Iron intake and markers of iron status and risk of Barrett's esophagus and esophageal adenocarcinoma

Evaluating tissue levels of the eight trace elements and heavy metals among esophagus and gastric cancer patients: A comparison between cancerous and non-cancerous tissues

BACKGROUND

Considering the affecting role of environmental factors including trace elements and heavy metals on the upper gastrointestinal (GI) cancers, there is paucity of empirical research in tissue evaluations.

OBJECTIVES

The present study aimed to measure the tissue content of some trace elements and heavy metals such as zinc (Zn), chromium (Cr), manganese (Mn), tin (Sn), copper (Cu), aluminum (Al), lead (Pb), and iron (Fe) in esophagus and gastric cancerous tissues compared to the adjacent healthy tissues.

METHODS

In a cross-sectional study, the aforementioned trace elements and heavy metals were evaluated among patients with esophagus and gastric cancers. During endoscopy, multiple samples were taken from cancerous lesions and the adjacent healthy tissues. The classic flame atomic absorption spectroscopy (FAAS) method was employed as the study framework.

RESULTS

Fifty patients with the mean age of 53.92 ± 8.73 were enrolled in the current study. Thirteen patients suffered from esophageal cancer and thirty-seven patients were afflicted with gastric cancer. The results revealed significant differences in the median concentrations of Zn, Cr, Sn and, Cu (P < 0.05) between the two groups. Although there were no significant changes in the tissue content in the esophageal samples, in the median concentrations of Zn, Cr and, Sn (P < 0.05) in gastric tissues, significant differences were observed. Further, the results indicated that gender enacted an affecting role in the level of some trace elements and heavy metals.

CONCLUSION

The tissue contents of some elements were altered in gastric and esophageal cancers; this difference may reflect the underlying mechanism of cellular changing during the tumorigenesis or direct exposure of these elements. It seems that under the shade of other coexisting risk factors, larger cohort studies are suggested to be conducted to investigate other probable aspects in this area of interest.

Lifestyle, WCRF/AICR Recommendations, and Esophageal Adenocarcinoma Risk: A Systematic Review of the Literature

One of the most notable changes in the epidemiology of esophageal cancer (EC) is the rising incidence and prevalence of esophageal adenocarcinoma (EAC) in developed countries. The aim of this systematic review was to collect and summarize all the available evidence regarding lifestyle, diet, and EAC risk. We searched the PubMed and Scopus databases in January 2021 for studies providing information about lifestyle, diet, WCRF/AICR recommendations, and EAC risk; published in English; without a time filter. The Newcastle-Ottawa Scale was used to assess risk of bias. The results are stratified by risk factor. A total of 106 publications were included. Half of the case-control studies were judged as high quality, whilst practically all cohort studies were judged as high quality. Body mass index and waist circumference were associated with increased EAC risk. Physical activity did not appear to have a significant direct role in EAC risk. A diet rich in fruit, vegetables, and whole grains appeared to be more protective than a Western diet. Alcohol does not seem to be related to EAC, whereas smokers, particularly heavy smokers, have an increased risk of EAC. Prevention remains the best option to avert EAC. Comprehensible and easy to follow recommendations should be provided to all subjects. Protocol ID number: CRD-42021228762, no funds received.

Association between circulating levels of sex steroid hormones and esophageal adenocarcinoma in the FINBAR Study

Background

Esophageal adenocarcinoma (EA) is characterized by a strong male predominance. Sex steroid hormones have been hypothesized to underlie this sex disparity, but no population-based study to date has examined this potential association.

Methods

Using mass spectrometry and ELISA, we quantitated sex steroid hormones and sex hormone binding globulin, respectively, in plasma from males– 172 EA cases and 185 controls–within the Factors Influencing the Barrett/Adenocarcinoma Relationship (FINBAR) Study, a case-control investigation conducted in Northern Ireland and Ireland. Multivariable adjusted logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for associations between circulating hormones and EA.

Results

Higher androgen:estrogen ratio metrics were associated with increased odds of EA (e.g., testosterone:estradiol ratio OR_{Q4 v. Q1} = 2.58, 95%CI = 1.23–5.43; P_trend = 0.009). All estrogens and androgens were associated with significant decreased odds of EA. When restricted to individuals with minimal to no decrease in body mass index, the size of association for the androgen:estrogen ratio was not greatly altered.

