancer risk. In this paper, we review the results from ecologic, case-control and cohort studies on the relationship between salt or salted foods and stomach cancer risk. The majority of ecological studies indicated that the average salt intake in each population was closely correlated with gastric cancer mortality. Most case-control studies showed similar results, indicating a moderate to high increase in risk for the highest level of salt or salted food consumption. The overall results from cohort studies are not totally consistent, but are suggestive of a moderate direct association. Since salt intake has been correlated with Helicobacter pylori (H pylori) infection, it is possible that these two factors may synergize to promote the development of stomach cancer. Additionally, salt may also cause stomach cancer through directly damaging gastric mucus, improving temporary epithelial proliferation and the incidence of endogenous mutations, and inducing hypergastrinemia that leads to eventual parietal cell loss and progression to gastric cancer. Based on the considerable evidence from ecological, case-control and cohort studies worldwide and the mechanistic plausibility, limitation on salt and salted food consumption is a practical strategy for preventing gastric cancer.

Cancer incidence rates among South Asians in four geographic regions: India, Singapore, UK and US

BACKGROUND

Data are limited regarding cancer incidence among Indians residing in different geographic regions around the world. Examining such rates may provide us with insights into future aetiological research possibilities as well as screening and prevention.

METHODS

Incidence rates for all cancers combined and 19 specific cancers were obtained for India from Globocan 2002, for Indians in Singapore from Cancer Incidence in Five Continents (VIII), and from national data sources for South Asians (SA) in the United Kingdom (UK) and for Asian Indians/Pakistanis (AIP) and whites in the United States (US).

RESULTS

We observed the lowest total cancer incidence rates in India (111 and 116 per 100,000 among males and females, respectively, age-standardized to the 1960 world population) and the highest among US whites (362 and 296). Cancer incidence rates among Indians residing outside of India were: intermediate Singapore (102 and 132), UK (173 and 179) and US ranges 152-176 and 142-164. A similar pattern was observed for cancers of the colorectum, prostate, thyroid, pancreas, lung, breast and non-Hodgkin lymphoma. In contrast, rates for cancers of the oral cavity, oesophagus, larynx and cervix uteri were highest in India. Although little geographic variability was apparent for stomach cancer incidence, Indians in Singapore had the highest rates compared with any other region. The UK SA and the US AIP appear with adopt the cancer patterns of their host country.

CONCLUSION

Variations in environmental exposures such as tobacco use, diet and infection, as well as better health care access and knowledge may explain some of the observed incidence differences.

Chronic Diseases and Dietary Changes in Relation to Korean Americans’ Length of Residence in the United States

BACKGROUND

National health in the United States is influenced by the dietary norms brought into the country by an increasing number of immigrants.

OBJECTIVES

This cross-sectional study aimed to document dietary changes and disease prevalence in relation to the length of residence in the United States for Korean Americans in Michigan.

DESIGN

Of 1,860 questionnaires mailed out, 637 (34.3%) were returned with respondent-reported information, including demographics, weight and height, chronic diseases, and dietary patterns.

SUBJECTS/SETTING

Included in the final analyses were 497 first-generation Korean-American immigrants (263 men, 234 women, aged 30 to 87 years).

STATISTICAL ANALYSES PERFORMED

Analysis of covariance with the Tukey test and logistic regression models provided sex-specific analysis of dietary changes and disease patterns. All statistical analyses were adjusted for age.

RESULTS

Chronic diseases reported most frequently by men and women, respectively, were hypertension, digestive diseases, arthritis, and diabetes. Length of residence in the United States (<or=15 years, 16 to 25 years, or >or=26 years) was inversely associated with the prevalence of digestive diseases in men (P=0.017) and women (P=0.001), and positively with respiratory diseases in men and thyroid disease in women (P<0.05). Length of residence in the United States was inversely associated with intake of rice/rice dishes in both men (servings per week, P<0.001) and women (P=0.012). The prevalence of digestive diseases associated inversely with length of residence and positively with servings of rice/rice dishes consumed for Korean-American men. The age-adjusted odds ratio for digestive diseases was highest among men who had the shortest length of residence in the United States (<or=15 years) and greater consumption of rice/rice dishes (>2 servings per day) (odds ratio 12.10; P=0.03).

CONCLUSIONS

Dietary changes of Korean-American immigrants in the United States over time were associated with changes in their chronic disease patterns. These findings may help food and nutrition professionals who work with minority immigrants because they identify factors that affect changes in dietary patterns and work toward preventing diet-related diseases. Prospective studies could address underlying mechanisms of the observed diet-disease relationship with subsequent generations of Korean Americans, as well as various ethnic minority immigrants in the United States.

Dietary acculturation and diet quality of hypertensive Korean Americans

AIM

This paper is a report of a study to describe the dietary acculturation of hypertensive and normotensive Korean Americans and native Koreans by comparing dietary pattern and diet quality.

BACKGROUND

Dietary acculturation is a major factor that influences the risks for cardiovascular disease in immigrants. Nurses play a key role in educating immigrants about dietary acculturation. Limited studies have examined dietary acculturation of Korean immigrants with hypertension.

METHOD

A descriptive study of hypertensive and normotensive Korean Americans and native Koreans (n = 398) was conducted in 2003-04, using the 24-hour dietary recall method. Dietary pattern was measured by consumption frequency of Korean, American and common food, and eating outside the home. Diet quality was measured by the revised version of the Diet Quality Index.

FINDINGS

Korean Americans showed greater consumption of American food, common food and fast food, and ate away from home more often than native Koreans. Overall Diet Quality Index scores were not statistically significantly different between the two groups after matching. Compared with native Koreans, Korean Americans consumed lower amounts of sodium, potassium, vegetables and fruits, and energy from carbohydrates. Hypertensive Korean Americans consumed fewer vegetables and fruits, and less sodium and potassium than hypertensive native Koreans. No statistically significant differences were found between hypertensive and normotensive Korean Americans in dietary acculturation.

CONCLUSION

Dietary acculturation of immigrants is a common phenomenon regardless of the country from which they immigrate. Healthcare professionals should consider the advantages and disadvantages of dietary acculturation in health promotion for immigrants.

Chemoprevention of gastric cancer

Gastric cancer is the second commonest cause of cancer-associated death in the world. The high mortality is largely attributed to the huge number of at-risk individuals as well as the delay in presentation. Hence, chemoprevention of gastric cancer appears to be the most promising approach in reducing the incidence and mortality related to this cancer. Among various chemoprevention strategies, Helicobacter pylori eradication is the one being most extensively examined. Results from several large-scale prospective randomized studies, however, showed marginal benefits of H. pylori eradication on regression of premalignant gastric lesions. Moreover, there is no significant reduction in gastric cancer incidence. Similarly, ascorbic acid and/or beta-carotene supplementation have borderline effects on premalignant gastric lesions. Based on epidemiological data, the use of non-steroidal anti-inflammatory drugs is associated with a reduced risk of stomach cancer. Future studies should evaluate the role of other chemopreventive agents, particularly specific cyclooxygenase-2 inhibitors, in reducing the risk of gastric cancer.

