Diet and Stomach Cancer Risk in Warsaw, Poland

Not all carotenoids can reduce the risk of gastric cancer: a systematic review with meta-analysis

BACKGROUND

Gastric cancer is characterized by high invasiveness, heterogeneity, and late diagnosis, leading to high incidence and mortality rates. It is a significant public health concern globally. Early prevention is crucial in reducing the occurrence of gastric cancer, and dietary prevention, particularly focusing on carotenoids, has been considered a convenient and effective approach. However, the association between carotenoid intake and gastric cancer incidence remains controversial.

METHODS

A systematic search was conducted in PubMed, Ovid Embase, Web of Science, and Cochrane databases from inception to January 5, 2023. Two reviewers independently screened search results, extracted relevant data, and evaluated study quality. Statistical analysis was performed using the "metan" command in STATA 16 software. Random-effects or fixed-effects models were chosen based on the magnitude of heterogeneity among studies.

RESULTS

This study included a total of 35 publications, consisting of 23 case-control studies and 12 cohort studies. Meta-analysis of case-control studies showed that alpha-carotene (OR = 0.71, 95% CI: 0.55-0.92), beta-carotene (OR = 0.62, 95% CI: 0.53-0.72), and lutein (OR = 0.82, 95% CI: 0.69-0.97) significantly reduced the risk of gastric cancer, while beta-cryptoxanthin (OR = 0.88, 95% CI: 0.75-1.04) and lycopene (OR = 0.86, 95% CI: 0.73-1.00) showed no significant correlation. Meta-analysis of cohort studies indicated no significant associations between any of the five carotenoids and gastric cancer incidence (alpha-carotene: RR = 0.81, 95% CI: 0.54-1.23; beta-carotene: RR = 0.86, 95% CI: 0.64-1.16; beta-cryptoxanthin: RR = 0.86, 95% CI: 0.64-1.16; lutein: RR = 0.94, 95% CI: 0.69-1.29; lycopene: RR = 0.89, 95% CI: 0.69-1.14).

CONCLUSIONS

The relationship between carotenoids and gastric cancer incidence may vary depending on the type of study conducted. Considering that evidence from cohort studies is generally considered stronger than evidence from case-control studies, and high-quality randomized controlled trials show no significant association between carotenoids and gastric cancer incidence, current evidence does not support the supplementation of carotenoids for gastric cancer prevention. Further targeted research is needed to explore the association between the two.

Long Follow-Up Times Weaken Observational Diet-Cancer Study Outcomes: Evidence from Studies of Meat and Cancer Risk

For years, prospective cohort studies of diet and cancer incidence have reported smaller effects than do retrospective case-control (CC) studies. The differences have been attributed to problems with CC studies, including dietary recall bias, poor matching of cases and controls, and confounding. The hypothesis evaluated here is that long follow-up periods between ascertainment of diet and cancer incidence weaken the findings. Prospective studies of cancer incidence with respect to serum 25-hydroxyvitamin D concentration have already shown reduced benefit of higher concentrations for longer follow-up periods. Evaluating that hypothesis for dietary factors involved searching the journal literature for meta-analyses of red meat and processed meat and cancer incidence. I used findings from observational studies for bladder, breast, colorectal, and gastric cancers. To evaluate the effect of duration of follow-up time, I used two approaches. First, I plotted the relative risks for CC studies for gastric cancer with respect to consumption of 100 g/day of red meat and for bladder cancer for 50 g/day of processed meat against the interval between the dietary data and cancer incidence. Second, I compared nested CC studies of meat and cancer incidence for five breast cancer studies and one colorectal cancer study. Both approaches yielded an inverse correlation between interval or follow-up time and relative risk. My findings strongly suggest that diet near time of cancer diagnosis is more important than for longer intervals, that results from meta-analyses should be revised when possible with appropriate adjustments for duration of follow-up, and that dietary guidelines be revised accordingly.

Potential Role of Natural Antioxidant Products in Oncological Diseases

Nutrition has a significant effect and a crucial role in disease prevention. Low consumption of fruit and vegetables and a sedentary lifestyle are closely related with the onset and development of many types of cancer. Recently, nutraceuticals have gained much attention in cancer research due to their pleiotropic effects and relatively non-toxic behavior. In fact, although in the past there have been conflicting results on the role of some antioxidant compounds as allies against cancer, numerous recent clinical studies highlight the efficacy of dietary phytochemicals in the prevention and treatment of cancer. However, further investigation is necessary to gain a deeper understanding of the potential anticancer capacities of dietary phytochemicals as well as the mechanisms of their action. Therefore, this review examined the current literature on the key properties of the bioactive components present in the diet, such as carotenoids, polyphenols, and antioxidant compounds, as well as their use in cancer therapy. The review focused on potential chemopreventive properties, evaluating their synergistic effects with anticancer drugs and, consequently, the side effects associated with current cancer treatments.

Effect of Dietary Salt Intake on Risk of Gastric Cancer: A Systematic Review and Meta-Analysis of Case-Control Studies

Aim: The effect of dietary salt intake on the risk of gastric cancer is not clear. A meta-analysis was performed to estimate the association between dietary salt intake and the risk of gastric cancer. Methods: Three major databases were searched to retrieve case-control studies published in English before 1 July 2022. Random effects model analysis was used to obtain the pooled odds ratios (ORs) and 95% confidence intervals (CIs) of the association between dietary salt intake and risk of gastric cancer. Subgroup analyses were used to identify possible sources of heterogeneity. Results: Thirty-eight case-control studies were included in this meta-analysis (total population: n = 37,225). The pooled ORs showed a significantly positive association between high salt intake and gastric cancer compared with low salt intake (OR = 1.55, 95% CI (1.45, 1.64); p < 0.001). In subgroup meta-analysis for geographic region, estimation method for dietary salt intake and the source of controls, this association was not changed. Conclusion: Higher dietary salt intake increased the risk of gastric cancer. This study has implications for the prevention of gastric cancer.

Macronutrients Intake and Risk of Stomach Cancer: Findings from Case-Control Study

Studies on the association between gastric cancer (GC) and the intake of nutrients in Jordan are very limited, while findings from other reports on the intake of energy and macronutrients are controversial. This study aimed to examine the associations between intake of energy and macronutrients and the risk of GC in a Jordanian population. A case-control study was carried out between March 2015 and August 2018 in four major hospitals, including an oncology center in Jordan. Study participants were 173 cases with incident and histologically confirmed GC and 314 frequency-matched controls. Interview-based questionnaires were used to obtain the study's information. Data on nutrient intake were collected using a validated Arabic food-frequency questionnaire (FFQ). Odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were calculated through multinomial logistic regression and adjusted for potential confounders, including age, marital status, education, body mass index (BMI), smoking, period of smoking, family history of gastric cancer, history of gastric ulcer, and physical activity. Intakes of total fat, saturated fat, monounsaturated fat, polyunsaturated fat, cholesterol, trans-fat, and omega-6 fatty acids were significantly associated with increased risk of GC. The ORs for the highest versus the lowest tertiles were 6.47 (95% Cl: 3.29-12.77), 2.97 (95% CI: 1.58-5.58), 6.84 (95% CI: 3.46-13.52), 6.19 (95% CI: 3.15-12.17), 3.05 (95% CI: 1.58-5.88), 8.11 (95% CI: 4.20-15.69), and 2.74 (95% CI: 1.47-5.09), respectively. No significant association was found for energy, protein, carbohydrate, sugar, fibers, and omega-3 fatty acids. The findings of this study suggest that high intake of selected types of fats was associated with an increased risk of GC.

Association of Dietary Cholesterol Intake With Risk of Gastric Cancer: A Systematic Review and Meta-Analysis of Observational Studies

Background: Many case–control studies have investigated the association between dietary cholesterol and gastric cancer, yielding inconsistent findings. We carried out a systematic review and meta-analysis of observational studies to assess the relationship between dietary cholesterol intake and gastric cancer among adults.

Methods: PubMed, Scopus, and Google Scholar were systematically searched to identify articles that evaluated the association of dietary cholesterol with gastric cancer up to May 2021. Pooled odds ratio (ORs) and 95% confidence intervals (CIs) were computed using random-effects models. Dose–response analysis was used to explore the shape and strength of the association.

