Genetic evidence that higher central adiposity causes gastro-oesophageal reflux disease: a Mendelian randomization study

Colorectal cancer risk stratification using a polygenic risk score in symptomatic primary care patients-a UK Biobank retrospective cohort study

Colorectal cancer (CRC) is a leading cause of cancer mortality worldwide. Accurate cancer risk assessment approaches could increase rates of early CRC diagnosis, improve health outcomes for patients and reduce pressure on diagnostic services. The faecal immunochemical test (FIT) for blood in stool is widely used in primary care to identify symptomatic patients with likely CRC. However, there is a 6-16% noncompliance rate with FIT in clinic and ~90% of patients over the symptomatic 10 µg/g test threshold do not have CRC. A polygenic risk score (PRS) quantifies an individual's genetic risk of a condition based on many common variants. Existing PRS for CRC have so far been used to stratify asymptomatic populations. We conducted a retrospective cohort study of 50,387 UK Biobank participants with a CRC symptom in their primary care record at age 40+. A PRS based on 201 variants, 5 genetic principal components and 22 other risk factors and markers for CRC were assessed for association with CRC diagnosis within 2 years of first symptom presentation using logistic regression. Associated variables were included in an integrated risk model and trained in 80% of the cohort to predict CRC diagnosis within 2 years. An integrated risk model combining PRS, age, sex, and patient-reported symptoms was predictive of CRC development in a testing cohort (receiver operating characteristic area under the curve, ROCAUC: 0.76, 95% confidence interval: 0.71-0.81). This model has the potential to improve early diagnosis of CRC, particularly in cases of patient noncompliance with FIT.

Socioeconomic traits and the risk of Barrett’s esophagus and gastroesophageal reflux disease: A Mendelian randomization study

BACKGROUND

Previous observational studies have shown that the prevalence of gastroesophageal reflux disease (GERD) and Barrett’s esophagus (BE) is associated with socioeconomic status. However, due to the methodological limitations of traditional observational studies, it is challenging to definitively establish causality.

AIM

To explore the causal relationship between the prevalence of these conditions and socioeconomic status using Mendelian randomization (MR).

METHODS

We initially screened single nucleotide polymorphisms (SNPs) to serve as proxies for eight socioeconomic status phenotypes for univariate MR analysis. The inverse variance weighted (IVW) method was used as the primary analytical method to estimate the causal relationship between the eight socioeconomic status phenotypes and the risk of GERD and BE. We then collected combinations of SNPs as composite proxies for the eight socioeconomic phenotypes to perform multivariate MR (MVMR) analyses based on the IVW MVMR model. Furthermore, a two-step MR mediation analysis was used to examine the potential mediation of the associations by body mass index, major depressive disorder (MDD), smoking, alcohol consumption, and sleep duration.

RESULTS

The study identified three socioeconomic statuses that had a significant impact on GERD. These included household income [odds ratio (OR): 0.46; 95% confidence interval (95%CI): 0.31-0.70], education attainment (OR: 0.23; 95%CI: 0.18-0.29), and the Townsend Deprivation Index at recruitment (OR: 1.57; 95%CI: 1.04-2.37). These factors were found to independently and predominantly influence the genetic causal effect of GERD. Furthermore, the mediating effect of educational attainment on GERD was found to be mediated by MDD (proportion mediated: 10.83%). Similarly, the effect of educational attainment on BE was mediated by MDD (proportion mediated: 10.58%) and the number of cigarettes smoked per day (proportion mediated: 3.50%). Additionally, the mediating effect of household income on GERD was observed to be mediated by sleep duration (proportion mediated: 9.75%)

CONCLUSION

This MR study shed light on the link between socioeconomic status and GERD or BE, providing insights for the prevention of esophageal cancer and precancerous lesions.

Socioeconomic traits and the risk of Barrett's esophagus and gastroesophageal reflux disease: A Mendelian randomization study

BACKGROUND

Previous observational studies have shown that the prevalence of gastroesophageal reflux disease (GERD) and Barrett's esophagus (BE) is associated with socioeconomic status. However, due to the methodological limitations of traditional observational studies, it is challenging to definitively establish causality.