A prospective study of dietary salt intake and gastric cancer incidence in a defined Japanese population: the Hisayama study

The results of prospective studies of the association between dietary salt intake and gastric cancer occurrence remain controversial. To examine this issue in a cohort study of a general population, 2,476 subjects aged 40 years or older were stratified into 4 groups according to the amount of daily salt intake: namely, <10.0, 10.0-12.9, 13.0-15.9, and > or = 16.0 per day and were followed up prospectively for 14 years. During the follow-up period, 93 subjects developed gastric cancer. The age- and sex-adjusted incidence was significantly higher in the second to fourth groups than in the first group (age- and sex-adjusted hazard ratio [95% confidence interval], 2.42 [1.24-4.71] for the second group; 2.10 [1.03-4.30] for the third group; 2.98 [1.53-5.82] for the fourth group). This association remained substantially unchanged even after adjusting for other confounding factors such as age, sex, Helicobacter pylori infection, atrophic gastritis, medical history of peptic ulcer, family history of cancer, body mass index, diabetes, total cholesterol, physical activity, alcohol intake, smoking habit and other dietary factors. In the stratified analysis, a significant salt-cancer association was observed only in subjects who had both Helicobacter pylori infection and atrophic gastritis (age- and sex-adjusted hazard ratio, 2.87 [1.14-7.24]). Our findings suggest that high dietary salt intake is a significant risk factor for gastric cancer; moreover, this association was found to be strong in the presence of Helicobacter pylori infection with atrophic gastritis.

Is systemic hypertension only a sign of chronic sodium chloride intoxication?

The most important obstacle for preventing hypertension is the belief that systemic hypertension has no identifiable cause. This belief, hiding the main offender, sodium chloride, causes too much time wasting for combating against hypertension. Accepting that sodium chloride is a drug and re-evaluating the situation at the light of current pharmacologic rules, it can be possible to get rid of the suspicions about the etiologic role of sodium chloride for developing systemic hypertension. It is apparent that systemic hypertension is a chronic intoxication produced by a drug (sodium chloride) whose dose is between minimal and maximal effective dose. Based on epidemiologic studies, minimal effective dose of salt, producing hypertension is estimated as 1.76 g/d. This suggests that the aim in this context should be removal of table salt from the human diet. Re-evaluating salt-hypertension relation by means of dose-response relation suggests that "salt sensitivity" is a baseless notion, because when the dose is between minimal and maximal effective dose, there are a number of individuals which respond up or down of any selected level, similar to other drugs. Another standpoint of refuting removal of salt is the belief that saltless diet is not palatable. According to the self-experiences of the Author, this belief is valid only for some time (for a few months), even a few years later saltless meals were perceived more palatable. The present paper describes evidences showing that systemic hypertension is formed by the chronic exposure to salt and it also answers contrary opinions.

Effects of dietary intake and genetic factors on hypermethylation of the hMLH1 gene promoter in gastric cancer

AIM: Hypermethylation of the promoter of the hMLH1 gene, which plays an important role in mismatch repair during DNA replication, occurs in more than 30% of human gastric cancer tissues. The purpose of this study was to investigate the effects of environmental factors, genetic polymorphisms of major metabolic enzymes, and microsatellite instability on hypermethylation of the promoter of the hMLH1 gene in gastric cancer.

METHODS: Data were obtained from a hospital-based, case-control study of gastric cancer. One hundred and ten gastric cancer patients and 220 age- and sex-matched control patients completed a structured questionnaire regarding their exposure to environmental risk factors. Hypermethylation of the hMLH1 gene promoter, polymorphisms of the GSTM1, GSTT1, CYP1A1, CYP2E1, ALDH2 and L-myc genes, microsatellite instability and mutations of p53 and Ki-ras genes were investigated.

RESULTS: Both smoking and alcohol consumption were associated with a higher risk of gastric cancer with hypermethylation of the hMLH1 gene promoter. High intake of vegetables and low intake of potato were associated with increased likelihood of gastric cancer with hypermethylation of the hMLH1 gene promoter. Genetic polymorphisms of the GSTM1, GSTT1, CYP1A1, CYP2E1, ALDH2, and L-myc genes were not significantly associated with the risk of gastric cancer either with or without hypermethylation in the promoter of the hMLH1 gene. Hypermethylation of the hMLH1 promoter was significantly associated with microsatellite instability (MSI): 10 of the 14 (71.4%) MSI-positive tumors showed hypermethylation, whereas 28 of 94 (29.8%) the MSI-negative tumors were hypermethylated at the hMLH1 promoter region. Hypermethylation of the hMLH1 gene promoter was significantly inversely correlated with mutation of the p53 gene.

CONCLUSION: These results suggest that cigarette smoking and alcohol consumption may influence the development of hMLH1-positive gastric cancer. Most dietary factors and polymorphisms of GSTM1, GSTT1, CYP1A1, CYP2E1, ALDH2, and L-myc genes are not independent risk factors for gastric cancer with hyperme-thylation of the hMLH1 promoter. These data also suggest that there could be two or more different molecular pathways in the development of gastric cancer, perhaps involving tumor suppression mechanisms or DNA mismatch repair.

Kimchi and soybean pastes are risk factors of gastric cancer

AIM

This case-control study investigated the effects of kimchi, soybean paste, fresh vegetables, nonfermented alliums, nonfermented seafood, nonfermented soybean foods, and the genetic polymorphisms of some metabolic enzymes on the risk of gastric cancer in Koreans.

METHODS

We studied 421 gastric cancer patients and 632 age- and sex-matched controls. Subjects completed a structured questionnaire regarding their food intake pattern. Polymorphisms of cytochrome P450 1A1 (CYP1A1), cytochrome P450 2E1 (CYP2E1), glutathione S-transferase mu 1 (GSTM1), glutathione S-transferase theta 1 (GSTT1) and aldehyde dehydrogenase 2 (ALDH2) were investigated.

RESULTS

A decreased risk of gastric cancer was noted among people with high consumption of nonfermented alliums and nonfermented seafood. On the other hand, consumption of kimchi, and soybean pastes was associated with increased risk of gastric cancer. Individuals with the CYP1A1 Ile/Val or Val/Val genotype showed a significantly increased risk for gastric cancer. Increased intake of kimchi or soybean pastes was a significant risk factor for the CYP1A1 Ile/Ile, the CYP2E1 c1/c1, the GSTM1 non-null, the GSTT1 non-null, or the ALDH2 *1/*1 genotype. In addition, eating soybean pastes was associated with the increased risk of gastric cancer in individuals with the GSTM1 null type. Nonfermented alliums were significant in individuals with the CYP1A1 Ile/Ile, the CYP2E1 c1/c2 or c2/c2, the GSTT1 null, the GSTT1 non-null, or the ALDH2 *1/*2 or *2/*2 genotype, nonfermented seafood was those with the CYP1A1 Ile/Ile, the CYP2E1 c1/c1, the ALDH2 *1/*1 genotype or any type of GSTM1 or GSTT1. In homogeneity tests, the odds ratios of eating kimchi for gastric cancer according to the GSTM1 or GSTT1 genotype were not homogeneous.

