The risk of Barrett's esophagus associated with abdominal obesity in males and females

Risk factors for Barrett's esophagus: Recent advances

Esophageal adenocarcinoma (EAC) is the most common malignant tumor of the esophagus in the West. During the past few decades, its morbidity has been increasing in China. Barrett's esophagus (BE) is defined as the replacement of normal squamous epithelium in the lower esophagus by metaplasia of columnar epithelium. BE is closely related to the occurrence of EAC. Knowledge regarding the risk factors for the occurrence and development of BE is of great significance for early screening and diagnosis of BE and prevention of EAC. In this paper, we review the clinical, demographics-related, lifestyle-related, and medications-related risk factors for BE to provide more valuable scientific evidence for the prevention and treatment of BE.

Lifestyle interventions can reduce the risk of Barrett's esophagus: a systematic review and meta-analysis of 62 studies involving 250,157 participants

Background

Barrett's esophagus (BE) is a well‐established risk factor for esophageal adenocarcinoma. Our objective was to investigate the effectiveness of lifestyle interventions on BE risk.

Methods

We searched PubMed, Embase, and Web of Science up to 30 September 2020. The summary relative risks (RRs) and 95% confidence intervals (CIs) for the highest versus lowest categories of exposure were assessed. Analyses of subgroup, dose–response, sensitivity, and publication bias were conducted.

Results

Sixty‐two studies were included that involved more than 250,157 participants and 22,608 cases. Seven lifestyle factors were investigated: smoking, alcohol, body mass index (BMI), physical activity, sleep time, medication, and diet. We observed statistically significant increased BE risks for smoking (RR = 1.35, 95% CI = 1.16–1.57), alcohol intake (RR = 1.23, 95% CI = 1.13–1.34), body fatness (RR = 1.08, 95% CI = 1.03–1.13), less sleep time (RR = 1.76, 95% CI = 1.24–2.49), and proton pump inhibitors use (RR = 1.64, 95% CI = 1.17–2.29). Reduced risks of BE were found for aspirin (RR = 0.70, 95% CI = 0.58–0.84) and the intake of vitamin C (RR = 0.59, 95% CI = 0.44–0.80), folate (RR = 0.47, 95% CI = 0.31–0.71), and fiber (RR = 0.95, 95% CI = 0.93–0.97). The quality of most included studies was high and the subgroup analysis according to the quality score showed significant results (p < 0.05). There was no publication bias for smoking and alcohol. Although the analysis suggested significant evidence of publication bias for BMI, sensitivity analysis showed that the changes in the recalculated RRs were not significant.

Conclusions

The large meta‐analysis revealed that lifestyle modifications could reduce the risks of BE and, consequently, esophageal adenocarcinoma.

Visceral Obesity, Metabolic Syndrome, and Esophageal Adenocarcinoma

Esophageal adenocarcinoma (EAC) represents an exemplar of obesity-associated carcinogenesis, with a progressive increase in EAC risk with increased body mass index. In this context, there is increased focus on visceral adipose tissue and associated metabolic dysfunction, including hypertension, diabetes mellitus and hyperlipidemia, or combinations of these in the metabolic syndrome. Visceral obesity (VO) may promote EAC via both directly impacting on gastro-esophageal reflux disease and Barrett's esophagus, as well as via reflux-independent effects, involving adipokines, growth factors, insulin resistance, and the microbiome. In this review these pathways are explored, including the impact of VO on the tumor microenvironment, and on cancer outcomes. The current evidence-based literature regarding the role of dietary, lifestyle, pharmacologic and surgical interventions to modulate the risk of EAC is explored.

Sex Differences in the Risk of Barrett's Esophagus Associated With the Metabolic Effects of Obesity

GOAL

The goal of this study was to determine if there is an association between the insulin-insulin-like growth factor axis, the metabolic syndrome (MetS), type 2 diabetes mellitus and risk of Barrett's esophagus (BE), and if these associations are modified by sex.

BACKGROUND

BE is more common in males. Gastroesophageal reflux disease, the major risk factor for BE occurs at similar frequencies in both sexes, suggesting that sex-related factors such as the metabolic effects of abdominal obesity may be important in the causation of BE.

MATERIALS AND METHODS

A structured interview, anthropometric measures, and fasting blood were collected within a population-based case-control study. We recruited 227 BE cases (70% male) and 241 population controls, frequency matched by age and sex. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) for association with BE using multivariable logistic regression models.

RESULTS

Hyperinsulinemia (highest vs. lowest tertile, OR=1.9; 95% CI: 1.2-3.1), Homeostatic Model Assessment of Insulin Resistance (OR=1.9; 95% CI: 1.2-3.1) and the MetS (OR=1.8; 95% CI: 1.2-2.6) were independently associated with an increased risk of BE. With each additional MetS criterion, there was a 20% increased risk of BE (OR=1.2; 95% CI: 1.0-1.4). When stratified by sex, these associations were found in males but not females. We found no association with serum measures of insulin-like growth factors or interleukin-6 and risk of BE.

CONCLUSION

Hyperinsulinemia, insulin resistance, and the MetS are associated with the risk of BE in males but not females, suggesting these factors may contribute to the higher prevalence of BE in males.

