Risk of esophageal adenocarcinoma decreases with height, based on consortium analysis and confirmed by Mendelian randomization

Height and cancer risk in East Asians: Evidence from a prospective cohort study and Mendelian randomization analyses

BACKGROUND

Height is associated with increased cancer risk, but most studies focus on Western populations. We aimed to evaluate this relationship in East Asians.

METHOD

Observational analyses were performed utilizing data from China Kadoorie Biobank (CKB) prospective cohort. Adjusted hazard ratios (HRs) and corresponding 95 % confidence intervals (CIs) were estimated using Cox proportional hazards models. Two-sample Mendelian randomization (MR) analyses explored causal effects between height and cancer using data from Korean Genome and Epidemiology Study (KoGES), Biobank Japan (BBJ), and CKB.

RESULTS

Over a median 10.1-years follow-up, 22,731 incident cancers occurred. In observational analyses, after Bonferroni correction, each 10 cm increase in height was significantly associated with higher risk of overall cancer (HR 1.16, 95 % CI 1.14-1.19, P < 0.001), lung cancer (1.18, 95 % CI 1.12-1.24, P < 0.001), esophageal cancer (1.21, 95 % CI 1.12-1.30, P < 0.001), breast cancer (1.41, 95 % CI 1.31-1.53, P < 0.001), and cervix uteri cancer (1.29, 95 % CI 1.15-1.45, P < 0.001). Each 10 cm increase in height was suggestively associated with increased risk for lymphoma (1.18, 95 % CI 1.04-1.34, P = 0.010), colorectal cancer (1.09, 95 % CI 1.02-1.16, P = 0.010), and stomach cancer (1.07, 95 % CI 1.00-1.14, P = 0.044). In MR analyses, genetically predicted height (per 1 standard deviation increase, 8.07 cm) was suggestively associated with higher risk of lung cancer (odds ratio [OR] 1.17, 95 % confidence interval [CI] 1.02-1.35, P = 0.0244) and gastric cancer (OR 1.14, 95 % CI 1.02-1.29, P = 0.0233).

CONCLUSIONS

Taller height was significantly related to a higher risk for overall cancer, lung cancer, esophageal cancer, breast cancer, and cervix uteri cancer. Our findings suggest that height may be a potential causal risk factor for lung and gastric cancers among East Asians.

Causal effects of genetic birth weight and gestational age on adult esophageal diseases: Mendelian randomization study

BACKGROUND

Few studies have investigated the association between gestational age, birth weight, and esophageal cancer risk; however, causality remains debated. We aimed to establish causal links between genetic gestational age and birth weight traits and gastroesophageal reflux disease (GERD), Barrett's esophagus (BE), and esophageal adenocarcinoma (EA). Additionally, we explored if known risk factors mediate these links.

AIM

To analyze of the relationship between gestational age, birth weight and GERD, BE, and EA.

METHODS

Genetic data on gestational age and birth weight (n = 84689 and 143677) from the Early Growth Genetics Consortium and outcomes for GERD (n = 467253), BE (n = 56429), and EA (n = 21271) from genome-wide association study served as instrumental variables. Mendelian randomization (MR) and mediation analyses were conducted using MR-Egger, weighted median, and inverse variance weighted methods. Robustness was ensured through heterogeneity, pleiotropy tests, and sensitivity analyses.

RESULTS

Birth weight was negatively correlated with GERD and BE risk [odds ratio (OR) = 0.78; 95% confidence interval (CI): 0.69-0.8] and (OR = 0.75; 95%CI: 0.60-0.9), respectively, with no significant association with EA. No causal link was found between gestational age and outcomes. Birth weight was positively correlated with five risk factors: Educational attainment (OR = 1.15; 95%CI: 1.01-1.31), body mass index (OR = 1.06; 95%CI: 1.02-1.1), height (OR = 1.12; 95%CI: 1.06-1.19), weight (OR = 1.13; 95%CI: 1.10-1.1), and alcoholic drinks per week (OR = 1.03; 95%CI: 1.00-1.06). Mediation analysis showed educational attainment and height mediated the birth weight-BE link by 13.99% and 5.46%.

CONCLUSION

Our study supports the protective role of genetically predicted birth weight against GERD, BE, and EA, independent of gestational age and partially mediated by educational attainment and height.

Body shape phenotypes of multiple anthropometric traits and cancer risk: a multi-national cohort study

BACKGROUND

Classical anthropometric traits may fail to fully represent the relationship of weight, adiposity, and height with cancer risk. We investigated the associations of body shape phenotypes with the risk of overall and site-specific cancers.