CONCLUSION

Kimchi, soybean pastes, and the CYP1A1 Ile/Val or Val/Val are risk factors, and nonfermented seafood and alliums are protective factors against gastric cancer in Koreans. Salt or some chemicals contained in kimchi and soybean pastes, which are increased by fermentation, would play important roles in the carcinogenesis of stomach cancer. Polymorphisms of the CYP1A1, CYP2E1, GSTM1, GSTT1, and ALDH2 genes could modify the effects of some environmental factors on the risk of gastric cancer.

[Epidemiological characteristics of gastric cancer]

INTRODUCTION

Gastric cancer was the third most common cancer worldwide in 2000, accounting for approximately 876 000 new cases or 9% of the global cancer burden.

EPIDEMIOLOGICAL CHARACTERISTICS

As a result of changes in diet, the incidence of gastric cancer has decreased in most countries. Nowdays, consumption of fresh vegetables and fruits is increasing in regard to canned food. In addition to unhealthy diet, the main risk factors for gastric cancer are H. pylori infection, alcohol consumption, smoking, gastritis, stomach ulcer, gastrectomy, stomach polyposis, positive family history for gastric cancer, pernicious anemia and blood type A. Diet rich in vegetables and fruits, and reduced salt intake can prevent 65-75% of gastric cancer cases among nonsmokers. Prevention of Helicobacter pylori infection can also reduce the incidence of this malignant disease.

Opportunities for cancer epidemiology in developing countries

Most cancer epidemiology studies involve people living in North America and Europe, which represent only a fraction of the global population. The wide variety of dietary, lifestyle and environmental exposures, as well as the genetic variation among people in developing countries can provide valuable new information on factors that contribute to cancer or that protect against it. What are the challenges and advantages to performing large epidemiological studies in developing nations?

Personal history and family history as a predictor of gastric cardiac adenocarcinoma risk: a case-control study in Taiwan

OBJECTIVES

To clarify the risk of gastric cardiac adenocarcinoma for patients with a personal and/or family history of gastrointestinal diseases.

METHODS

The present study was a hospital-based case-control study conducted from 1992 to 1997 in Kaohsiung, Taiwan, consisting of 176 cases and 579 controls matched by age, sex, and time of hospitalization. With informed oral consent, each subject completed a structured questionnaire during hospitalization regarding sociodemographic status, lifestyle, and health history.

RESULTS

The response rate was 98%. Adjusting for age, sex, years of schooling, socioeconomic status, body mass index (BMI), and smoking. Multivariate logistic regression models indicated a reduced effect for patients with a personal history of duodenal ulcer (DU) (odds ratio (OR) = 0.8, 95% confidence interval (CI) 0.5-0.9). No association was observed between the risk of gastric cardiac cancer and other forms of gastric disease. Furthermore, we also demonstrated that individuals with a family history of gastric cancer had a higher risk than those who lacked a family history (OR = 2.5, 95% CI 1.3-4.8).

CONCLUSIONS

Our findings provide further evidence that individuals with DU history are less likely to have gastric cardiac cancer, and we infer that Helicobacter pylori (H. pylori) infection (85-95% DU patients infected with H. pylori) alone may not be sufficient to cause gastric cardiac adenocarcinoma. In addition, this study also suggests that a positive family history of gastric cancer may predict an increased risk for the disease.

Diet and Stomach Cancer Risk in Warsaw, Poland

Some of the world's highest rates of stomach cancer are found in Poland. Reasons for the increased incidence are not known, but high intake of sausages and other preserved foods and low intake of fresh fruits and vegetables may be involved. A case-control study comprising residents newly diagnosed with stomach cancer during 1994-96 and controls randomly selected from the general population was conducted in Warsaw, Poland. Standardized interviews were conducted to ascertain usual consumption of 118 common foods and beverages and other exposures. Using data from direct interviews with 274 cases and 463 controls, odds ratios of stomach cancer were calculated as estimates of risks associated with dietary factors, adjusting for age, sex, education, smoking, and caloric intake. Risk of stomach cancer was inversely related to intake of total fruits and dark green-yellow vegetables and to indices of vitamins C and E and alpha- and beta-carotenes. However, risk was not significantly increased among those with high intake of pickled/salted vegetables and sausages. Risks were positively associated with increased intake of breads/cereals/rice/pasta and other refined grains, as well as a high carbohydrate index. Our findings add to the evidence of a protective effect of fruits and certain vegetables on stomach cancer risk, but do not indicate that high intake of sausage and other preserved foods typical in the Polish diet has contributed to the country's elevated stomach cancer incidence. Our data also suggest that high carbohydrate consumption may influence risk, but further confirmation is needed.

[Diet and gastric cancer]

The aim of this case-control study, conducted in Serbia during the period 1998-2000, was to investigate whether diet was associated with the development of gastric cancer. The case group consisted of 131 patients with histologically confirmed gastric cancer, and the control group of 131 patients with orthopedics diseases and injuries. Cases and controls were individually matched by age (+/- 2 years), gender, and place of residence. On the basis of multivariate logistic regression analysis, following factors were found as independent risk factors for gastric cancer: more frequent consumption of high-fat milk [Odds ratio (OR) = 1.45, 95% confidence interval (CI) = 0.99-2.16]; mutton, lamb and/or calf meat (OR = 2.46, 95% CI = 1.11-5.47), sugar (OR = 2.13, 95% CI = 1.43-3.18), semi-white bread (OR = 2.09, 95% CI = 1.25-3.50), and salting food (OR = 5.72, 95% CI = 2.63-12.42). Factors found as protective were: more frequent consumption of margarine (OR = 0.41, 95% CI = 0.25-0.69), "other" cheeses (OR = 0.47, 95% CI = 0.29-0.77), and fish (OR = 0.39, 95% CI = 0.19-0.76).

Epidemiologic evidence of the protective effect of fruit and vegetables on cancer risk

BACKGROUND

Diets rich in fruit and vegetables have been recommended for preventing cancer. The evidence supporting this recommendation is based on observational studies, although results of several prospective studies have cast some doubts on whether fruit and vegetables are associated with cancer risk reduction.

OBJECTIVE

We sought to summarize evidence from case-control and prospective studies on fruit and vegetable intake and cancer risk with a meta-analytic approach.

DESIGN

Published case-control and cohort studies that reported on total vegetable and fruit intake and risk of cancer of several sites were included. Relative risks were estimated by using linear logistic regression models.

RESULTS

Case-control studies overall support a significant reduction in the risks of cancers of the esophagus, lung, stomach, and colorectum associated with both fruit and vegetables; breast cancer is associated with vegetables but not with fruit; and bladder cancer is associated with fruit but not with vegetables. The overall relative risk estimates from cohort studies suggest a protective effect of both fruit and vegetables for most cancer sites considered, but the risk reduction is significant only for cancers of the lung and bladder and only for fruit.