Results: Fourteen case–control studies with 6,490 gastric cancer patients and 17,793 controls met our inclusion criteria. In the meta-analysis of the highest vs. the lowest dietary cholesterol categories, a significantly higher (~35%) risk of gastric cancer was observed in association with high cholesterol consumption (pooled OR: 1.35, 95% CI: 1.29–1.62, I² = 68%; 95%CI: 45–81%). Subgroup analysis also showed this positive relationship in population-based case–control studies, those conducted on non-US countries, those with a higher number of cases and high-quality studies, those that collected dietary data via interviews, studies not adjusted for Helicobacter pylori infection, and studies where the body mass index was controlled. Besides, a non-linear dose–response association was also identified (P = 0.03).

Conclusion: This study demonstrated that dietary cholesterol intake could significantly augment the risk of gastric cancer in case–control studies. Prospective cohort studies with large sample sizes and long durations of follow-up are required to verify our results.

Fasting Plasma Glucose Variability and Gastric Cancer Risk in Individuals Without Diabetes Mellitus: A Nationwide Population-Based Cohort Study

Long-term glycemic variability is associated with various adverse health outcomes in patients with diabetes mellitus (DM). However, the relationship between glycemic variability and gastric cancer remains unclear. We aimed to investigate the association between glycemic variability and gastric cancer incidence in individuals without DM.

Macronutrients Intake and Stomach Cancer Risk in Iran: A Hospital-based Case-Control Study

Background: Stomach cancer (SC) is one of the most common cancers in the world. Dietary risk factors of SC are not fully understood. This study aimed to investigate the association between macronutrient intakes and the risk of SC.

Study design: A hospital-based case-control study.

Methods: The data were obtained from a hospital-based case-control study conducted at the Cancer Institute of Iran from 2010 to 2012. Patients were 40 years or older and were diagnosed with SC in less than one year with no history of any cancers. On the other hand, the controls were healthy subjects who were caregivers or visitors of the patients. Demographic characteristics were collected using a structured questionnaire through face to face interviews by trained interviewers. Dietary data were obtained using a validated Diet History Questionnaire. The age and gender-adjusted odds ratios (ORs), as well as the adjusted ORs of age, gender, energy, education, smoking, and body mass index, were reported for continuous and tertiles of intakes.

Results: Totally, 207 SC patients and 217 controls participated in this study. In the full adjusted model, after comparing the highest tertiles to the lowest ones, the intake of sucrose (OR: 2.94; 95% CI: 1.66-5.19; P-trend<0.001), protein (OR: 2.04; 95% CI: 1.17-3.55; P-trend=0.011), cholesterol (OR: 2.22; 95% CI: 1.28-3.85; P-trend=0.005), and percent of calories from protein (OR: 3.09; 95% CI: 1.69-5.61; P-trend<1.001) showed a positive significant association with SC. Moreover, a significantly negative association was found between the percent of calories obtained from carbohydrates and SC (OR: 0. 57; 95% CI: 0.33-0.98; P-trend=0.015).

Conclusion: The findings in this study showed that macronutrient intakes might be associated with the etiology of SC in Iran.

Whole Grains, Refined Grains, and Cancer Risk: A Systematic Review of Meta-Analyses of Observational Studies

PubMed, Web of Science, and the Cochrane Database of Systematic Reviews were searched for meta-analyses that provided risk estimates (±95% confidence intervals) for associations between intakes of whole and refined grains and risk of total and site-specific cancer. The preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines were followed. Only meta-analyses that included whole grains and refined grains as separate food groups, and not as part of dietary patterns, were included. A total of 17 publications were identified that met inclusion criteria. Within these, results from a total of 54 distinct meta-analyses were reported for whole grains and 5 meta-analyses for refined grains. For total cancer mortality, 7 meta-analyses of cohort studies indicated that whole grain intake was associated with 6% to 12% lower risk in comparison of highest vs. lowest intake groups, and 3% to 20% lower risk for doses ranging from 15 to 90 g/day. For site-specific cancers, meta-analyses indicated that whole grain intake was consistently associated with lower risks of colorectal, colon, gastric, pancreatic, and esophageal cancers. Limited data were available for refined grains, with only 4 publications providing risk estimates, and only 1 of the meta-analyses included more than 3 studies. High intake of refined grains was associated with increased risk of colon and gastric cancer. By contrast, in the only dose-response meta-analysis, each 90 g/day consumption of refined grains was associated with a 6% lower risk of total cancer. In addition to the limited number of published meta-analyses on refined grains, results were also weakened due to the fact that refined grains were frequently defined to include both staple grain foods and indulgent grain foods, and the majority of studies included in the meta-analyses provided no specific definition of refined grains. Overall, meta-analyses of cohort and case-control studies consistently demonstrate that whole grain intake is associated with lower risk of total and site-specific cancer, and support current dietary recommendations to increase whole grain consumption. By contrast, the relationship between refined grain intake and cancer risk is inconclusive.

Association of whole grains intake and the risk of digestive tract cancer: a systematic review and meta-analysis

BACKGROUND

Several epidemiological studies have investigated the association between whole grains intake and digestive tract cancer risk; however, the results are still controversial. The purpose of this meta-analysis was to assess the association.

METHODS

Studies published before March 2020 were searched in database and other sources. The risk ratio (RR) with the 95% confidence interval (CI) were pooled using fix or random-effects models.

RESULTS

This meta-analysis included 34 articles reporting 35 studies, 18 studies of colorectal cancer, 11 studies of gastric cancer and 6 studies of esophagus cancer, involving 2,663,278 participants and 28,921 cases. Comparing the highest-intake participants with the lowest-intake participants for whole grains, we found that the intake of whole grains were inversely related to colorectal cancer (RR = 0.89, 95% CI: 0.84-0.93, P < 0.001), gastric cancer (RR = 0.64, 95% CI: 0.53-0.79, P < 0.001), esophagus cancer (RR = 0.54, 95% CI: 0.44-0.67, P < 0.001), respectively. However, subgroup analysis of colorectal cancer found no significant association in the case-control studies and studies of sample size < 500, and subgroup analysis of gastric cancer found no significant association in the cohort studies and studies of American population. No study significantly affected the findings in the sensitivity analysis. No publication bias was found in the studies for colorectal cancer and esophagus cancer except in the studies for gastric cancer.

CONCLUSION

This meta-analysis provides further evidence that whole grains intake was associated with a reduced risk of digestive tract cancer. Our result supports the dietary guidelines that increase whole grains intake to reduce the risk of digestive tract cancer.

Nutritional Factors Involved in the Etiology of Gastric Cancer: A Systematic Review

CONTEXT

Since treatment options for GC are limited, the best and most effective way is to try to reduce the incidences and understanding prevention strategies.

OBJECTIVE

The success in prevention strategies depends on understanding etiologic mechanisms. Our goal is to identify the major nutritional risk factors for GC, and we will examine the controversial evidence.

DATA SOURCES

We used Pub Med, Google Scholar, Scopus, Science Direct, Elsevier, Springer, and MEDLINE databases for extracting articles.

DATA EXTRACTION

Human studies published in English from 1997to2018 were included. Two reviewers other than authors initially assessed abstract of 742 papers and 248papers were selected for future assessments. After full review and consideration of the inclusion and exclusion criteria, we used 85 articles.

RESULTS

Dietary salt is a strong independent risk for GC whereas alcohol is most likely a risk only in the presence of heavy alcohol consumption. Red meat and high-fat diet increase the risk of developing GC but fresh fruits, vegetables and certain micronutrients like selenium and vitamin C are protective.

CONCLUSION

Some nutrients such as selenium, vitamin C, folate, iron, and zinc are involved in the etiology of GC. On the other hand; salt, fats, alcohol, red meat, and pepper were reported to be risk factors for GC. Since the GC is a heterogeneous malignancy and multiple factors are involved in its genesis.

Dietary Intake of Fatty Acids, Total Cholesterol, and Stomach Cancer in a Chinese Population

To investigate the associations between dietary fatty acids and cholesterol consumption and stomach cancer (SC), we analyzed data from a population-based case-control study with a total of 1900 SC cases and 6532 controls. Dietary data and other risk or protective factors were collected by face-to-face interviews in Jiangsu Province, China, from 2003 to 2010. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multiple unconditional logistic regression models and an energy-adjusted method. The joint associations between dietary factors and known risk factors on SC were examined. We observed positive associations between dietary saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), and total cholesterol and the development of SC, comparing the highest versus lowest quarters. Increased intakes of dietary SFAs (p-trend = 0.005; aOR, 1.11; 95% CI, 1.01–1.22 with a 7 g/day increase as a continuous variable) and total cholesterol (p-trend < 0.001; aOR, 1.13; 95% CI, 1.06–1.22 with a 250 mg/day increase as a continuous variable) were monotonically associated with elevated odds of developing SC. Our results indicate that dietary SFAs, MUFAs, and total cholesterol are associated with stomach cancer, which might provide a potential dietary intervention for stomach cancer prevention.