Conclusions

This first study of sex steroid hormones and EA provides tentative evidence that androgen:estrogen balance may be a factor related to EA. Replication of these findings in prospective studies is needed to enhance confidence in the causality of this effect.

The Epidemiology of Esophageal Adenocarcinoma

The incidence of esophageal adenocarcinoma (EAC) has increased in many Western countries and is higher in men than women. Some risk factors for EAC have been identified-mainly gastroesophageal reflux disease, Barrett's esophagus, obesity, and tobacco smoking. It is not clear whether interventions to address these factors can reduce risk of EAC, although some evidence exists for smoking cessation. Although consumption of alcohol is not associated with EAC risk, other exposures, such as physical activity, nutrition, and medication use, require further study. Genetic variants have been associated with risk for EAC, but their overall contribution is low. Studies are needed to investigate associations between risk factors and the molecular subtypes of EAC. The prognosis for patients with EAC has slightly improved, but remains poor-screening and surveillance trials of high-risk individuals are needed.

Micronutrients: A double-edged sword in microbial-induced gastric carcinogenesis

Epidemiologic studies throughout the world have uniformly demonstrated significant relationships between the intake of dietary micronutrients and gastric cancer risk. An exciting concept that has gained considerable traction recently is that micronutrients modulate gene expression within Helicobacter pylori, the strongest identified risk factor for gastric carcinogenesis. We present evidence here that essential micronutrients have a direct effect on H. pylori virulence, which subsequently affects interactions at the host-pathogen interface, thereby facilitating the development of premalignant and malignant lesions in the stomach. Further, these fundamental concepts provide a framework for understanding mechanisms driving the development of other malignancies that arise from foci of gastrointestinal inflammation.

Dietary Risk Reduction Factors for the Barrett's Esophagus-Esophageal Adenocarcinoma Continuum: A Review of the Recent Literature

Esophageal adenocarcinoma (EA) incidence is among the most rapidly increasing of any cancer type in the U.S., and prognosis is poor. Prevalence of the potential precursor lesion, Barrett's esophagus (BE), is also increasing. Candidates for safe and effective risk reduction strategies are needed, potentially including dietary components. In this qualitative review, we summarize recently published epidemiologic studies, in context of earlier work, on dietary intake and BE-EA outcomes. Potential cohort study/intervention trial candidates which could be increased to reduce BE-EA development include intake of: (1) fruits and vegetables; vegetables; fruit (EA only); (2) β-carotene and vitamins C and E; (3) folate (EA only); and (4) total fiber (EA only). Also, (5) red and processed meat intake could be targeted for dietary reduction/omission to reduce EA development. Few dietary constituents have been evaluated among EA patients to examine associations with mortality, thus interventions conducted among EA patients are premature.

Toenail iron, genetic determinants of iron status, and the risk of glioma

PURPOSE

Iron is essential for oxygen transport and oxidative metabolism; however, elevated iron stores can trigger overproduction of reactive oxygen species and induce DNA damage. Little is known about the association between body iron stores and glioma risk. This study examined the associations of iron levels measured in toenails and genetic variants linked to body iron stores with risk of glioma in a clinic-based case-control study.

METHODS

Samples were collected a median of 24 days following glioma diagnosis in the cases (10th-90th percentile, range: 10-44 days). Nail iron levels were measured in 300 cases and 300 controls using neutron activation analysis. A total of 24 genetic variants associated with iron status were genotyped in 622 cases and 628 controls. Logistic regression was used to estimate odds ratios (OR) and 95 % confidence intervals (CI) for glioma risk according to toenail iron and the examined genotypes.

RESULTS

No association was observed between toenail iron and glioma risk when restricting to cases with nails collected within ~3 weeks of diagnosis (OR = 0.93; 95 % CI 0.46, 1.87 comparing those with high (≥14 μg/g) vs. low (<6 μg/g) iron levels). In contrast, an inverse association with increasing iron was observed after restricting to cases with a delay of 3 weeks or greater (OR = 0.42; 95 % CI 0.19, 0.95), reflecting potentially insidious effects of advancing disease on iron levels among the cases. No associations were observed for any of the examined genetic variants.

CONCLUSION

The results do not support a role for body iron stores as a determinant of glioma risk.