Proton Pump Inhibitors and Radiofrequency Ablation for Treatment of Barrett's Esophagus

Gastroesophageal Reflux Disease (GERD) is characterized by acid and bile reflux in the distal oesophagus, and this may cause the development of reflux esophagitis and Barrett's oesophagus (BE). The natural histological course of untreated BE is non-dysplastic or benign BE (ND), then lowgrade (LGD) and High-Grade Dysplastic (HGD) BE, with the expected increase in malignancy transfer to oesophagal adenocarcinoma (EAC). The gold standard for BE diagnostics involves high-resolution white-light endoscopy, followed by uniform endoscopy findings description (Prague classification) with biopsy performance according to Seattle protocol. The medical treatment of GERD and BE includes the use of proton pump inhibitors (PPIs) regarding symptoms control. It is noteworthy that long-term use of PPIs increases gastrin level, which can contribute to transfer from BE to EAC, as a result of its effects on the proliferation of BE epithelium. Endoscopy treatment includes a wide range of resection and ablative techniques, such as radio-frequency ablation (RFA), often concomitantly used in everyday endoscopy practice (multimodal therapy). RFA promotes mucosal necrosis of treated oesophagal region via high-frequency energy. Laparoscopic surgery, partial or total fundoplication, is reserved for PPIs and endoscopy indolent patients or in those with progressive disease. This review aims to explain distinct effects of PPIs and RFA modalities, illuminate certain aspects of molecular mechanisms involved, as well as the effects of their concomitant use regarding the treatment of BE and prevention of its transfer to EAC.

Interactive decision support for esophageal adenocarcinoma screening and surveillance

Background

A key barrier to controlling esophageal adenocarcinoma (EAC) is identifying those most likely to benefit from screening and surveillance. We aimed to develop an online educational tool, termed IC-RISC™, for providers and patients to estimate more precisely their absolute risk of developing EAC, interpret this estimate in the context of risk of dying from other causes, and aid in decision-making.

Results

U.S. incidence and mortality data and published relative risk estimates from observational studies and clinical trials were used to calculate absolute risk of EAC over 10 years adjusting for competing risks. These input parameters varied depending on presence of the key precursor, Barrett’s esophagus. The open source application works across common devices to gather risk factor data and graphically illustrate estimated risk on a single page. Changes to input data are immediately reflected in the colored graphs. We used the calculator to compare the risk distribution between EAC cases and controls from six population-based studies to gain insight into the discrimination metrics of current practice guidelines for screening, observing that current guidelines sacrifice a significant amount of specificity to identify 78–86% of eventual cases in the US population.

Conclusions

This educational tool provides a simple and rapid means to graphically communicate risk of EAC in the context of other health risks, facilitates “what-if” scenarios regarding potential preventative actions, and can inform discussions regarding screening, surveillance and treatment options. Its generic architecture lends itself to being easily extended to other cancers with distinct pathways and/or intermediate stages, such as hepatocellular cancer. IC-RISC™ extends current qualitative clinical practice guidelines into a quantitative assessment, which brings the possibility of preventative actions being offered to persons not currently targeted for screening and, conversely, reducing unnecessary procedures in those at low risk. Prospective validation and application to existing well-characterized cohort studies are needed.

Electronic supplementary material

The online version of this article (10.1186/s12876-019-1022-0) contains supplementary material, which is available to authorized users.

Gene-Environment Interactions and the Risk of Barrett's Esophagus in Three US Cohorts

OBJECTIVES

Several single-nucleotide polymorphisms (SNPs) have been associated with Barrett's esophagus (BE) risk. In addition, environmental factors including smoking, alcohol consumption, and heartburn increase BE risk. However, data on potential interactions between these genetic and environmental factors on BE risk are scant. Understanding how genes and environmental risk factors interact may provide key insight into the pathophysiology of BE, and potentially identify opportunities for targeted prevention and treatment. The objectives of this study were to examine the main effects and the potential effect modification between known genetic loci (SNPs) and established environmental risk factors for BE.

METHODS

We performed a nested case-control study using data on 401 incident BE cases and 436 age-matched controls from the Nurses' Health Study, Nurses' Health Study II, and Health Professionals Follow-up Study cohorts, who gave blood and completed biennial questionnaires. Overall, we genotyped 46 SNPs identified in previous BE genome-wide association studies as well as SNPs in candidate genes related to BE susceptibility (i.e., related to excess body fat, fat distribution, factors associated with insulin resistance, and inflammatory mediators). A genetic risk score (GRS) was constructed to evaluate the combined effect of the selected SNPs on BE risk. Interactions between SNPs and BE risk factors were also assessed.

RESULTS

We observed a suggestive, but not statistically significant, association between our GRS and BE risk: a one-allele increase in the unweighted GRS increased the risk of BE by a factor of 1.20 (95% confidence interval = 1.00-1.44; P = 0.057). We did not observe any meaningful multiplicative interactions between smoking, alcohol consumption, or heartburn duration and BE genotypes. When we assessed the joint effect of weighted GRS and BE risk factors, we did not observe any significant interaction with alcohol and heartburn duration, whereas smoking showed a significant multiplicative interaction (P = 0.016).

