Habitual coffee intake and risk for nonalcoholic fatty liver disease: a two-sample Mendelian randomization study

Association of Sugar-Sweetened, Artificially Sweetened, and Unsweetened Coffee Consumption with Chronic Liver Disease and Liver-Related Events: A Large Prospective Cohort Study

BACKGROUND

Previous observational studies have not reached an agreement on the association between coffee consumption and risk of liver diseases. Also, none of these studies took sweetener added in coffee into consideration.

OBJECTIVES

We aim to explore the associations of consumption of sweetened and unsweetened coffee with chronic liver disease (CLD) and liver-related events (LREs), and evaluate the degree to which sweetener added counteracted the effect of coffee.

METHODS

We performed a longitudinal cohort study of 170,044 participants without liver diseases or cancer at baseline investigation (2006-2010) and followed until 2022. Consumption of coffee and sweetener was assessed by 24-h dietary recall questionnaire. Cox proportional hazards models and restricted cubic splines were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

During a median follow-up of 12.4 y, we identified 4152 incident of CLD and 853 LREs. Compared with nonconsumers, unsweetened coffee consumers of various amount had lower risk of CLD (HR: 0.75; 95% CI: 0.67, 0.83 for 1.5∼2.5 drinks/d) and LREs (HR: 0.60; 95% CI: 0.46, 0.80 for 2.5∼3.5 drinks/d) in the multivariable Cox models. U-shaped associations of unsweetened coffee with CLD and LREs were observed. The results for sweetened coffee were less consistent and conclusive in both CLD and LREs. We detected positive associations between sweetener and CLD and LREs. Compared with unsweetened coffee consumers, consumers of different amount of sugar added to coffee had higher risk of CLD in the multivariable Cox model. For artificial sweetener, a significant higher risk of CLD (HR: 1.61; 95% CI: 1.25, 2.05)and LREs (HR: 1.82; 95% CI: 1.11, 2.98) was only found in those who added ≥2 teaspoons/drink. We detected significant interaction between artificial sweetener and coffee intake on the risk of CLD (HR for product term: 0.76; 95% CI: 0.60, 0.96; P = 0.018; relative excess risk due to interaction: -0.32; 95% CI: -0.58, -0.06).

CONCLUSIONS

Moderate consumption of unsweetened coffee was associated with lower risk of CLD and LREs. Adding sweetener into coffee could bring additional risk of liver diseases in coffee consumers.

Caffeine intake associated with a lower risk of liver fibrosis in different glucose status

BACKGROUND AND AIMS

To investigate the prevalence of liver fibrosis, and the association between caffeine intake and fibrosis in populations with different glucose metabolism status.

METHODS

This was a cross-sectional study based on the National Health and Nutrition Examination Survey (2005-March 2020). Of the 39,221 adult individuals with no necessary laboratory results missing, a total of 23,711 eligible individuals were included in the study. Individuals were divided into T2DM, prediabetes, and diabetes-free groups. Fibrosis-4 index was calculated to evaluate the risk of liver fibrosis. Caffeine intake was obtained through a 24-hour dietary recall.

RESULTS

The mean ± SE age of prediabetes group was 53 ± 0·4 years, and in type 2 diabetes mellitus group, the individuals have a mean ± SE age of 62 ± 0·3 years. The participants with type 2 diabetes mellitus had significantly higher risk of liver fibrosis than those with prediabetes or normal glucose tolerance (5·9% vs. 3·2% vs. 2·5%, P < 0·001). Compared to individuals with daily caffeine intake < 78 mg, individuals with daily caffeine intake ≥ 78 mg had significantly lower risk of liver fibrosis in all subgroups (odds ratio: diabetes-free group: 0·698[0·577-0·846]; prediabetes group: 0·553[0·397-0·769]; type 2 diabetes mellitus group: 0·720[0·556-0·933]; all P < 0·05).

CONCLUSIONS

Prevalence of liver fibrosis is high in patients with type 2 diabetes mellitus and prediabetes. It is indicated that individuals with prediabetes should also be screened for fibrosis. Caffeine intake ≥ 78 mg per day is associated with a lower risk of liver fibrosis.

Assessment of relationships between epigenetic age acceleration and multiple sclerosis: a bidirectional mendelian randomization study

BACKGROUND

The DNA methylation-based epigenetic clocks are increasingly recognized for their precision in predicting aging and its health implications. Although prior research has identified connections between accelerated epigenetic aging and multiple sclerosis, the chronological and causative aspects of these relationships are yet to be elucidated. Our research seeks to clarify these potential causal links through a bidirectional Mendelian randomization study.

METHODS

This analysis employed statistics approaches from genome-wide association studies related to various epigenetic clocks (GrimAge, HannumAge, PhenoAge, and HorvathAge) and multiple sclerosis, utilizing robust instrumental variables from the Edinburgh DataShare (n = 34,710) and the International Multiple Sclerosis Genetics Consortium (including 24,091 controls and 14,498 cases). We applied the inverse-variance weighted approach as our main method for Mendelian randomization, with additional sensitivity analyses to explore underlying heterogeneity and pleiotropy.

RESULTS

Using summary-based Mendelian randomization, we found that HannumAge was associated with multiple sclerosis (OR = 1.071, 95%CI:1.006-1.140, p = 0.033, by inverse-variance weighted). The results suggest that an increase in epigenetic age acceleration of HannumAge promotes the risk of multiple sclerosis. In reverse Mendelian randomization analysis, no evidence of a clear causal association of multiple sclerosis on epigenetic age acceleration was identified.

CONCLUSIONS

Our Mendelian randomization analysis revealed that epigenetic age acceleration of HannumAge was causally associated with multiple sclerosis, and provided novel insights for further mechanistic and clinical studies of epigenetic age acceleration-mediated multiple sclerosis.

Causality between gut microbiota, immune cells, and breast cancer: Mendelian randomization analysis

The association between gut microbiota (GM) and breast cancer (BC) has been studied. Nevertheless, the causal relationship between them and the potential mediating factors have not been clearly defined. Therefore, in this study, Mendelian randomization analysis (MR) was employed to explore the causal relationship between 473 GM and BC, as well as the mediating effect of potential immune cells. In this investigation, we availed ourselves of the publicly accessible summary statistics from the genome-wide association study to undertake two-sample and reverse Mendelian randomization analyses on GM and BC, with the intention of clarifying the causal association between GM and BC. Subsequently, through the application of the two-step Mendelian randomization analysis, it was revealed that the relationship between GM and BC was mediated by immune cells. The stability of the research outcomes was verified via sensitivity analysis. Mendelian randomization analysis elucidated the protective impacts of 8 genera on BC (such as Phylum Actinobacteriota, Species Bacteroides A plebeius A, Species Bifidobacterium adolescentis, Species CAG-841 sp002479075, Family Fibrobacteraceae, Order Fibrobacterales, Class Fibrobacteria, and Species Phascolarctobacterium sp003150755). Additionally, there are 23 immune cell traits related to BC. Our research findings showed that the species Megamonas funiformis was associated with an increased risk of BC, and 11.20% of this effect was mediated by CD38 on IgD+ CD24-. Likewise, HLA DR on CD33br HLA DR+ CD14- mediated the causal relationship between Species Prevotellamassilia and BC, having a mediating ratio of 7.89%. This study clarifies a potential causal relationship between GM, immune cells, and BC and provides genetic evidence for this causal connection. It offers research directions for the subsequent prevention and treatment of BC through the interaction between GM and immune cells, and provides a reference for future mechanistic and clinical studies in this field.

Coffee consumption and cardiometabolic health: a comprehensive review of the evidence

This review provides a comprehensive synthesis of longitudinal observational and interventional studies on the cardiometabolic effects of coffee consumption. It explores biological mechanisms, and clinical and policy implications, and highlights gaps in the evidence while suggesting future research directions. It also reviews evidence on the causal relationships between coffee consumption and cardiometabolic outcomes from Mendelian randomization (MR) studies. Findings indicate that while coffee may cause short-term increases in blood pressure, it does not contribute to long-term hypertension risk. There is limited evidence indicating that coffee intake might reduce the risk of metabolic syndrome and non-alcoholic fatty liver disease. Furthermore, coffee consumption is consistently linked with reduced risks of type 2 diabetes (T2D) and chronic kidney disease (CKD), showing dose-response relationships. The relationship between coffee and cardiovascular disease is complex, showing potential stroke prevention benefits but ambiguous effects on coronary heart disease. Moderate coffee consumption, typically ranging from 1 to 5 cups per day, is linked to a reduced risk of heart failure, while its impact on atrial fibrillation remains inconclusive. Furthermore, coffee consumption is associated with a lower risk of all-cause mortality, following a U-shaped pattern, with the largest risk reduction observed at moderate consumption levels. Except for T2D and CKD, MR studies do not robustly support a causal link between coffee consumption and adverse cardiometabolic outcomes. The potential beneficial effects of coffee on cardiometabolic health are consistent across age, sex, geographical regions, and coffee subtypes and are multi-dimensional, involving antioxidative, anti-inflammatory, lipid-modulating, insulin-sensitizing, and thermogenic effects. Based on its beneficial effects on cardiometabolic health and fundamental biological processes involved in aging, moderate coffee consumption has the potential to contribute to extending the healthspan and increasing longevity. The findings underscore the need for future research to understand the underlying mechanisms and refine health recommendations regarding coffee consumption.