Grain consumption and risk of gastric cancer: a meta-analysis

This study evaluated the relationship between grain consumption and the risk of gastric cancer. A total of 19 studies met the inclusion criteria. For whole grain consumption, there was a 13% reduction in the risk of gastric cancer (p = .003), and a subgroup analysis showed that a large amount of whole grain consumption reduced the risk of gastric cancer by 44% (p < .001). For refined grain consumption, there was a 36% increase in the risk of gastric cancer (p < .001); a subgroup analysis showed that a large and a moderate amount of refined grain consumption increased the risk of gastric cancer by 63% (p < .001) and 28% (p < .001), respectively. A large intake of whole grains might be protective against gastric cancer, whereas the ingestion of refined cereals may be a risk factor for gastric cancer. Moreover, the risk of cancer increases with the increase of refined grain intake.

Cruciferous Vegetable Consumption and Stomach Cancer: A Case-Control Study

Objective: To investigate the association between regular cruciferous vegetable intake and stomach cancer.Methods: A hospital-based, case-control study was conducted at Roswell Park Comprehensive Cancer Center in Buffalo, NY, which included 292 stomach cancer patients and 1168 cancer-free controls recruited between 1992 and 1998 as part of the Patient Epidemiology Data System (PEDS). Dietary and other epidemiologic and confounding variables were collected by questionnaire. Multivariable logistic regression analyses were utilized to estimate odds ratios (OR) and 95% confidence intervals (CI) for associations between usual pre-diagnostic cruciferous vegetable intake and stomach cancer, with adjustment for other stomach cancer risk factors and dietary characteristics.Results: We observed strong inverse associations between stomach cancer and highest versus lowest intakes of total cruciferous vegetables (OR = 0.59, 95% CI: 0.42-0.83), raw cruciferous vegetables (OR = 0.53, 95% CI: 0.38-0.73), raw broccoli (OR = 0.61, 95% CI: 0.43-0.86), raw cauliflower (OR = 0.51, 95% CI: 0.35-0.73), and Brussels sprouts (OR = 0.66, 95% CI = 0.48-0.91).Conclusions: These data suggest that consuming raw cruciferous vegetables may be associated with a lower odds of stomach cancer, even after considering other dietary characteristics.

Effect of Red, Processed, and White Meat Consumption on the Risk of Gastric Cancer: An Overall and Dose⁻Response Meta-Analysis

Whether the risk of gastric cancer varies by the types of meat consumption still remains disputable. The purpose of this meta-analysis was to identify the exact associations that red, processed, and white meat have with gastric cancer. We searched relevant studies in Medline, EMBASE, and the Cochrane Library before November 2018, including cohort and case-control studies. We used random-effect models to estimate the adjusted relative risk (RR), and Egger’s tests to evaluate publication bias. Through stepwise screening, 43 studies were included in this analysis (11 cohort studies and 32 case-control studies with 16,572 cases). In a meta-analysis for the highest versus lowest categories of meat consumption, both red (RR: 1.41, 95% confidence interval (CI): 1.21–1.66) and processed (RR: 1.57, 95% CI: 1.37–1.81) meat consumption were positively associated with gastric cancer risk, while white meat consumption was negatively associated with gastric cancer risk (RR: 0.80, 95% CI: 0.69–0.92). In a dose–response meta-analysis, the RRs of gastric cancer were 1.26 (95% CI: 1.11–1.42) for every 100 g/day increment in red meat consumption, 1.72 (95% CI: 1.36–2.18) for every 50 g/day increment in processed meat consumption, and 0.86 (95% CI: 0.64–1.15) for every 100 g/day increment in white meat consumption. The increase of white meat consumption may reduce the risk of gastric cancer, while red or processed meat may increase the risk of gastric cancer. Further studies are required to identify these associations, especially between white meat and gastric cancer.

Dietary carbohydrate intake, glycaemic index, glycaemic load and digestive system cancers: an updated dose-response meta-analysis

Several studies analysed the associations between dietary carbohydrate intake, glycaemic index (GI) and glycaemic load (GL) and digestive system cancers; however, the results remain controversial. This study was to perform a meta-analysis evaluating the quantitative and dose-response associations between carbohydrate intake, GI and GL, and risk of digestive system cancers. We searched medical and biological databases up to June 2018 and identified twenty-six cohort studies and eighteen case-control studies. Meta-analytic fixed or random effects models were applied to process data. We also performed dose-response analysis, meta-regression and subgroup analyses. We found that high levels of GI were significantly associated with the risk of digestive system cancers at the highest compared with the lowest categories from cohort studies (summary relative risk (RR)=1·10, 95 % CI 1·05, 1·15). Similar effects were observed from case-control studies of the comparison between the extreme categories, but the difference did not reach statistical significance (summary OR=1·28, 95 % CI 0·97, 1·69). We also observed significant dose-response association between GI and digestive system cancers, with every 10-unit increase in GI (summary RR=1·003; 95 % CI 1·000, 1·012 for cohort studies; summary OR=1·09; 95 % CI 1·06, 1·11 for case-control studies). In addition, both cohort studies and case-control studies indicated that neither dietary carbohydrate intake nor GL bore any statistical relationship to digestive system cancers from the results of the highest compared with the lowest categories analyses and dose-response analyses. The results suggest a moderate association between high-GI diets and the risk of digestive system cancers.

Association of whole grain, refined grain, and cereal consumption with gastric cancer risk: A meta-analysis of observational studies

Many studies have analyzed the relationship between cereal, whole, or refined grain and the risk of gastric cancer (GC) and have yielded mixed results. Therefore, we performed a meta-analysis of observational studies to summarize the available evidence on this topic. Databases such as PubMed, EMBASE, Web of Science, MEDLINE, and the Cochrane Library were searched for studies focusing on these associations from inception to October 2017. Summary odd ratios (OR) and 95% confidence intervals (CI) were calculated by using either a random- or fixed-effect model according to the between-studies heterogeneity. Subgroup analysis was also performed. In total, eleven studies that included 530,176 participants were identified. In a pooled analysis of all studies, cereal exposure was not associated with GC risk (OR, 1.11, 95%CI, 0.85-1.36). Specific analyses indicated that whole grain consumption was associated with decreased GC risk (OR, 0.61, 95%CI, 0.40-0.83) and that refined grain consumption was associated with increased GC risk (OR, 1.65, 95%CI, 1.36-1.94). Higher whole grain and lower refined grain intake but not cereal consumption reduces GC risk. This study has been registered at ClinicalTrials.gov (ID: NCT03419663).

Dietary Carotenoids Intake and the Risk of Gastric Cancer: A Case-Control Study in Korea

Although the incidence of gastric cancer (GC) has declined, it remains the second most common cancer in Korea. As a class of phytochemicals, carotenoids are fat-soluble pigments that are abundant in fruits and vegetables and have health-promoting properties, including cancer prevention effects. This case-control study investigated the effects of total dietary carotenoids, dietary carotenoid subclasses (α-carotene, β-carotene, β-cryptoxanthin, lutein/zeaxanthin, and lycopene), and foods contributing to the dietary intake of each carotenoid on the risk of GC. Four hundred and fifteen cases and 830 controls were recruited from the National Cancer Center Hospital in Korea between March 2011 and December 2014. A significant inverse association between total dietary carotenoids and GC risk was observed among women (odds ratio (OR) 0.56, 95% confidence interval (CI) 0.32⁻0.99). A higher intake of dietary lycopene was inversely associated with GC risk overall in the subjects (OR 0.60, 95% CI 0.42⁻0.85, p for trend = 0.012), men (OR 0.60, 95% CI 0.39⁻0.93), and women (OR 0.54, 95% CI 0.30⁻0.96, p for trend = 0.039). This significant association between dietary lycopene intake and GC risk was also observed in the subgroups of Helicobacter pylori (H. pylori)-positive subjects and those who had ever smoked. Among the major contributing foods of dietary lycopene, consumption of tomatoes and tomato ketchup was inversely associated with GC risk in the overall subjects, men, and women. Based on our findings, a higher intake of dietary lycopene and contributing foods of lycopene (tomatoes and tomato ketchup) may be inversely associated with the risk of GC.