CONCLUSIONS

Our results suggest that SNPs associated with BE at genome-wide significant levels can be combined into a GRS with a potential positive association with BE risk.

Impact of Obesity on a Chinese Population with Erosive Esophagitis and Barrett's Esophagus

Background/Aims

The aim of this study was to investigate the associations between obesity and erosive esophagitis (EE) or Barrett's esophagus (BE) in a Chinese population.

Methods

Data from subjects were retrospectively collected from 2006 to 2009. Individuals with BE were identified and age- and sex-matched at a 1:2 ratio with normal esophagocardial junction and EE patients. The subjects were stratified into two groups: the normal weight group and overweight/ obesity group (body mass index ≥25 mg/m²) or the normal waist group and abdominal obesity group (waist circumference ≥90 cm for men and ≥80 cm for women).

Results

Overall, 45%, 72%, and 52% were overweight/obese and 23%, 65%, and 18% had abdominal obesity in the normal, EE, and BE groups, respectively. Positive associations were identified between EE and overweight/obesity (odds ratio [OR], 3.14; 95% confidence interval [CI], 1.75 to 5.66) and abdominal obesity (OR, 6.22; 95% CI, 3.34 to 11.57); however, the associations were nonsignificant between BE and overweight/obesity (OR, 1.32; 95% CI, 0.67 to 2.61) or abdominal obesity (OR, 0.73; 95% CI, 0.31 to 1.73). Female BE patients had a significantly increased rate of being overweight/obese.

Conclusions

Obesity is a contributing factor in EE. The association of BE and obesity was not significant, with the exception of female BE cases.

Effects of socioeconomic status on esophageal adenocarcinoma stage at diagnosis, receipt of treatment, and survival: A population-based cohort study

The incidence of esophageal adenocarcinoma (EAC) is increasing worldwide and has overtaken squamous histology in occurrence. We studied the impact of socioeconomic status (SES) on EAC stage at diagnosis, receipt of treatment, and survival. A population-based retrospective cohort study was conducted using Ontario Cancer Registry-linked administrative health data. Multinomial logistic regression was used to examine the association between SES (income quintile) and stage at EAC diagnosis and EAC treatment. Survival times following EAC diagnosis were estimated using Kaplan-Meier method. Cox proportional-hazards regression analysis was used to examine the association between SES and EAC survival. Between 2003–2012, 2,125 EAC cases were diagnosed. Median survival for the lowest-SES group was 10.9 months compared to 11.6 months for the highest-SES group; the 5-year survival was 9.8% vs. 15.0%. Compared to individuals in the highest-SES group, individuals in the lowest-SES category experienced no significant difference in EAC treatment (91.6% vs. 93.3%, P = 0.314) and deaths (78.9% vs. 75.6%, P = 0.727). After controlling for covariates, no significant associations were found between SES and cancer stage at diagnosis and EAC treatment. Additionally, after controlling for age, gender, urban/rural residence, birth country, health region, aggregated diagnosis groups, cancer stage, treatment, and year of diagnosis, no significant association was found between SES and EAC survival. Moreover, increased mortality risk was observed among those with older age (P = 0.001), advanced-stage of EAC at diagnosis (P < 0.001), and those receiving chemotherapy alone, radiotherapy alone, or surgery plus chemotherapy (P < 0.001). Adjusted proportional-hazards model findings suggest that there is no association between SES and EAC survival. While the unadjusted model suggests reduced survival among individuals in lower income quintiles, this is no longer significant after adjusting for any covariate. Additionally, there is an apparent association between SES and survival when considering only those individuals diagnosed with stage 0-III EAC. These analyses suggest that the observed direct relationship between SES and survival is explained by patient-level factors including receipt of treatment, something that is potentially modifiable.

Insulin promotes HER2 signaling activation during Barrett's Esophagus carcinogenesis

BACKGROUND

Insulin-resistance and hyperinsulinemia could have a role in the growing incidence of esophageal adenocarcinoma (EAC) and its pre-cancerous lesion Barrett's Esophagus (BE). HER2 activation has also a pivotal role in EAC carcinogenesis but no data correlate these two phenomena in this disease context.

AIMS

To investigate the role of hyperinsulinemia in BE-dysplasia-adenocarcinoma sequence and the possible relationship between insulin-mediated and HER2 signaling in EAC development.

METHODS

Serum insulin, C-peptide, IGF1, glucagon, IL-6, TNF-alpha, leptin, adiponectin and Insulin-Resistance-index were analyzed in 19 patients with gastro-esophageal reflux disease, 51 with BE, 24 with dysplastic-BE and 14 with EAC. Insulin/IGF1/HER2 pathways were analyzed in esophageal biopsies using Luminex^® Technology. Insulin effect was also evaluated in EAC-derived OE19 cells. Data were analyzed by Fisher's exact test, Kruskal-Wallis test, Mann-Whitney U-test, Cuzick's test and Spearman correlation coefficient calculation.

RESULTS

Insulin-Resistance-index, insulin and C-peptide levels increased along with disease progression (p=0.019, p=0.002, p<0.0001, respectively) and correlated with HER2 expression and with downstream mediators phospho-Akt and phospho-mTOR in esophageal tissue. In vitro, insulin was also able to induce cell proliferation through HER2 activation.