Association of SOGPI in mediating the effect of Phosphatidylcholine on polycystic Ovary Syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder in women of reproductive age, marked by hormonal imbalances and disruptions in glucose and lipid metabolism. Emerging research has indicated a correlation between lipids and PCOS, yet the specific lipid profiles or associated genes identified in various studies vary, and observational data alone cannot establish causation. Therefore, our study seeks to establish a causal association between lipidome and PCOS.

METHODS

Data from genome-wide association studies, liposomes, metabolites, and PCOS-related information were collected. Four rounds of double-sample bidirectional intermediate Mendelian Randomization analyses including liposomes to disease, liposomes to metabolites, metabolites to disease, and reverse Mendelian Randomization analysis of lipids, total effect values and intermediary effect values were calculated. The proportion mediated by the intermediary effect was determined by dividing the intermediary effect value by the total effect value.

RESULTS

The analyses revealed that three liposomes and nine metabolites were causally associated with PCOS. Specifically, phosphatidylcholine and 1-Stearoyl-2-Oleoyl-Glycosylphosphatidylinositol were identified as independent risk factors for PCOS through further Mendelian Randomization analysis. The risk of developing PCOS increased by 32% for every one standard deviation increase in phosphatidylcholine and by 17% for every one standard deviation increase in 1-Stearoyl-2-Oleoyl-Glycosylphosphatidylinositol. Furthermore, the study revealed that phosphatidylcholine can influence the development of PCOS with 1-Stearoyl-2-Oleoyl-Glycosylphosphatidylinositol acting as a mediator, explaining 4.97% of the effect.

CONCLUSIONS

This study confirmed a causal relationship between phosphatidylcholine and 1-Stearoyl-2-Oleoyl-Glycosylphosphatidylinositol with PCOS, where phosphatidylcholine can influence the occurrence of PCOS with 1-Stearoyl-2-Oleoyl-Glycosylphosphatidylinositol as a mediator.

Causal relationship between lipidome and acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS), with high morbidity and mortality, is a common clinical syndrome of acute respiratory failure caused by diffuse lung inflammation and edema. ARDS can precipitate in various ways. The complex pathophysiology of ARDS involves the activation and dysregulation of multiple metabolisms and immune responses. Using summary-level data from a genome-wide association study (GWAS), a two-sample Mendelian randomization (MR) analysis of 179 genetically predicted lipid species and ARDS (375 cases, 406,518 controls) was performed and validated in plasma and pulmonary edema fluid from 24 patients. Furthermore, we used a two-step MR to quantify the effect of immune cell-mediated lipids on ARDS. We identified 8 lipids (Cholesterol, Phosphatidylcholine (14:0_16:0), Phosphatidylcholine (16:0_20:5), Phosphatidylcholine (18:0_18:2), Phosphatidylethanolamine (18:1_18:1), Triacylglycerol (51:2), Triacylglycerol (52:4), and Triacylglycerol (54:3) ) associated with ARDS. The proportions of genetically-predicted lipids mediated by the four types of immune cells were determined. Sensitivity analysis did not reveal any obvious pleiotropy or heterogeneity. Our study demonstrates the power of multivariate genetic analysis in correlated lipidomic data and reveals genetic links between ARDS and lipid species beyond standard lipids.

Unveiling the truth: Pathogen infections linked to miscarriage: A STROBE-Compliant Mendelian randomization study

Miscarriage represents a prevalent yet insufficiently studied adverse pregnancy outcome. The definitive causal links between various pathogens and miscarriage remain to be established. To investigate the causal connections between pathogen infections and miscarriage, we utilized a two-sample bidirectional Mendelian randomization (MR) analysis. We sourced genome-wide association studies data on pathogen infections from the UK Biobank, which included serological markers for infectious diseases and comprehensive whole-genome genetic information from approximately 10,000 individuals. Additionally, genome-wide association studies data on miscarriages were collected from 3 distinct European populations for our analysis. The MR analysis was primarily conducted using the inverse variance weighted method, complemented by Bayesian weighted MR and the weighted median method for robustness. To ensure the reliability of our findings, we performed heterogeneity and pleiotropy tests, leave-one-out sensitivity analyses, and a meta-analysis. Our extensive research has identified a causal association between miscarriage and infections by several human herpesviruses (HHV-1, HHV-3, HHV-4, HHV-6, and HHV-7), polyomaviruses (BK, JC, and Merkel cell polyomaviruses), and Chlamydia trachomatis (inverse variance weighted, P < .05). Notably, a meta-analysis of the integrated data highlighted the particularly high accuracy and consistency of the association with Merkel cell polyomavirus. Our MR analysis has clarified the causal relationships between specific pathogen infections and miscarriage, providing a critical foundation for the prevention and treatment of this adverse pregnancy outcome.

Immune cells mediate the effects of gut microbiota on neuropathic pain: a Mendelian randomization study

BACKGROUND

The gut microbiota may be involved in neuropathic pain. However, the causal association between gut microbiota and neuropathic pain remains unclear. Whether immune cells and inflammatory factors mediate the pathway from gut microbiota to neuropathic pain has not been elucidated.

METHODS

We obtained the summary data of 412 gut microbiota, 731 immune cells, 91 inflammatory factors, and five types of neuropathic pain (drug-induced neuropathy, postherpetic neuralgia, sciatica, trigeminal neuralgia, and unspecified neuralgia) from large-scale genome-wide association study (GWAS) datasets and the FinnGen database. We used bidirectional Mendelian randomization (MR) analysis to explore the causal association between gut microbiota and neuropathic pain. Additionally, we conducted a mediation analysis to identify whether immune cells and inflammatory factors act as mediators within these causal relationships.

RESULTS

Our study revealed 30 causal relationships between 26 gut bacterial taxa and five types of neuropathic pain, including four associated with drug-induced neuropathy, six with postherpetic neuralgia, five with sciatica, eight with trigeminal neuralgia, and seven with unspecified neuralgia. Moreover, we identified 35 gut bacterial pathway abundances causally involved in neuropathic pain. The reverse MR analysis showed no evidence of reverse causality from gut microbiota to neuropathic pain. Mediation analysis demonstrated that the immune cell phenotype "HLA-DR++ monocyte % leukocyte" mediated the causal relationship between p_Proteobacteria and sciatica with a mediation proportion of 36.15% (P = 0.038), whereas "CD11c on CD62L+ myeloid dendritic cell" mediated the causal pathway from assimilatory sulfate reduction to trigeminal neuralgia with a mediation proportion of 27.90% (P = 0.041).

CONCLUSION

This study identified the causal relationships between several specific gut microbiota and various neuropathic pain subtypes. Additionally, two immune cells may act as potential mediators in the pathways from gut microbiota to neuropathic pain.

Relationship between myocardial infarction and atrial fibrillation: A bidirectional Mendelian randomization study

Many studies have shown that myocardial infarction (MI) is significantly associated with atrial fibrillation (AF), but the causal relationship between MI and AF has not been established. Therefore, we performed this Mendelian randomization (MR) study to investigate the relationship between MI and AF. We used a publicly available summary statistical dataset for MI based on genome-wide analysis studies (GWAS; ebi-a-GCST011364; 14,825 cases and 2680 controls) and a summary statistical dataset for AF based on an European GWAS (finn-b-I9_AF_REIMB; 10,516 cases and 116,926 controls). The 2-sample bidirectional MR analysis was performed using the inverse-variance weighted (IVW), MR-Egger, and weighted median methods. The causal effect of MI on AF was analyzed using 30 MI-specific single nucleotide polymorphisms (SNPs) that were characterized as instrumental variables (IVs) based on the GWAS data. The causal effect of MI on AF was confirmed by the IVW (odds ratio [OR] 1.42; 95% confidence interval [CI] 1.27-1.58; P < .001), MR-Egger (OR: 1.49; 95% CI: 1.15-1.93; P = .005), and weighted median (OR: 1.42; 95% CI: 1.24-1.63; P < .001) analyses. Furthermore, in the reverse MR analyses, the causal effect of AF on MI was analyzed using 20 AF-specific SNPs that were screened as IVs. The causal effect of AF on MI was significant based on the results from the IVW method (OR: 1.05; 95% CI: 1.00-1.09; P = .033). In conclusion, the bidirectional MR analyses demonstrated a clear bidirectional causal association between MI and AF.