METHODS

We derived four distinct body shape phenotypes from principal component (PC) analysis on height, weight, body mass index (BMI), waist (WC) and hip circumferences (HC), and waist-to-hip ratio (WHR). The study included 340,152 men and women from 9 European countries, aged mostly 35-65 years at recruitment (1990-2000) in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Cox proportional hazards regression was used to estimate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

After a median follow-up of 15.3 years, 47,110 incident cancer cases were recorded. PC1 (overall adiposity) was positively associated with the risk of overall cancer, with a HR per 1 standard deviation (SD) increment equal to 1.07 (95% confidence interval 1.05 to 1.08). Positive associations were observed with 10 cancer types, with HRs (per 1 SD) ranging from 1.36 (1.30-1.42) for endometrial cancer to 1.08 (1.03-1.13) for rectal cancer. PC2 (tall stature with low WHR) was positively associated with the risk of overall cancer (1.03; 1.02-1.04) and five cancer types which were not associated with PC1. PC3 (tall stature with high WHR) was positively associated with the risk of overall cancer (1.04; 1.03-1.05) and 12 cancer types. PC4 (high BMI and weight with low WC and HC) was not associated with overall risk of cancer (1.00; 0.99-1.01).

CONCLUSIONS

In this multi-national study, distinct body shape phenotypes were positively associated with the incidence of 17 different cancers and overall cancer.

Systematic review of Mendelian randomization studies on risk of cancer

BACKGROUND

We aimed to map and describe the current state of Mendelian randomization (MR) literature on cancer risk and to identify associations supported by robust evidence.

METHODS

We searched PubMed and Scopus up to 06/10/2020 for MR studies investigating the association of any genetically predicted risk factor with cancer risk. We categorized the reported associations based on a priori designed levels of evidence supporting a causal association into four categories, namely robust, probable, suggestive, and insufficient, based on the significance and concordance of the main MR analysis results and at least one of the MR-Egger, weighed median, MRPRESSO, and multivariable MR analyses. Associations not presenting any of the aforementioned sensitivity analyses were not graded.

RESULTS

We included 190 publications reporting on 4667 MR analyses. Most analyses (3200; 68.6%) were not accompanied by any of the assessed sensitivity analyses. Of the 1467 evaluable analyses, 87 (5.9%) were supported by robust, 275 (18.7%) by probable, and 89 (6.1%) by suggestive evidence. The most prominent robust associations were observed for anthropometric indices with risk of breast, kidney, and endometrial cancers; circulating telomere length with risk of kidney, lung, osteosarcoma, skin, thyroid, and hematological cancers; sex steroid hormones and risk of breast and endometrial cancer; and lipids with risk of breast, endometrial, and ovarian cancer.

CONCLUSIONS

Despite the large amount of research on genetically predicted risk factors for cancer risk, limited associations are supported by robust evidence for causality. Most associations did not present a MR sensitivity analysis and were thus non-evaluable. Future research should focus on more thorough assessment of sensitivity MR analyses and on more transparent reporting.

Epigenomics and genotype-phenotype association analyses reveal conserved genetic architecture of complex traits in cattle and human

Background

Lack of comprehensive functional annotations across a wide range of tissues and cell types severely hinders the biological interpretations of phenotypic variation, adaptive evolution, and domestication in livestock. Here we used a combination of comparative epigenomics, genome-wide association study (GWAS), and selection signature analysis, to shed light on potential adaptive evolution in cattle.

Results

We cross-mapped 8 histone marks of 1300 samples from human to cattle, covering 178 unique tissues/cell types. By uniformly analyzing 723 RNA-seq and 40 whole genome bisulfite sequencing (WGBS) datasets in cattle, we validated that cross-mapped histone marks captured tissue-specific expression and methylation, reflecting tissue-relevant biology. Through integrating cross-mapped tissue-specific histone marks with large-scale GWAS and selection signature results, we for the first time detected relevant tissues and cell types for 45 economically important traits and artificial selection in cattle. For instance, immune tissues are significantly associated with health and reproduction traits, multiple tissues for milk production and body conformation traits (reflecting their highly polygenic architecture), and thyroid for the different selection between beef and dairy cattle. Similarly, we detected relevant tissues for 58 complex traits and diseases in humans and observed that immune and fertility traits in humans significantly correlated with those in cattle in terms of relevant tissues, which facilitated the identification of causal genes for such traits. For instance, PIK3CG, a gene highly specifically expressed in mononuclear cells, was significantly associated with both age-at-menopause in human and daughter-still-birth in cattle. ICAM, a T cell-specific gene, was significantly associated with both allergic diseases in human and metritis in cattle.