CONCLUSIONS

Our data pinpoint a possible role of hyperinsulinemia in the Barrett's Esophagus metaplasia-dysplasia-adenocarcinoma sequence through HER2 activation in esophageal epithelial cells.

The Evaluation and Management of Suspicious Gastric Lesions Following Bariatric Surgery

Obesity has reached epidemic proportions worldwide and is associated with a higher mortality from several diseases, including adenocarcinoma of the esophagus and of the gastric cardia. Increased body mass index is associated with an increased incidence of gastroesophageal reflux disease (GERD), Barrett metaplasia, and adenocarcinoma of the cardia. Bariatric surgery remains the most effective therapy for morbid obesity and has the potential to improve weight-related GERD. A high index of suspicion is paramount for early detection of foregut neoplasia after bariatric surgery.

Inverse Association Between Gluteofemoral Obesity and Risk of Barrett's Esophagus in a Pooled Analysis

BACKGROUND & AIMS

Gluteofemoral obesity (determined by measurement of subcutaneous fat in the hip and thigh regions) could reduce risks of cardiovascular and diabetic disorders associated with abdominal obesity. We evaluated whether gluteofemoral obesity also reduces the risk of Barrett's esophagus (BE), a premalignant lesion associated with abdominal obesity.

METHODS

We collected data from non-Hispanic white participants in 8 studies in the Barrett's and Esophageal Adenocarcinoma Consortium. We compared measures of hip circumference (as a proxy for gluteofemoral obesity) from cases of BE (n = 1559) separately with 2 control groups: 2557 population-based controls and 2064 individuals with gastroesophageal reflux disease (GERD controls). Study-specific odds ratios (ORs) and 95% confidence intervals (95% CIs) were estimated using individual participant data and multivariable logistic regression and combined using a random-effects meta-analysis.

RESULTS

We found an inverse relationship between hip circumference and BE (OR per 5-cm increase, 0.88; 95% CI, 0.81-0.96), compared with population-based controls in a multivariable model that included waist circumference. This association was not observed in models that did not include waist circumference. Similar results were observed in analyses stratified by frequency of GERD symptoms. The inverse association with hip circumference was statistically significant only among men (vs population-based controls: OR, 0.85; 95% CI, 0.76-0.96 for men; OR, 0.93; 95% CI, 0.74-1.16 for women). For men, within each category of waist circumference, a larger hip circumference was associated with a decreased risk of BE. Increasing waist circumference was associated with an increased risk of BE in the mutually adjusted population-based and GERD control models.

CONCLUSIONS

Although abdominal obesity is associated with an increased risk of BE, there is an inverse association between gluteofemoral obesity and BE, particularly among men.

Oesophageal adenocarcinoma and gastric cancer: should we mind the gap?

Over recent decades we have witnessed a shift in the anatomical distribution of gastric cancer (GC), which increasingly originates from the proximal stomach near the junction with the oesophagus. In parallel, there has been a dramatic rise in the incidence of oesophageal adenocarcinoma (OAC) in the lower oesophagus, which is associated with antecedent Barrett oesophagus (BO). In this context, there has been uncertainty regarding the characterization of adenocarcinomas spanning the area from the lower oesophagus to the distal stomach. Most relevant to this discussion is the distinction, if any, between OAC and intestinal-type GC of the proximal stomach. It is therefore timely to review our current understanding of OAC and intestinal-type GC, integrating advances from cell-of-origin studies and comprehensive genomic alteration analyses, ultimately enabling better insight into the relationship between these two cancers.

Obesity and increased risk of esophageal adenocarcinoma

There has been a substantial increase in the incidence of esophageal adenocarcinoma over the past 40 years. Meta-analyses of large prospective cohorts and population-based case-control studies demonstrate consistent associations between obesity and the development of adenocarcinoma of the esophagus and esophago-gastric junction, with an approximate doubling of risk of esophageal adenocarcinoma among patients who are obese, and an almost five-fold increased risk among those with BMI >40 kg/m². The pathologic precursor, specialized intestinal metaplasia in Barrett's esophagus, is also associated with increased adiposity. Epidemiologic evidence suggests that this cancer risk is not solely due to increased gastro-esophageal reflux, and that adipose tissue itself, in particular visceral adipose, may fuel carcinogenesis through the production of adipokines, cytokines, growth factors, and increased inflammation. The robust epidemiologic evidence linking obesity with esophageal adenocarcinoma makes it an exemplar model for investigating the molecular mechanisms underpinning obesity-associated malignant progression, which are discussed in this review.

Association between the body mass index and the risk of Barrett's esophagus in Japan

BACKGROUND

We investigated the association between long-segment Barrett's esophagus and obesity in the Japanese population in a multicenter case-control trial.

METHODS

One hundred thirteen patients with endoscopically detected Barrett's esophagus with a length of more than 2 cm and the same number of sex- and age-matched controls were prospectively enrolled. Barrett's esophagus was diagnosed based on the Prague C and M criteria. The body mass index (BMI) of the subjects was categorized into the following groups: normal, BMI <22.9; overweight, BMI 23.0-24.9, and obese, BMI >25.0. To determine the association between BMI and the risk of Barrett's esophagus, multivariate logistic regression analyses were performed.

