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

The protective effect of dietary folate intake on gastric cancer is modified by alcohol consumption: A pooled analysis of the StoP Consortium

Dietary folate intake has been identified as a potentially modifiable factor of gastric cancer (GC) risk, although the evidence is still inconsistent. We evaluate the association between dietary folate intake and the risk of GC as well as the potential modification effect of alcohol consumption. We pooled data for 2829 histologically confirmed GC cases and 8141 controls from 11 case-control studies from the international Stomach Cancer Pooling Consortium. Dietary folate intake was estimated using food frequency questionnaires. We used linear mixed models with random intercepts for each study to calculate adjusted odds ratios (OR) and 95% confidence interval (CI). Higher folate intake was associated with a lower risk of GC, although this association was not observed among participants who consumed >2.0 alcoholic drinks/day. The OR for the highest quartile of folate intake, compared with the lowest quartile, was 0.78 (95% CI, 0.67-0.90, P-trend = 0.0002). The OR per each quartile increment was 0.92 (95% CI, 0.87-0.96) and, per every 100 μg/day of folate intake, was 0.89 (95% CI, 0.84-0.95). There was a significant interaction between folate intake and alcohol consumption (P-interaction = 0.02). The lower risk of GC associated with higher folate intake was not observed in participants who consumed >2.0 drinks per day, ORQ4v Q1 = 1.15 (95% CI, 0.85-1.56), and the OR100 μg/day = 1.02 (95% CI, 0.92-1.15). Our study supports a beneficial effect of folate intake on GC risk, although the consumption of >2.0 alcoholic drinks/day counteracts this beneficial effect.

Protective effect of dietary micronutrients on gastric cancer risk among Jordanians

Introduction

Objective: several dietary and non-dietary factors and genetic predisposition may play an important role in gastric carcinogenesis. The findings about associations between micronutrients and gastric cancer (GC) is still inconsistent. This study aimed to investigate the effect of dietary micronutrients on gastric cancer risk. Methods: a case-control study comprised of 173 GC (107 males: 66 females) patients and 313 (190 males: 123 females) population-based controls matched for age, occupation, and marital status. Demographics, medical history, physical activity, and nutrient intake information were collected using reliable interview-based questionnaires. Information on dietary micronutrient intake was collected from the participants using a validated food frequency questionnaire (FFQ). Multinomial logistic regression was used to calculate Odds ratios (ORs) and their corresponding 95 % confidence intervals (CIs) and evaluate associations between dietary micronutrients and GC risk. Results: GC was inversely associated with the consumption of vitamin A, beta-carotene, vitamins D, E, K, B2, B3, B6, B12, and C, folate, chromium, iodine, and selenium. Additionally, a protective effect was observed for consumption of calcium, copper, iron, magnesium, phosphate, sodium, and zinc. In almost all the micronutrients, the second tertile showed a more pronounced reduction in GC risk as compared to the first tertile. Conclusions: our data support favorable effects of dietary consumption of some vitamins and minerals against GC risk.

Scientific opinion on the tolerable upper intake level for folate

Following a request from the European Commission (EC), the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver a scientific opinion on the revision of the tolerable upper intake level (UL) for folic acid/folate. Systematic reviews of the literature were conducted to assess evidence on priority adverse health effects of excess intake of folate (including folic acid and the other authorised forms, (6S)-5-methyltetrahydrofolic acid glucosamine and l-5-methyltetrahydrofolic acid calcium salts), namely risk of cobalamin-dependent neuropathy, cognitive decline among people with low cobalamin status, and colorectal cancer and prostate cancer. The evidence is insufficient to conclude on a positive and causal relationship between the dietary intake of folate and impaired cognitive function, risk of colorectal and prostate cancer. The risk of progression of neurological symptoms in cobalamin-deficient patients is considered as the critical effect to establish an UL for folic acid. No new evidence has been published that could improve the characterisation of the dose-response between folic acid intake and resolution of megaloblastic anaemia in cobalamin-deficient individuals. The ULs for folic acid previously established by the Scientific Committee on Food are retained for all population groups, i.e. 1000 μg/day for adults, including pregnant and lactating women, 200 μg/day for children aged 1-3 years, 300 μg/day for 4-6 years, 400 μg/day for 7-10 years, 600 μg/day for 11-14 years and 800 μg/day for 15-17 years. A UL of 200 μg/day is established for infants aged 4-11 months. The ULs apply to the combined intake of folic acid, (6S)-5-methyltetrahydrofolic acid glucosamine and l-5-methyltetrahydrofolic acid calcium salts, under their authorised conditions of use. It is unlikely that the ULs for supplemental folate are exceeded in European populations, except for regular users of food supplements containing high doses of folic acid/5-methyl-tetrahydrofolic acid salts.