CONCLUSIONS

Prospective studies provide weaker evidence than do case-control studies of the association of fruit and vegetable consumption with reduced cancer risk. The discrepancies may be related to recall and selection biases in case-control studies. In contrast, the association may have been underestimated in prospective studies because of the combined effects of imprecise dietary measurements and limited variability of dietary intakes within each cohort.

Capsaicin consumption, Helicobacter pylori positivity and gastric cancer in Mexico

Gastric cancer (GC) incidence has not declined in Mexico. We assessed whether the intake of capsaicin (CAP), the pungent compound of chili peppers, increases the risk of GC independently of H. pylori positivity (Hp). From 1994 to 1996, a hospital-based case-control study was performed in 3 areas of Mexico; 234 cases of GC and 468 matched controls were enrolled and their diet and other characteristics were inquired. Chili pepper intake was queried by interview and CAP content of chilies was determined in a separate analysis by gas chromatography to estimate CAP intake; IGg Hp serum antibodies were determined by ELISA. The risk of GC was increased (OR = 1.71; 95% CI = 0.76-3.88) among high-level consumers of CAP (90-250 mg of capsaicin per day, approximately 9-25 jalapeño peppers per day) as compared to low-level consumers (0-29.9 mg of capsaicin per day, approximately 0 to less than 3 jalapeño peppers per day; p for trend p = 0.026); this effect was independent of Hp status and other potential GC determinants and was higher among diffuse GC cases (OR = 3.64; 95% CI = 1.09-12.2; p for trend = 0.002) compared to intestinal GC cases (OR = 1.36; 95% CI = 0.31-5.89; p for trend = 0.493). No significant interaction was found between CAP intake and Hp on GC risk. Chili pepper consumption might be an independent determinant of GC in Mexico.

Gastric cancer and other organ cancer history in the parents of patients with gastric cancer

A case-control study in a population from the Eastern Black Sea region of Turkey was performed to evaluate the risk of gastric cancer development in patients with gastric cancer reporting gastric cancer or other organ cancer history in their parents. Gastric cancer and/or other organ cancer history in the parents were found in 215 of 1240 patients with gastric cancer versus 73 of 1240 controls (odds ratio (OR) 3.35, P<0.001). The frequency of gastric cancer history among the parents was significantly different between the patients and the controls (148 versus 25, respectively; OR 6.59, P<0.001). The frequency of other organ cancer history was not significantly different between the patients and the controls (63 versus 48, respectively; OR 1.33, P>0.05). The frequency of gastric cancer history was significantly higher than the frequency of other organ cancer history in the parents of the patients (OR 4.51, P<0.001). Gastric cancer history was significantly higher in first- to third-degree relatives of the patients reporting gastric cancer and/or other organ cancer history in their parents than in the controls (OR 14.72, P<0.001). Familial clustering of gastric cancer defined by the presence of at least four cancer cases in family members, including parents, was reported by 12% of the patients. Overall, the result of this study of gastric cancer and other organ cancer history in the parents of patients with gastric cancer may suggest a genetic susceptibility for gastric carcinoma. A high risk of gastric cancer occurred in subjects reporting a gastric cancer history in their parents, and there was a higher predisposition to gastric cancer compared with other organ cancer in relatives and a familial clustering of the disease.

Prospective cohort study of comprehensive prevention to gastric cancer

AIM: To evaluate the preliminary effects of comprehensive prevention of gastric cancer in Zhuanghe County epidemiologically.

METHODS: Stratified sampling and cluster sampling were applied to define the intervention group and the control group. The prospective cohort study was used for evaluating the effect of preventing gastric cancer. The relative risk (RR) and attributable risk percent (AR%) of intervention on gastric cancer death were calculated. Potential years of life lost (PLYY) of the disease was analyzed, and the RR and AR% of PYLL were calculated. Survival analysis was applied among the screened patients.

RESULTS: In the first 4 years after intervening, the relative risk (RR) of intervention on death was 0.5059 (95%CI: 0.3462-0.7392, P < 0.05) with significance statistically. AR% of the intervention on death was 49.41%. The RR of intervention on cumulative PYLL was 0.6778 (95%CI: 0.5604-0.8198, P < 0.05) with statistic significance. AR% of the intervention on cumulative PYLL was 30.32%. The four-year survival rate of the screened patients was 0.6751 (95%CI: 0.5298-0.9047).

CONCLUSION: The initiative intervention results showed that the intervention approach used in the trial was effective, it reduced mortality and increased survival rate, and alleviated the adverse effect of gastric cancer on the health and life of screened population.

Gastric cancer epidemiology and risk factors

We performed a detailed analysis of the epidemiology of gastric carcinoma, based upon a review of the literature in English. The analysis reveals many puzzling features. There has been a steady fall in the incidence of gastric carcinoma in most societies studied, but a more recent steady rise in the incidence of adenocarcinoma of the cardia and lower esophagus, largely confined to White males. Although the evidence for a major role for Helicobacter pylori (H. pylori) in the etiology of gastric corpus cancer is compelling; in Western society, it probably accounts for fewer than half the cases. The relative roles of dietary constituents such as salt and nitrites and the phenotyping of H. pylori in causation and the beneficial effects of a high fruit and vegetable diet and an affluent lifestyle, for all of which there is some evidence, are yet to be quantified.

Helicobacter pylori strain and the pattern of gastritis among first-degree relatives of patients with gastric carcinoma

BACKGROUND

Relatives of gastric cancer patients have an increased risk of gastric cancer, possibly related to genetically-related strains of Helicobacter pylori or a common environment.

METHODS

The pattern of gastritis and H. pylori from gastric cancer patients and their first-degree relatives were compared using detailed DNA fingerprints and vacA, cagA, and iceA genotyping.

RESULTS

Sixteen index cases from Korea, the US, or Colombia and their 38 first-degree relatives (brothers, sisters, sons and daughters) were studied. No definite, or consistent, relationship between the pattern of gastritis and the relatedness of the H. pylori strain was observed (i.e. relatives could have an identical or a totally different pattern of gastritis regardless if they were infected with identical or highly similar organisms). For example, three elderly siblings of an index case with atrophic pangastritis had identical H. pylori isolates and environments in childhood and yet two had antral predominant nonatrophic gastritis, which is typically associated with duodenal ulcer instead of gastric cancer.

CONCLUSIONS

The results of this study are not consistent with the hypothesis that specific virulence factors or similar H. pylori strains correlate with a specific histologic pattern or outcome even among those sharing the same environment in childhood.