Conclusion

Collectively, our results highlighted that comparative epigenomics in conjunction with GWAS and selection signature analyses could provide biological insights into the phenotypic variation and adaptive evolution. Cattle may serve as a model for human complex traits, by providing additional information beyond laboratory model organisms, particularly when more novel phenotypes become available in the near future.

Clinical course of gastroesophageal reflux disease and impact of treatment in symptomatic young patients

In symptomatic young patients with gastroesophageal reflux symptoms, early identification of progressive gastroesophageal reflux disease (GERD) is critical to prevent long-term complications associated with hiatal hernia, increased esophageal acid and nonacid exposure, release of proinflammatory cytokines, and development of intestinal metaplasia, endoscopically visible Barrett's esophagus, and dysplasia leading to esophageal adenocarcinoma. Progression of GERD may occur in asymptomatic patients and in those under continuous acid-suppressive medication. The long-term side effects of proton-pump inhibitors, chemopreventive agents, and radiofrequency ablation are contentious. In patients with early-stage disease, when the lower esophageal sphincter function is still preserved and before endoscopically visible Barrett's esophagus develops, novel laparoscopic procedures, such as magnetic and electric sphincter augmentation, may have a greater role than conventional surgical therapy. A multidisciplinary approach to GERD by a dedicated team of gastroenterologists and surgeons might impact the patients' lifestyle, the therapeutic choices, and the course of the disease. Biological markers are needed to precisely assess the risk of disease progression and to tailor surveillance, ablation, and management.

No Barrett's-No Cancer: A Proposed New Paradigm for Prevention of Esophageal Adenocarcinoma

Esophageal adenocarcinoma is inflammation-associated cancer with a recognizable preneoplastic stage, Barrett's. Barrett's describes the metaplastic transformation of esophageal squamous mucosa into columnar epithelium that typically results secondary to mucosal damage caused by acidic gastroduodenal reflux. Continued acid reflux may then result in mucosal inflammation which results in progressive inflammation-induced genetic instability that may eventuate in esophageal adenocarcinoma. Barrett's is the only recognized precursor lesion to esophageal carcinoma. Barrett's mucosa is unique among preneoplastic lesions; ablation therapy results in restitution of a squamous epithelium reducing or eliminating accumulated genetic instabilities and resetting the biological clock progressing toward invasive cancer. However, recurrence of Barrett's after ablation is common. We propose that both Barrett's and recurrence of Barrett's after ablation can be prevented and discuss how current approaches to therapy for gastroesophageal reflux disease, for Barrett's screening, chemoprevention, and ablation therapy all might be reconsidered. We propose (1) improved approaches to Barrett's prevention, (2) universal Barrett's screening by linking Barrett's screening to colon cancer screening, (3) ablation of all Barrett's mucosa along with (4) acid-suppressive-antireflux therapy tailored to prevent development of Barrett's or the recurrence of Barrett's after ablation therapy. We propose that ultimately, treatment decisions for gastroesophageal reflux disease and prevention of Barrett's and esophageal carcinoma should be based on assessing and maintaining esophageal mucosal integrity. This will require development and verification of specific measurements that reliably correlate with prevention of Barrett's. We outline the new research and technical advances needed to cost-effectively achieve these goals.

The impact of Helicobacter pylori on the presence of Barrett's esophagus in Azerbaijan, a high-prevalence area of infection