AIM

To explore the causal relationship between the prevalence of these conditions and socioeconomic status using Mendelian randomization (MR).

METHODS

We initially screened single nucleotide polymorphisms (SNPs) to serve as proxies for eight socioeconomic status phenotypes for univariate MR analysis. The inverse variance weighted (IVW) method was used as the primary analytical method to estimate the causal relationship between the eight socioeconomic status phenotypes and the risk of GERD and BE. We then collected combinations of SNPs as composite proxies for the eight socioeconomic phenotypes to perform multivariate MR (MVMR) analyses based on the IVW MVMR model. Furthermore, a two-step MR mediation analysis was used to examine the potential mediation of the associations by body mass index, major depressive disorder (MDD), smoking, alcohol consumption, and sleep duration.

RESULTS

The study identified three socioeconomic statuses that had a significant impact on GERD. These included household income [odds ratio (OR): 0.46; 95% confidence interval (95%CI): 0.31-0.70], education attainment (OR: 0.23; 95%CI: 0.18-0.29), and the Townsend Deprivation Index at recruitment (OR: 1.57; 95%CI: 1.04-2.37). These factors were found to independently and predominantly influence the genetic causal effect of GERD. Furthermore, the mediating effect of educational attainment on GERD was found to be mediated by MDD (proportion mediated: 10.83%). Similarly, the effect of educational attainment on BE was mediated by MDD (proportion mediated: 10.58%) and the number of cigarettes smoked per day (proportion mediated: 3.50%). Additionally, the mediating effect of household income on GERD was observed to be mediated by sleep duration (proportion mediated: 9.75%).

CONCLUSION

This MR study shed light on the link between socioeconomic status and GERD or BE, providing insights for the prevention of esophageal cancer and precancerous lesions.

Hyperglycaemia is a causal risk factor for upper limb pathologies

BACKGROUND

Diabetes (regardless of type) and obesity are associated with a range of musculoskeletal disorders. The causal mechanisms driving these associations are unknown for many upper limb pathologies. We used genetic techniques to test the causal link between glycemia, obesity and musculoskeletal conditions.

METHODS

In the UK Biobank's unrelated European cohort (N = 379 708) we performed mendelian randomisation (MR) analyses to test for a causal effect of long-term high glycaemia and adiposity on four musculoskeletal pathologies: frozen shoulder, Dupuytren's disease, carpal tunnel syndrome and trigger finger. We also performed single-gene MR using rare variants in the GCK gene.

RESULTS

Using MR, we found evidence that long-term high glycaemia has a causal role in the aetiology of upper limb conditions. A 10-mmol/mol increase in genetically predicted haemoglobin A1C (HbA1c) was associated with frozen shoulder: odds ratio (OR) = 1.50 [95% confidence interval (CI), 1.20-1.88], Dupuytren's disease: OR = 1.17 (95% CI, 1.01-1.35), trigger finger: OR = 1.30 (95% CI, 1.09-1.55) and carpal tunnel syndrome: OR = 1.20 (95% CI, 1.09-1.33). Carriers of GCK mutations have increased odds of frozen shoulder: OR = 7.16 (95% CI, 2.93-17.51) and carpal tunnel syndrome: OR = 2.86 (95% CI, 1.50-5.44) but not Dupuytren's disease or trigger finger. We found evidence that an increase in genetically predicted body mass index (BMI) of 5 kg/m2 was associated with carpal tunnel syndrome: OR = 1.13 (95% CI, 1.10-1.16) and associated negatively with Dupuytren's disease: OR = 0.94 (95% CI, 0.90-0.98), but no evidence of association with frozen shoulder or trigger finger. Trigger finger (OR 1.96 (95% CI, 1.42-2.69) P = 3.6e-05) and carpal tunnel syndrome [OR 1.63 (95% CI, 1.36-1.95) P = 8.5e-08] are associated with genetically predicted unfavourable adiposity increase of one standard deviation of body fat.