Milk/dairy products consumption and gastric cancer: an update meta-analysis of epidemiological studies

The relationship between dairy consumption and gastric cancer risk has not been well studied. We therefore performed a update meta-analysis to evaluate the relationship. Published cohort and case-control studies were identified via computer searches and reviewing the reference lists of the key articles. Random effects meta-analysis was used to pool effects from 5 cohort and 29 case-control studies. The odds ratio for the overall association between dairy consumption and gastric cancer was 1.20 (95%confidence interval: 1.04–1.39). The combined risk estimate was similar for population-based case-control studies (odds ratio = 1.27, 95%confidence interval: 1.00–1.61), but was reduced for hospital-based studies (odds ratio = 1.22; 95%confidence interval: 0.95–1.57) and cohort studies (odds ratio = 0.99; 95%confidence interval: 0.77–1.28). There was high heterogeneity in overall analyses. In the population-based subgroup analyses, the odds ratio was 0.96 (95%confidence interval: 0.69–1.34) when considering five studies assessing exposure two or more years before interview, and the association strengthened (odds ratio = 1.91, 95%confidence interval: 1.60–2.28) when dairy consumption was evaluated one year or less prior to interview. In conclusion, we found adverse effect of dairy consumption associated with gastric cancer.

Associations between dietary folate intake and risks of esophageal, gastric and pancreatic cancers: an overall and dose-response meta-analysis

There are still some controversies on the association between dietary folate intake and the risk of upper gastrointestinal cancers including esophageal, gastric and pancreatic cancers. Hence, a comprehensive meta-analysis on all available literatures was performed to clarify the relationship between dietary folate intake and risks of upper gastrointestinal cancers. An electric search was performed up to December 12^th, 2016 within the PubMed, MEDLINE AND EMBASE databases. Ultimately, a total of 46 studies which evaluated the association between folate intake and risks of upper gastrointestinal cancers were included. According to the data from included studies, the pooled results showed significant association between folate intake and esophageal (OR = 0.545, 95%CI = 0.432-0.658), gastric (OR=0.762, 95%CI=0.648-0.876) and pancreatic (OR=0.731, 95%CI=0.555-0.907) cancers. Linearity dose-response analysis indicated that with 100μg/day increment in dietary folate intake, the risk of esophageal, gastric and pancreatic cancers would decrease by 9%, 1.5% and 6%, respectively. These findings indicated that higher level of dietary folate intake could help for preventing upper gastrointestinal cancers including esophageal, gastric and pancreatic cancers.

Dietary resistant starch contained foods and breast cancer risk: a case-control study in northwest of Iran

BACKGROUND

A protective effect of resistant starch (RS) containing foods on carcinogenesis has been shown from several lines of experimental evidence for gastrointestinal cancers. Therefore, we aimed to investigate the association between RS contained foods and breast cancer (BC) risk in a hospital-based, age- and origin- matched, case-control study.

MATERIALS AND METHODS

A validated, semi-quantitative, food frequency questionnaire (FFQ) was completed by 306 women newly diagnosed with BC aged 25 to 65 years, and 309 healthy women as matched controls. Odds ratios (ORs) and 95% confidence intervals (95%CI) were estimated using conditional logistic regression models.

RESULTS

Reduced BC risk was associated with the highest tertile of whole-wheat bread and boiled potato consumption with adjusted ORs at 0.34 (95%CI: 0.19-0.59) and 0.61 (95%CI: 0.37- 0.99), respectively. Among consumers of whole-wheat bread consumers were considered, the protective role of cereals remained relatively apparent at higher intakes level of fiber rich breads at adjusted models (OR=0.53, 95%CI: 0.28-1.01). Moreover, high intake of legumes was found out to be a significant protective dietary factor against risk of BC development with an OR of 0.01 (95%CI: 0.03-0.13). However, consumption of white bread and biscuits was positively related to BC risk.

CONCLUSIONS

Our results show that certain RS containing foods, in particular whole wheat bread, legumes and boiled potato may reduce BC risk, whereas higher intake of white bread and biscuits may be related to increased BC risk.

Association between dietary carbohydrate intake, glycemic index and glycemic load, and risk of gastric cancer

PURPOSE

The association between dietary carbohydrate intake, glycemic index (GI) and glycemic load (GL), and risk of gastric cancer (GC) has been investigated by many studies. However, the results of these studies were controversial. The aim of our study was to systematically assess this issue.

METHODS

PUBMED and EMBASE were searched up to March 2015, and either a fixed- or a random-effects model was adopted to estimate overall relative risks (RRs). Dose-response, meta-regression, subgroup, and publication bias analyses were applied.

RESULTS

Twenty-six studies with approximately 540,000 participants were finally included in this meta-analysis. High level of dietary carbohydrate intake (pooled RR 1.17, 95 % CI 0.91-1.50), GI (pooled RR 1.17, 95 % CI 0.80-1.69), and GL (pooled RR 1.06, 95 % CI 0.90-1.26) were all nonsignificantly associated with incidence of GC. In addition, no significant dose-response relationship was observed between carbohydrate intake, GI and GL, and the risk of GC. However, further subgroup analyses based on gender and geographic region suggested a significant association between higher carbohydrate intake (pooled RR 1.52, 95 % CI 1.10-2.08), GL (pooled RR 1.41, 95 % CI 1.04-1.92), and GC risk in males subgroup, and between higher carbohydrate intake (pooled RR 1.69, 95 % CI 1.36-2.09) and GC risk in Asian studies.

CONCLUSIONS

No significant association was found between dietary carbohydrate intake, GI and GL, and risk of GC. However, significantly positive association was observed in the males subgroup and Asian studies.

Macronutrient intake and stomach cancer

PURPOSE

This study examines the association between intake of selected macronutrients and the risk of stomach cancer in a Northern American population.

METHODS

Mailed questionnaires were completed between 1994 and 1997 in eight Canadian provinces by 1,181 incident, histologically confirmed cases of stomach cancer and 5,039 population controls. Information on nutrient intake was obtained using a food frequency questionnaire. Odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) were derived through unconditional logistic regression to adjust for potential confounders, including an estimate of total energy intake.

RESULTS

Intakes of total fat, saturated fat, and cholesterol were significantly associated with the risk of stomach cancer: The ORs for the highest versus the lowest quartile were 1.58 (95% CI 1.13-2.20), 1.86 (95% CI 1.37-2.52), and 1.75 (95% CI 1.36-2.25), respectively. Total fiber was inversely associated with stomach cancer (p = 0.03). The positive associations with intake of total fat and saturated fat were apparently stronger in women, overweight or obese subjects, and ever smokers. Saturated fat was specifically associated with increased risk of gastric cardia cancer, with an OR of 3.31 (95% CI 1.48-7.43).

CONCLUSIONS

A diet high in saturated fat appears to increase the risk of stomach cancer, particularly among obese subjects and for gastric cardia cancer.

Association of carotenoids with risk of gastric cancer: A meta-analysis

BACKGROUND & AIMS

Prior studies on carotenoids and gastric cancer risk have generated inconsistent results. We performed a meta-analysis of observational studies to summarize the evidence regarding the relation of carotenoids and gastric cancer risk.

METHODS

A comprehensive search was performed to identify all observational studies providing quantitative estimates between gastric cancer risk and carotenoids. The fixed or random effect model was selected based on the homogeneity test among studies in the highest vs. lowest categorical analyses.

RESULTS

13 published case-control studies with 14 results including 3919 cases and 7400 controls, and 8 cohort studies involving 1972 cases of gastric cancer and 96,691 participants, met the inclusion criteria. For case-control studies, only intake of β-carotene and α-carotene were significantly associated with a reduced gastric cancer risk. The summary OR(95%CI) for β-carotene, α-carotene, lycopene and lutein were 0.52(0.46-0.59), 0.59(0.37-0.92), 0.88(0.55-1.41) and 0.85(0.56-1.30) respectively. In contrast, the summary RR(95%CI) for β-carotene, α-carotene, lycopene and lutein were 0.72(0.50-1.03), 0.79(0.58-1.07), 0.80(0.60-1.07) and 0.95(0.77-1.18), respectively.

CONCLUSION

Although data from case-control studies suggested that β-carotene, α-carotene were inversely associated with risk of gastric cancer, there was no conclusive evidence on this association because of inconsistencies between case-control and cohort studies.