There is a strong evidence that Helicobacter pylori infection is inversely associated with Barrett's esophagus. In a high-prevalence region of H. pylori, low rates of esophageal cancer and its precursor BE may indicate its preventive effect. The aim of this study is to determine the impact of H. pylori on characteristics of Barrett's esophagus. A total of 3317 outpatient upper endoscopy reports from 2013 to 2015 from an urban center in Azerbaijan from all patients with dyspepsia were retrospectively analyzed for patients with Barrett's esophagus. This was matched in a 1:2 ratio to age and gender matched control patients without Barrett's esophagus. The prevalence of H. pylori on Barrett's esophagus and the randomly selected control group were compared. There were 83 patients with BE and 167 control group cases. Biopsy-proven BE was diagnosed in 83 patients: 39 (47%) females, with mean age 43.1 ± 13.3 years. Of these, 13 (15.7%) had long segment and 70 (84.3%) had short segment Barrett's esophagus. A control group included 167 patients: 78 (46.7%) females, with mean age (45.8 ± 13.9). All patients were Caucasians. The rates of gastric inflammation, the presence of atrophy, and intestinal metaplasia in gastric specimens did not differ in patients versus controls. The prevalence of H. pylori was determined as 63.2% in male and 61.5 in female groups (odd ratio (OR) = 0.99 95%CI 0.97, 1.01; P = 0.22). Inflammation of gastric mucosa was strongly associated with the infection (67% vs. 33%; OR = 4.46 95% CI: 2.01, 9.92, P < 0.001). Atrophy was noted in majority of H. pylori-positive cases (OR = 1.43, 95% CI: 0.36, 5.65; P = 0.61). Gastric intestinal metaplasia was observed in 55.6% of H. pylori-positive patients and in 44.4% of negative individuals (OR = 0.74, 95% CI: 0.28, 1.94; P = 0.54). There was not a significant difference in the prevalence of HP in BE and control groups; 63.9% were positive for infection in BE cases and 61.7% of controls (OR = 1.10, 95% CI: 0.64, 1.90; P = 0.74). We found that neither presence of erosive esophagitis, length of BE nor dysplasia (45.5% of H. pylori-positive group, whereas 54.5%) was associated with the presence of the H. pylori infection (Table 1). In a predominantly Caucasian nation with a high prevalence of H. pylori gastritis, the presence of H. pylori was not inversely associated with the presence of Barrett's esophagus. These data challenge the mechanistic implications of this association.

Adult height, body mass index change, and body shape change in relation to esophageal squamous cell carcinoma risk: A population-based case-control study in China

The relationship between risk of esophageal squamous cell carcinoma (ESCC) and adult height, changes in individual body mass index (BMI) and body shape is not established. We performed a large population‐based case‐control study, which enrolled a total of 1414 ESCC cases and 1989 controls in a high‐incidence area in China. Using face‐to‐face interview with a structured questionnaire, information on participants' heights, weights, and perceived body shapes at 20 years of age was collected. Additionally, data on weight and perceived body shape among the same participants 10 years prior to ascertainment were collected using the same method. Odd ratios (ORs) of ESCC risk in relation to BMI and body shape were estimated using unconditional logistic regression models. The adjusted results indicated that ESCC risk in adults rapidly rose as height increased, plateauing at 170 cm among men and 157 cm among women. Among participants who were underweight, normal weight, or thinner than body shape 4, body weight loss was associated with increased risk of ESCC, and body weight gain was associated with decreased incidence of ESCC (ORs ranging from 0.40 to 0.76). Notably, however, changes in body weight did not significantly affect ESCC risk among participants who were overweight, obese, or larger than body shape 3. Maintaining a fit body shape and a reasonable BMI is advisable and of vital importance to reduce the risk of ESCC, especially in high‐risk areas.

Elevated Platelet Count Appears to Be Causally Associated with Increased Risk of Lung Cancer: A Mendelian Randomization Analysis

BACKGROUND

Platelets are a critical element in coagulation and inflammation, and activated platelets are linked to cancer risk through diverse mechanisms. However, a causal relationship between platelets and risk of lung cancer remains unclear.

METHODS

We performed single and combined multiple instrumental variable Mendelian randomization analysis by an inverse-weighted method, in addition to a series of sensitivity analyses. Summary data for associations between SNPs and platelet count are from a recent publication that included 48,666 Caucasian Europeans, and the International Lung Cancer Consortium and Transdisciplinary Research in Cancer of the Lung data consisting of 29,266 cases and 56,450 controls to analyze associations between candidate SNPs and lung cancer risk.

RESULTS

Multiple instrumental variable analysis incorporating six SNPs showed a 62% increased risk of overall non-small cell lung cancer [NSCLC; OR, 1.62; 95% confidence interval (CI), 1.15-2.27; P = 0.005] and a 200% increased risk for small-cell lung cancer (OR, 3.00; 95% CI, 1.27-7.06; P = 0.01). Results showed only a trending association with NSCLC histologic subtypes, which may be due to insufficient sample size and/or weak effect size. A series of sensitivity analysis retained these findings.

CONCLUSIONS

Our findings suggest a causal relationship between elevated platelet count and increased risk of lung cancer and provide evidence of possible antiplatelet interventions for lung cancer prevention.

IMPACT

These findings provide a better understanding of lung cancer etiology and potential evidence for antiplatelet interventions for lung cancer prevention.