CONCLUSIONS

Our study consistently demonstrates a causal role of long-term high glycaemia in the aetiology of upper limb musculoskeletal conditions. Clinicians treating diabetes patients should be aware of these complications in clinic, specifically those managing the care of GCK mutation carriers. Upper limb musculoskeletal conditions should be considered diabetes complications.

Exploring the causality between educational attainment and gastroesophageal reflux disease: A Mendelian randomization study

BACKGROUND AND OBJECTIVES

Observational studies suggest that higher educational attainment (EA) contributes to the prevention and treatment of gastroesophageal reflux disease (GERD). However, the causality of this relationship is not supported by strong evidence. We used publicly available genetic summary data, including that on EA, GERD, and the common risk of GERD, to prove this causality.

METHODS

Multiple methods in Mendelian randomization (MR) were employed to evaluate the causality. The leave-one-out sensitivity test, MR-Egger regression, and multivariable MR (MVMR) analysis were applied to evaluate the MR results.

RESULTS

Higher EA was significantly associated with lower GERD risk (inverse variance weighted method, odds ratio [OR]: 0.979, 95% confidence interval [CI]: 0.975-0.984, P <0.001). Similar results were obtained when the weighted median and weighted mode were used for causal estimation. After adjusting for potential mediators, the MVMR analysis showed that body mass index (BMI) and EA were still significantly correlated and negatively correlated with GERD (OR: 0.997, 95% CI: 0.996-0.998, P =0.008 and OR: 0.981, 95% CI: 0.977-0.984, P <0.001), respectively.

CONCLUSIONS

Higher levels of EA may have a protective effect against GERD by having a negative causal relationship. Additionally, BMI may be a crucial factor in the EA-GERD pathway.

Shift work and risk of incident gastroesophageal reflux disease: the association and mediation

Introduction

Shift work has become an increasingly common work mode globally. This study aimed to investigate the association between shift work and the risk of incident gastroesophageal reflux disease (GORD), an upward gastrointestinal disorder disease worldwide, and to explore the mediating factors.

Method

A total of 262,722 participants from the UK Biobank free of GORD and related gastrointestinal diseases were included to investigate the association and potential mediators between shift work and incident GORD. Multivariate-adjusted Cox models were used to evaluate the association between shift work status and GORD incidence.

Results

Compared to non-shift workers, shift workers had a 1.10-fold greater risk of incident GORD [95% confidence intervals (CIs): 1.03, 1.18], after adjusting for a range of potential confounders. However, the excess risk of GORD attenuated to the null after further adjusting for selected mediators. Specifically, the association was mediated by sleep patterns (25.7%), healthy behaviors (16.8%), depressive symptoms (20.2%), chronic conditions (13.3%), and biological factors (17.6%). After adjustment for all the mediators together, the association was attenuated by 71.5%.

Discussion

Our findings indicated that long-term shift workers may have a higher risk of incident GORD, yet the excess risk may be explained by poor sleep quality, unhealthy behaviors, depressive symptoms, etc. This has positive implications for protecting the health of shift workers.

Causal analysis between gastro-oesophageal reflux disease and obstructive sleep apnoea

Background

Based on evidence from existing observational research, clarifying the causal relationship between gastro-oesophageal reflux disease (GORD) and obstructive sleep apnoea (OSA) is challenging. Here, Mendelian randomisation, a method based on genetics, was used to provide new evidence for causality.

Methods

Summary statistics from two publicly available genome-wide association studies were used to evaluate the causal relationship between GORD and OSA (the GORD database was used as an exposure variable and the OSA database as an outcome). Inverse variance weighting was used as the main analytical tool in Mendelian randomisation to estimate causal effects. The robustness of the results was evaluated by sensitivity analysis. Possible mediators were evaluated using multivariate Mendelian randomisation.