Cigarette smoking, alcohol consumption and subsequent gastric cancer risk by subsite and histologic type

The effect of cigarette smoking or alcohol consumption on the risk of gastric cancer has not been clarified. We investigated this relationship, considering the anatomic subsite and histologic type of gastric cancer. A total of 19,657 men (aged 40-59 years at baseline), who responded to the baseline questionnaire and reported no serious illness at that time, were followed for 10 years, from January 1990 to December 1999. Gastric cancer was confirmed histologically in 293 men. Smoking was associated with an increased risk of the differentiated type of distal gastric cancer; compared to the group who never smoked, the adjusted rate ratios (RRs) of gastric cancer for past and current smokers were 2.0 (95% CI 1.1-3.7) and 2.1 (95% CI 1.2-3.6), respectively. No association was observed between cigarette smoking and risk of the undifferentiated type of distal gastric cancer except for a suggestive association with cardia cancer. For alcohol consumption, elevated risk was suggested only for cardia cancer of all histologic types, though the relationship failed to reach significance. Among those who drank alcohol at least once per week, RRs for ethanol intake of 2.7-161.0, 162.0-322.0 and 322.5+ g/week compared to those who drank 0-3 times/month were 2.5 (95% CI 0.7-9.5), 3.3 (0.9-11.6) and 3.0 (0.8-11.1), respectively (p(trend) = 0.66). In conclusion, our results confirm that smoking is related to gastric cancer of the differentiated type. Further studies with more cases are needed to detect a positive association between cigarette smoking or alcohol consumption and cardia cancer.

U-shaped effect of drinking and linear effect of smoking on risk for stomach cancer in Japan

A case-control study was conducted to evaluate the relationship between smoking or drinking doses and risk for stomach cancer, and to clarify whether the relationship is dose-dependent or U-shaped. Smoking dose was categorized as 0, 1 - 399, 400 - 799, or 800 + cigarette-years, and drinking dose as 0, occasional/0.1 - 134.9, 135 - 1349.9, or 1350 + alcohol-years (ml of pure alcohol intake per day multiplied by years of drinking). Helicobacter pylori status was determined by serology for adjustment. Using logistic regression, the adjusted effects of smoking and drinking doses on risk for stomach cancer were calculated for both genders. Among male subjects, the odds ratios (95% confidence intervals (CIs)) were 1.29 (0.76, 2.18) for 1 - 399, 1.71 (1.05, 2.80) for 400 - 799 and 2.46 (1.49, 4.07) for 800 + cigarette-years compared with never-smokers, and 1.89 (0.97, 3.69) for never-drinkers, 2.82 (1.63, 4.86) for 135 - 1349.9 and 2.84 (1.97, 4.83) for 1350.0 +, compared with occasional/0.1 - 134.9 alcohol-years. Among female subjects, they were 0.44 (0.20, 1.00) for 1 - 399 and 2.471 (0.91, 6.68) for 400 + cigarette-years compared with never-smokers, and 1.54 (0.90, 2.63) for never-drinkers and 1.39 (0.66, 2.93) for 135.0 + alcohol-years. Smoking seems to exert a linear effect and drinking, a J- or U-shaped effect on risk for stomach cancer, although there might be a dip of risk in light smokers among female subjects.

Dietary factors and stomach cancer mortality

The present study examined the relationship between stomach cancer and the low intake of fresh fruit and vegetables and/or a high intake of pickled, preserved or salted foods and frequent use of cooking oil. During 139,390 person-year of follow-up of over 13,000 subjects, 116 died from stomach cancer. Using a Cox proportional hazards-regression analysis of relative risk (RR, 95% CI) controlling for age, sex, smoking and other dietary factors, a significant decline was found with a high consumption of green and yellow vegetables (RR=0.4, 95% CI=0.2-0.9). Reductions of between 40 and 50% were also observed with a high consumption of fresh foods (fruit, cuttle fish, tofu, and potatoes), but these associations were not statistically significant. The risk was significantly increased by the high consumption of processed meat (RR=2.7, 95% CI=1.0-7.4) and by the frequent use of cooking oil (RR=4.0, 95% CI=1.3-11.8). The high consumption of pickled food and traditional soups also increased risk, but not significantly. The findings suggest that a diet high in salt and low in vitamins may be associated with an increase in stomach cancer.

An estimate of premature cancer mortality in the U.S. due to inadequate doses of solar ultraviolet-B radiation

BACKGROUND

There are large geographic gradients in mortality rates for a number of cancers in the U.S. (e.g., rates are approximately twice as high in the northeast compared with the southwest). Risk factors such as diet fail to explain this variation. Previous studies have demonstrated that the geographic distributions for five types of cancer are related inversely to solar radiation. The purpose of the current study was to determine how many types of cancer are affected by solar radiation and how many premature deaths from cancer occur due to insufficient ultraviolet (UV)-B radiation.

METHODS

UV-B data for July 1992 and cancer mortality rates in the U.S. for between 1970-1994 were analyzed in an ecologic study.

RESULTS

The findings of the current study confirm previous results that solar UV-B radiation is associated with reduced risk of cancer of the breast, colon, ovary, and prostate as well as non-Hodgkin lymphoma. Eight additional malignancies were found to exhibit an inverse correlation between mortality rates and UV-B radiation: bladder, esophageal, kidney, lung, pancreatic, rectal, stomach, and corpus uteri. The annual number of premature deaths from cancer due to lower UV-B exposures was 21,700 (95% confidence interval [95% CI], 20,400-23,400) for white Americans, 1400 (95% CI, 1100-1600) for black Americans, and 500 (95% CI, 400-600) for Asian Americans and other minorities.

CONCLUSIONS

The results of the current study demonstrate that much of the geographic variation in cancer mortality rates in the U.S. can be attributed to variations in solar UV-B radiation exposure. Thus, many lives could be extended through increased careful exposure to solar UV-B radiation and more safely, vitamin D3 supplementation, especially in nonsummer months.

Dietary factors and gastric cancer in Korea: a case-control study

To assess gastric cancer (GC) risk in relation to dietary intake in Korea, a case-control study was performed. Trained dietitians interviewed 136 patients diagnosed with GC, and the same number of controls were selected by matching sex, age and hospital. A significant decrease in GC risk was observed with increased intake of Baiechu kimchi (prepared with salted Chinese cabbage and red pepper, etc.), Baiechu kimchi-stew, garlic, mushroom and soybean milk. On the contrary, a significant increase in the risk of GC was observed with increased intake of cooked rice with bean, charcoal grilled beef, pollack soup, Kkakduki (a kind of kimchi prepared with salted radish and red pepper, etc.), Dongchimi (a kind of kimchi prepared with radish and a large quantity of salt water) and cooked spinach. In food groups, increased intake of soybean products was associated with decreased risk of GC. Intake of citrus fruits rather than total fruits was shown to have a protective effect on the risk of GC, but was not significant. In this study, intake of total vegetables was shown to have a protective effect, whereas high nitrate-containing vegetables increased the risk of GC. In conclusion, our study suggests that the risk of GC decreased with high consumption of fresh vegetables and fruits, whereas high consumption of foods rich in nitrate and carcinogenic substances produced during the cooking process increased the risk of GC.