Adult height and risk of 50 diseases: a combined epidemiological and genetic analysis

BACKGROUND

Adult height is associated with risk of several diseases, but the breadth of such associations and whether these associations are primary or due to confounding are unclear. We examined the association of adult height with 50 diseases spanning multiple body systems using both epidemiological and genetic approaches, the latter to identify un-confounded associations and possible underlying mechanisms.

METHODS

We examined the associations for adult height (using logistic regression adjusted for potential confounders) and genetically determined height (using a two-sample Mendelian randomisation approach with height-associated genetic variants as instrumental variables) in 417,434 individuals of white ethnic background participating in the UK Biobank. We undertook pathway analysis of height-associated genes to identify biological processes that could link height and specific diseases.

RESULTS

Height was associated with 32 diseases and genetically determined height associated with 12 diseases. Of these, 11 diseases showed a concordant association in both analyses, with taller height associated with reduced risks of coronary artery disease (odds ratio per standard deviation (SD) increase in height OR_epi = 0.80, 95% CI 0.78-0.81; OR per SD increase in genetically determined height OR_gen = 0.86, 95% CI 0.82-0.90), hypertension (OR_epi = 0.83, 95% CI 0.82-0.84; OR_gen = 0.88, 95% CI 0.85-0.91), gastro-oesophageal reflux disease (OR_epi = 0.85, 95% CI 0.84-0.86; OR_gen = 0.94, 95% CI 0.92-0.97), diaphragmatic hernia (OR_epi = 0.81, 95% CI 0.79-0.82; OR_gen = 0.91, 95% CI 0.88-0.94), but increased risks of atrial fibrillation (OR_epi = 1.42, 95% CI 1.38-1.45; OR_gen = 1.33, 95% CI 1.26-1.40), venous thromboembolism (OR_epi = 1.18, 95% CI 1.16-1.21; OR_gen = 1.15, 95% CI 1.11-1.19), intervertebral disc disorder (OR_epi = 1.15, 95% CI 1.13-1.18; OR_gen = 1.14, 95% CI 1.09-1.20), hip fracture (OR_epi = 1.19, 95% CI 1.12-1.26; OR_gen = 1.27, 95% CI 1.17-1.39), vasculitis (OR_epi = 1.15, 95% CI 1.11-1.19; OR_gen = 1.20, 95% CI 1.14-1.28), cancer overall (OR_epi = 1.09, 95% CI 1.08-1.11; OR_gen = 1.06, 95% CI 1.04-1.08) and breast cancer (OR_epi = 1.08, 95% CI 1.06-1.10; OR_gen = 1.07, 95% CI 1.03-1.11). Pathway analysis showed multiple height-associated pathways associating with individual diseases.

CONCLUSIONS

Adult height is associated with risk of a range of diseases. We confirmed previously reported height associations for coronary artery disease, atrial fibrillation, venous thromboembolism, intervertebral disc disorder, hip fracture and cancer and identified potential novel associations for gastro-oesophageal reflux disease, diaphragmatic hernia and vasculitis. Multiple biological mechanisms affecting height may affect the risks of these diseases.

Mendelian randomization studies of cancer risk: a literature review

Purpose of review

In this paper, we summarize prior studies that have used Mendelian Randomization (MR) methods to study the effects of exposures, lifestyle factors, physical traits, and/or biomarkers on cancer risk in humans. Many such risk factors have been associated with cancer risk in observational studies, and the MR approach can be used to provide evidence as to whether these associations represent causal relationships. MR methods require a risk factor of interest to have known genetic determinants that can be used as proxies for the risk factor (i.e., "instrumental variables" or IVs), and these can be used to obtain an effect estimate that, under certain assumptions, is not prone to bias caused by unobserved confounding or reverse causality. This review seeks to describe how MR studies have contributed to our understanding of cancer causation.

Recent findings

We searched the published literature and identified 76 MR studies of cancer risk published prior to October 31, 2017. Risk factors commonly studied included alcohol consumption, Vitamin D, anthropometric traits, telomere length, lipid traits, glycemic traits, and markers of inflammation. Risk factors showing compelling evidence of a causal association with risk for at least one cancer type include alcohol consumption (for head/neck and colorectal), adult body mass index (increases risk for multiple cancers, but decreases risk for breast), height (increases risk for breast, colorectal, and lung; decreases risk for esophageal), telomere length (increases risk for lung adenocarcinoma, melanoma, renal cell carcinoma, glioma, B-cell lymphoma subtypes, chronic lymphocytic leukemia, and neuroblastoma), and hormonal factors (affects risk for sex-steroid sensitive cancers).