Results

A statistically significant causal relationship was observed between GORD and OSA (OR 1.597, 95% CI 1.401-1.821, p<0.001), and similar results were observed in weighted median and Mendelian randomisation-Egger regression analyses. No bias was found in the sensitivity analysis of Mendelian randomisation estimation. Multivariate Mendelian randomisation showed that GORD significantly increased the risk of developing OSA, even when the possible mediator was excluded (OR 1.107, 95% CI 1.101-1.212, p<0.001).

Conclusion

Our study confirmed a causal relationship between GORD and OSA and suggests that intervention measures should be taken for patients with GORD to prevent the occurrence of OSA.

Causal links between socioeconomic status, leisure sedentary behaviours and gastro-oesophageal reflux disease: a multivariable two-sample Mendelian randomisation study

INTRODUCTION

We implemented a two-sample multivariable Mendelian randomisation (MR) analyses to estimate the causal effect of socioeconomic status and leisure sedentary behaviours on gastro-oesophageal reflux disease (GERD).

METHODS

Independent single-nucleotide polymorphisms associated with socioeconomic status and leisure sedentary behaviours at the genome-wide significance level from the Medical Research Council Integrative Epidemiology Unit (MRC-IEU) UK Biobank were selected as instrumental variables. Summary-level data for GERD were obtained from a recent publicly available genome-wide association involving 78 707 GERD cases and 288 734 controls of European descent. Univariable and multivariable two-sample MR analyses, using inverse variance weighted method for primary analyses, were performed to jointly evaluate the effect of socioeconomic status and leisure sedentary behaviours on GERD risk.

RESULTS

Three socioeconomic status, including educational attainment (OR 0.46; 95% CI 0.30 to 0.69; p<0.001), average total household income before tax (OR 0.65; 95% CI 0.47 to 0.90; p=0.009) and Townsend Deprivation Index at recruitment (OR 1.60; 95% CI 1.06 to 2.41; p=0.026), were independently and predominately responsible for the genetic causal effect on GERD. In addition, one leisure sedentary behaviour, such as time spent watching television, was independently and predominately responsible for genetic causal effect on GERD (OR 3.74; 95% CI 2.89 to 4.84; p<0.001). No causal effects of social activities and driving on GERD were observed.

CONCLUSIONS

Genetically predicted Townsend Deprivation Index at recruitment and leisure watching television were causally associated with increased risk of GERD, and age at completion of full-time education and average total household income before tax were causally associated with decreased risk of GERD.

Association of educational attainment with esophageal cancer, Barrett's esophagus, and gastroesophageal reflux disease, and the mediating role of modifiable risk factors: A Mendelian randomization study

Background

Observational studies have reported that educational attainment has been related to the risk of esophageal cancer (EC) and its precancerous lesions. However, the causal relationship remains controversial. We aimed to apply the Mendelian randomization (MR) design to determine the causal associations between genetically predicted educational attainment and EC, Barrett's esophagus (BE), and gastroesophageal reflux disease (GERD), and to explore whether modifiable risk factors play a mediating role.

Methods

Using summary statistics from genome-wide association studies (GWASs) based on European ancestry individuals of several years in education (EduYears, primary analysis, n = 293,723), college completion (College, secondary analysis, n = 95,427), EC (n = 420,531), BE (n = 361,194), and GERD (n = 420,531), genetic associations between two education phenotypes and EC, BE, and GERD were tested by two-sample MR analyses. Then, two-step MR mediation analyses were used to assess the proportion of the aforementioned association that might be mediated by body mass index (BMI), major depressive disorder (MDD), smoking, drinking, carbohydrates, fat, and protein intake.