Vitamin intake reduce the risk of gastric cancer: meta-analysis and systematic review of randomized and observational studies

AIM

The association between vitamin intake and gastric cancer (GC) has been widely debated due to the relatively weak evidence. In this study, a meta-analysis of prospective and well designed observational studies were performed to explore this association.

METHODS

MEDLINE, Cochrane Library, and Sciencedirect were searched for studies of vitamin consumption and gastric cancer. This produced 47 relevant studies covering 1,221,392 human subjects. Random effects models were used to estimate summary relative risk (RR). Dose-response, subgroup, sensitivity, meta-regression, and publication bias analyses were conducted.

RESULTS

The RR of gastric cancer in the group with the highest vitamin intake was compared to that of the lowest intake group. Total vitamin intake was 0.78 (95% CI, 0.71-0.83). In 9 studies that individuals were given doses at least 4 times above the tolerable upper intake (UL) vitamins, the RR was 1.20 (95% CI, 0.99-1.44). However, in 17 studies that individuals received doses below the UL, the RR was 0.76 (95% CI, 0.68-0.86). Dose-response analysis was conducted on different increments in different types of vitamins (vitamin A: 1.5 mg/day, vitamin C: 100 mg/day, vitamin E: 10 mg/day) intake with a significant reduction in the risk of gastric cancer, respectively, 29% in vitamin A, 26% in vitamin C, and 24% in vitamin E.

CONCLUSION

This meta-analysis clearly demonstrated that low doses of vitamins can significantly reduce the risk of GC, especially vitamin A, vitamin C, vitamin E.

Dairy product consumption and gastric cancer risk: A meta-analysis

AIM: To investigate whether dairy product consumption is a risk factor for gastric cancer.

METHODS: We searched the PubMed and Web of Science databases for English-language studies on dairy product consumption and gastric cancer risk that were published between October 1980 and September 2013. One author independently extracted data and assessed study quality. Based on the heterogeneity results, we used either the fixed effects model or the random effects model to compute the summary relative risks and 95% confidence intervals (CIs). We also analyzed subgroups according to the study design, geographic region, sex, and whether there were adjustments for confounders (smoking and drinking) with respect to the sources of heterogeneity.

RESULTS: We found 39 studies that were potentially eligible for inclusion in this meta-analysis, including 10 cohort studies and 29 case-control studies. The summary relative risk for gastric cancer, comparing the highest and lowest dairy product consumption categories, was 1.06 (95%CI: 0.95-1.18). Specific analyses for milk, butter, and margarine yielded similar results, but the results for cheese and yogurt were different. There was significant heterogeneity for all studies (Q = 112.61; P = 0.000; I² = 67.1%). No publication bias was observed (Egger’s test: P = 0.135; Begg’s test: P = 0.365). There was a nonsignificant association between dairy product consumption and gastric cancer risk in the subgroup analysis for the study design, sex, geographic region, and whether there were adjustments for confounders (smoking and drinking).

CONCLUSION: In our meta-analysis, dairy product consumption was associated with a nonsignificantly increased risk of gastric cancer. However, this result should be verified using large, well-designed prospective studies.

Association between dairy intake and gastric cancer: a meta-analysis of observational studies

Purpose

Observational studies have given inconsistent findings on the relationship between intake of dairy products and gastric cancer. We therefore conducted a systematic review with a meta-analysis of observational studies to summarize available evidence on this point.

Methods

We searched the electronic literature databases of PubMed (Medline), EMBASE and the Chinese Biomedical Literature Database up until August 30, 2013. All studies were limited to the English language. Random-effects models were used to pool study results between dairy products consumption and the risk of gastric cancer. We also performed subgroup, publication bias and sensitivity analysis.

Results

Eight prospective studies and 18 case-control studies were included in our analysis, with a total number of 7272 gastric cancer cases and 223,355 controls. Pooled relative risks of all studies showed no significant association between dairy intake and gastric cancer (odds ratio [OR]: 1.09, 95% confidence interval [CI]: 0.96–1.25). When study design was separately analyzed, population-based case-control studies showed a positive association between dairy intake and gastric cancer risk (OR: 1.36; 95% CI: 1.07–1.74), whereas no associations were shown by hospital-based case-control studies (OR: 0.86, 95% CI: 0.72–1.02) or cohort studies (OR = 1.01, 95% CI = 0.91–1.13).

Conclusions

The meta-analysis shows that no clear association apparently exists between consumption of dairy products and gastric cancer risk. Further well-designed cohort and intervention studies should be conducted to verify this lack of association.

Association between vitamin A, retinol intake and blood retinol level and gastric cancer risk: A meta-analysis

BACKGROUND & AIMS

The association between dietary vitamin A, retinol intake and blood retinol level and gastric cancer risk has been investigated by many studies. However, the results of these studies were controversial. The aim of our study was to systematically assess this issue.

METHODS

PUBMED and EMBASE were searched, supplemented with manual-screening for relevant publications. Meta-analyses were performed to evaluate the association between vitamin A, retinol dietary intake or blood retinol level and gastric cancer risk.

RESULTS

Thirty-one studies were included in this meta-analysis. Comparing the highest with the lowest categories, vitamin A intake significantly reduced gastric cancer risk (pooled RR = 0.66, 95% CI: 0.52-0.84), whereas a marginally inverse association was found between retinol intake (pooled RR = 0.94, 95% CI: 0.87-1.03) or blood retinol level (pooled RR = 0.87, 95% CI: 0.73-1.05) and gastric cancer risk. Interestingly, the results of subgroup analysis indicated that high vitamin A intake and blood retinol level were associated with reduced gastric cancer risk in Western countries, while a marginally inverse association was found between retinol and gastric cancer risk in Western countries.

CONCLUSIONS

Vitamin A intake was inversely associated with gastric cancer risk, while no significant association was found with retinol intake or blood retinol level.

Association between dietary antioxidant vitamins intake/blood level and risk of gastric cancer

We aimed to systematically evaluate the association between dietary intake/blood levels of antioxidant vitamins (vitamin C, vitamin E, β-carotene, and α-carotene) and gastric cancer risk. Systematic literature searches were conducted until April 2013 in Pubmed and Embase to identify relevant studies. Either a fixed- or a random-effects model was adopted to estimate overall odds ratios (ORs). Dose-response, meta-regression, subgroup, and publication bias analyses were applied. Forty articles were finally included in the present study. Higher dietary intake of vitamin C, vitamin E, β-carotene, and α-carotene was inversely associated with gastric cancer risk (for vitamin C, pooled OR=0.58, 95% CI 0.51-0.65; for vitamin E, pooled OR=0.65, 95% CI 0.57-0.74; for β-carotene, pooled OR=0.59, 95% CI 0.49-0.70; for α-carotene, pooled OR=0.69, 95% CI 0.52-0.93). Subgroup analyses suggested the effects of these antioxidant vitamins were different in gastric cancer subtypes. As indicated by dose-response analysis, a 100 mg/day increment of vitamin C intake conferred an OR of 0.78 (95% CI 0.67-0.90); a 15 mg/day increment of vitamin E intake conferred an OR of 0.79 (95% CI 0.66-0.94); and a 5 mg/day increment in β-carotene intake conferred an OR of 0.80 (95% CI 0.60-1.04). No significant association was observed between blood vitamin C, α-tocopherol, γ- tocopherol, β-carotene and α-carotene levels and gastric cancer risk. In conclusion, dietary intake of vitamin C, vitamin E, β-carotene and α-carotene was inversely associated with gastric cancer risk while no such association was observed for blood levels of these antioxidant vitamins, thus the results should be interpreted cautiously.

Folate intake and the risk of upper gastrointestinal cancers: a systematic review and meta-analysis

BACKGROUND AND AIM

There is conflicting evidence on the association between folate intake and the risk of upper gastrointestinal tract cancers. In order to further elucidate this relationship, we performed a systematic review and quantitative meta-analysis of folate intake and the risk of esophageal, gastric, and pancreatic cancer.

METHODS

Four electronic databases (Medline, PubMed, Embase, and Current Contents Connect) were searched to July 26, 2013, with no language restrictions for observational studies that measured folate intake and the risk of esophageal cancer, gastric cancer, or pancreatic cancer. Pooled odds ratios and 95% confidence intervals were calculated using a random effects model.