RESULTS

The basically adjusted regression model adjusted for smoking and alcohol consumption revealed that overweight and obesity were significantly associated with an elevated risk of Barrett's esophagus (OR 2.4, 95% CI 1.2-4.7, and OR 2.5, 95% CI 1.3-4.6, respectively). The intensity of the association was not attenuated even after adjustment for gastroesophageal reflux disease-related parameters.

CONCLUSIONS

An increased BMI was associated with an increased risk for Barrett's esophagus through a gastroesophageal reflux-independent mechanism in the Japanese population. Further, unlike in Caucasian populations, being even slightly overweight with a BMI of 23.0-24.9 was an independent risk factor in the Japanese population.

Symptoms of Obstructive Sleep Apnea, Gastroesophageal Reflux and the Risk of Barrett's Esophagus in a Population-Based Case-Control Study

Background

Gastroesophageal reflux is overrepresented in people with obstructive sleep apnea (OSA) and it has been suggested that OSA worsens gastroesophageal reflux symptoms. Aggravated reflux might lead to an increased risk of Barrett’s esophagus.

Aim

To assess the association between sleep apnea symptoms and Barrett’s esophagus.

Methods

Included in a case-control study in Brisbane, Australia were 237 patients with histologically confirmed Barrett’s esophagus and 247 population controls. The controls were randomly selected from the electoral roll and frequency-matched to the cases by age and sex. Information on OSA symptoms (excessive daytime sleepiness and sleep related apnea symptoms), gastroesophageal reflux symptoms and anthropometric measures were collected through interviews and written questionnaires. Multivariable logistic regression provided odds ratios (OR) and 95% confidence intervals (CI), adjusted for potential confounding by BMI and gastroesophageal reflux.

Results

The prevalence of Barrett’s esophagus was higher among people with excessive daytime sleepiness than those without (24% vs. 18%; p-value 0.1142) and in participants with sleep-related apnea symptoms (20% vs. 13%; p-value 0.1730). However, there were non-significantly increased ORs of Barrett’s esophagus among people with excessive daytime sleepiness (OR 1.42, 95% CI 0.90–2.34) and sleep related apnea symptoms (OR 1.32, 95% CI 0.74–2.36) when adjusting for age, sex and BMI. After further adjustment for gastroesophageal reflux symptoms, the point ORs were no longer increased (OR 1.02, 95% CI 0.61–1.70 for daytime sleepiness and OR 0.72, 95% CI 0.38–1.38 for sleep related apnea symptoms).

Conclusions

Symptoms of OSA are possibly associated with an increased risk of Barrett’s esophagus, an association that appears to be mediated entirely by gastroesophageal reflux.

Chemoprevention in Barrett's Esophagus: Current Status

Chemoprevention in Barrett's esophagus is currently applied only in research settings. Identifying pathways that can be targeted by safe, pharmaceutical or natural compounds is key to expanding the scope of chemoprevention. Defining meaningful surrogate markers of cancer progression is critical to test the efficacy of chemopreventive approaches. Combinatorial chemoprevention that targets multiple components of the same pathway or parallel pathways could reduce the risk and improve the efficacy of chemoprevention. Here we discuss the role of chemoprevention as an independent or an adjuvant management option in BE-associated esophageal adenocarcinoma.

Role of Obesity in the Pathogenesis and Progression of Barrett's Esophagus

Central obesity is involved in the pathogenesis and progression of Barrett's esophagus to esophageal adenocarcinoma. Involved are likely both mechanical and nonmechanical effects. Mechanical effects of increased abdominal fat cause disruption of the gastroesophageal reflux barrier leading to increased reflux events. Nonmechanical effects may be mediated by inflammation, via classically activated macrophages, pro-inflammatory cytokines, and adipokines such as Leptin, all of which likely potentiate reflux-mediated inflammation. Insulin resistance, associated with central obesity, is also associated with both Barrett's pathogenesis and progression to adenocarcinoma. Molecular pathways activated in obesity, inflammation and insulin resistance overlap with those involved in Barrett's pathogenesis and progression.

Risk factors affecting the Barrett's metaplasia-dysplasia-neoplasia sequence

Esophageal adenocarcinoma has the fastest growing incidence rate of any cancer in the United States, and currently carries a very poor prognosis with 5 years relative survival rates of less than 15%. Current curative treatment options are limited to esophagectomy, a procedure that suffers from high complication rates and high mortality rates. Metaplasia of the esophageal epithelium, a condition known as Barrett’s esophagus (BE), is widely accepted as the precursor lesion for adenocarcinoma of the esophagus. Recently, radio-frequency ablation has been shown to be an effective method to treat BE, although there is disagreement as to whether radio-frequency ablation should be used to treat all patients with BE or whether treatment should be reserved for those at high risk for progressing to esophageal adenocarcinoma while continuing to endoscopically survey those with low risk. Recent research has been targeted towards identifying those at greater risk for progression to esophageal adenocarcinoma so that radio-frequency ablation therapy can be used in a more targeted manner, decreasing the total health care cost as well as improving patient outcomes. This review discusses the current state of the literature regarding risk factors for progression from BE through dysplasia to esophageal adenocarcinoma, as well as the current need for an integrated scoring tool or risk stratification system capable of differentiating those patients at highest risk of progression in order to target these endoluminal therapies.