Dietary protective and risk factors for esophageal and stomach cancers in a low-epidemic area for stomach cancer in Jiangsu Province, China: comparison with those in a high-epidemic area

Comparative epidemiological studies with ecological and case-control approaches in high- and low-epidemic areas of China have provided us with much evidence with regard to risk and benefit in the environment. To clarify how dietary factors are involved in esophageal and stomach cancer development, we performed a case-control study in a low-epidemic area, and compared the findings with those obtained earlier for a high-epidemic area for stomach cancer in the same Jiangsu Province, China. We recruited 199 and 187 cases with esophageal and stomach cancers, respectively, and 333 population-based common controls. Odds ratios (ORs) for esophageal and stomach cancers were calculated with adjustment for potential confounding factors, using an unconditional logistic model. Current and former smoking elevated the OR for esophageal cancer, along with high intake of pickled vegetables and broiled meat, while decreased ORs were observed for frequently consumed raw vegetables and garlic. With regard to stomach cancer, ORs were increased with frequent consumption of salty fish, leftover gruel, and broiled meat, and lowered by snap bean consumption. The present risk factors were common to the previously obtained results in the high-epidemic area, and similarly distributed in each general population. While more protective factors were observed in the high-epidemic area, their penetrance was much greater in the low-epidemic area. The present study thus suggests that frequent vegetable and garlic consumption contributes to low mortality rates for esophageal and stomach cancers in a low-epidemic area, counteracting similar exposure levels for risk factors as in the high-epidemic area.

Riot control agents: pharmacology, toxicology, biochemistry and chemistry

The desired effect of all riot control agents is the temporary disablement of individuals by way of intense irritation of the mucous membranes and skin. Generally, riot control agents can produce acute site-specific toxicity where sensory irritation occurs. Early riot control agents, namely, chloroacetophenone (CN) and chlorodihydrophenarsazine (DM), have been replaced with 'safer' agents such as o-chlorobenzylidene malononitrile (CS) and oleoresin of capsicum (OC). Riot control agents are safe when used as intended: however, the widespread use of riot control agents raises questions and concerns regarding their health effects and safety. A large margin exists between dosages that produce harassment and dosages likely to cause adverse health effects for modern riot control agents such as CS and dibenz[b,f]1 : 4-oxazepine (CR). Yet, despite the low toxicity of modern riot control agents, these compounds are not entirely without risk. The risk of toxicity increases with higher exposure levels and prolonged exposure durations. Ocular, pulmonary and dermal injury may occur on exposure to high levels of these substances, and exposure to riot control agents in enclosed spaces may produce significant toxic effects. Reported deaths are few involving riot control agents, and then only under conditions of prolonged exposure and high concentrations. Recently, concern has focused on the deaths resulting from law enforcement use of OC, a riot control agent generally regarded as safe because it is a natural product. As with other xenobiotics, not enough is known concerning the long-term/chronic effects of riot control agents. Clearly, there is considerable need for additional research to define and delineate the biological and toxicological actions of riot control agents and to illuminate the full health consequences of these compounds as riot control agents.

Geographic differences in the distribution of intestinal metaplasia in duodenal ulcer patients

OBJECTIVE

A strong correlation exists between atrophic gastritis and the intestinal type of gastric carcinoma. Duodenal ulcer disease characteristically has an antral predominant gastritis and a lower risk for gastric cancer. The aim of this study was to investigate the extent and distribution of intestinal metaplasia in duodenal ulcer in countries differing in gastric cancer incidence.

METHODS

Topographically mapped gastric biopsy specimens (median 11) were obtained from patients with duodenal ulcer in four countries (Korea, Colombia, USA, and South Africa). Sections were stained with a triple stain and evaluated for Helicobacter pylori (H. pylori), active inflammation, and intestinal metaplasia.

RESULTS

One hundred and sixty-five patients with duodenal ulcer were examined (29 from Korea, 52 from Colombia, 62 from the USA, and 22 from South Africa). The percentage of biopsies with intestinal metaplasia was significantly greater in Korean patients (86%) compared with that in other countries (50%) (p = 0.0004). Intestinal metaplasia was most prevalent in the antrum lesser curve and greater curve, and the body lesser curve. Intestinal metaplasia was present in the gastric corpus of 38% of duodenal ulcer patients from Korea compared with an average of 10% elsewhere (p = 0.018). No differences were observed in the density or distribution of H. pylori infection or in the degree of active gastritis between countries.

CONCLUSIONS

Although antral predominant gastritis is the prevalent pattern of gastritis in duodenal ulcer, intestinal metaplasia in the gastric corpus may be found with geographic differences. These findings suggest that duodenal ulcer and gastric cancer are not mutually exclusive diseases but are rather ends of the spectrum of H. pylori infection.

Increased survival after cecal ligation and puncture in mice consuming diets enriched with sesame seed oil

OBJECTIVES

Lignans that present in the nonfat portion of sesame seed oil (SSO) can inhibit delta-5 desaturase activity, resulting in an increase in the accumulation of dihomo-gamma-linolenic acid and, subsequently, decrease the production of proinflammatory dienoic eicosanoids with a concomitant increase in the secretion of less inflammatory monoenoic eicosanoids.

DESIGN

Female Balb/c mice were fed diets supplemented with 5wt% SSO or a physical mixture of oils (control) whose fatty acid composition resembled that of SSO for 3 wks.

MEASUREMENTS AND MAIN RESULTS

During a 4-day observation period after cecal ligation and puncture, only 20% of the controls and as many as 65% in the SSO group survived. Furthermore, the levels of cytokines and dienoic eicosanoids produced in response to an intraperitoneal injection of a nonlethal dose (50 microg/mouse) of endotoxin were measured in both groups. The interleukin (IL)-10 levels were markedly higher in mice fed SSO diets compared with the controls. However, the plasma concentrations of prostaglandin E1 + 2, tumor necrosis factor-alpha, IL-6, and IL-12 did not differ significantly between the two groups of mice.

CONCLUSIONS

Because the fatty acid composition is almost similar between the two diets, sesamin, sesamol and other lignans in SSO appear to be responsible for an increase in survival after cecal ligation and puncture and also for an increase in the IL-10 levels in response to a nonlethal dose of endotoxin in mice.

In vivo DNA damage in gastric epithelial cells

A number of risk factors have been linked epidemiologically with gastric cancer, but studies of DNA damage in gastric epithelial cells are limited. The comet assay is a simple technique for determining levels of DNA damage in individual cells. In this study, we have validated the comet assay for use in epithelial cells derived directly from human gastric biopsies, determined optimal conditions for biopsy digestion and investigated the effects of oxidative stress and digestion time on DNA damage. Biopsies taken at endoscopy were digested using combinations of pronase and collagenase, ethylenediaminetetra-acetic acid (EDTA) and vigorous shaking. The resultant cell suspension was assessed for cell concentration and epithelial cell and leukocyte content. A score for DNA damage, the comet %, was derived from the cell suspension, and the effect of various digestion conditions was studied. Cells were incubated with H(2)O(2) and DNA damage was assessed. Pronase and collagenase provided optimum digestion conditions, releasing 1. 12x10(5) cells per biopsy, predominantly epithelial. Of the 23 suspensions examined, all but three had leukocyte concentrations of less than 20%. The comet assay had high inter-observer (6.1%) and inter-assay (4.5%) reproducibility. Overnight storage of the biopsy at 4 degrees C had no significant effect on DNA migration. Comet % increased from a median of 46% in untreated cells to 88% in cells incubated for 45 min in H(2)O(2) (p=0.005). Serial 25-min digestions were performed on biopsies from 13 patients to release cells from successively deeper levels in the crypt. Levels of DNA migration were significantly lower with each digestion (r=-0.94, p<0.001), suggesting that DNA damage is lower in younger cells released from low in the gastric crypt. The comet assay is a reproducible measure of DNA damage in gastric epithelial cells. Damage accumulates in older, more superficial cells, and can be induced by oxidative stress.