RESULTS

The meta-analysis of dietary folate and esophageal cancer risk comprising of nine retrospective studies showed a decreased risk of esophageal cancer (odds ratio [OR] 0.59; 95% confidence interval [95% CI] 0.51-0.69). The meta-analysis of dietary folate and gastric cancer risk comprising of 16 studies showed no association (OR 0.94; 95% CI 0.78-1.14). The meta-analysis of dietary folate and pancreatic cancer risk comprising of eight studies showed a decreased risk of pancreatic cancer (OR 0.66; 95% CI 0.49-0.89).

CONCLUSION

Dietary folate intake is associated with a decreased risk of esophageal and pancreatic cancer, but not gastric cancer. Interpretation of these relationships is complicated by significant heterogeneity between studies when pooled, and by small numbers of studies available to analyze when stratification is performed to reduce heterogeneity.

Red and processed meat intake is associated with higher gastric cancer risk: a meta-analysis of epidemiological observational studies

BACKGROUND

Red and processed meat was concluded as a limited-suggestive risk factor of gastric cancer by the World Cancer Research Fund. However, recent epidemiological studies have yielded inconclusive results.

METHODS

We searched Medline, EMBASE, and the Cochrane Library from their inception to April 2013 for both cohort and case-control studies which assessed the association between red and/or processed meat intake and gastric cancer risk. Study-specific relative risk estimates were polled by random-effect or fixed-effect models.

RESULTS

Twelve cohort and thirty case-control studies were included in the meta-analysis. Significant associations were found between both red (RR: 1.45, 95% CI: 1.22-1.73) and processed (RR: 1.45, 95% CI: 1.26-1.65) meat intake and gastric cancer risk generally. Positive findings were also existed in the items of beef (RR: 1.28, 95% CI: 1.04-1.57), bacon (RR: 1.37, 95% CI: 1.17-1.61), ham (RR: 1.44, 95% CI: 1.00-2.06), and sausage (RR: 1.33, 95% CI: 1.16-1.52). When conducted by study design, the association was significant in case-control studies (RR: 1.63, 95% CI: 1.33-1.99) but not in cohort studies (RR: 1.02, 95% CI: 0.90-1.17) for red meat. Increased relative risks were seen in high-quality, adenocarcinoma, cardia and European-population studies for red meat. And most subgroup analysis confirmed the significant association between processed meat intake and gastric cancer risk.

CONCLUSIONS

Our findings indicate that consumption of red and/or processed meat contributes to increased gastric cancer risk. However, further investigation is needed to confirm the association, especially for red meat.

Cruciferous vegetable consumption and gastric cancer risk: a meta-analysis of epidemiological studies

The relationship between consumption of cruciferous vegetables (CV) and risk of gastric cancer has been investigated by many studies, but remains controversial. We carried out a meta-analysis to summarize available evidence from epidemiological studies on this point. Relevant published reports of CV intake and gastric cancer were identified using MEDLINE (PubMed), EMBASE, and Web of Science databases through to the end of September 2012. We pooled the relative risk from individual studies using a fixed- or random-effects model and carried out heterogeneity and publication bias analyses. Sixteen case-control and six prospective studies were included in our analysis. When all studies were pooled, we yielded a significantly inverse association between CV (relative risk = 0.81; 95% confidence interval, 0.75-0.88) intake and gastric cancer risk, with little heterogeneity (Q = 27.27, P = 0.292, I(2) = 12.0%). Specific analysis for cabbage intake yielded similar result. When separately analyzed, case-control studies of CV intake yielded significant results and the results of prospective studies showed borderline statistical significance. Moreover, significant results were consistent for high-quality studies, for North American, European, and Asian studies, for studies on males, and for studies on non-cardia gastric cancer. Findings from this meta-analysis provide evidence that high intake of CV was inversely associated with the risk of gastric cancer and non-cardia gastric cancer in humans. Further studies on other specific CV, food preparation methods, and stratified results by anatomic cancer site and histological type should be extended in the future.

Dietary fiber intake reduces risk for gastric cancer: a meta-analysis

BACKGROUND & AIMS

The association between dietary fiber intake and gastric cancer risk has been investigated by many studies, with inconclusive results. We conducted a meta-analysis of case-control and cohort studies to analyze this association.

METHODS

Relevant studies were identified by searching PubMed and Embase through October 2012. We analyzed 21 articles, which included 580,064 subjects. Random-effects models were used to estimate summary relative risks. Dose-response, subgroup, sensitivity, meta-regression, and publication bias analyses were performed.

RESULTS

The summary odds ratios of gastric cancer for the highest, compared with the lowest, dietary fiber intake was 0.58 (95% confidence interval, 0.49-0.67) with significant heterogeneity among studies (P < .001, I(2) = 62.2%). Stratified analysis for study design, geographic area, source and type of fiber, Lauren's classification, publication year, sample size, and quality score of study yielded consistent results. Dose-response analysis associated a 10-g/day increment in fiber intake with a significant (44%) reduction in gastric cancer risk. Sensitivity analysis restricted to studies with control for conventional risk factors produced similar results, and omission of any single study had little effect on the combined risk estimate.

CONCLUSIONS

In a meta-analysis, we show that dietary fiber intake is associated inversely with gastric cancer risk; the effect probably is independent of conventional risk factors. The direction of the protective association of dietary fiber was consistent among all studies, but the absolute magnitude was less certain because of heterogeneity among the studies. Further studies therefore are required to establish this association.

The role of tomato products and lycopene in the prevention of gastric cancer: a meta-analysis of epidemiologic studies

BACKGROUND

Gastric cancer is the second most common cause of death from cancer worldwide. Epidemiologic studies have examined the possible association between tomato products consumption and gastric cancer, but the relationship between tomato products and the risk of gastric cancer is controversial. We performed a meta-analysis of cohort and case-control studies to analyze this association.

METHODS

We systematically searched MEDLINE and EMBASE and contacted authors to identify potential studies published from January 1966 to June 2012. We pooled the relative risks from individual studies using a random-effects model and performed heterogeneity and publication bias analyses.

RESULTS

Twenty-one studies were eligible for our inclusion criteria, in a pooled analysis of all studies, consumption of large amounts of tomato products (in a comparison of the highest and lowest consumption groups) reduced the risk for gastric cancer (odds ratio, 0.73; 95% confidence interval, 0.60-0.90). The pooled OR of lycopene consumption and serum lycopene was 0.88 (95% CI=0.67-1.16) and 0.79 (95% CI=0.59-1.07), respectively.

CONCLUSIONS

Consumption of large amounts of tomato products is associated with a reduced risk of gastric cancer. However, because of potential confounding factors and exposure misclassification, further studies are required to establish these findings.

A meta-analysis of the effects of energy intake on risk of digestive cancers

AIM: To quantitatively assess the relationship between energy intake and the incidence of digestive cancers in a meta-analysis of cohort studies.

METHODS: We searched MEDLINE, EMBASE, Science Citation Index Expanded, and the bibliographies of retrieved articles. Studies were included if they reported relative risks (RRs) and corresponding 95% CIs of digestive cancers with respect to total energy intake. When RRs were not available in the published article, they were computed from the exposure distributions. Data were extracted independently by two investigators and discrepancies were resolved by discussion with a third investigator. We performed fixed-effects meta-analyses and meta-regressions to compute the summary RR for highest versus lowest category of energy intake and for per unit energy intake and digestive cancer incidence by giving each study-specific RR a weight that was proportional to its precision.

RESULTS: Nineteen studies consisting of 13 independent cohorts met the inclusion criteria. The studies included 995 577 participants and 5620 incident cases of digestive cancer with an average follow-up of 11.1 years. A significant inverse association was observed between energy intake and the incidence of digestive cancers. The RR of digestive cancers for the highest compared to the lowest caloric intake category was 0.90 (95% CI 0.81-0.98, P < 0.05). The RR for an increment of 239 kcal/d energy intake was 0.97 (95% CI 0.95-0.99, P < 0.05) in the fixed model. In subgroup analyses, we noted that energy intake was associated with a reduced risk of colorectal cancer (RR 0.90, 95% CI 0.81-0.99, P < 0.05) and an increased risk of gastric cancer (RR 1.19, 95% CI 1.08-1.31, P < 0.01). There appeared to be no association with esophageal (RR 0.96, 95% CI 0.86-1.07, P > 0.05) or pancreatic (RR 0.79, 95% CI 0.49-1.09, P > 0.05) cancer. Associations were also similar in studies from North America and Europe. The RR was 1.02 (95% CI 0.79-1.25, P > 0.05) when considering the six studies conducted in North America and 0.87 (95% CI 0.77-0.98, P < 0.05) for the five studies from Europe.