Meat and heme iron intake and esophageal adenocarcinoma in the European Prospective Investigation into Cancer and Nutrition study

Although recent studies suggest that high intakes of meat and heme iron are risk factors for several types of cancer, studies in relation to esophageal adenocarcinoma (EAC) are scarce. Previous results in the European Prospective Investigation into Cancer and Nutrition (EPIC) based on a relatively small number of cases suggested a positive association between processed meat and EAC. In this study, we investigate the association between intake of different types of meats and heme iron intake and EAC risk in a larger number of cases from EPIC. The study included 481,419 individuals and 137 incident cases of EAC that occurred during an average of 11 years of follow-up. Dietary intake of meat (unprocessed/processed red and white meat) was assessed by validated center-specific questionnaires. Heme iron was calculated as a type-specific percentage of the total iron content in meat. After adjusting for relevant confounders, we observed a statistically significant positive association of EAC risk with heme iron and processed meat intake, with HR: 1.67, 95% CI: 1.05-2.68 and HR: 2.27, 95% CI:1.33-3.89, respectively, for comparison of the highest vs. lowest tertile of intake. Our results suggest a potential association between higher intakes of processed meat and heme iron and risk of EAC.

Long-term stability of biomarkers of the iron status in human serum and plasma

CONTEXT

In epidemiological research, it is very important to test the stability of biomarkers as function of both storage time and temperature.

OBJECTIVE

In this study, the stability of biomarkers of the iron status was tested up to 1 year of storage.

MATERIALS AND METHODS

The biomarkers include total iron, unsaturated iron binding capacity, ferritin, transferrin, soluble transferrin receptor, ceruloplasmin and haptoglobin.

RESULTS

The concentrations of all biomarkers tested remain constant upon storage at -20, -70 and -196 °C.

CONCLUSION

All biomarkers of the iron status were stable at the temperatures tested for 1 year.

Dietary N-nitroso compounds, endogenous nitrosation, and the risk of esophageal and gastric cancer subtypes in the Netherlands Cohort Study

BACKGROUND

Dietary N-nitroso compounds and endogenous nitrosation are important carcinogenic factors, but human evidence of their role is scarce for esophageal cancer and inconsistent for gastric cancer.

OBJECTIVE

We studied the relation between risks of esophageal and gastric cancer subtypes and dietary intake of N-nitrosodimethylamine, heme iron, nitrite, and nitrate in the Netherlands Cohort Study.

DESIGN

A total of 120,852 men and women aged 55-69 y were recruited in 1986, and diet, based on a 150-item food-frequency questionnaire, and other risk factors were assessed. The cohort was followed for 16.3 y, and 110 esophageal squamous cell carcinoma (ESCC), 151 esophageal adenocarcinoma, 166 gastric cardia adenocarcinoma, and 497 gastric noncardia adenocarcinoma (GNCA) cases were analyzed along with 4032 subcohort members in a case-cohort analysis.

RESULTS

Positive associations were observed between N-nitrosodimethylamine intake and ESCC risk (HR for 0.1-μg/d increase in intake: 1.15; 95% CI: 1.05, 1.25; P-trend = 0.01 based on tertiles of intake) and GNCA risk (1.06; 95% CI: 1.01, 1.10; P-trend = 0.09) in men. ESCC risk was associated with nitrite intake (HR for 0.1-mg/d increase: 1.19; 95% CI: 1.05, 1.36; P-trend = 0.06) and heme-iron intake (HR for 1-mg/d increase: 1.83; 95% CI: 0.98, 3.39; P-trend = 0.03). Among women, exposure levels were lower, and we found no convincing positive associations.

CONCLUSION

These results suggest that N-nitroso compounds may influence the risk of ESCC in men, but there are no clear associations for other esophageal and gastric subtypes.

Red and processed meat intake and risk of esophageal adenocarcinoma: a meta-analysis of observational studies

AIMS

Inconsistent results relating dietary red and processed meat intake and risk of esophageal adenocarcinoma (EAC) have been reported. This article summarizes and quantifies the current evidence in a meta-analysis of observational studies.

METHODS

Electronic search of MEDLINE and EMBASE databases was performed to identify peer-reviewed manuscripts up to 31 May 2012. Random-effects models were used to pool study results.