Effect of icosapent ethyl (eicosapentaenoic acid ethyl ester) on omeprazole plasma pharmacokinetics in healthy adults

Background

Icosapent ethyl (IPE) is a high-purity prescription form of eicosapentaenoic acid ethyl ester approved by the US Food and Drug Administration as an adjunct to diet to reduce triglyceride levels in adult patients with severe hypertriglyceridemia. Patients with high serum triglycerides may be taking concurrent medications for associated conditions such as obesity and/or diabetes mellitus.

Objective

To evaluate the effect of IPE on the plasma pharmacokinetics (PK) of omeprazole, a commonly used proton pump inhibitor and a substrate of cytochrome P450 (CYP) 2C19.

Study design

Omeprazole (40 mg/day for 7 days) was administered orally without and with 4 g/day IPE at steady state. The primary PK endpoint was area under the concentration-time curve from time 0 to 24 h (AUC_0–24); secondary endpoints included maximum observed plasma concentration (C_max). Safety was monitored in all subjects who received one or more dose(s) of the study drug.

Participants

Thirty healthy adult subjects were enrolled and 28 completed the study.

Results

IPE 4 g/day at steady state did not significantly change the AUC_0–24 or C_max of omeprazole when co-administered at 40 mg/day to steady state. The ratios of least squares geometric means (90 % confidence interval) for AUC_0–24 and C_max (omeprazole with IPE vs. omeprazole alone) were 0.84 (76.0–91.9) and 1.01 (87.4–116.3), respectively. There were no clinically significant findings from laboratory tests, vital signs, or physical examinations.

Conclusions

At steady-state concentrations, IPE 4 g/day did not inhibit the AUC_0–24 or C_max of omeprazole 40 mg/day, a CYP2C19 substrate. Co-administration of IPE with omeprazole was safe and well tolerated.

Chemoradiation in oesophageal cancer

Oesophageal cancer is the 8th most common cancer worldwide, and has significant mortality and morbidity rates. The two most common histological types, squamous cell carcinoma and adenocarcinoma, have different localizations, distinctive risk factors, and molecular mechanisms. Survival for patients with locoregional oesophageal cancer is poor when treated with surgery only, with 5-year survival less than 10-15%. Radiation therapy has limited efficacy when given alone. Concurrent chemoradiation improves local-regional control and facilitates margin-free resection when delivered preoperatively. Chemoradiation prolongs survival when given as definitive treatment or combined with surgery. Neoadjuvant chemoradiation also reduces risk of distant recurrence. To date, there is no data supporting the addition of targeted therapy to concurrent chemoradiation. Understanding molecular pathways regulating both radiosensitivity and tumorigenesis/invasion may lead to the discovery of new targeted agents, improving outcome of chemoradiation in terms of both locoregional and systemic control, ultimately resulting in prolonged survival.

Chemoprevention in Barrett's oesophagus

Increasing incidence of oesophageal adenocarcinoma along with poor survival entails novel preventive strategies. Agents that target pro-oncogenic pathways in Barrett's mucosa could halt this neoplastic transformation. In this review, we will use epidemiological associations and molecular mechanisms to identify novel chemoprevention targets in Barrett's oesophagus. We will also discuss recent chemoprevention trials.

Pathophysiological mechanisms linking obesity and esophageal adenocarcinoma

In recent decades there has been a dramatic rise in the incidence of esophageal adenocarcinoma (EAC) in the developed world. Over approximately the same period there has also been an increase in the prevalence of obesity. Obesity, especially visceral obesity, is an important independent risk factor for the development of gastro-esophageal reflux disease, Barrett’s esophagus and EAC. Although the simplest explanation is that this mediated by the mechanical effects of abdominal obesity promoting gastro-esophageal reflux, the epidemiological data suggest that the EAC-promoting effects are independent of reflux. Several, not mutually exclusive, mechanisms have been implicated, which may have different effects at various points along the reflux-Barrett’s-cancer pathway. These mechanisms include a reduction in the prevalence of Helicobacter pylori infection enhancing gastric acidity and possibly appetite by increasing gastric ghrelin secretion, induction of both low-grade systemic inflammation by factors secreted by adipose tissue and the metabolic syndrome with insulin-resistance. Obesity is associated with enhanced secretion of leptin and decreased secretion of adiponectin from adipose tissue and both increased leptin and decreased adiponectin have been shown to be independent risk factors for progression to EAC. Leptin and adiponectin have a set of mutually antagonistic actions on Barrett’s cells which appear to influence the progression of malignant behaviour. At present no drugs are of proven benefit to prevent obesity associated EAC. Roux-en-Y reconstruction is the preferred bariatric surgical option for weight loss in patients with reflux. Statins and aspirin may have chemopreventative effects and are indicated for their circulatory benefits.