CONCLUSION: Our findings suggest that high energy intake may reduce the total digestive cancer incidence and has a preventive effect on colorectal cancer.

Vegetarian diets and the incidence of cancer in a low-risk population

BACKGROUND

Cancer is the second leading cause of death in the United States. Dietary factors account for at least 30% of all cancers in Western countries. As people do not consume individual foods but rather combinations of them, the assessment of dietary patterns may offer valuable information when determining associations between diet and cancer risk.

METHODS

We examined the association between dietary patterns (non-vegetarians, lacto, pesco, vegan, and semi-vegetarian) and the overall cancer incidence among 69,120 participants of the Adventist Health Study-2. Cancer cases were identified by matching to cancer registries. Cox proportional hazard regression analysis was conducted to estimate hazard ratios, with "attained age" as the time variable.

RESULTS

A total of 2,939 incident cancer cases were identified. The multivariate HR of overall cancer risk among vegetarians compared with non-vegetarians was statistically significant [HR, 0.92; 95% confidence interval (CI), 0.85-0.99] for both genders combined. Also, a statistically significant association was found between vegetarian diet and cancers of the gastrointestinal tract (HR, 0.76; 95% CI, 0.63-0.90). When analyzing the association of specific vegetarian dietary patterns, vegan diets showed statistically significant protection for overall cancer incidence (HR, 0.84; 95% CI, 0.72-0.99) in both genders combined and for female-specific cancers (HR, 0.66; 95% CI, 0.47-0.92). Lacto-ovo-vegetarians appeared to be associated with decreased risk of cancers of the gastrointestinal system (HR, 0.75; 95% CI, 0.60-0.92).

CONCLUSION

Vegetarian diets seem to confer protection against cancer.

IMPACT

Vegan diet seems to confer lower risk for overall and female-specific cancer than other dietary patterns. The lacto-ovo-vegetarian diets seem to confer protection from cancers of the gastrointestinal tract.

Association Study between Folate Pathway Gene Single Nucleotide Polymorphisms and Gastric Cancer in Koreans

Gastric cancer is ranked as the most common cancer in Koreans. A recent molecular biological study about the folate pathway gene revealed the correlation with a couple of cancer types. In the folate pathway, several genes are involved, including methylenetetrahydrofolate reductase (MTHFR), methyltetrahydrofolate-homocysteine methyltransferase reductase (MTRR), and methyltetrahydrofolate-homocysteine methyltransferase (MTR). The MTHFR gene has been reported several times for the correlation with gastric cancer risk. However, the association of the MTRR or MTR gene has not been reported to date. In this study, we investigated the association between the single nucleotide polymorphisms (SNPs) of the MTHFR, MTRR, and MTR genes and the risk of gastric cancer in Koreans. To identify the genetic association with gastric cancer, we selected 17 SNPs sites in folate pathway-associated genes of MTHFR, MTR, and MTRR and tested in 1,261 gastric cancer patients and 375 healthy controls. By genotype analysis, estimating odds ratios and 95% confidence intervals (CI), rs1801394 in the MTRR gene showed increased risk for gastric cacner, with statistical significance both in the codominant model (odds ratio [OR], 1.39; 95% CI, 1.04 to 1.85) and dominant model (OR, 1.34; 95% CI, 1.02 to 1.75). Especially, in the obese group (body mass index ≥ 25 kg/m²), the codominant (OR, 9.08; 95% CI, 1.01 to 94.59) and recessive model (OR, 3.72; 95% CI, 0.92 to 16.59) showed dramatically increased risk (p < 0.05). In conclusion, rs1801394 in the MTRR gene is associated with gastric cancer risk, and its functional significance need to be validated.

Alimentary factors in the development of gastric intestinal metaplasia in functional dyspeptic patients

CONTEXT: Intestinal metaplasia of the stomach is a lesion in which metaplasia of gastric epithelial cells occurs for an intestinal phenotype. Gastric intestinal metaplasia is a lesion associated with an increase in the risk of gastric carcinoma development. Epidemiologic studies indicate a relation between dietary habits and stomach cancer development, some habits increasing the risk for it, and others have a protective effect, suggesting that antioxidants, such as vitamins A, C, and E, decrease the risk of this type of cancer. The relationship of these alimentary factors and intestinal metaplasia is unknown. METHODS: It is a case-control, observational study in which 320 patients with functional dyspepsia, divided in two groups, were assessed. The case I group (individuals with intestinal metaplasia) had their dietary pattern compared to that of the control group, constituted of individuals similar to those in the case group but without intestinal metaplasia, through a food frequency questionnaire. RESULTS: The analysis of the dietary pattern of functional dyspeptic patients with intestinal metaplasia, and its comparison with those without intestinal metaplasia, showed a higher frequency of canned and smoked foods consumption in the first group and, on the other hand, a higher consumption of fruits and vegetables in patients without intestinal metaplasia. No effect of salt consumption was detected. CONCLUSIONS: The results obtained in this study suggest changes in the diet, with a decrease in the consumption of smoked and canned foods, and an increase in the consumption of fruits and vegetables, can lead to a diminution of gastric intestinal metaplasia cases.

Pickled food and risk of gastric cancer--a systematic review and meta-analysis of English and Chinese literature

BACKGROUND

Ecological and experimental studies have suggested an increased risk of gastric cancer in relation to consumption of pickled vegetables in East Asia.

METHODS

We conducted a meta-analysis of epidemiologic observational studies to evaluate the existing evidence. Searching PubMed, Vip Chinese Periodical, and China National Knowledge Infrastructure databases, we found a total of 60 studies, 50 case-control, and 10 prospective. We compared gastric cancer risk in pickled vegetable/food users versus nonusers (11 studies) or versus those in the lowest reported category of use (49 studies). Pooled results were computed with random-effects models.

RESULTS

Among case-control studies, 30 showed significant increased risk and one showed significant decreased risk. Among prospective studies, two showed a significant increased risk but none showed a significant decreased risk. The OR (95% CI) was 1.52 (1.37-1.68) for the overall association, 1.56 (1.39-1.75) for case-control, and 1.32 (1.10-1.59) for cohort studies. The OR (95% CI) was 1.89 (1.29-2.77) in Korean, 1.86 (1.61-2.15) in Chinese, and 1.16 (1.04-1.29) in Japanese studies, and 1.14 (0.96-1.35) in studies from other countries. There was high heterogeneity in overall and subgroup analyses. There was little evidence for publication bias.

CONCLUSION

Our results suggest a potential 50% higher risk of gastric cancer associated with intake of pickled vegetables/foods and perhaps stronger associations in Korea and China.

IMPACT

The results of this study may offer ways to reduce the risk of gastric cancer in highly populated areas with high incidence of gastric cancer.

Dietary micronutrients and gastric cancer: hospital based study

The association between micronutrients and gastric cancer is still unclear. The aim of this study is to determine the relationship between dietary intake of micronutrients and risk for gastric cancer. We used data from hospital-based case control study conducted at Clinical Centre Nis (Serbia) from 2005 and 2006. Patients (n=102) with first histologically confirmed gastric cancer and matched non-cancer patients (controls, n=204) were interviewed using structured questionnaire and FFQ (Food frequency questionnaire). Multivariate logistic regression analysis showed a significant positive association between gastric cancer and dietary intake of sodium (OR=6.22; 95%CI 1.99–7.86), but a significant negative association between potassium (OR 0.01; 95%CI 0.00–0.08), iron (OR 0.05; 95%CI 0.01–0.56), vitamin C (OR 0.05; 95%CI 0.01–0.38), vitamin E (OR 0.04; 95%CI 0.01–0.29) and niacin (OR 0.07; 95%CI 0.00–0.38) dietary intake. Intake of phosphorus, calcium, magnesium, zinc, retinol, β carotene, tiamin, vitamin B6, and folic acid was not significantly related to gastric cancer risk.

In conclusion, we found that a dietary pattern of high consumption of antioxidants (vitamin C, vitamin E, niacin), iron and potassium and low consumption of foods that are sources of sodium, decreased risk for gastric cancer. Our results require confirmation in future studies.