Results

Genetically predicted EduYears was negatively associated with the risk of EC, BE, and GERD {odds ratio (OR), 0.64 [95% confidence interval (CI) 0.44–0.94], 0.86 (95% CI, 0.75–0.99), and 0.62 (95%CI, 0.58–0.67)}. EduYears was negatively associated with BMI, MDD, and smoking (range of OR: 0.76–0.84). There were positive associations between BMI, smoking with EC, BE, and GERD, as well as between MDD with GERD (range of OR: 1.08–1.50). For individual mediating effect, BMI and smoking mediated 15.75 and 14.15% of the EduYears-EC association and 15.46 and 16.85% of the EduYears-BE association. BMI, MDD, and smoking mediated 5.23, 4.98, and 4.49% of the EduYears-GERD association. For combined mediation, the aforementioned mediators explained 26.62, 28.38, and 11.48% of the effect of EduYears on EC, BE, and GERD. The mediating effects of drinking and dietary composition were not significant in the effect of education on EC, BE, and GERD.

Conclusion

Our study supports that genetically predicted higher educational attainment has a protective effect on EC, BE, and GERD, and is partly mediated by reducing adiposity, smoking, and depression.

Body Composition and COPD: A New Perspective

The proportion of obese or overweight patients in COPD patients is increasing. Although BMI, WC and other easy to measure indicators have been proven to be related to the risk of COPD, they cannot accurately reflect the distribution and changes of body composition, ignoring the body composition (such as fat distribution, muscle content, water content, etc.), the relationship between it and disease risk may be missed. By analyzing the correlation between different body composition indexes and COPD patients, we can provide new research ideas for the prognosis judgment or intervention of COPD disease.

Mendelian Randomization Analysis Reveals a Complex Genetic Interplay among Atopic Dermatitis, Asthma, and Gastroesophageal Reflux Disease

Rationale: Gastroesophageal reflux disease (GERD) is commonly associated with atopic disorders, but cause-effect relationships remain unclear. Objectives: We applied Mendelian randomization analysis to explore whether GERD is causally related to atopic disorders of the lung (asthma) and/or skin (atopic dermatitis [AD]). Methods: We conducted two-sample bidirectional Mendelian randomization to infer the magnitude and direction of causality between asthma and GERD, using summary statistics from the largest genome-wide association studies conducted on asthma (Ncases = 56,167) and GERD (Ncases = 71,522). In addition, we generated instrumental variables for AD from the latest population-level genome-wide association study meta-analysis (Ncases = 22,474) and assessed their fidelity and confidence of predicting the likely causal pathway(s) leading to asthma and/or GERD. Measurements and Main Results: Applying three different methods, each method revealed similar magnitude of causal estimates that were directionally consistent across the sensitivity analyses. Using an inverse variance-weighted method, the largest effect size was detected for asthma predisposition to AD (odds ratio [OR], 1.46; 95% confidence interval [CI], 1.34-1.59), followed by AD to asthma (OR, 1.34; 95% CI, 1.24-1.45). A significant association was detected for genetically determined asthma on risk of GERD (OR, 1.06; 95% CI, 1.03-1.09) but not genetically determined AD on GERD. In contrast, GERD equally increased risks of asthma (OR, 1.21; 95% CI, 1.09-1.35) and AD (OR, 1.21; 95% CI, 1.07-1.37). Conclusions: This study uncovers previously unrecognized causal pathways that have clinical implications in European-ancestry populations: 1) asthma is a causal risk for AD, and 2) the predisposition to AD, including asthma, can arise from specific pathogenic mechanisms manifested by GERD.

Genetic estimation of correlations and causalities between multifaceted modifiable factors and gastro-oesophageal reflux disease

BACKGROUND

Gastro-oesophageal reflux disease (GORD) is a common gastrointestinal dysfunction that significantly affects the quality of daily life, and health interventions are challenging to prevent the risk of GORD. In this study, we used Mendelian randomization framework to genetically determine the causal associations between multifaceted modifiable factors and the risk of GORD.

MATERIALS AND METHODS

Sixty-six exposures with available instrumental variables (IVs) across 6 modifiable pathways were included in the univariable MR analysis (UVMR). Summary-level genome-wide association studies (GWAS) datasets for GORD were retrieved from the Neale Lab (GORD _Neale , Ncases = 29975, Ncontrols = 390556) and FinnGen (GORD _Finn , Ncases = 13141, Ncontrols = 89695). Using the METAL software, meta-analysis for single nucleotide polymorphisms (SNPs) from GORD _Neale and GORD _Finn was conducted with an inverse variance weighted (IVW) fixed-effect model. Moreover, we leveraged partition around medoids (PAM) clustering algorithm to cluster genetic correlation subtypes, whose hub exposures were conditioned for multivariable MR (MVMR) analyses. P-values were adjusted with Bonferroni multiple comparisons.