Risk factors associated with temporomandibular joint disorder: A mendelian randomization analysis

BACKGROUND

Temporomandibular joint disorder (TMD), a prevalent orofacial disorder with complex aetiologies and considerable socioeconomic costs. This underscores the critical importance of developing a comprehensive understanding of the risk factors associated with TMD, as existing research is hindered by deficiencies in establishing causal relationships and the limitations of traditional research methodologies.

OBJECTIVES

This research explores the causal link between certain risk factors and temporomandibular joint disorder (TMD) through Mendelian randomization (MR), providing multidimensional perspectives in addressing this worldwide health issue.

METHODS

Utilizing instrumental variables, we applied advanced statistical methods, including the weighted median, inverse variance weighted (IVW) and MR-Egger, to evaluate the impact of twelve potential risk factors on TMD.

RESULTS

Our results identified a significant positive association of TMD with malocclusion (p < .001), sleeping disorders (p = .006), anxiety (p = .002), major depression (p = .0002), daily cigarettes consumption (p = .029) and autoimmune diseases (p = .039). Conversely, a negative association was observed with educational attainment (p = .003).

CONCLUSION

These findings suggest that malocclusion, sleeping disorders, anxiety, major depression, daily cigarettes consumption and autoimmune diseases, could potentially increase TMD risk while educational attainment might mitigate its increase. No direct causal relationships were established between serum 25-hydroxyvitamin D levels, menopause, frequent alcohol consumption, coffee intake and severely worn dentition and TMD.

A Mendelian randomization study on causal effects of leisure sedentary behavior on the risk of erectile dysfunction

BACKGROUND

Erectile dysfunction has been associated with leisure sedentary behavior in several epidemiological and observational studies. However, the interpretation of these findings is difficult due to residual confounding or reverse causality.

OBJECTIVES

To explore the causal association between leisure sedentary behavior and erectile dysfunction, and to explore the underlying mechanism using Mendelian randomization.

MATERIALS AND METHODS

In the present study, publicly available large-scale genome-wide association studies of leisure sedentary behaviors (television watching, computer use, and driving), erectile dysfunction, sex hormones (total testosterone, bioactive testosterone, estradiol, follicle-stimulating hormone, luteinizing hormone, prolactin, and sex hormone binding globulin), biomarkers of endothelial function (C reactive protein, E-selectin, and matrix metalloproteinase 7), and psychiatric symptoms (depression and anxiety) were used to perform two-sample Mendelian randomization analyses. The inverse variance weighting method was the main method used to estimate the association, and sensitivity analyses were also performed.

RESULTS

A greater risk of erectile dysfunction was significantly associated with a higher genetic susceptibility to leisure computer usage (odds ratio = 3.57; 95% confidence interval = 1.78-7.16; p < 0.001). No evidence was obtained to suggest that watching television or driving for leisure increased the risk of erectile dysfunction. No association was found between computer use and depression, anxiety, C reactive protein, E-selectin, matrix metalloproteinase 7, or other sex hormones, with the exception of follicle-stimulating hormone levels (odds ratio = 0.29; 95% confidence interval = 0.12-0.69; p = 0.01). No indication of heterogeneity or pleiotropy was identified by sensitivity analysis.

DISCUSSION

Extended computer usage for leisure raised the likelihood of developing erectile dysfunction, which may be associated to lower follicle-stimulating hormone levels; however, the role of endothelial dysfunction and psychological disorders in the development of erectile dysfunction should not be underestimated. Moderate physical activity may help to correct the dysfunction.

CONCLUSION

The present study offered substantial evidence for a positive causal association between computer use and the risk of erectile dysfunction. However, a definitive causal association needs to be established by further research.

Personal history of irradiation and risk of breast cancer: A Mendelian randomisation study

Background

Studies on the relationship between personal history of irradiation and breast cancer have been reported for a long time. Still, epidemiological studies have not been conclusive, and the causal relationship is unclear. To address this issue, we employed Mendelian randomisation (MR) analysis to examine the association between individual radiation exposure history and breast cancer.

Methods

We used a series of quality control methods to select single nucleotide polymorphism (SNP) closely related to exposure. Meanwhile, several analysis methods were used to analyse the sample data to make the conclusion more reliable. To evaluate the horizontal pleiotropy, heterogeneity and stability of SNPs for breast cancer, the MR-Egger intercept test, Cochran's Q test and 'leave one' sensitivity analysis were used. Finally, the outlier variation determined by the Mendelian Randomisation Pleiotropy RESidual Sum and Outlier test is gradually eliminated to reduce the influence of heterogeneity and horizontal pleiotropy.

Results

After implementing rigorous quality control procedures, we carefully chose 102 qualified instrumental variables closely associated with the selected exposure for sensitivity analysis. This was conducted to evaluate the heterogeneity, level multiplicity, and stability of SNPs in the context of personal radiation history and its correlation with breast cancer. The results of the inverse variance weighted method analysis revealed a positive correlation between personal radiation and a heightened risk of breast cancer (odds ratio (OR) = 1.52; 95% confidence interval (CI) = 1.30-1.77). We also validated on another data set; the results were similar (OR = 1.51; 95% CI = 1.27-1.81). Furthermore, the findings from the sensitivity analysis were consistent. At the genetic level, our research demonstrated that personal radiation exposure is associated with an elevated risk of breast cancer.

Conclusions

Using genetic data provides evidence and strengthens the causal link that personal radiation causes breast cancer.

Decoding skin mysteries: Unveiling the link between microbiota and keloid scars through a Mendelian randomization study

The cause of keloids remains unclear, but studies suggest a link between skin microbiota and keloid formation. However, the causal relationship has not been confirmed. This study utilized Genome-Wide Association Studies (GWAS) data from 2 population-based German cohorts, comprising a total of 1656 skin samples. To bolster the reliability of our results, we incorporated GWAS data from 3 keloid cohorts, encompassing 2555 patients and 870,556 controls (GWAS ID: keloid1, ebi-a-GCST90018874; keloid2, bbj-a-131; keloid3, ebi-a-GCST90018654). Subsequently, we employed bidirectional 2-sample Mendelian randomization (MR) analysis to probe the causal relationship between the variables. The primary method employed was the inverse-variance weighted (IVW) method, supported by heterogeneity analysis, horizontal pleiotropy testing, outlier detection, and "leave-one-out" sensitivity analysis. By synthesizing the results from 3 groups of MR analyses, we discovered a negative causal association between a.ASV063 [Finegoldia (unc.)] located on the volar forearm and keloid disease (IVW (keloid1) odds ratio (OR): 0.939, 95% confidence interval (CI): 0.886-0.994, P = .032; IVW (keloid2) OR: 0.897, 95% CI: 0.813-0.990, P = .031; IVW (keloid3) OR: 0.900, 95% CI: 0.825-0.981, P = .017). Similarly, a negative causal relationship may also exist between the genus: Bacteroides from the antecubital fossa and keloid disease (IVW (keloid1) OR: 0.928, 95% CI: 0.884-0.973, P = .002; IVW (keloid2) OR: 0.891, 95% CI: 0.820-0.968, P = .007; IVW (keloid3) OR: 0.918, 95% CI: 0.849-0.992, P = .030). Additionally, no reverse causation was found, with all analyses showing no signs of horizontal pleiotropy or heterogeneity. This study offers new insights for the prevention and treatment of keloids.

Mediating role of chiro-inositol metabolites on the effects of HLA-DR-expressing CD14 + monocytes in inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD), a chronic inflammatory condition, is caused by several factors involving aberrant immune responses. Genetic factors are crucial in IBD occurrence. Mendelian randomization (MR) can offer a new perspective in understanding IBD's genetic background.

METHODS

Single nucleotide polymorphisms (SNPs) were considered instrumental variables (IVs). We analyzed the relationship between 731 immunophenotypes, 1,400 metabolite phenotypes, and IBD. The total effect was decomposed into indirect and direct effects, and the ratio of the indirect effect to the total effect was calculated.

RESULTS

We identified the causal effects of HLA-DR-expressing CD14 + monocytes on IBD through MR analysis. The phenotype "HLA-DR expression on CD14 + monocytes" showed the strongest association among the selected 48 immune phenotypes. Chiro-inositol metabolites mediated the effect of CD14 + monocytes expressing HLA-DR on IBD. An increase in Chiro-inositol metabolites was associated with a reduced risk of IBD occurrence, accounting for 4.97%.