Diet and Esophageal Cancer Risk: An Umbrella Review of Systematic Reviews and Meta-Analyses of Observational Studies

Diet may play an important role in the occurrence of esophageal cancer (EC). The aim of this umbrella review was to grade the evidence for the association between dietary factors and EC risk. A protocol for this review was registered with the PROSPERO database (CRD42021283232). Publications were identified by searching PubMed, EMBASE, Web of Science, Cochrane Database of Systematic Reviews, and CINAHL databases. Only systematic reviews and meta-analyses of observational studies (cohort studies, case-cohort studies, nested case-control studies) were eligible. AMSTAR-2 (A Measurement Tool to Assess Systematic Reviews) was used to assess the methodological quality of included systematic reviews. For each association, random-effects pooled effect size, 95% CI, number of cases, 95% prediction interval, heterogeneity, small-study effect, and excess significance bias were calculated to grade the evidence. From 882 publications, 107 full-text articles were evaluated for eligibility, and 20 systematic reviews and meta-analyses describing 32 associations between dietary factors and EC risk were included in the present umbrella review. By assessing the strength and validity of the evidence, 1 association (positively associated with alcohol intake) was supported by highly suggestive evidence and 1 (inversely associated with calcium intake) showed a suggestive level of evidence. Evidence for 7 associations was weak (positively associated with red meat and processed-meat intake; inversely associated with whole grains, fruits, green leafy vegetables, green tea, and zinc intake). The remaining 23 associations were nonsignificant. In conclusion, the findings of this umbrella review emphasize that habitually consuming calcium, whole grains, fruits, green leafy vegetables, green tea, and zinc and reducing alcohol, red meat, and processed-meat intake are associated with a lower risk of EC. Since this umbrella review included only observational study data and some of the associations were graded as weak, caution should be exercised in interpreting these relations.

Folic Acid Inhibited Vasculogenic Mimicry in Esophageal Cancer Cell Line Eca-109, the One Target Was EphA2

The degree of vasculogenic mimicry(VM) is correlated with the prognosis of esophageal cancer, and folic acid supplementation could decrease esophagus cancer deaths among populations. This study aimed to explore the effect of folic acid on VM formation of esophageal cancer cell, and the target. Human esophageal squamous cancer cell lines(Eca-109) were cultured with different concentrations of folic acid (0,1,10,100,200,400, 600,800 μg/ml). A cell counting kit-8 (CCK-8) assay was used to measure the cell proliferation. Then, the amount of VM under the effect of different concentrations of folic acid was observed. Target genes were screened out from several possible targets genes including MMP2, MMP9, EphA2, VE-cad or Ln-5γ2 by employing reverse transcription-quantitative polymerase chain reaction(RT-qPCR). Finally, western blot analysis was used to verify the target proteins. In conclusion, this study found that folic acid inhibited the formation of VM in Eca-109 cells, and the one target protein was EphA2.

Folate Intake and Risk of Pancreatic Cancer: A Systematic Review and Updated Meta-Analysis of Epidemiological Studies

INTRODUCTION

Pancreatic cancer is one of the most fatal malignancies and primary prevention strategies are limited. Epidemiological studies focusing on the association between folate intake and pancreatic cancer risk have reported inconsistent findings.