Summary

This review highlights alcohol consumption, body mass index, height, telomere length, and the hormonal exposures as factors likely to contribute to cancer causation. This review also highlights the need to study specific cancer types, ideally subtypes, as the effects of risk factors can be heterogeneous across cancer types. As consortia-based genome-wide association studies increase in sample size and analytical methods for MR continue to become more sophisticated, MR will become an increasingly powerful tool for understanding cancer causation.

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.

Body height and mortality - mortality follow-up of four Swiss surveys

BACKGROUND

Adult body height is largely determined by genetics, but also by dietary factors, which in turn depend on socioeconomic status and lifestyle. We examined the association between adult body height and mortality in Switzerland, a country with three main language regions with different cultural background.

METHODS

We included 16,831 men and 18,654 women, who participated in Swiss population-based health surveys conducted 1977-1993 and who were followed up until end of 2008. Multivariable Cox proportional hazards models were computed to examine the association of body height with overall, cardiovascular, and cancer mortality.

RESULTS

We observed a positive association between adult body height and all-cause mortality in women (HR=1.34, 95% CI 1.10-1.62, tallest vs. average women). In men, mortality risk decreased with increasing height, with shortest men tending to have higher (1.06, 0.94-1.19) and tallest men a lower (0.94, 0.77-1.14) risk compared with men of average height (p-trend 0.0001). Body height was associated with cancer mortality in women, such that tallest women had a higher risk of dying from cancer than women of average height (1.37, 1.02-1.84), but there was no such association in men (0.95, 0.69-1.30). In both sexes, height was not associated with cardiovascular mortality in a statistically significant manner.

CONCLUSION

Our study does not support an inverse association of body height with all-cause mortality. On the contrary, our data suggests a higher overall risk in taller women, mainly driven by a positive association between body height and cancer mortality.

A systematic SNP selection approach to identify mechanisms underlying disease aetiology: linking height to post-menopausal breast and colorectal cancer risk

Data from GWAS suggest that SNPs associated with complex diseases or traits tend to co-segregate in regions of low recombination, harbouring functionally linked gene clusters. This phenomenon allows for selecting a limited number of SNPs from GWAS repositories for large-scale studies investigating shared mechanisms between diseases. For example, we were interested in shared mechanisms between adult-attained height and post-menopausal breast cancer (BC) and colorectal cancer (CRC) risk, because height is a risk factor for these cancers, though likely not a causal factor. Using SNPs from public GWAS repositories at p-values < 1 × 10⁻⁵ and a genomic sliding window of 1 mega base pair, we identified SNP clusters including at least one SNP associated with height and one SNP associated with either post-menopausal BC or CRC risk (or both). SNPs were annotated to genes using HapMap and GRAIL and analysed for significantly overrepresented pathways using ConsensuspathDB. Twelve clusters including 56 SNPs annotated to 26 genes were prioritised because these included at least one height- and one BC risk- or CRC risk-associated SNP annotated to the same gene. Annotated genes were involved in Indian hedgehog signalling (p-value = 7.78 × 10⁻⁷) and several cancer site-specific pathways. This systematic approach identified a limited number of clustered SNPs, which pinpoint potential shared mechanisms linking together the complex phenotypes height, post-menopausal BC and CRC.

Risk Profiles for Barrett's Esophagus Differ between New and Prevalent, and Long- and Short-Segment Cases

Background

Previous studies on Barrett’s esophagus (BE) risk factors have had differing case definitions and control groups. The purpose of this study was to examine differences in risk factors between newly diagnosed vs. prevalent BE, long- vs. short-segment BE, and endoscopy-only BE without specialized intestinal metaplasia (SIM).

Methods

We conducted a cross-sectional study among eligible patients scheduled for elective esophagogastroduodenoscopy (EGD) and patients eligible for screening colonoscopy, recruited from primary care clinics at a Veterans Affairs center. All participants completed a survey on demographics, gastroesophageal reflux disease (GERD) symptoms and medication use prior to undergoing study EGD. We compared BE cases separately to two control groups: 503 primary care controls and 1353 endoscopy controls. Associations between risk factors and differing BE case definitions were evaluated with multivariate logistic regression models.