Trace element levels in drinking water and the incidence of colorectal cancer

We determined the levels of 15 elements in drinking water from 34 water treatment plants in Aomori Prefecture and studied how element levels relate to colorectal cancer incidence by district. Colorectal cancer incidence was calculated from the data of Aomori Colorectal Cancer Registry. Multiple regression analysis was performed by using age-adjusted incidences of rectal cancer and colon cancer by gender as object variables and each element level as an explanatory variable. The standardized partial regression coefficient was significant in gold (p < 0.01), magnesium (p < 0.01), selenium (p < 0.01) and tin (p < 0.05) for age-adjusted rectal cancer incidence in men as objective variable; in gold (p < 0.05), calcium (p < 0.01) and phosphorus (p < 0.01) with age-adjusted colon cancer incidence in men as the objective variable; and in sodium (p < 0.05), phosphorus (p < 0.05), tin (p < 0.05) and strontium (p < 0.01) with age-adjusted colon cancer incidence in women as the objective variable. These results confirm the need to further study trace elements in drinking water and food, and relationship to colorectal carcinogenesis.

Garlic or jalapeño peppers for treatment of Helicobacter pylori infection

OBJECTIVE

There have been a number of reports that natural foods such as garlic, honey, and capsaicin can inhibit Helicobacter pylori in vitro and each report has suggested the natural ingredient be used for treatment of the infection. We investigated whether garlic or capsaicin-containing peppers would actually inhibit H. pylori in vivo.

METHODS

We performed a prospective crossover study in healthy H. pylori-infected adults. We used the urea breath test to assess the status of the H. pylori infection. On separate days subjects received three test meals consisting of beef, tortillas, and salad with one of the following: fresh garlic (10 sliced cloves), capsaicin (six sliced fresh jalapeños), two tablets of bismuth subsalicylate (Pepto-Bismol, positive control), or nothing added (negative control). Breath testing was done before the first meal, the evening meal, and the following morning. At least 2 days elapsed between the test substances.

RESULTS

Twelve subjects participated (seven men, five women), with an average age of 41.4 yr, range 27-51 yr. Ten subjects received garlic, six received jalapeños, and 11 received bismuth. Neither garlic nor capsaicin had any in vivo effect on H. pylori (median urease activity 28.5 vs 39.8 and 43.7 vs 46.6 before and after garlic and jalapeños, respectively) (p > 0.8). Bismuth had a marked inhibitory effect (median 55.8 vs 14.3 before and after bismuth) (p < 0.001), respectively.

CONCLUSIONS

This study did not support a role for either garlic or jalapeños in the treatment of H. pylori infection. Caution must be used when attempting to extrapolate data from in vitro studies to the in vivo condition.

Epidemiology of gastric cancer in relation to diet and Helicobacter pylori infection

Gastric cancer is the second most common fatal malignancy in the world. In China, gastric cancer is now the second most common malignancy, while in Hong Kong, the mortality rate ranked fourth among all cancers in 1995. Dietary factors in gastric carcinogenesis came mostly from case-control studies. N-Nitroso compounds from dietary sources such as preserved, smoked and salted foods were found to be associated with gastric cancer. ß-Carotene, selenium and α-tocopherol have been shown in an intervention study to be favourable in the reduction of stomach cancer mortality. Fruits and vegetables showed the most consistent results of inverse association with gastric cancer. Dietary salt intake in preserved or salted foods is also shown to be associated with gastric cancer. Tea drinking, especially green tea, has a protective effect against gastric cancer as shown in some studies. Prospective case-control studies of the association between Helicobacter pylori infection and the subsequent development of gastric cancer showed that the odds ratio ranged from 2.8 to 6.0. However, results of similar case-control studies in countries with a high frequency of gastric cancer are controversial. Infection with H. pylori leads to changes in the vitamin C content of gastric juice, reactive oxygen metabolites, epithelial cell proliferation and apoptosis. Recently, CagA-positive strains were found to be associated with gastric cancer and also duodenal ulcers. The exact role of H. pylori in gastric carcinogenesis is still under investigation. Large-scale intervention studies are underway to examine dietary supplementation, H. pylori infection and gastric cancer. Helicobacter pylori eradication for gastric cancer prevention is being conducted in China and other parts of the world. In high-risk areas, for example in China, a combination approach including H. pylori eradication and dietary supplementation may be necessary.

Family history and subsite of gastric cancer: data from a case-referent study in Japan

A comparative case-referent study was conducted using data from the Hospital-Based Epidemiologic Research Program at Aichi Cancer Center (HERPACC) (Nagoya, Japan), with the aim of clarifying the effect of family history on gastric cancer by subsite. Our study comprised 995 histologically confirmed gastric cancer cases (180 cardia, 430 middle, 365 antrum and 20 unclassified) and a total of 43,846 non-cancer outpatients at Aichi Cancer Center Hospital between 1988 and 1995. Logistic regression was used to calculate odds ratios (ORs) for family history of gastric cancer and other cancers, adjusted for age, year and season at first hospital visit, habitual smoking, habitual alcohol drinking, regular physical exercise, preference for salty food and raw vegetable intake. In both genders, a positive family history of gastric cancer was associated with a moderate, but statistically significant increase in risk of gastric cancer [OR = 1.51, 95% confidence interval (95% CI) = 1.29-1.76], while no association was observed between the risk of gastric cancer and a family history of other cancers [OR = 0.97, 95% CI = 0.84-1.13]. OR increased for the middle and antrum parts of gastric cancer, but an increment for the cardiac part was observed only in those with a maternal history of gastric cancer. Our results suggest that the risk of gastric cancer in relation to family history varies by subsite and, furthermore, that the subsite-specific risk of gastric cancer is linked to a maternal history of gastric cancer.