METHODS

A systematic search of the literature was conducted using the PubMed and EMBASE databases. A systematic review and meta-analysis of eligible studies was performed to assess the association between folate intake and risk of pancreatic cancer.

RESULTS

A total of 16 studies involving 5654 cases and 1,009,374 individuals were included. The result showed a significant association of folate intake with a decreased risk of pancreatic cancer, with a pooled OR of 0.82 (95% CI: 0.69-0.97, P = 0.019) for the highest category of intake vs. the lowest. The data suggested that high intake of folate may contribute to the prevention of pancreatic cancer. However, the association was observed only in case-control studies (OR = 0.78, 95% CI: 0.65-0.93, P = 0.006), but not in cohort studies (RR = 0.85, 95% CI: 0.66-1.09, P = 0.244). Dose-response meta-analysis showed that an increment of folate intake (100 μg/day) was marginally associated with the risk of pancreatic cancer, with a pooled OR of 0.97 (95% CI: 0.93-1.00, P = 0.053).

CONCLUSION

High folate intake might be inversely associated with pancreatic cancer risk, which needs to be confirmed.

The association of dietary β-carotene and vitamin A intake on the risk of esophageal cancer: a meta-analysis

BACKGROUND AND PURPOSE

dietary β-carotene and vitamin A intake have shown some potential effect in the development of esophageal cancer. This meta-analysis was performed to investigate the association of β-carotene and vitamin A intake on the risk of esophageal cancer.

METHODS

the PubMed, Embase, Web of Science and Wanfang Med online databases were systematically searched to collect the relevant articles regarding the impact of β-carotene and vitamin A intake on esophageal cancer risk. Pooled odds ratios (OR) with 95 % confidence intervals (CI) were combined using the Review Manager Version 5.3 software.

RESULTS

this meta-analysis included 14 articles. The highest category of β-carotene intake may significantly reduce the risk of esophageal cancer compared with the lowest category (OR = 0.62, 95 % CI = 0.50-0.77). Similar significant results were found in American and European populations but not in other populations with β-carotene intake. An inverse association was found between vitamin A intake and esophageal cancer risk (OR = 0.79, 95 % CI = 0.63-0.99). No potential publication bias was detected.

CONCLUSIONS

our study suggested that dietary β-carotene and vitamin A intake may reduce the risk of esophageal cancer. More relevant studies are needed to further explore this association, as there were some limitations in our analysis.

Riboflavin intake, MTRR genetic polymorphism (rs1532268) and gastric cancer risk in a Korean population: a case-control study

The vitamin B group, including riboflavin, plays paramount roles in one-carbon metabolism (OCM), and disorders related to this pathway have been linked to cancer development. The variants of genes encoding OCM enzymes and the insufficiency of B vitamins could contribute to carcinogenesis. Very few observational studies have revealed a relationship between riboflavin and gastric cancer (GC), especially under conditions of modified genetic factors. We carried out a study examining the association of riboflavin intake and its interaction with MTRR (rs1532268) genetic variants with GC risk among 756 controls and 377 cases. The OR and 95 % CI were evaluated using unconditional logistic regression models. We observed protective effects of riboflavin intake against GC, particularly in the female subgroup (OR = 0·52, 95 % CI 0·28, 0·97, Ptrend = 0·031). In the MTRR (rs1532268) genotypes analysis, the dominant model showed that the effects of riboflavin differed between the CC and CT + TT genotypes. Compared with CC carriers, low riboflavin intake in T+ carriers was significantly associated with a 93 % higher GC risk (OR = 1·93, 95 % CI 1·09, 3·42, Pinteraction = 0·037). In general, higher riboflavin intake might help reduce the risk of GC in both CC and TC + TT carriers, particularly the T+ carriers, with marginal significance (OR = 0·54, 95 % CI 0·28, 1·02, Pinteraction = 0·037). Our study indicates a protective effect of riboflavin intake against GC. Those who carry at least one minor allele and have low riboflavin intake could modify this association to increase GC risk in the Korean population.