RESULTS

Significant causal associations were identified between 26 exposures (15 risk exposures and 11 protective exposures) and the risk of GORD. Among them, 13 risk exposures [lifetime smoking, cigarette consumption, insomnia, short sleep, leisure sedentary behavior (TV watching), body mass index (BMI), body fat percentage, whole body fat mass, visceral adipose tissue, waist circumference, hip circumference, major depressive disorder, and anxious feeling], and 10 protective exposures (leisure sedentary behavior (computer use), sitting height, hand grip strength (left and right), birth weight, life satisfaction, positive affect, income, educational attainment, and intelligence) showed novel significant causal associations with the risk of GORD. Moreover, 13 exposures still demonstrated independent associations with the risk of GORD following MVMR analyses conditioned for hub exposures (educational attainment, smoking initiation and BMI). In addition, 12 exposures showed suggestive causal associations with the risk of GORD.

CONCLUSION

This study systematically elucidated the modifiable factors causally associated with the risk of GORD from multifaceted perspectives, which provided implications for prevention and treatment of GORD.

Association between the body mass index, waist circumference, and body fat percentage with erosive esophagitis in adults with obesity after sleeve gastrectomy

Background: High anthropometric indexes before sleeve gastrectomy (SG) are associated with an increased risk of erosive esophagitis (EE) in bariatric surgery candidates. Reasons that explain how these indexes influence the development of esophageal pathology after surgery remains unclear. Objectives: To assess the association between the body mass index (BMI), waist circumference (WC), and body fat percentage (BFP) with the development of EE in adults with obesity three months after SG. Setting: Clínica Avendaño, Lima, Peru. Methods: Retrospective cohort using a database including adults with obesity who underwent SG during 2017-2020. All the patients included had an endoscopy before and after the surgery. Sociodemographic, clinical and laboratory characteristics were compared according to BMI, WC and BFP, as well as by the development of de novo esophagitis. The association was evaluated by crude and adjusted generalized linear models with the log-Poisson family. Results: From a total of 106 patients, 23 (21.7%) developed EE. We did not find significant differences in sociodemographic, clinical and laboratory characteristics between patients with de novo EE compared to those who did not develop EE. After adjustment, BMI (aRR = 0.59, 95% CI = 0.18-1.40), BFP (aRR = 0.41, 95% CI = 0.15-1.19) and WC (aRR = 0.91, 95% CI = 0.69-1.16) were not associated with the development of EE three months post SG. Conclusions: We found no association between preoperative anthropometric indexes and the development of de novo EE; therefore, morbid obesity should not be a criterion to exclude the patients to undergo SG as primary surgery because of the risk of developing EE.

Adiposity, diabetes, lifestyle factors and risk of gastroesophageal reflux disease: a Mendelian randomization study

Adiposity, diabetes, and lifestyle factors are linked to gastroesophageal reflux disease (GERD) in observational studies. We conducted a two-sample Mendelian randomization analysis to determine whether those associations are causal. Independent genetic variants associated with body mass index (BMI), waist circumference (with and without adjustment for BMI), type 2 diabetes, smoking, and alcohol, coffee and caffeine consumption at the genome-wide significance level were selected as instrumental variables. Summary-level data for GERD were available from a genome-wide association meta-analysis of 71,522 GERD cases and 261,079 controls of European descent from the UK Biobank and QSkin Sun and Health studies. The odds ratio (OR) of GERD was 1.49 (95% confidence interval (CI), 1.40-1.60) for one standard deviation (SD) increase in BMI, 1.07 (95% CI, 1.04-1.10) for one-unit increase in log-transformed OR of type 2 diabetes, and 1.41 (95% CI, 1.31-1.52) for one SD increase in prevalence of smoking initiation. There were suggestive associations with GERD for higher genetically predicted waist circumference (OR per one SD increase, 1.14, 95% CI, 1.02-1.26) and caffeine consumption (OR per 80 mg increase, 1.08, 95% CI, 1.02-1.15). Genetically predicted waist circumference adjusted for BMI, alcohol or coffee consumption was not associated GERD. This study suggests causal roles of adiposity, diabetes, and smoking, and a possible role of high caffeine consumption in the development of GERD.