The role of obesity in oesophageal cancer development

The incidence of oesophageal adenocarcinoma has increased dramatically in the developed world in the last half century. Over approximately the same period there has been an increase in the prevalence of obesity. Multiple epidemiological studies and meta-analyses have confirmed that obesity, especially abdominal, visceral obesity, is a risk factor for gastro-oesophageal reflux, Barrett's oesophagus and oesophageal adenocarcinoma. Although visceral obesity enhances gastro-oesophageal reflux, the available data also show that visceral obesity increases the risk of Barrett's oesophagus and adenocarcinoma via reflux-independent mechanisms. Several possible mechanisms could link obesity with the risk of oesophageal adenocarcinoma in addition to mechanical effects increasing reflux. These include reduced gastric Helicobacter pylori infection, altered intestinal microbiome, factors related to lifestyle, the metabolic syndrome and associated low-grade inflammation induced by obesity and the secretion of mediators by adipocytes which may directly influence the oesophageal epithelium. Of these adipocyte-derived mediators, increased leptin levels have been independently associated with progression to oesophageal adenocarcinoma and in laboratory studies leptin enhances malignant behaviours in cell lines. Adiponectin is also secreted by adipocytes and levels decline with obesity: decreased serum adiponectin levels are associated with malignant progression in Barrett's oesophagus and experimentally adiponectin exerts anticancer effects in Barrett's cell lines and inhibits growth factor signalling. At present there are no proven chemopreventative interventions that may reduce the incidence of obesity-associated oesophageal cancer: observational studies suggest that the combined use of a statin and aspirin or another cyclo-oxygenase inhibitor is associated with a significantly reduced cancer incidence in patients with Barrett's oesophagus.

Obesity and risk of esophageal adenocarcinoma and Barrett's esophagus: a Mendelian randomization study

BACKGROUND

Data from observational studies suggest that body mass index (BMI) is causally related to esophageal adenocarcinoma (EAC) and its precursor, Barrett's esophagus (BE). However, the relationships may be affected by bias and confounding.

METHODS

We used data from the Barrett's and Esophageal Adenocarcinoma Genetic Susceptibility Study: 999 patients with EAC, 2061 patients with BE, and 2169 population controls. We applied the two-stage control function instrumental variable method of the Mendelian randomization approach to estimate the unbiased, unconfounded effect of BMI on risk of EAC and BE. This was performed using a genetic risk score, derived from 29 genetic variants shown to be associated with BMI, as an instrument for lifetime BMI. A higher score indicates propensity to obesity. All tests were two-sided.

RESULTS

The genetic risk score was not associated with potential confounders, including gastroesophageal reflux symptoms and smoking. In the instrumental variable analyses (IV), EAC risk increased by 16% (IV-odds ratio [OR] = 1.16, 95% confidence interval [CI] = 1.01 to 1.33) and BE risk increased by 12% (IV-OR = 1.12, 95% CI = 1.00 to 1.25) per 1kg/m(2) increase in BMI. BMI was statistically significantly associated with EAC and BE in conventional epidemiologic analyses.

CONCLUSIONS

People with a high genetic propensity to obesity have higher risks of esophageal metaplasia and neoplasia than people with low genetic propensity. These analyses provide the strongest evidence to date that obesity is independently associated with BE and EAC, and is not due to confounding or bias inherent in conventional epidemiologic analyses.

Total body fat and the risk of Barrett's oesophagus - a bioelectrical impedance study

BACKGROUND

Body mass index is associated with the risk of Barrett's oesophagus (BO). It is uncertain whether this is related to total body fat or other factors that correlate with body mass index. We aimed to quantify the association between total body fat (measured by bioelectrical impedance) and risk of BO and examine if this association was modified by gastro-oesophageal reflux (GOR) and abdominal obesity.

METHODS

In 2007-2009, we surveyed 235 cases (69% Males, Mean age 62.1 years) and 244 age and sex matched population controls from a population based case-control study of BO. We conducted structured interviews, standard anthropometry and bioimpedance analysis of total body fat. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using multivariable logistic regression analysis.

RESULTS

There was a significantly increased risk of BO among those in the highest tertile of total body fat weight (OR 2.01; 95%CI 1.26-3.21) and total body fat percentage (OR 1.86; 95%CI 1.10-3.15). These risks were largely attenuated after adjustment for GOR and waist circumference. There was a significantly increased risk of BO among those in the highest tertile of waist circumference (OR 2.21; 95%CI 1.39-3.51) and this was minimally attenuated after adjustment for total body fat and moderately attenuated after adjustment for GOR.

CONCLUSIONS

Total body fat is associated with an increased risk of BO but this appears to be mediated via both abdominal obesity and GOR. These findings provide evidence that abdominal obesity is more important than total body fat in the development of BO.