Dietary carbohydrate intake and the risk of esophageal cancer: a meta-analysis

BACKGROUND

Previous studies had been published to explore the association about carbohydrate intake on esophageal cancer risk, with inconsistent results. This meta-analysis aimed to assess the association between dietary carbohydrate intake and the risk of esophageal cancer.

METHODS

Suitable studies were carefully searched with the databases of PubMed, Embase, the Cochrane Library, and Wanfang Database. A random-effects model was used for combined odds ratio (OR) and 95% confidence interval (CI). Stata software 14.0 was adopted for the analysis.

RESULTS

At the end, 13 publications were included in our study. Pooled results suggested that highest category versus lowest category of carbohydrate intake could reduce the risk of esophageal cancer (summarized OR = 0.627, 95% CI = 0.505-0.778, I2 = 59.9%, Pfor heterogeneity = 0.001). The results for carbohydrate intake on the risk of esophageal adenocarcinoma (summarized OR = 0.569, 95% CI = 0.417-0.777) and esophageal squamous cell carcinoma (summarized OR = 0.665, 95% CI = 0.453-0.975) were consistent with the overall result. A positive association was found in European, Asian, North American populations, instead of South American populations.

CONCLUSIONS

In conclusions, dietary carbohydrate intake may have a protective effect against the risk of esophageal cancer.

Association Between Folate and Health Outcomes: An Umbrella Review of Meta-Analyses

Background: There is no study that has systematically investigated the breadth and validity of the associations of folate and multiple health outcomes. We aimed to evaluate the quantity, validity, and credibility of evidence regarding associations between folate and multiple health outcomes by using umbrella review of meta-analysis. Methods: We searched the MEDLINE, EMBASE, and Cochrane Library databases from inception to May 20, 2018, to identify potential meta-analyses that examined the association of folate with any health outcome. For each included meta-analysis, we estimated the summary effect size and their 95% confidence interval using the DerSimonian and Laird random-effects model. We used the AMSTAR 2 (A Measurement Tool to Assess Systematic Reviews) to assess methodological quality and the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation working group classification) to assess the quality of evidence for each outcome included in the umbrella review. Results: Overall, 108 articles reporting 133 meta-analyses of observational studies and 154 meta-analyses of randomized controlled trials (RCTs) were included in the study. Among them, 108 unique exposure-outcome-population triplets (referred to as unique meta-analyses hereafter) of RCTs and 87 unique meta-analyses of observational studies were reanalyzed. Beneficial effects of folate were observed in the all-cause mortality rate and in a number of chronic diseases, including several birth/pregnancy outcomes, several cancers, cardiovascular disease and metabolic-related outcomes, neurological conditions, and several other diseases. However, adverse effects of folate were observed for prostate cancer, colorectal adenomatous lesions, asthma or wheezing, and wheezing as an isolated symptom and depression. Conclusions: Current evidence allows for the conclusion that folate is associated with decreased risk of all-cause mortality and a wide range of chronic diseases. However, folate may be associated with an increased risk of prostate cancer. Further research is warranted to improve the certainty of the estimates.

Gene Polymorphisms Involved in Folate Metabolism and DNA Methylation with the Risk of Head and Neck Cancer

BACKGROUND

Folate is essential for DNA synthesis, repair, and methylation. Polymorphisms in genes associated with folate metabolism may alter these processes and, consequently, modulate cancer development.

AIM

We aimed to assess DNMT3B -149C/T (rs2424913), DNMT3B -283T/C (rs6087990), DNMT3B -579G/T (rs2424909), DHFR 19-pb ins/del (rs70991108), SHMT1 1420C/T (rs1979277), and TYMS 28-bp tandem repeat (rs34743033) polymorphisms with risk of head and neck cancer.

METHODS

A case-control study was conducted in 1,086 Brazilian individuals. Real-time and conventional polymerase chain reactions-PCR were performed for genotyping the polymorphisms.