Results

For comparisons with primary care controls, early onset frequent GERD symptoms were more strongly associated with risk of long-segment BE (OR 19.9; 95% CI 7.96–49.7) than short-segment BE (OR 8.54; 95% CI 3.85–18.9). Likewise, the inverse association with H. pylori infection was stronger for long-segment BE (OR, 0.45; 95% CI, 0.26–0.79) than short-segment BE (OR, 0.71; 95% CI, 0.48–1.05). GERD symptoms and H. pylori infection was also more strongly associated with prevalent BE than newly diagnosed BE. Few differences were observed between BE cases and endoscopy controls. Endoscopy-only BE was associated with GERD symptoms (OR 2.25, 95% CI 1.32–3.85) and PPI/H2RA use (OR 4.44; 95% CI 2.61–7.54) but to a smaller degree than BE with SIM.

Conclusion

We found differences in the strength and profiles of risk factors for BE. The findings support that epidemiological studies of BE should make a distinction between long and short, new and prevalent, endoscopy-only and BE with SIM as well as type of controls.

Determination of risk for Barrett's esophagus and esophageal adenocarcinoma

PURPOSE OF REVIEW

The incidence of esophageal adenocarcinoma and its precursor, Barrett's esophagus, have increased greatly over the past 40 years and continue to rise. This report summarizes the most recent data on the risk factors for Barrett's esophagus and esophageal adenocarcinoma.

RECENT FINDINGS

Other factors, highly correlated with increasing trends for obesity, are the dominant driver of the increase in incidence of esophageal adenocarcinoma, interacting with gastroesophageal reflux disease symptoms. Abdominal obesity, independently of gastroesophageal reflux disease symptoms, is associated with increased risk of Barrett's esophagus and this association is likely mediated by high levels of leptin and insulin. Use of aspirin, nonsteroidal anti-inflammatory drugs, statins, and proton pump inhibitors are associated with a reduced risk of Barrett's esophagus as well as lower risk of neoplastic progression in patients with Barrett's esophagus. An increasing number of genetic loci have been associated with risk of Barrett's esophagus and esophageal adenocarcinoma.

SUMMARY

Recent advances in identifying risk factors and reporting of more precise estimates of effect for the main risk factors will positively impact clinical risk stratification efforts for Barrett's esophagus and esophageal adenocarcinoma. Large pooling studies are underway to derive and validate reliable clinical risk models.

Premature Birth and Large for Gestational Age Are Associated with Risk of Barrett's Esophagus in Adults

BACKGROUND

Birth characteristics, including weight and gestational age, may be associated with risk of Barrett's esophagus (BE), the only known precursor for esophageal adenocarcinoma; however, data are limited.

AIMS

To examine associations between various birth characteristics and BE, and whether these associations are mediated by known risk factors for BE.

METHODS

Data were obtained from a cross-sectional study among eligible Veterans Affairs patients scheduled for an upper endoscopy, and a sample identified from primary care clinics. Participants underwent an esophagogastroduodenoscopy and completed a survey that captured information on sociodemographic and clinical factors, as well as birth information. We compared 263 patients with histologically confirmed BE to 1416 controls without BE on endoscopy. Odds ratios (ORs) and 95 % confidence intervals (CIs) were calculated using multivariate logistic regression.

RESULTS

Premature birth was independently associated with risk of BE after adjusted by age, sex, race, and other birth characteristics (OR 3.28, 95 % CI 1.22-8.79). On the other hand, large for gestational age was inversely associated with risk of BE (OR 0.46, 95 % CI 0.21-0.98). These effects were stronger for patients with long-segment BE than with short-segment BE. The associations were not mediated by gastroesophageal reflux disease symptoms, use of proton pump inhibitors, Helicobacter Pylori infection, waist-hip-ratio, height or the presence of hiatus hernia.

CONCLUSIONS

Premature birth and large for gestational age may be associated with risk of BE in adults. These associations do not appear to be mediated through known risk factors for BE; however, additional studies are required to confirm our findings.

The Male Predominance in Esophageal Adenocarcinoma

The incidence of esophageal adenocarcinoma (EAC) has increased rapidly during the past 4 decades in many Western populations, including North America and Europe. The established etiological factors for EAC include gastroesophageal reflux and obesity, Helicobacter pylori infection, tobacco smoking, and consumption of fruit and vegetables. There is a marked male predominance of EAC with a male-to-female ratio in incidence of up to 9:1. This review evaluates the available literature on the reasons for the male predominance, particularly an update on epidemiologic evidence from human studies during the past decade. The striking sex difference does not seem to be explained by established risk factors, given that the prevalence of the etiological factors and the strengths of associations between these factors and EAC risk are similar between the sexes. Sex hormonal factors may play a role in the development of EAC; estrogenic exposures may prevent such development, whereas androgens might increase the risk of EAC. However, continuing research efforts are still needed to fully understand the reasons for the male predominance of EAC.