CONCLUSION

Our findings revealed a new pathway by which HLA-DR-expressing CD14 + monocytes indirectly reduced the risk of IBD occurrence by increasing the levels of Chiro-inositol metabolites. The results provided a new perspective on the immunoregulatory mechanisms underlying IBD, laying a theoretical foundation for developing new therapeutic targets in the future.

The association between three prevalent autoimmune disorders and the likelihood of developing prostate cancer: a Mendelian randomization study

Numerous studies establish a significant correlation between autoimmune disorders (AIDs) and prostate cancer (PCa). Our Mendelian randomization (MR) analysis investigates the potential connection between rheumatoid arthritis (RA) and PCa, aiming to confirm causal links between systemic lupus erythematosus (SLE), hyperthyroidism, and PCa. Summary statistics from genome-wide association studies provided data on PCa and three AIDs. MR analysis, using IVW as the main approach, assessed causal relationships, validated by sensitivity analysis. IVW revealed a correlation between genetically anticipated RA and PCa, notably in Europeans (OR = 1.03; 95% CI 1.01-1.04, p = 2*10-5). Evidence supported a lower PCa risk in individuals with SLE (OR = 0.94; 95% CI 0.91-0.97, p = 2*10-4) and hyperthyroidism (OR = 0.02; 95% CI 0.001-0.2, p = 2*10-3). Weighted mode and median confirmed these findings. No pleiotropic effects were observed, and MR heterogeneity tests indicated dataset homogeneity. Our study establishes a causal link between RA, SLE, hyperthyroidism, and PCa.

Relationship between plasma brain-derived neurotrophic factor levels and neurological disorders: An investigation using Mendelian randomisation

Background

Altered brain-derived neurotrophic factor (BDNF) concentrations have been detected in the central nervous system tissues and peripheral blood. These alterations are associated with a series of neurological disorders.

Objective

To investigate the potential causal relationships between genetically determined plasma BDNF levels and various neurological diseases using a two-sample Mendelian randomisation study.

Methods

We selected single nucleotide polymorphisms strongly related to plasma BDNF levels as instrumental variables. Within the Mendelian randomisation framework, we used summary-level statistics for exposure (plasma BDNF levels) and outcomes (neurological disorders).

Results

We observed suggestive evidence of a relation between higher plasma BDNF levels and less risk of nontraumatic intracranial haemorrhage (nITH) (odds ratio [OR] = 0.861, 95 % confidence interval [CI]: 0.774-0.958, P = 0.006, PFDR = 0.078), epilepsy (OR = 0.927, 95 % CI: 0.880-0.976, P = 0.004, PFDR = 0.078), focal epilepsy (OR = 0.928, 95 % CI: 0.874-0.986, P = 0.016, PFDR = 0.139), and non-lesional focal epilepsy (OR = 0.981, 95 % CI: 0.964-0.999, P = 0.041, PFDR = 0.267). Combined with the UK Biobank dataset, the association of plasma BDNF levels with nITH remained significant (OR = 0.88, 95 % CI: 0.81-0.96, P < 0.01). The combined analysis of three consortium datasets demonstrated a considerable impact of plasma BDNF on epilepsy (OR = 0.94, 95 % CI: 0.90-0.98, P < 0.01) and a suggestive impact on focal epilepsy (OR = 0.94, 95 % CI: 0.89-0.99, P = 0.02). However, there was no apparent correlation between plasma BDNF levels and other neurological disorders or related subtypes.

Conclusions

Our study supports a possible causal relationship between elevated plasma BDNF levels and a reduced risk of nITH, epilepsy, and focal epilepsy.

Genetically predicted gut microbiota mediate the association between plasma lipidomics and primary sclerosing cholangitis

BACKGROUND

Primary sclerosing cholangitis (PSC) is a complex disease with pathogenic mechanisms that remain to be elucidated. Previous observational studies with small sample sizes have reported associations between PSC, dyslipidemia, and gut microbiota dysbiosis. However, the causality of these associations is uncertain, and there has been no systematic analysis to date.

METHODS

The datasets comprise data on PSC, 179 lipid species, and 412 gut microbiota species. PSC data (n = 14,890) were sourced from the International PSC Study Group, while the dataset pertaining to plasma lipidomics originated from a study involving 7174 Finnish individuals. Data on gut microbiota species were derived from the Dutch Microbiome Project study, which conducted a genome-wide association study involving 7738 participants. Furthermore, we employed a two-step Mendelian randomization (MR) analysis to quantify the proportion of the effect of gut microbiota-mediated lipidomics on PSC.

RESULTS

Following a rigorous screening process, our MR analysis revealed a causal relationship between higher levels of gene-predicted Phosphatidylcholine (O-16:1_18:1) (PC O-16:1_18:1) and an increased risk of developing PSC (inverse variance-weighted method, odds ratio (OR) 1.30, 95% confidence interval (CI) 1.03-1.63). There is insufficient evidence to suggest that gene-predicted PSC impacts the levels of PC O-16:1_18:1 (OR 1.01, 95% CI 0.98-1.05). When incorporating gut microbiota data into the analysis, we found that Eubacterium rectale-mediated genetic prediction explains 17.59% of the variance in PC O-16:1_18:1 levels.

CONCLUSION

Our study revealed a causal association between PC O-16:1_18:1 levels and PSC, with a minor portion of the effect mediated by Eubacterium rectale. This study aims to further explore the pathogenesis of PSC and identify promising therapeutic targets. For patients with PSC who lack effective treatment options, the results are encouraging.

The Causal Relationship between Angina Pectoris and Gout Based on Two Sample Mendelian Randomization

Purpose

Two-sample Mendelian randomization (MR) was conducted to assess the causal relationship between angina pectoris and gout. Material and Methods. Based on genome-wide association studies, single nucleotide polymorphisms (SNPs) that were closely associated with gout were selected from the UK Biobank-Neale Lab (ukb-a-107) as genetic instrumental variables. Considering that gout is characterized by elevated blood uric acid levels, SNPs related to blood uric acid levels were screened from BioBank Japan (bbj-a-57) as auxiliary gene instrumental variables. SNPs closely associated with angina pectoris onset were screened from the FINN dataset (finn-b-I9_ANGINA) as outcome variables. Two-sample MR was conducted, with inverse variance weighting (IVW) of the random effects model as the primary result, along with the weighted median method (WME) and the MR-Egger regression method. To further confirm the causal relationship between angina and gout incidence, a meta-analysis was conducted on the IVW results of the ukb-a-107 and bbj-a-57.

Results

The odds ratios and 95% confidence intervals of the IVW, WME, and MR-Egger results of ukb-a-107 were (OR = 33.72; 95% CI: 2.07∼550.38), (OR = 57.94; 95% CI: 2.75∼1219.82), and (OR = 96.38; 95% CI: 0.6∼15556.93), respectively. The P values of IVW and WME were 0.014 and 0.014 (both <0.05), respectively, indicating that the development of angina pectoris was significantly associated with the incidence of gout. The odds ratios and 95% confidence intervals of the IVW, WME, and MR-Egger about bbj-a-57 were (OR = 1.20; 95% CI: 1.07∼1.34), (OR = 1.19; 95% CI: 1.02∼1.38), and (OR = 1.30; 95% CI; 1.06∼1.60), respectively. The P values of IVW, WME and MR-Egger were 0.001, 0.027 and 0.017 (all <0.05), respectively, indicating a significant correlation between angina and blood uric acid levels. Scatter plots of ukb-a-107 and bbj-a-57 showed that the causal association estimates of the IVW, MR-Egger, and weighted median methods were similar and that the MR results were accurate. Funnel plots and the MR-Egger intercept of ukb-a-107 and bbj-a-57 showed the absence of horizontal pleiotropy. The leave-out sensitivity analysis results of ukb-a-107 and bbj-a-57 are stable. The meta-analysis of IVW results for ukb-a-107 and bbj-a-57 showed (OR = 1.20; 95% CI: 1.07-1.34, P=0.02), confirming that gout characterized by high blood uric acid levels significantly increases the risk of angina attacks.

Conclusions

This MR study found a clear causal relationship between angina pectoris and gout, which increases the risk of angina pectoris.