Disease consequences of higher adiposity uncoupled from its adverse metabolic effects using Mendelian randomisation

Background

Some individuals living with obesity may be relatively metabolically healthy, whilst others suffer from multiple conditions that may be linked to adverse metabolic effects or other factors. The extent to which the adverse metabolic component of obesity contributes to disease compared to the non-metabolic components is often uncertain. We aimed to use Mendelian randomisation (MR) and specific genetic variants to separately test the causal roles of higher adiposity with and without its adverse metabolic effects on diseases.

Methods

We selected 37 chronic diseases associated with obesity and genetic variants associated with different aspects of excess weight. These genetic variants included those associated with metabolically 'favourable adiposity' (FA) and 'unfavourable adiposity' (UFA) that are both associated with higher adiposity but with opposite effects on metabolic risk. We used these variants and two sample MR to test the effects on the chronic diseases.

Results

MR identified two sets of diseases. First, 11 conditions where the metabolic effect of higher adiposity is the likely primary cause of the disease. Here, MR with the FA and UFA genetics showed opposing effects on risk of disease: coronary artery disease, peripheral artery disease, hypertension, stroke, type 2 diabetes, polycystic ovary syndrome, heart failure, atrial fibrillation, chronic kidney disease, renal cancer, and gout. Second, 9 conditions where the non-metabolic effects of excess weight (e.g. mechanical effect) are likely a cause. Here, MR with the FA genetics, despite leading to lower metabolic risk, and MR with the UFA genetics, both indicated higher disease risk: osteoarthritis, rheumatoid arthritis, osteoporosis, gastro-oesophageal reflux disease, gallstones, adult-onset asthma, psoriasis, deep vein thrombosis, and venous thromboembolism.

Conclusions

Our results assist in understanding the consequences of higher adiposity uncoupled from its adverse metabolic effects, including the risks to individuals with high body mass index who may be relatively metabolically healthy.

Funding

Diabetes UK, UK Medical Research Council, World Cancer Research Fund, National Cancer Institute.

Effects of Coffee on the Gastro-Intestinal Tract: A Narrative Review and Literature Update

The objective of the present research was to review the state of the art on the consequences of drinking coffee at the different levels of the gastrointestinal tract. At some steps of the digestive process, the effects of coffee consumption seem rather clear. This is the case for the stimulation of gastric acid secretion, the stimulation of biliary and pancreatic secretion, the reduction of gallstone risk, the stimulation of colic motility, and changes in the composition of gut microbiota. Other aspects are still controversial, such as the possibility for coffee to affect gastro-esophageal reflux, peptic ulcers, and intestinal inflammatory diseases. This review also includes a brief summary on the lack of association between coffee consumption and cancer of the different digestive organs, and points to the powerful protective effect of coffee against the risk of hepatocellular carcinoma. This review reports the available evidence on different topics and identifies the areas that would most benefit from additional studies.

Causal role of high body mass index in multiple chronic diseases: a systematic review and meta-analysis of Mendelian randomization studies

BACKGROUND

Obesity is a worldwide epidemic that has been associated with a plurality of diseases in observational studies. The aim of this study was to summarize the evidence from Mendelian randomization (MR) studies of the association between body mass index (BMI) and chronic diseases.

METHODS

PubMed and Embase were searched for MR studies on adult BMI in relation to major chronic diseases, including diabetes mellitus; diseases of the circulatory, respiratory, digestive, musculoskeletal, and nervous systems; and neoplasms. A meta-analysis was performed for each disease by using results from published MR studies and corresponding de novo analyses based on summary-level genetic data from the FinnGen consortium (n = 218,792 individuals).