Adult height, nutrition, and population health

In this review, the potential causes and consequences of adult height, a measure of cumulative net nutrition, in modern populations are summarized. The mechanisms linking adult height and health are examined, with a focus on the role of potential confounders. Evidence across studies indicates that short adult height (reflecting growth retardation) in low- and middle-income countries is driven by environmental conditions, especially net nutrition during early years. Some of the associations of height with health and social outcomes potentially reflect the association between these environmental factors and such outcomes. These conditions are manifested in the substantial differences in adult height that exist between and within countries and over time. This review suggests that adult height is a useful marker of variation in cumulative net nutrition, biological deprivation, and standard of living between and within populations and should be routinely measured. Linkages between adult height and health, within and across generations, suggest that adult height may be a potential tool for monitoring health conditions and that programs focused on offspring outcomes may consider maternal height as a potentially important influence.

Epidemiology, Diagnosis, and Management of Esophageal Adenocarcinoma

Esophageal adenocarcinoma (EAC) is rapidly increasing in incidence in Western cultures. Barrett's esophagus is the presumed precursor lesion for this cancer. Several other risk factors for this cancer have been described, including chronic heartburn, tobacco use, white race, and obesity. Despite these known associations, most patients with EAC present with symptoms of dysphagia from late-stage tumors; only a small number of patients are identified by screening and surveillance programs. Diagnostic analysis of EAC usually commences with upper endoscopy followed by cross-sectional imaging. Endoscopic ultrasonography is useful to assess the local extent of disease as well as the involvement of regional lymph nodes. T1a EAC may be treated endoscopically, and some patients with T1b disease may also benefit from endoscopic therapy. Locally advanced disease is generally managed with esophagectomy, often accompanied by neoadjuvant chemoradiotherapy or chemotherapy. The prognosis is based on tumor stage; patients with T1a tumors have an excellent prognosis, whereas few patients with advanced disease have long-term survival.

General and abdominal obesity and risk of esophageal and gastric adenocarcinoma in the European Prospective Investigation into Cancer and Nutrition

General obesity, as reflected by BMI, is an established risk factor for esophageal adenocarcinoma (EAC), a suspected risk factor for gastric cardia adenocarcinoma (GCC) and appears unrelated to gastric non-cardia adenocarcinoma (GNCC). How abdominal obesity, as commonly measured by waist circumference (WC), relates to these cancers remains largely unexplored. Using measured anthropometric data from 391,456 individuals from the European Prospective Investigation into Cancer and Nutrition (EPIC) study and 11 years of follow-up, we comprehensively assessed the association of anthropometric measures with risk of EAC, GCC and GNCC using multivariable proportional hazards regression. One hundred twenty-four incident EAC, 193 GCC and 224 GNCC were accrued. After mutual adjustment, BMI was unrelated to EAC, while WC showed a strong positive association (highest vs. lowest quintile HR = 1.19; 95% CI, 0.63-2.22 and HR = 3.76; 1.72-8.22, respectively). Hip circumference (HC) was inversely related to EAC after controlling for WC, while WC remained positively associated (HR = 0.35; 0.18-0.68, and HR=4.10; 1.94-8.63, respectively). BMI was not associated with GCC or GNCC. WC was related to higher risks of GCC after adjustment for BMI and more strongly after adjustment for HC (highest vs. lowest quintile HR = 1.91; 1.09-3.37, and HR = 2.23; 1.28-3.90, respectively). Our study demonstrates that abdominal, rather than general, obesity is an indisputable risk factor for EAC and also provides evidence for a protective effect of gluteofemoral (subcutaneous) adipose tissue in EAC. Our study further shows that general obesity is not a risk factor for GCC and GNCC, while the role of abdominal obesity in GCC needs further investigation.

A review of the epidemiology of Barrett's oesophagus and oesophageal adenocarcinoma

While the incidence rates of many cancers have decreased in past decades, the incidence of oesophageal adenocarcinoma continues to increase. The only known precursor for oesophageal adenocarcinoma is Barrett's oesophagus. Studies conducted have identified white race, male sex, GORD, cigarette smoking, obesity, and the absence of Helicobacter pylori status as risk factors for oesophageal adenocarcinoma. Other potential associations include dietary factors and the absence of non-steroidal anti-inflammatory drug use. Many individual studies have been limited by sample size and several meta-analyses have pooled data from studies to address this limitation. In this review we present a synthesis of these studies and summarize current knowledge of risk factors for both oesophageal adenocarcinoma and Barrett's oesophagus.