Beverages - a scoping review for Nordic Nutrition Recommendations 2023

Background: Coffee, tea, sugar-sweetened beverages (SSBs), and low- and no-calorie sweetened beverages (LNCSBs) are generally frequently consumed in the Nordic and Baltic countries. These beverages have also been related to potential health effects. This scoping review describes the evidence for the role of coffee, tea, SSBs, and LNCSBs for health-related outcomes as a basis for setting and updating food-based dietary guidelines. We used evidence from several qualified systematic reviews (i.e. World Cancer Research Fund, US Dietary Guidelines Advisory Committee, European Food Safety Authority, and World Health Organization) and performed a search for additional systematic reviews. The evidence suggests that moderate coffee and tea consumption do not have long-term adverse health effects. The long-term favorable effects of coffee consumption are related to reduced risk of endometrial and liver cancer, type 2 diabetes, and cardiovascular deaths. However, results from randomized controlled trials (RCTs) suggest that coffee brews that are rich in diterpenes, such as boiled coffee, increase serum cholesterol concentrations. High caffeine intake in pregnancy is associated with higher risk of pregnancy loss, preterm birth, and low birth weight. High consumption of SSBs has been associated with increased risk of obesity, type 2 diabetes, hypertension, and cardiovascular disease, based on data from RCTs and prospective cohort studies. The consumption of LNCSBs may result in a small reduction in body weight in adults, likely mediated through the effect of reduced energy intake, but has neutral effects on other cardiometabolic risk markers using evidence from RCTs. However, evidence from observational studies indicates increased risk of cardiometabolic diseases among high LNCSB consumers. In conclusion, current evidence suggests that moderate coffee and tea consumption have no long-term adverse health effects. The evidence of beneficial effects of coffee consumption on liver and endometrial cancer risk, and some cardiovascular outcomes, comes from observational studies. High consumption of boiled coffee should be avoided due to negative effect on lipid profile. Pregnant women should not exceed the recommended daily dose of caffeine intake of 200 mg set by the European Food Safety Authority as a safe level for the fetus. High consumption of SSBs has consistently been associated with adverse health effects, which is mainly due to excess energy intake, and should be limited. The conflicting results from RCTs and observational studies regarding LNCSBs may be due to revere causation and should be explored further.

Causal effects of genetically predicted testosterone on Alzheimer's disease: a two-sample mendelian randomization study

OBJECTIVE

Although several studies have reported that testosterone may protect against Alzheimer's disease, no evidence of a causal relationship has been demonstrated.

METHODS

A Mendelian randomization (MR) study was performed to determine the causal role of testosterone in Alzheimer's disease. The study utilized public databases obtained from separately published genome-wide associationstudies (GWAS). Single-nucleotide polymorphisms (SNPs) for testosterone were extracted from the most recent and largest published GWAS meta-analysis (178,782 participants), and SNPs for Alzheimer's disease were extracted from UK Biobank (954 AD cases and 487,331 controls). The odds ratio (OR) of the inverse variance weighting (IVW) approach was the primary outcome, and the weighted median and MR Egger regression were used for sensitivity analysis.

RESULTS

Through IVW, we observed a causal association between genetically predicted testosterone and the risk of Alzheimer's disease, with an OR of 0.99 (95% confidence interval [CI] = 0.998-0.999, p = 0.047). In the sensitivity analyses, the weighted median regression showed directionally similar estimates (OR = 0.99, 95% CI = 0.998-0.999, p = 0.048). The MR Egger regression showed similar estimates (OR = 0.99, 95% CI = 0.998-1.00, p = 0.35), but with lower precision. Funnel plots, MR Egger intercepts, and Mendelian randomization pleiotropy residual sum and outlier (MR-PRESSO) analysis indicated the absence of directional pleiotropy effects.

CONCLUSION

In conclusion, our MR study provides evidence of a causal relationship between testosterone levels and Alzheimer's disease; however, this relationship must be validated in future studies with larger sample sizes. Early testosterone monitoring may enable the prevention of Alzheimer's and related diseases.

Mendelian randomization analysis reveals a protective association between genetically predicted systemic lupus erythematosus and renal cell carcinoma

Observational studies have suggested that there may be a connection between systemic lupus erythematosus (SLE) and a higher likelihood of developing urological cancers, although the exact cause-effect relationship is still unclear. This study therefore investigated the causal relationship between SLE and urological cancers using the Mendelian randomization (MR) approach. Our primary MR analysis involved using the inverse variance weighted method, which employed an inverse-variance-weighted approach, to examine the causal relationship between SLE and urological conditions. In addition, we performed various sensitivity analyses, such as MR-Egger regression, tests for heterogeneity, and leave-one-out sensitivity tests, to assess the reliability of our results. The findings from our analysis using Two-Sample MR showed that genetically predicted SLE was linked to a reduced likelihood of developing renal cell carcinoma (RCC) (odds ratio = 0.9996, 95% confidence interval = 0.9993-0.9999, P value = .0159). These results suggest a possible protective impact of SLE against RCC. Nevertheless, no substantial correlation was detected between SLE and the likelihood of developing bladder cancer or prostate cancer. Collectively, these findings offer significant fresh perspectives on the possible correlation between SLE and genitourinary malignancies, specifically RCC, which will provide ideas and basis for the treatment of RCC.

Beverage consumption in patients with metabolic syndrome and its association with non-alcoholic fatty liver disease: a cross-sectional study

Introduction

Previous research has examined the association between coffee and tea consumption and non-alcoholic fatty liver disease (NAFLD). Preclinical studies have indicated the potential hepatoprotective properties of cocoa/chocolate. However, clinical research on the consumption of cocoa/chocolate and soft drinks and their relation to NAFLD, particularly among individuals with metabolic syndrome, is limited. This study primarily aimed to assess the association between beverage consumption and NAFLD in these patients.

Methods

This cross-sectional study enrolled adult patients with metabolic syndrome visited the Medicine Outpatient Department at Siriraj Hospital, Thailand, from November 2011 to January 2013. The exclusion criteria were secondary causes of hepatic steatosis, such as excessive alcohol use, viral hepatitis, or drug-induced hepatitis. Participants completed a 23-item self-administered questionnaire covering their beverage consumption habits, including type, frequency, volume, duration, and additives in drinks, namely, coffee, tea, cocoa/chocolate, and soft drinks. To ensure accurate responses, these questionnaires were supplemented by face-to-face interviews. Ultrasonography was employed early in the methodology to diagnose NAFLD. Univariable analyses were used to compare the beverage consumption behaviors of participants with and without NAFLD. Multivariable logistic regression was used to adjust for potential confounders, including total beverage energy intake, age, anthropometric data, laboratory results, and comorbidities.

Results

This study included 505 patients with metabolic syndrome. Of these, 341 (67.5%, 95%CI: 63.2-71.6%) were diagnosed with NAFLD. The consumption rates of coffee, cocoa/chocolate, and soft drinks were similar between the two groups. However, tea consumption was significantly more common in patients with NAFLD (68.3% vs. 51.8%, p < 0.001). The groups had no significant differences in caffeine intake or total energy intake from beverages. Notably, daily intake of three or more cups of coffee was correlated with a reduced prevalence of NAFLD, with an adjusted odds ratio of 0.35 (95%CI: 0.14-0.89).

Conclusion

This study revealed that patients with metabolic syndrome, irrespective of NAFLD status, exhibited similar patterns of beverage consumption. While no definitive associations were identified between the intake of coffee, tea, cocoa/chocolate, or soft drinks and NAFLD, a notable exception was observed. A higher consumption of coffee (≥3 cups daily) was associated with a lower prevalence of NAFLD.

Dark chocolate intake and cardiovascular diseases: a Mendelian randomization study

Previous intervention studies have shown some benefits of dark chocolate for the cardiovascular system, but it has not been established whether dark chocolate intake is associated with the risk of cardiovascular diseases (CVDs). To investigate the causality between dark chocolate intake and the risk of CVDs, a Mendelian randomization (MR) study was conducted. We obtained summary-level data on dark chocolate intake and CVDs from publicly available genome-wide association studies. In this MR study, the main approach was to use a fixed-effect model with inverse variance weighted (IVW) and evaluate the robustness of the results via sensitivity analysis. We found that dark chocolate intake was significantly associated with the reduction of the risk of essential hypertension (EH) (OR = 0.73; 95% CI 0.60-0.88; p = 1.06 × 10-3), as well as with the suggestive association to the reduced risk of venous thromboembolism (OR = 0.69; 95% CI 0.50-0.96; p = 2.81 × 10-2). However, no association was found between dark chocolate intake and the other ten CVDs. Our study provides evidence for a causality between dark chocolate intake and a reduced risk of EH, which has important implications for the prevention of EH in the population.