RESULTS

In a meta-analysis of results from published MR studies and de novo analyses of the FinnGen consortium, genetically predicted higher BMI was associated with increased risk of type 2 diabetes mellitus, 14 circulatory disease outcomes, asthma, chronic obstructive pulmonary disease, five digestive system diseases, three musculoskeletal system diseases, and multiple sclerosis as well as cancers of the digestive system (six cancer sites), uterus, kidney, and bladder. In contrast, genetically predicted higher adult BMI was associated with a decreased risk of Dupuytren's disease, osteoporosis, and breast, prostate, and non-melanoma cancer, and not associated with Alzheimer's disease, amyotrophic lateral sclerosis, or Parkinson's disease.

CONCLUSIONS

The totality of the evidence from MR studies supports a causal role of excess adiposity in a plurality of chronic diseases. Hence, continued efforts to reduce the prevalence of overweight and obesity are a major public health goal.

Assessing the genetic relationship between gastro-esophageal reflux disease and risk of COVID-19 infection

Background

Symptoms related with Gastro-esophageal reflux disease (GERD) were previously shown to be linked with increased risk for the 2019 coronavirus disease (COVID-19). We aim to interrogate the possibility of a shared genetic basis between GERD and COVID-19 outcomes.

Methods

Using published GWAS data for GERD (78 707 cases; 288 734 controls) and COVID-19 susceptibility (up to 32 494 cases; 1.5 million controls), we examined the genetic relationship between GERD and three COVID-19 outcomes: risk of developing severe COVID-19, COVID-19 hospitalization and overall COVID-19 risk. We estimated the genetic correlation between GERD and COVID-19 outcomes followed by Mendelian randomization (MR) analyses to assess genetic causality. Conditional analyses were conducted to examine whether known COVID-19 risk factors (obesity, smoking, type-II diabetes, coronary artery disease) can explain the relationship between GERD and COVID-19.

Results

We found small to moderate genetic correlations between GERD and COVID-19 outcomes (rg between 0.06–0.24). MR analyses revealed a OR of 1.15 (95% CI: 0.96–1.39) for severe COVID-19; 1.16 (1.01–1.34) for risk of COVID-19 hospitalization; 1.05 (0.97–1.13) for overall risk of COVID-19 per doubling of odds in developing GERD. The genetic correlation/associations between GERD and COVID-19 showed mild attenuation towards the null when obesity and smoking was adjusted for.

Conclusions

Susceptibility for GERD and risk of COVID-19 hospitalization were genetically correlated, with MR findings supporting a potential causal role between the two. The genetic association between GERD and COVID-19 was partially attenuated when obesity is accounted for, consistent with obesity being a major risk factor for both diseases.

Can lower preoperative 48-hour pH score predict reflux resolution after sleeve gastrectomy

BACKGROUND

Morbidly-obese patients with reflux who are undergoing sleeve gastrectomy (SG) may experience resolution, or persistent reflux. We studied factors associated with reflux resolution after SG.

METHOD

We evaluated baseline weight, body mass index, and DeMeester score (DMS) in patients with reflux undergoing SG. Outcome measure was resolution of reflux post-operatively.

RESULTS

Study group included 70 patients; 33 (47.1%) patients reported resolution of reflux (RR group) after surgery; 37 (52.9%) patients didn't have resolution (NR group). Pre-operative weight, body mass index, percent excess BMI loss and presence of ≤2 cm hiatal hernia (HH) were similar between the two groups. Males and lower pre-operative DMS were associated with resolution of reflux (18.4 ± 13 vs. 29.1 ± 26, p = 0.03).

CONCLUSION

Lower pre-SG DeMeester score tend to imply ability to resolve reflux in morbidly-obese patients thus, SG may still be offered, without repair of ≤2 cm HH if present. Unfortunately, it can't be used as the only factor.