Chemopreventive agents: protease inhibitors

Certain protease inhibitors, called the anticarcinogenic protease inhibitors in this review, are capable of preventing carcinogenesis in a wide variety of in vivo and in vitro model systems. The anticarcinogenic protease inhibitors are extremely potent agents with the ability to prevent cancer, with some unique characteristics as anticarcinogenic agents. The anticarcinogenic protease inhibitors have the ability to irreversibly suppress the carcinogenic process. They do not have to be continuously present to suppress carcinogenesis. They can be effective when applied in both in vivo and in vitro carcinogenesis assay systems at long time periods after carcinogen exposure, and are effective as anticarcinogenic agents at extremely low molar concentrations. While several different types of protease inhibitors can prevent the carcinogenic process, the most potent of the anticarcinogenic protease inhibitors on a molar basis are those with the ability to inhibit chymotrypsin or chymotrypsin-like proteases. The soybean-derived protease inhibitor, Bowman-Birk inhibitor (BBI), is a potent chymotrypsin inhibitor that has been extensively studied for its ability to prevent carcinogenesis in many different model systems. Much of this review is focused on the characteristics of BBI as the anticarcinogenic protease inhibitor, as this is the protease inhibitor that has risen to the human trial stage as a human cancer chemopreventive agent. Part of this review hypothesizes that the Bowman-Birk family of protease inhibitors plays a role in plants similar to that of alpha1-antichymotrypsin in people. Both BBI and alpha1-antichymotrypsin are potent inhibitors of chymotrypsin and chymotrypsin-like enzymes, are highly anti-inflammatory, and are thought to play important roles in the defense of their respective organisms. It is believed that BBI will be shown to play a major role in the prevention and/or treatment of several different diseases, in addition to cancer.

Association of Helicobacter pylori infection with gastric adenocarcinoma

Gastric adenocarcinoma is the most prevalent cancer in South Korea, and Helicobacter pylori (H. pylori) infection is also common. This study was performed to examine the association between H. pylori infection and gastric cancer, taking into account various other factors. To investigate the association between gastric adenocarcinoma and H. pylori infection, determined by urease-positive reaction in the CLO test, a total of 175 paired specimens (175 tumor and 175 tissues adjacent to tumor) of stomach cancer patients and a total of 113 control specimens were obtained. The positive H. pylori infection rates were 78.9% (138/175) among the patients in specimens of tumor or tissues adjacent to the tumor and 41.6% (47/113) among controls in the CLO test. A positive correlation between H. pylori infection and gastric cancer was observed (age-adjusted odds ratio, 7.0; MH chi2=34.5 with P<0.0005). These data suggest that stomach cancer patients in Korea have high infection rates of H. pylori regardless of site specificity, and this infection might be causally associated with stomach cancer.

Dietary habits and stomach cancer in Shanghai, China

Stomach cancer remains the second leading cancer in incidence in Shanghai, China, despite its decline over the past 2 decades. To clarify risk factors for this common malignancy, we conducted a population-based case-control study in Shanghai, China. Included in the study were 1,124 stomach cancer patients (age 20-69) newly diagnosed in 1988-1989 and 1,451 controls randomly selected among Shanghai residents. Usual adult dietary intake was assessed using a comprehensive food frequency questionnaire. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models. Risks of stomach cancer were inversely associated with high consumption of several food groups, including fresh vegetables and fruits, poultry, eggs, plant oil, and some nutrients, such as protein, fat, fiber and antioxidant vitamins. By contrast, risks increased with increasing consumption of dietary carbohydrates, with odds ratios (ORs) of 1.5 (95% confidence interval [CI] 1.1-2.1) and 1.9 (95% CI 1.3-2.9) in the highest quartile of intake among men (p for trend=0.02) and women (p=0.0007), respectively. Similar increases in risk were associated with frequent intake of noodles and bread in both men (p=0.07) and women (p=0.05) after further adjustment for fiber consumption. In addition, elevated risks were associated with frequent consumption of preserved, salty or fried foods, and hot soup/porridge, and with irregular meals, speed eating and binge eating. No major differences in risk were seen according to subsite (cardia vs. non-cardia). Our findings add to the evidence that diet plays a major role in stomach cancer risk and suggest the need for further evaluation of risks associated with carbohydrates and starchy foods as well as the mechanisms involved.

Protection against oral and gastrointestinal diseases: importance of dietary nitrate intake, oral nitrate reduction and enterosalivary nitrate circulation

Over the last 20 years, dietary nitrate has been implicated in the formation of methemoglobin and carcinogenic nitrosamines in humans. This has led to restrictions of nitrate and nitrite levels in food and drinking water. However, there is no epidemiological evidence for an increased risk of gastric and intestinal cancer in population groups with high dietary vegetable or nitrate intake. A reevaluation of our currently very negative perception of dietary nitrates comes from recent research into the metabolism and enterosalivary circulation of nitrate in mammals. These studies showed that nitrate is converted to nitrite in the oral cavity that then "fuels" an important mammalian resistance mechanism against infectious diseases. Moreover, there is now evidence that the conversion of nitrate into oxides of nitrogen prevents the formation carcinogenic nitrosamines.

Evaluation of the aetiological role of dietary salt exposure in gastric and other cancers in humans

The findings in laboratory and epidemiological studies relevant to the assessment of salt for carcinogenic potential are reviewed. Associations between the high consumption of certain highly salted foodstuffs, particularly in some oriental countries, and increased risk of cancer of the stomach do not incriminate salt per se. Some highly spiced foods contain potent genotoxic carcinogens, irrespective of whether they also contain salt. There is evidence in laboratory animals that high concentrations of salt may increase the incidence of gastric cancer caused by such carcinogens. This may well be attributable to a marked and sustained regenerative response in the gastric mucosa of laboratory animals chronically exposed to the cytotoxicity of hyperosmolar concentrations of salt, such a mitogenic response favouring the progression towards neoplasia. However, there is no laboratory evidence whatsoever to indicate that salt per se is a carcinogen for any site in the body; neither is there any reliable epidemiological evidence to indicate that dietary salt affects the incidence of gastric or other cancers. A particular problem in the interpretation of epidemiological studies is that the consumption of diets containing highly salted, spicy foods is often associated with low intakes of fruit and green vegetables, which contain cancer-protective antioxidants. In Western countries the incidence of cancer of the stomach has been falling for some 50 years. The consensus view is that this fall is attributable to improved food hygiene and increasingly available facilities for refrigeration. There are no grounds for supposing that the fall is attributable to a decreasing intake of salt. A high dietary salt intake does not necessarily entail exposure to salt in concentrations high enough to damage the gastric mucosa. The typical Western diet would not be expected to provide such high salt concentrations. It is concluded that there are no grounds for believing that a reduction in the average daily salt intake in the Western diet would have any effect on the risk of developing any form of cancer.

Diet and stomach cancer in Korea

Stomach cancer is the most prevalent malignant neoplasm in Korea. As of 1991-1992 in Seoul, the cumulative rates reported for the age span 0-74 were 7.6% in males and 3.1% in females. A recent case-control study reported that several food items and cooking methods are associated with increased or decreased risk of stomach cancer among Koreans. An increased risk of stomach cancer was noted among people who frequently consume broiled meats and fishes, salted side dishes (salted/fermented fish products) and salty stewed foods, such as soybean paste thick stew. Frequent consumption of mung bean pancake, tofu, cabbage, spinach and sesame oil decreased the risk. Analysis by cooking method showed that risk of stomach cancer from the same foods varied with preparation. For meat and fish, pan frying was associated with decreased risk, whereas stewing or broiling was associated with increased risk. Pickled vegetables increased the risk, whereas fresh vegetables did not. In a recent cohort study in Seoul, green vegetables and soybean foods were associated with a decreased risk of stomach cancer. Case-control and cohort studies have reported that ginseng intake decreased the risk of gastric cancer.