Different Associations of Coffee Consumption with the Risk of Incident Metabolic Dysfunction-Associated Steatotic Liver Disease and Advanced Liver Fibrosis

Although coffee has a potential hepatoprotective effect, evidence of the relationship between coffee consumption and metabolic dysfunction-associated steatotic liver disease (MASLD) remains conflicting. There is limited evidence regarding the most appropriate coffee intake to prevent advanced liver fibrosis (ALF) in patients with MASLD. We investigated the effect of coffee consumption on MASLD and ALF among 5266 participants without MASLD and 1326 with MASLD but without ALF. Participants were grouped by coffee intake: non-consumers, >0 and <1 cups/day, ≥1 and <2 cups/day, and ≥2 cups/day. Over a median follow-up of 11.6 years for MASLD and 15.7 years for ALF, coffee consumption did not significantly affect the incidence of MASLD, with 2298 new cases observed. However, a notable inverse association was found with ALF risk in patients with MASLD among those consuming coffee ≥2 cups/day (adjusted HR 0.57, 95% CI: 0.37-0.90, p = 0.014), especially among those consuming coffee ≥2 and <3 cups/day (adjusted HR 0.51, 95% CI: 0.30-0.89, p = 0.018). This suggests a potential hepatoprotective effect of coffee, especially in preventing the progression of liver fibrosis in patients with MASLD. These findings propose that coffee consumption could be a simple and effective approach to mitigate the risk of ALF in individuals with MASLD.

Association between the gut microbiota and nonalcoholic fatty liver disease: A two-sample Mendelian randomization study

BACKGROUND

Increasing studies have shown that there is a significant association between gut microbiota and non-alcoholic fatty liver disease.

AIMS

To show the potential association between gut microbiota and non-alcoholic fatty liver disease, we performed a two-sample Mendelian randomization analysis.

METHODS

We analyzed summary statistics from genome-wide association studies of gut microbiota and non-alcoholic fatty liver disease and conducted Mendelian randomization studies to evaluate relationships between these factors.

RESULTS

Of the 211 gut microbiota taxa examined, the inverse variance weighted method identified Lactobacillaceae (OR = 0.83, 95% CI = 0.72 - 0.95, P = 0.007), Christensenellaceae (OR = 0.74, 95% CI = 0.59 - 0.92, P = 0.007), and Intestinibacter (OR = 0.85, 95% CI = 0.73 - 0.99, P = 0.035) were negatively correlated with non-alcoholic fatty liver disease. And Coriobacteriia (OR = 1.22, 95% CI = 1.01 - 1.42, P = 0.038), Actinomycetales (OR = 1.25, 95% CI = 1.02 - 1.53, P = 0.031), Oxalobacteraceae (OR = 1.10, 95% CI = 1.01 - 1.21, P = 0.036), Ruminococcaceae_UCG005 (OR = 1.18, 95% CI = 1.01 - 1.38, P = 0.033) are positively associated with non-alcoholic fatty liver disease.

CONCLUSIONS

Our study found that the abundance of certain strains was associated with the progression of nonalcoholic fatty liver disease.

Causality between depression and ankylosing spondylitis in a European population: Results from a Mendelian randomization analysis

The aim of this study was to explore the application of Mendelian randomization (MR) Egger and inverse variance weighted (IVW) in a causal effect on depression and ankylosing spondylitis (AS). Instrumental variables (IVs) were determined using genome-wide association studies. The 2-sample MR analysis was conducted by MR Egger to test the causal effect between depression and AS. The pleiotropy of potential instrumental variables was evaluated. The results of MR Egger and IVW were further compared. A total of 3 single nucleotide polymorphisms as the construct IVs were included. IVW results showed a significant causal effect between depression and AS (P < .001). Depression could promote the risk of AS (odds ratio = 1.060, 95% confidence interval: 1.026-1.094). However, the MR Egger showed no causal effect (P = .311). Heterogeneity statistics suggested that no heterogeneity was existed (P > .05). It was also suggested that there was no horizontal pleiotropy in IVs (MR Egger intercept: -0.0004, P = .471). Reverse MR analysis suggested that there was no causal effect between AS and depression (P > .05). Gene expression quantitative trait locus (QTLs) suggested that rs2517601 and RNF39 were positively correlated (beta = 1.066, P < .001). Depression may be one of the causes of AS by MR analysis in a European population. We can estimate the causal effect based on IVW when horizontal pleiotropy is very tiny.

Investigating causal associations among gut microbiota, metabolites, and liver diseases: a Mendelian randomization study

Objective

There is some evidence for an association between gut microbiota and nonalcoholic fatty liver disease (NAFLD), alcoholic liver disease (ALD), and viral hepatitis, but no studies have explored their causal relationship.

Methods

Instrumental variables of the gut microbiota (N = 13266) and gut microbiota-derived metabolites (N = 7824) were acquired, and a Mendelian randomization study was performed to explore their influence on NAFLD (1483 European cases and 17,781 European controls), ALD (2513 European cases and 332,951 European controls), and viral hepatitis risk (1971 European cases and 340,528 European controls). The main method for examining causality is inverse variance weighting (IVW).

Results

IVW results confirmed that Anaerotruncus (p = 0.0249), Intestinimonas (p = 0.0237), Lachnoclostridium (p = 0.0245), Lachnospiraceae NC2004 group (p = 0.0083), Olsenella (p = 0.0163), and Peptococcus (p = 0.0472) were protective factors for NAFLD, and Ruminococcus 1 (p = 0.0120) was detrimental for NAFLD. The higher abundance of three genera, Lachnospira (p = 0.0388), Desulfovibrio (p = 0.0252), and Ruminococcus torques group (p = 0.0364), was correlated with a lower risk of ALD, while Ruminococcaceae UCG 002 level was associated with a higher risk of ALD (p = 0.0371). The Alistipes (p = 0.0069) and Ruminococcaceae NK4A214 group (p = 0.0195) were related to a higher risk of viral hepatitis. Besides, alanine (p = 0.0076) and phenyllactate (p = 0.0100) were found to be negatively correlated with NAFLD, while stachydrine (Op = 0.0244) was found to be positively associated with NAFLD. The phenylacetate (p = 0.0353) and ursodeoxycholate (p = 0.0144) had a protective effect on ALD, while the threonate (p = 0.0370) exerted a detrimental influence on ALD. The IVW estimates of alanine (p = 0.0408) and cholate (p = 0.0293) showed their suggestive harmful effects against viral hepatitis, while threonate (p = 0.0401) displayed its suggestive protective effect against viral hepatitis.

Conclusion

In conclusion, our research supported causal links between the gut microbiome and its metabolites and NAFLD, ALD, and viral hepatitis.

Lung function and nonalcoholic fatty liver disease: a Mendelian randomization study

Introduction

Associations of pulmonary function as evaluated by forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) with non-alcoholic fatty liver disease (NAFLD) have been reported in observational studies. Nevertheless, observational studies are susceptible to bias and reverse causality, making it difficult to infer the existence and direction of causality. We aimed to evaluate the causal effect of pulmonary function on NAFLD using the Mendelian randomization (MR) method.

Material and methods

We performed univariate MR, multivariate MR, and bidirectional two-sample MR analyses to jointly assess the causal relationship between pulmonary function and NAFLD. In addition to the inverse variance weighting method as the primary MR analysis, three complementary methods were also performed. A series of sensitivity analyses were carried out to rule out pleiotropy.

Results

We found that each genetically predicted (standard deviation) SD increase in FEV1 and FVC was associated with decreased NAFLD risk. However, after adjusting for height in the multivariate MR, only the effect of FEV1 on NAFLD risk remained significant. Furthermore, we found no causal effect of NAFLD on lung function in the reverse MR analysis.

Conclusions

Our findings indicated that reduced lung function, especially FEV1, is causally associated with the risk of NAFLD. Although the mechanism remains unclear, FEV1 could be considered when assessing NAFLD risk and as a potential target for NAFLD prevention.

Causal relationship of sugar-sweetened and sweet beverages with colorectal cancer: a Mendelian randomization study

BACKGROUND AND AIM

Prospective cohort studies have suggested that sugar-sweetened beverages (SSBs) intake is significantly associated with the risk of colorectal cancer (CRC). However, it remains unclear whether this observed association was susceptible to potential confounding factors due to the long-term development process of CRC, and the risk of CRC associated with sweet beverages has rarely been reported. We aimed to investigate the association between SSBs/sweet beverages and CRC risk.

METHODS

We performed two-sample Mendelian randomization (MR) analysis using independent genetic variants for SSBs and sweet beverages from a published genome-wide association study (GWAS). Summary statistics for instrument-outcome associations from two databases for malignant neoplasms of the colon and the rectum (FinnGen and UK Biobank). The inverse weighted method (IVW) meta-analysis was the main method used to estimate the relationship, and sensitivity analyses were performed with Cochran's Q test, leave-one-out analysis, MR-Egger regression, Steiger filtering, and the MR PRESSO test.

RESULTS

Genetically predicted SSBs intake was associated with a higher colonic malignant neoplasms risk (odds ratio (OR): 1.013; 95% confidence interval (CI) 1.001, 1.026; P = 0.036) in a combined sample size of 579,986 individuals (4029 cases). Such a significant causal effect of SSBs on rectal malignant neoplasms or sweet beverages on CRC was not observed.