RESULTS

Ten manuscripts from 3 cohort studies and 7 case-control studies were identified. The summary relative risks (SRRs) of EAC for highest versus lowest intake categories were 1.31 (95 % confidence intervals [CIs]: 1.05-1.64) for red meat consumption, and 1.41 (95 % CIs 1.09-1.83) for processed meat consumption. Subgroup analyses indicated that these positive relations were seen in case-control studies, but not in cohort studies. Based on dose-response analysis, similar results were found; the SRRs were 1.45(95 % CIs 1.09-1.93) per 100 g/day of red meat intake and 1.37 (95 % CIs 1.03-1.81) per 50 g/day of processed meat intake.

CONCLUSIONS

The results of this meta-analysis indicate that consumption of red and processed meat may be associated with increased risk of esophageal adenocarcinoma. More studies, particularly prospective studies, are needed.

Toenail trace element status and risk of Barrett's oesophagus and oesophageal adenocarcinoma: results from the FINBAR study

Trace elements have been cited as both inhibitory and causative agents of cancer but importantly exposure to them is potentially modifiable. Our study aimed to examine toenail trace element status and risk of Barrett's oesophagus (BO) and oesophageal adenocarcinoma (OAC). Toenail clippings from each hallux were obtained from 638 participants of the FINBAR (Factors Influencing the Barrett's Adenocarcinoma Relationship) study comprising 221 healthy controls, 98 reflux oesophagitis, 182 BO and 137 OAC cases. The concentrations of eight toenail trace elements were determined using instrumental neutron activation analysis. Using multivariable adjusted logistic regression analysis, odds ratios (OR) and 95% confidence intervals (CIs) were calculated within tertiles of trace element concentrations. A twofold increased risk of BO was observed, but not OAC, among individuals in the highest tertile of toenail zinc status OR 2.21 (95% CI, 1.11-4.40). A higher toenail selenium status was not associated with risk of OAC OR 0.94 (95% CI, 0.44-2.04) or BO OR 0.89 (95% CI, 0.37-2.12). A borderline significant increased risk of BO was detected with a higher toenail cobalt concentration, OR 1.97 (95% CI, 1.01-3.85). No association was found between toenail levels of chromium, cerium, mercury and OAC or BO risk. This is the first case-control study to investigate a variety of trace elements in relation to OAC and BO risk. Despite antioxidant and proapoptotic properties, no associations were found with selenium. Higher concentrations of toenail zinc and cobalt were associated with an increased BO risk, but not OAC. These findings need confirmation in prospective analysis.

Review: Experimental models for Barrett's esophagus and esophageal adenocarcinoma

Several different cell culture systems and laboratory animal models have been used over the years to study Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC). Most of the existing models have key differences with the human esophagus and complex pathogenesis of disease. None of the models offers an ideal system for the complex study of environmental exposure, genetic risk, and prevention strategies. In fact, different model systems may be required to answer different specific research questions about the pathogenesis of BE and EAC. Given the high mortality associated with EAC and the fact that current screening strategies miss most cases of EAC, advances in basic and translational science related to esophageal injury, repair, and carcinogenesis are clearly needed. This review describes several of the existing and potential model systems for BE and EAC with their benefits and disadvantages.

Heme iron from meat and risk of adenocarcinoma of the esophagus and stomach

Iron can cause oxidative stress and DNA damage, and heme iron can catalyze endogenous formation of N-nitroso compounds, which are potent carcinogens. Dietary iron promotes esophageal cancer incidence in animal studies and has been identified as a growth factor for Helicobacter pylori, an established risk factor for stomach cancer. We conducted a population-based case-control study of adenocarcinoma of the esophagus (n=124) and stomach (n=154) and 449 controls in Nebraska. Heme iron and total iron intake were estimated from a food frequency questionnaire and databases of heme and total iron. We used logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for known risk factors. Esophageal cancer was positively associated with higher intakes of heme iron (ORQ4 vs. Q1=3.04, 95% CI: 1.20-7.72; P trend=0.009) and total iron from meat sources (ORQ4 vs. Q1=2.67, 95% CI: 0.99-7.16; P trend=0.050). Risk of stomach cancer was elevated among those with higher intakes of heme iron (ORQ4 vs.Q1=1.99, 95% CI: 1.00-3.95; P trend=0.17) and total iron from meat (OR=2.26, 95% CI: 1.14-4.46; P trend=0.11). Iron intake from all dietary sources was not significantly associated with risk of either cancer. Our results suggest that high intakes of heme and iron from meat may be important dietary risk factors for esophageal and stomach cancer and may partly explain associations with red meat.