RESULTS

The single nucleotide polymorphism (SNP), DNMT3B -283T/C, revealed a higher risk of head and neck squamous cell carcinoma (HNSCC) when compared with the C group in the codominant (p < 0.001), dominant (p <0.001), and overdominant (p= 0.001) models for T/C and C/C genotypes. DNMT3B -149C/T and DNMT3B -579G/T revealed no association between groups in any model. The DHFR 19-pb ins/del polymorphism protected against HNSCC development compared to the C group by the codominant (p < 0.001), dominant (p < 0.001), and overdominant (p < 0.001) models. In the TYMS, the 3R/3R genotype had a protective effect against HNSCC development compared with the C group by the recessive models (p= 0.009). In contrast, SHMT1 1420 C/T presented no association between the HNSCC and C groups. DHFR 19-pb ins/del polymorphisms protected against oral cavity cancer (p= 0.003), and only TYMS-28 3R/3R decreased the risk of tumor progression (p= 0.023). In the Kaplan-Meier curve, an association was found between DHFR ins/ins and TYMS -28 3R carriers with respect to relapse-free time; further, DNMT3B -579 T and TYMS-28 2R/2R carriers had longer survival times.

CONCLUSION

DNMT3B -283T/C is associated with higher risk, whereas DHFR 19-pb ins/del and TYMS 28 3R/3R protect against head and neck cancer. We also highlighted the association of TYMS 3R/3R genotype carriers with relapse-free cancer protection and survival time.

The association between dietary protein intake and esophageal cancer risk: a meta-analysis

Several papers studied dietary protein intake as a potential influence factor for esophageal cancer, but their findings were inconsistent. Thus, this meta-analysis was performed to identify the effect of protein intake on esophageal cancer risk. Potential case–control studies or cohort studies from the databases of Embase, Web of Science and PubMed were searched. The strength of association was quantified by pooling odds ratio (OR) and 95% confidence interval (CI). In total, 11 articles involving 2537 cases and 11432 participants were included in this meta-analysis. As a result, dietary protein intake had non-significant association on esophageal cancer risk overall (pooled OR = 1.11, 95% CI = 0.88–1.40). Meanwhile, we obtained consistent results in the subgroups analyses by study design, protein type, geographic locations and number of cases. Interestingly, dietary protein intake could significantly increase the risk of esophageal squamous cell carcinoma (pooled OR = 1.29, 95% CI = 1.02–1.62), instead of other disease type. To sum up, dietary protein intake had no significant association with esophageal cancer risk in the overall analysis; but, protein intake may be associated with the risk of esophageal squamous cell carcinoma. While some limitations existed in the present paper, more studies with large sample size are warranted to further confirm this result.

Effect of dietary cholesterol intake on the risk of esophageal cancer: a meta-analysis

Objective

This systematic review aimed to explore the potential association between dietary cholesterol intake and esophageal cancer risk.

Methods

A literature search was conducted using PubMed, Embase, and Web of Science databases from inception to March 2019 according to specific inclusion and exclusion criteria. Pooled estimates with odds ratio (ORs) and 95% confidence intervals (CIs) were obtained using random effects models.

Results

Nine articles of 12 independent studies were included in the final meta-analysis. Pooled analysis suggested that dietary cholesterol intake may increase the risk of esophageal cancer (summarized OR = 1.424, 95% CI = 1.191–1.704). Consistent results were found in American (summarized OR = 1.410, 95% CI = 1.130–1.758) and European populations (summarized OR = 1.556, 95% CI = 1.021–2.373). Subgroup analysis by disease type showed that dietary cholesterol intake had a significant association with the development of esophageal adenocarcinoma and esophageal squamous cell carcinoma.

Conclusion

Our findings indicated that dietary cholesterol intake could significantly increase the risk of developing esophageal cancer in both European and American populations. Further high-quality studies are necessary to confirm the effects of cholesterol intake.

Global Patterns and Trends in Pancreatic Cancer Incidence: Age, Period, and Birth Cohort Analysis

OBJECTIVES

We aim to provide a global geographical picture of pancreatic cancer incidence and temporal trends from 1973 to 2015 for 41 countries.

METHODS

Joinpoint regression and age-period-cohort model was used.