Hormone replacement therapy and oral contraceptives and risk of oesophageal adenocarcinoma: a systematic review and meta-analysis

There is an unexplained strong male predominance in the aetiology of oesophageal adenocarcinoma (OAC). The hypothesis that oestrogens are protective, deserves attention. A potential protective influence of exogenous oestrogen exposure, that is, hormone replacement therapy (HRT) and oral contraceptives (OC) has been addressed only in studies of limited statistical power, and the individual studies have not provided conclusive results. We conducted a systematic literature search and meta-analysis on HRT and OC and the risk of OAC. We used the databases PubMed and the Web of Science. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by the Mantel-Haenszel random-effect method. A total of five studies were included. Compared to never users, ever users of HRT had a statistically significantly decreased risk of OAC (pooled OR = 0.75; 95% CI: 0.58-0.98), and ever users of OC had a borderline significantly decreased risk of this cancer (pooled OR = 0.76; 95% CI: 0.57-1.00). In conclusion, HRT and OC use seems to be associated with a decreased risk of OAC. However, further research is warranted.

Fat mass by bioelectrical impedance analysis is not associated with increased risk of Barrett esophagus

GOAL

To evaluate whether the association between obesity and Barrett esophagus (BE) is due to total body fatness, abdominal obesity, or both.

BACKGROUND

BE risk seems to be more strongly related to central obesity than total obesity. However, no studies have investigated the association between total obesity and BE using direct measures of total body fatness.

STUDY

We conducted a case-control study among patients scheduled for elective esophagogastroduodenoscopy, and a sample of patients eligible for screening colonoscopy recruited from primary care clinics. BE cases were patients with specialized intestinal metaplasia, whereas controls had no endoscopic or histopathologic BE. All patients underwent a study esophagogastroduodenoscopy and had body measurements taken. Fat mass and fat-free mass were estimated from bioelectrical impedance analysis (BIA). We calculated odds ratios (OR) and 95% confidence intervals (95% CI) using multivariable logistic regression.

RESULTS

There were 70 BE cases, 229 endoscopy controls, and 118 primary care controls. BMI and BIA-derived fat mass were highly correlated; however, we found no association between BMI, fat mass, and BE (vs. all controls: BMI, OR/1 SD=1.01; 95% CI, 0.76-1.34; fat mass, OR=1.02; 95% CI, 0.77-1.36). Waist-to-hip ratio was significantly associated with increased BE risk (vs. all controls: OR/1 SD=1.45; 95% CI, 1.03-2.04). We found similar results when we analyzed the control groups separately.

CONCLUSION

Waist-to-hip ratio, but not fat mass or BMI, was associated with increased BE risk. This study provides strong evidence that BE is related to body size and composition through central adiposity and not through total body fatness.

Central adiposity is associated with increased risk of esophageal inflammation, metaplasia, and adenocarcinoma: a systematic review and meta-analysis

BACKGROUND & AIMS

Central adiposity has been implicated as a risk factor for Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC), possibly promoting the progression from inflammation to metaplasia and neoplasia. We performed a systematic review and meta-analysis of studies to evaluate the association between central adiposity and erosive esophagitis (EE), BE, and EAC, specifically exploring body mass index (BMI)-independent and gastroesophageal reflux (GERD)-independent effects of central adiposity on the risk of these outcomes.

METHODS

We performed a systematic search of multiple databases through March 2013. Studies were included if they reported effect of central adiposity (visceral adipose tissue area, waist-hip ratio, and/or waist circumference) on the risk of EE, BE, and EAC. Summary adjusted odds ratio (aOR) estimates with 95% confidence intervals (CIs), comparing highest category of adiposity with the lowest category of adiposity, were calculated by using random-effects model.

RESULTS

Forty relevant articles were identified. Compared with patients with normal body habitus, patients with central adiposity had a higher risk of EE (19 studies; aOR, 1.87; 95% CI, 1.51-2.31) and BE (17 studies; aOR, 1.98; 95% CI, 1.52-2.57). The association between central adiposity and BE persisted after adjusting for BMI (5 studies; aOR, 1.88; 95% CI, 1.20-2.95). Reflux-independent association of central adiposity and BE was observed in studies that used GERD patients as controls or adjusted for GERD symptoms (11 studies; aOR, 2.04; 95% CI, 1.44-2.90). In 6 studies, central adiposity was associated with higher risk of EAC (aOR, 2.51; 95% CI, 1.54-4.06), compared with normal body habitus.

CONCLUSIONS

On the basis of a meta-analysis, central adiposity, independent of BMI, is associated with esophageal inflammation (EE), metaplasia (BE), and neoplasia (EAC). Its effects are mediated by reflux-dependent and reflux-independent mechanisms.

Role of the gastroenterologist in managing obesity

Obesity has become a major public health problem as a consequence of its prevalence, negative impact on morbidity, mortality and quality of life and its associated direct and indirect healthcare costs. The etiology of obesity is multifactorial and reflects complex interactions of genetic, neurohumoral, environmental, behavioral and possibly, microbial factors. Available treatments for obesity include diet and exercise, behavioral modification, medications and surgery. Gastroenterologists are becoming increasingly involved in the care of obese patients. Although much of this care has historically centered on the preoperative and postoperative care of the bariatric patient, gastroenterologists are also evaluating and managing a variety of gastrointestinal symptoms and disorders that occur more commonly among obese individuals and are increasingly involved in the primary treatment of obesity. In this review, the gastrointestinal symptoms and disorders that are associated with obesity will be reviewed, the gastrointestinal contribution to the pathogenesis of obesity will be described and the current treatment options of obesity and where the gastroenterologist typically plays a role in the management will be discussed.