CONCLUSION

Our findings corroborated a causal association between SSBs and colonic malignant neoplasms risk but did not support such a relationship in the analysis of the rectal malignant neoplasms nor the sweet beverage intake, which might be interpreted with caution and further confirmed.

No causal association between tea consumption and 7 cardiovascular disorders: A two-sample Mendelian randomization study

Background: Previous studies have reported inconsistent results on the causal association between habitual tea consumption and the risk of cardiovascular disease (CVD). This study is aim to determine the association between habitual tea intake and CVD using two-sample Mendelian randomization (MR) analysis. Methods: The genetically predicted causation between tea consumption and 7 common cardiovascular diseases (atrial fibrillation, hypertension, acute myocardial infarction, coronary atherosclerosis, peripheral vascular disease, angina, and heart failure) was evaluated using MR analysis model. We performed a total of 9 MR analysis methods to analyze the final results. The IVW methods was used as the primary outcome. The other MR analysis method (simple mode, weighted mode, simple median, weighted median, penalized weighted median, MR Egger, and MR-Egger (bootstrap)) were performed as the complement to IVW. Also, the robustness of the MR analysis results was assessed using a leave-one-out analysis. Results: The IVW analysis methods indicated that there is no causal association between tea consumption and risk of CVD (AF: OR, 0.997, 95% CI, 0.992-1.0001, p = 0.142; hypertension: OR, 0.976, 95% CI, 0.937-1.017, p = 0.242; AMI: OR, 0.996, 95% CI, 0.991-1.000, p = 0.077; CA: OR, 1.001, 95% CI, 0.993-1.009, p = 0.854; PVD: OR, 1.002, 95% CI, 1.000-1.005, p = 0.096; angina: OR, 0.999, 95% CI, 0.993-1.006, p = 0.818; HF: OR, 0.999, 95% CI, 0.996-1.002, p = 0.338). The other MR analysis method and further leave-one-out sensitivity analysis suggested the results were robust. Conclusion: This MR study indicated that there was no genetically predicted causal association between habitual tea intake and risk of CVD.

Caffeine in liver diseases: Pharmacology and toxicology

We have previously shown that adenosine A1AR antagonists, adenosine A2aAR antagonists, and caffeine have significant inhibitory effects on the activation and proliferation of hepatic stellate cells in alcoholic liver fibrosis. Many recent studies have found that moderate coffee consumption is beneficial for various liver diseases. The main active ingredient of coffee is caffeine, which is a natural non-selective adenosine receptor antagonist. Moreover, numerous preclinical epidemiological studies and clinical trials have examined the association between frequent coffee consumption and the risk of developing different liver diseases. In this review, we summarize and analyze the prophylactic and therapeutic effects of caffeine on various liver diseases, with an emphasis on cellular assays, animal experiments, and clinical trials. To review the prevention and treatment effects of caffeine on different liver diseases, we searched all literature before 19 July 2022, using “caffeine” and “liver disease” as keywords from the PubMed and ScienceDirect databases. We found that moderate coffee consumption has beneficial effects on various liver diseases, possibly by inhibiting adenosine binding to its receptors. Caffeine is a potential drug for the prevention and treatment of various liver diseases.

Lifestyle and metabolic factors for nonalcoholic fatty liver disease: Mendelian randomization study

The risk factors for nonalcoholic fatty liver disease (NAFLD) have not been clearly identified. We conducted a Mendelian randomization (MR) study to explore this. Independent genetic variants strongly associated with 5 lifestyle and 9 metabolic factors were selected as instrumental variables from corresponding genome-wide association studies (GWASs). Summary-level data for NAFLD were obtained from a GWAS meta-analysis of 8434 cases and 770,180 non-cases (discovery dataset) and another GWAS meta-analysis of 1483 cases and 17,781 non-cases (replication dataset). Univariable and multivariable MR analyses were performed. There were associations with NAFLD for lifetime smoking index (odds ratio (OR) 1.59, 95% confidence interval (CI) 1.31–1.93 per SD-increase), body mass index (BMI, OR 1.33, 95% CI 1.23–1.43 per SD-increase), waist circumference (OR 1.82; 95% CI 1.48–2.24 per SD-increase), type 2 diabetes (OR 1.21, 95% CI 1.15–1.27 per unit increase in log-transformed odds), systolic blood pressure (OR 1.17; 95% CI 1.07–1.26 per 10 mmHg increase), high-density lipoprotein cholesterol (OR 0.84, 95% CI 0.77–0.90 per SD-increase), and triglycerides (OR 1.23, 95% CI 1.15–1.33 per SD-increase). The associations for type 2 diabetes, systolic blood pressure, triglycerides, but not for high-density lipoprotein cholesterol remained strong after adjusting for genetically-predicted BMI. Genetic liability to type 2 diabetes mediated 51.4% (95% CI 13.4–89.3%) of the BMI-effects on NAFLD risk. There were suggestive inverse associations of genetically-predicted alcohol, coffee, and caffeine consumption, and vigorous physical activity with NAFLD risk. This study identified several lifestyle and metabolic factors that may be causally implicated in NAFLD.

A Mild Causal Relationship Between Tea Consumption and Obesity in General Population: A Two-Sample Mendelian Randomization Study

Evidence from observational studies for the effect of tea consumption on obesity is inconclusive. This study aimed to verify the causal association between tea consumption and obesity through a two-sample Mendelian randomization (MR) analysis in general population-based datasets. The genetic instruments, single nucleotide polymorphisms (SNPs) associated with tea consumption habits, were obtained from genome-wide association studies (GWAS): UK Biobank, Nurses' Health Study, Health Professionals Follow-up Study, and Women's Genome Health Study. The effect of the genetic instruments on obesity was analyzed using the UK Biobank dataset (among ∼500,000 participants). The causal relationship between tea consumption and obesity was analyzed by five methods of MR analyses: inverse variance weighted (IVW) method, MR-Egger regression method, weighted median estimator (WME), weighted mode, and simple mode. Ninety-one SNPs were identified as genetic instruments in our study. A mild causation was found by IVW (odds ratio [OR] = 0.998, 95% confidence interval [CI] = 0.996 to 1.000, p = 0.049]), which is commonly used in two-sample MR analysis, indicating that tea consumption has a statistically significant but medically weak effect on obesity control. However, the other four approaches did not show significance. Since there was no heterogeneity and pleiotropy in this study, the IVW approach has the priority of recommendation. Further studies are needed to clarify the effects of tea consumption on obesity-related health problems in detail.

Investigating the Association Between Seven Sleep Traits and Nonalcoholic Fatty Liver Disease: Observational and Mendelian Randomization Study

Background and Aim: Aberrant sleep parameters are associated with the risk of nonalcoholic fatty liver disease (NAFLD). However, existing information is inconsistent among studies and involves reverse causation. Therefore, we aimed to investigate the observational associations and causations between sleep traits and NAFLD. Methods: We performed multivariable regression to assess observational associations of seven sleep traits (sleep duration, easiness of getting up in the morning, chronotype, nap during day, snoring, insomnia, and narcolepsy), and NAFLD in the UK Biobank (1,029 NAFLD). The Cox proportional hazards model was applied to derive hazard ratios and 95% confidence intervals (CIs). Furthermore, a bidirectional two-sample Mendelian randomization (MR) approach was used to explore the causal relationships between sleep traits and NAFLD. Results: In the multivariable regression model adjusted for potential confounders, getting up in the morning not at all easy (HR, 1.51; 95% CI, 1.27-1.78) and usually insomnia (HR, 1.46; 95% CI, 1.21-1.75) were associated with the risk of NAFLD. Furthermore, the easiness of getting up in the morning and insomnia showed a dose-response association with NAFLD (P_trend <0.05). MR analysis found consistent causal effects of NAFLD on easiness of getting up in the morning (OR, 0.995; 95% CI, 0.990-0.999; p = 0.033) and insomnia (OR, 1.006; 95% CI, 1.001-1.011; p = 0.024). These results were robust to weak instrument bias, pleiotropy, and heterogeneity. Conclusions: Findings showed consistent evidence of observational analyses and MR analyses that trouble getting up in the morning and insomnia were associated with an increased risk of NAFLD. Bidirectional MR demonstrated causal effects of NAFLD on sleep traits.