RESULTS

In 2012, the highest age-adjusted rate was in Central and Eastern Europe for males and North America for females. Most regions showed sex disparities. During the recent 10 years, increasing trends were observed in North America, Western Europe, and Oceania. The greatest increase occurred in France. For recent birth cohorts, cohort-specific increases in risk were pronounced in Australia, Austria, Brazil, Canada, Costa Rica, Denmark, Estonia, France, Israel, Latvia, Norway, Philippines, Republic of Korea, Singapore, Spain, Sweden, the Netherlands, United States, and US white male populations and in Australia, Austria, Brazil, Bulgaria, Canada, China, Czech Republic, Finland, France, Italy, Japan, Lithuania, Norway, Republic of Korea, Singapore, Spain, The Netherlands, United Kingdom, United States, and US white female populations.

CONCLUSIONS

In contrast to the favorable effect of the decrease in smoking prevalence, other factors, including the increased prevalence of obesity and diabetes and increased physical inactivity, increased intake of red or processed meat and inadequate intake of fruits and vegetables are likely to have an unfavorable role in pancreatic cancer incidence worldwide.

Tea consumption is associated with decreased risk of oral cancer: A comprehensive and dose-response meta-analysis based on 14 case-control studies (MOOSE compliant)

The associations of tea consumption with risk of oral cancer remain not clear. The present meta-analysis aims to clarify the real relationship between tea intake and the risk of oral cancer and quantifies the potential dose-response relationship between them.A Web search was performed within Pubmed, Embase, and Web of Science databases to identify potential studies that evaluated the relationship between tea consumption and the risk of oral cancer on Mar 21th, 2018 without language restriction. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were extracted and combined to evaluate the strength of associations. Dose-response analysis was performed to quantitate the relationship between tea intake and risk of oral cancer.Total 14 articles were included in the final analysis. The pooled OR for evaluating the risk of oral cancer and tea intake was 0.700 (95% CI = 0.609-0.805, P <.001). The linearity model of dose-response analysis indicated that with increased 1 cup daily, the risk of oral cancer decreased by 6.2% degree (OR = 0.938, 95% CI = 0.922-0.955, P <.001). Subgroup analysis indicated an inverse association between tea intake and the risk of oral cancer except subgroup analysis of black tea and American people.These results suggest tea intake provides protection against oral cancer carcinogenesis. Additionally, more large-scale pooling and high-quality studies are necessary for detecting the precise relationship between tea intake and oral cancer risk in the future.

Intake of Dietary One-Carbon Metabolism-Related B Vitamins and the Risk of Esophageal Cancer: A Dose-Response Meta-Analysis

Several B vitamins are essential in the one-carbon metabolism pathway, which is central to DNA methylation, synthesis, and repair. Moreover, an imbalance in this pathway has been linked to certain types of cancers. Here, we performed a meta-analysis in order to investigate the relationship between the intake of four dietary one-carbon metabolism-related B vitamins (B2, B6, folate, and B12) and the risk of esophageal cancer (EC). We searched PubMed, Web of Science, and Embase for relevant studies published through 1 March 2018. The odds ratio (OR) with 95% confidence interval (CI) for the highest versus the lowest level of each dietary B vitamin was then calculated. From 21 articles reporting 26 studies including 6404 EC cases and 504,550 controls, we found an inverse correlation between the consumption of vitamin B6 and folate and the risk of EC; this association was specific to the US, Europe, and Australia, but was not found in Asia. A dose-response analysis revealed that each 100 μg/day increase in folate intake reduced the risk of EC by 12%. Moreover, each 1 mg/day increase in vitamin B6 intake decreased the risk of EC by 16%. Surprisingly, we found that each 1 μg/day increase in vitamin B12 intake increased the risk of esophageal adenocarcinoma by 2%, particularly in the US and Europe, suggesting both geographic and histological differences. Together, our results suggest that an increased intake of one-carbon metabolism-related B vitamins may protect against EC, with the exception of vitamin B12, which should be consumed in moderation.