Possible association between a genetic polymorphism at 8q24 and risk of upper gastrointestinal cancer

Over recent years, genome-wide association studies have contributed to our understanding of genetic susceptibility to sporadic cancer. In this study, we assessed the association between upper gastrointestinal cancer risk and four genome-wide association studies-identified single nucleotide polymorphisms (SNPs), implicated earlier in prostate and colorectal cancer susceptibility. Genotyping for each SNP was performed in two independent Caucasian population-based case-control studies. The first study comprised 290 gastric cancer cases and 374 controls. The second study included 185 noncardia gastric cancers, 123 cardia cancers, 158 oesophageal cancers and 209 controls. Odds ratios (ORs) were computed from logistic models and adjusted for potential confounding variables. An inverse association was observed between the SNP rs1447295, located at 8q24, and gastric cancer risk in the first study population (OR=0.63; 95% confidence interval: 0.41-0.97). A positive association was observed for the same SNP and oesophageal squamous cell carcinoma in the second study population (OR=7.43; 95% confidence interval: 1.37-49.98). No significant associations were detected in either study for the three remaining SNPs (rs6983297, rs10505477 and rs719725). Our data represent novel findings on heritable susceptibility to gastric and oesophageal cancer and warrant validation in additional populations.

An age-period-cohort analysis of gastric cancer mortality from 1950 to 2007 in Europe

PURPOSE

To analyze the components of the favorable trends in gastric cancer in Europe.

METHODS

From official certified deaths from gastric cancer and population estimates for 42 countries of the European geographical region, during the period 1950 to 2007, age-standardized death rates (World Standard Population) were computed, and an age-period-cohort analysis was performed.

RESULTS

Central and Northern countries with lower rates in the 2005 to 2007 period, such as France (5.28 and 1.93/100,000, men and women respectively) and Sweden (4.49 and 2.21/100,000), had descending period and cohort effects that decreased steeply from the earliest cohorts until those born in the 1940s, to then stabilize. Former nonmarket economy countries had mortality rates greater than 20/100,000 men and 10/100,000 women, and displayed a later start in the cohort effect fall, which continued in the younger cohorts. Mortality remained high in some countries of Southern and Eastern Europe.

CONCLUSIONS

The decrease in gastric cancer mortality was observed in both cohort and period effects but was larger in the cohorts, suggesting that the downward trends are likely to persist in countries with higher rates. In a few Western countries with very low rates an asymptote appears to have been reached for cohorts born after the 1940s, particularly in women.

Prognostic relevance of demographics and surgical practice for patients with gastric cancer in two centers: in Poland versus Germany

BACKGROUND

Although studies comparing the surgical treatment of gastric carcinoma in Japan and Western industrialized countries have revealed differing survival rates, no studies to date have been performed comparing Western and Eastern Europe. This study aimed to compare demographics and surgical practice as well as the related prognostic impact on gastric cancer patients treated in Poland and Germany.

METHODS

This retrospective study included gastric cancer patients treated between 1999 and 2004 by surgical departments in Gdansk (Poland) and Cologne (Germany). Univariate and multivariate analyses of demographic, histopathological, surgical, and prognostic data were performed.

RESULTS

Included were 117 patients from Gdansk and 130 patients from Cologne. The Cologne patients showed higher incidence rates of serious comorbidity, pT1 cancer, and distant metastasis than those from Gdansk. Indications for and frequency of selected surgical procedures differed significantly. D2-lymphadenectomy was performed in 89% of the Cologne patients, while D1-lymphadenectomy was done for 85% of the Gdansk patients. Univariate analysis yielded a 5-year survival rate of 28.3% for the Gdansk patients, and 40.3% for the Cologne patients (p = 0.056). Independent prognostic factors were pT category (p = 0.002), pN category (p < 0.001), pM category (p = 0.027), residual tumor (R) category (p = 0.004), age (p = 0.012), and number of resected lymph nodes (p = 0.005).

CONCLUSIONS

Significant differences of clinical and surgical parameters exist between gastric cancer patients treated in Poland and Germany. In addition to established independent prognostic factors, we found that survival improved with each additionally resected lymph node.

Blood leukocyte DNA hypomethylation and gastric cancer risk in a high-risk Polish population

Global hypomethylation has been shown to increase genome instability potentially leading to increased cancer risk. We determined whether global methylation in blood leukocyte DNA was associated with gastric cancer in a population-based study on 302 gastric cancer cases and 421 age- and sex-matched controls in Warsaw, Poland, between 1994 and 1996. Using PCR-pyrosequencing, we analyzed methylation levels of Alu and LINE-1, 2 CG-rich repetitive elements, to measure global methylation levels. Gastric cancer risk was highest among those with lowest level of methylation in either Alu (OR = 1.3, 95% CI = 0.9-1.9) or LINE-1 (OR = 1.4, 95% CI = 0.9-2.0) relative to those with the highest levels, although the trends were not statistically significant. For Alu, the association was stronger among those aged 70 or older (OR = 2.6, 95% CI = 1.3-5.5, p for interaction = 0.02). We did not observe meaningful differences in the associations by other risk factors and polymorphisms examined. For LINE-1, the association tended to be stronger among individuals with a family history of cancer (OR = 3.1, 95% CI = 1.4-7.0, p for interaction = 0.01), current alcohol drinkers (OR = 1.9, 95% CI = 1.0-3.6, p for interaction = 0.05), current smokers (OR = 2.3, 95% CI = 1.1-4.6, p for interaction = 0.02), those who rarely or never consumed fruit (OR = 3.1, 95% CI = 1.2-8.1, p for interaction = 0.03), CC carriers for the MTRR Ex5+123C>T polymorphism (OR = 2.3, 95% CI = 1.2-4.4, p for interaction = 0.01) and TT carriers for the MTRR Ex15+572T>C polymorphism (OR = 1.7, 95% CI = 1.0-2.8, p for interaction = 0.06). The association was not different by sex, Helicobacter pylori infection, intake of folate, vitamin B6 and total protein and the remaining polymorphisms examined. Our results indicate that interactions between blood leukocyte DNA hypomethylation and host characteristics may determine gastric cancer risk.

Dietary folate intake and the risk of 11 types of cancer: a case-control study in Uruguay

BACKGROUND

There is limited, but inconclusive, epidemiological evidence that high folate intake decreases the risk of colorectal and esophageal cancers. For other cancer sites, the evidence is even less consistent or extensive.

MATERIALS AND METHODS

We conducted a case-control study of dietary folate intake and risk of 11 cancer sites in Uruguay between 1996 and 2004, including 3539 cancer cases and 2032 hospital controls. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) of cancer associated with folate intake.

RESULTS

In the multivariable model, there was a significant decrease in the risk of cancers of the oral cavity and pharynx (OR = 0.49, 95% CI 0.24-0.98), esophagus (OR = 0.29, 95% CI 0.14-0.60), upper aerodigestive tract (OR = 0.41, 95% CI 0.26-0.65), colorectum (OR = 0.42, 95% CI 0.23-0.76) and kidney (OR = 0.35, 95% CI 0.13-0.93) for the highest versus the lowest quartile of dietary folate intake.

CONCLUSIONS

Our results not only confirm earlier findings of decreased risk of colorectal and esophageal cancers with a high dietary folate intake but also suggest decreased risk of several other cancers. However, we cannot exclude the possibility that residual confounding, multiple comparisons or other forms of bias could explain these results.

Education, economic status and other risk factors in gastric cancer: "a case-control study of Turkish Oncology Group"

Diet and lifestyle related to socioeconomic status emerged as risk factors for gastric cancer in several studies. However, the results were not always consistent with the socioeconomic status. The aim of this study was to evaluate the risk factors independent from education as a measure of socioeconomic status. Two hundred and fifty-three patients with gastric cancer diagnosed in 2005 and equal number of control subjects were interviewed for several characteristics and diet. Matching was done for age, gender, city of residence and also for the level of education. Despite these matching preferences, patients had significantly lower income when compared to the control subjects (P = 0.0001). Higher rate of patients were smoking more than 2 packs/day of cigarettes (P = 0.018). Also significantly higher rate of control subjects were using antibiotics (P = 0.002). Coffee (P < 0.0001), salad (P = 0.006), bread (P = 0.005), vegetable-derived cooking oil (P = 0.003) consumptions appeared as highly protective factors against gastric cancer in univariate analysis in the present trial. In multivariate analysis, significant risk reducing factors were bread (P = 0.005) and coffee consumption (P = 0.0001) other than the level income (P = 0.002). In conclusion, the goal of obtaining comparable socioeconomic status by including the level of education in the matching criteria was not met in our study because of the difference in income level. The only risk reducing factor that was not in accordance with income level was the unexpectedly higher rate of bread consumption in control group.