Causal Effects of Genetically Predicted Cystatin C on Osteoporosis: A Two-Sample Mendelian Randomization Study

Objectives: Although it has long been reported that high levels of cystatin C could contribute to the development of osteoporosis in some studies, no evidence has established a causal association between them thus far. Methods: A Mendelian randomization (MR) study was conducted to determine the causal effect of cystatin C on osteoporosis based on public databases obtained from separately published genome-wide association studies (GWASs). The single-nucleotide polymorphisms (SNPs) for cystatin C were extracted from the MR-Base (CKDGen, 33,152 participants), and the SNPs for osteoporosis were extracted from the United Kingdom Biobank project (United Kingdom Biobank, including 5,266 osteoporosis cases and 331,893 controls). We defined the odds ratio (OR) of IVW methods as the primary outcome. In addition, weighted median and MR-Egger regressions were used in the sensitivity analysis. Results: In IVW, we found that genetically predicted cystatin C was causally associated with the risk of osteoporosis with an OR of 1.02 [95% confidence interval (CI) = 1.003-1.025, p = 0.01]. In the further sensitivity analysis, weighted median regression also showed directionally similar estimates (OR = 1.02, 95% CI = 1.005-1.03, p = 0.005), and MR-Egger regression (OR = 1.02, 95% CI = 1.000-1.036, p = 0.15) revealed similar estimates but with lower precision. The funnel plot, MR-Egger intercept, and MR-PRESSO all indicate that no directional pleiotropic effect was observed. Conclusion: In conclusion, our MR study showed evidence of a causal association between serum cystatin C levels and osteoporosis, which also needs to be verified by studies with larger sample sizes in the future. Early monitoring of cystatin C may enable us to prevent osteoporosis-related diseases.

Association between genetically predicted leukocyte telomere length and non-scarring alopecia: A two-sample Mendelian randomization study

Background

The most commonly acknowledged non-scarring alopecia are androgenetic alopecia (AGA) and alopecia areata (AA). Previous studies have revealed various risk factors associated with alopecia. However, the relationship between leukocyte telomere length (LTL) and non-scarring alopecia remains unclear.

Methods

A two-sample Mendelian randomization (MR) analysis was performed to evaluate the causality between genetically predicted LTL and the risk of non-scarring alopecia. MR analyses were performed using the inverse variance-weighted (IVW) method and complemented with other MR methods.

Results

The summary statistics of the genome-wide association studies (GWAS) for AGA and AA were obtained from the FinnGen biobank, which included 119,185 and 211,428 individuals, respectively. A total of 126 single nucleotide polymorphisms (SNPs) with genome-wide significance were selected as the instrumental variables for LTL. The MR analyses suggested a causal relationship between LTL and AGA, and the risk of AGA increased by 3.19 times as the genetically predicted LTL was shortened by one standard deviation in log transformed form under the IVW method (OR = 4.19, 95% CI = 1.20-14.61, p = 0.024). The other MR methods also demonstrated a similar trend of the effect of LTL on AGA. There was no causal relationship between LTL and AA (p > 0.05). Sensitivity analyses further demonstrated that the current results were less likely to be affected by confounders and bias.

Conclusion

Our results suggested a potential causal relationship between LTL and AGA, and shortened LTL was associated with an increased risk of AGA.

Genetically predicted C-reactive protein mediates the association between rheumatoid arthritis and atlantoaxial subluxation

OBJECTIVE

Investigating the causal relationship between rheumatoid arthritis (RA) and atlantoaxial subluxation (AAS) and identifying and quantifying the role of C-reactive protein (CRP) as a potential mediator.

METHODS

Using summary-level data from a genome-wide association study (GWAS), a two-sample Mendelian randomization (MR) analysis of genetically predicted rheumatoid arthritis (14,361 cases, and 43,923 controls) and AAS (141 cases, 227,388 controls) was performed. Furthermore, we used two-step MR to quantitate the proportion of the effect of c-reactive protein-mediated RA on AAS.

RESULTS

MR analysis identified higher genetically predicted rheumatoid arthritis (primary MR analysis odds ratio (OR) 0.61/SD increase, 95% confidence interval (CI) 1.36-1.90) increased risk of AAS. There was no strong evidence that genetically predicted AAS had an effect on rheumatoid arthritis risk (OR 1.001, 95% CI 0.97-1.03). The proportion of genetically predicted rheumatoid arthritis mediated by C-reactive protein was 3.7% (95%CI 0.1%-7.3%).

CONCLUSION

In conclusion, our study identified a causal relationship between RA and AAS, with a small proportion of the effect mediated by CRP, but a majority of the effect of RA on AAS remains unclear. Further research is needed on additional risk factors as potential mediators. In clinical practice, lesions of the upper cervical spine in RA patients need to be given more attention.

The Association Between Coffee Consumption and Nonalcoholic Fatty Liver Disease in the South Korean General Population

SCOPE

To identify the cross-sectional and prospective association between coffee consumption and nonalcoholic fatty liver disease (NAFLD) among South Korean adults.

METHODS AND RESULTS

Participants are selected from the Health Examinees study. NAFLD is defined using three non-invasive indexes: fatty liver index (FLI), hepatic steatosis index, and fibrosis-4 calculator (FIB-4). In the cross-sectional analysis, higher habitual coffee consumption is associated with a lower risk for NAFLD, define using the FLI, (men, odds ratio [OR] 0.702; women, OR 0.810) compared with non-consumers. Participants who consumed coffee with sugar and creamer also have a lower risk for NAFLD, defined using the FIB-4, compared with non-coffee-consumers (men, OR 0.739; women, OR 0.807). A prospective analysis indicated that higher coffee consumption is associated with a lower incidence of NAFLD, defined using the FLI, in men (hazard ratio, 0.706). In both men and women, a lower FIB-4 index score is associated with higher coffee consumption regardless of coffee type (all p-value <0.05).

CONCLUSIONS

 Coffee consumption of >3 cups per day has a protective effect against the development of NAFLD to a certain extent, and a negative association is found between coffee consumed with sugar and creamer and the FIB-4 index score in South Korean adults.

All coffee types decrease the risk of adverse clinical outcomes in chronic liver disease: a UK Biobank study

BACKGROUND

Chronic liver disease (CLD) is a growing cause of morbidity and mortality worldwide, particularly in low to middle-income countries with high disease burden and limited treatment availability. Coffee consumption has been linked with lower rates of CLD, but little is known about the effects of different coffee types, which vary in chemical composition. This study aimed to investigate associations of coffee consumption, including decaffeinated, instant and ground coffee, with chronic liver disease outcomes.

METHODS

A total of 494,585 UK Biobank participants with known coffee consumption and electronic linkage to hospital, death and cancer records were included in this study. Cox regression was used to estimate hazard ratios (HR) of incident CLD, incident CLD or steatosis, incident hepatocellular carcinoma (HCC) and death from CLD according to coffee consumption of any type as well as for decaffeinated, instant and ground coffee individually.

RESULTS

Among 384,818 coffee drinkers and 109,767 non-coffee drinkers, there were 3600 cases of CLD, 5439 cases of CLD or steatosis, 184 cases of HCC and 301 deaths from CLD during a median follow-up of 10.7 years. Compared to non-coffee drinkers, coffee drinkers had lower adjusted HRs of CLD (HR 0.79, 95% CI 0.72-0.86), CLD or steatosis (HR 0.80, 95% CI 0.75-0.86), death from CLD (HR 0.51, 95% CI 0.39-0.67) and HCC (HR 0.80, 95% CI 0.54-1.19). The associations for decaffeinated, instant and ground coffee individually were similar to all types combined.

CONCLUSION

The finding that all types of coffee are protective against CLD is significant given the increasing incidence of CLD worldwide and the potential of coffee as an intervention to prevent CLD onset or progression.

Plant-Based Foods and Their Bioactive Compounds on Fatty Liver Disease: Effects, Mechanisms, and Clinical Application

Fatty liver disease (FLD), including nonalcoholic fatty liver disease (NAFLD) and alcoholic fatty liver disease (AFLD), is a serious chronic metabolic disease that affects a wide range of people. Lipid accumulation accompanied by oxidative stress and inflammation in the liver is the most important pathogenesis of FLD. The plant-based, high-fiber, and low-fat diet has been recommended to manage FLD for a long time. This review discusses the current state of the art into the effects, mechanisms, and clinical application of plant-based foods in NAFLD and AFLD, with highlighting related molecular mechanisms. Epidemiological evidence revealed that the consumption of several plant-based foods was beneficial to alleviating FLD. Further experimental studies found out that fruits, spices, teas, coffee, and other plants, as well as their bioactive compounds, such as resveratrol, anthocyanin, curcumin, and tea polyphenols, could alleviate FLD by ameliorating hepatic steatosis, oxidative stress, inflammation, gut dysbiosis, and apoptosis, as well as regulating autophagy and ethanol metabolism. More importantly, clinical trials confirmed the beneficial effects of plant-based foods on patients with fatty liver. However, several issues need to be further studied especially the safety and effective doses of plant-based foods and their bioactive compounds. Overall, certain plant-based foods are promising natural sources of bioactive compounds to prevent and alleviate fatty liver disease.