Obesity and binge alcohol intake are deadly combination to induce steatohepatitis: A model of high-fat diet and binge ethanol intake

Neutrophils in Cancer immunotherapy: friends or foes?

Neutrophils play a Janus-faced role in the complex landscape of cancer pathogenesis and immunotherapy. As immune defense cells, neutrophils release toxic substances, including reactive oxygen species and matrix metalloproteinase 9, within the tumor microenvironment. They also modulate the expression of tumor necrosis factor-related apoptosis-inducing ligand and Fas ligand, augmenting their capacity to induce tumor cell apoptosis. Their involvement in antitumor immune regulation synergistically activates a network of immune cells, bolstering anticancer effects. Paradoxically, neutrophils can succumb to the influence of tumors, triggering signaling cascades such as JAK/STAT, which deactivate the immune system network, thereby promoting immune evasion by malignant cells. Additionally, neutrophil granular constituents, such as neutrophil elastase and vascular endothelial growth factor, intricately fuel tumor cell proliferation, metastasis, and angiogenesis. Understanding the mechanisms that guide neutrophils to collaborate with other immune cells for comprehensive tumor eradication is crucial to enhancing the efficacy of cancer therapeutics. In this review, we illuminate the underlying mechanisms governing neutrophil-mediated support or inhibition of tumor progression, with a particular focus on elucidating the internal and external factors that influence neutrophil polarization. We provide an overview of recent advances in clinical research regarding the involvement of neutrophils in cancer therapy. Moreover, the future prospects and limitations of neutrophil research are discussed, aiming to provide fresh insights for the development of innovative cancer treatment strategies targeting neutrophils.

Interaction between fatty acid oxidation and ethanol metabolism in liver

Fatty acid oxidation (FAO) releases the energy stored in fat to maintain basic biological processes. Dehydrogenation is a major way to oxidize fatty acids, which needs NAD+ to accept the released H+ from fatty acids and form NADH, which increases the ratio of NADH/NAD+ and consequently inhibits FAO leading to the deposition of fat in the liver, which is termed fatty liver or steatosis. Consumption of alcohol (ethanol) initiates simple steatosis that progresses to alcoholic steatohepatitis, which constitutes a spectrum of liver disorders called alcohol-associated liver disease (ALD). ALD is linked to ethanol metabolism. Ethanol is metabolized by alcohol dehydrogenase (ADH), microsomal ethanol oxidation system (MEOS), mainly cytochrome P450 2E1 (CYP2E1), and catalase. ADH also requires NAD+ to accept the released H+ from ethanol. Thus, ethanol metabolism by ADH leads to increased ratio of NADH/NAD+, which inhibits FAO and induces steatosis. CYP2E1 directly consumes reducing equivalent NADPH to oxidize ethanol, which generates reactive oxygen species (ROS) that lead to cellular injury. Catalase is mainly present in peroxisomes, where very long-chain fatty acids and branched-chain fatty acids are oxidized, and the resultant short-chain fatty acids will be further oxidized in mitochondria. Peroxisomal FAO generates hydrogen peroxide (H2O2), which is locally decomposed by catalase. When ethanol is present, catalase uses H2O2 to oxidize ethanol. In this review, we introduce FAO (including α-, β-, and ω-oxidation) and ethanol metabolism (by ADH, CYP2E1, and catalase) followed by the interaction between FAO and ethanol metabolism in the liver and its pathophysiological significance.

The ameliorative effect of turmeric (Curcuma longa Linn) extract and its major constituent, curcumin, and its analogs on ethanol toxicity

Ethanol toxicity is a major public health problem that can cause damage to various organs in the body by several mechanisms inducing oxidative stress, inflammation, and apoptosis. Recently, there has been a growing interest in the potential of herbal medicines as therapeutic agents for the prevention and treatment of various disorders. Turmeric (Curcuma longa) extracts and its main components including curcumin have antioxidant, anti-inflammatory, and anti-apoptotic properties. This review aims to evaluate the literature on the ameliorative effects of turmeric extracts and their main components on ethanol toxicity. The relevant studies were identified through searches of Google Scholar, PubMed, and Scopus without any time limitation. The underlying mechanisms of turmeric and curcumin were also discussed. The findings suggest that turmeric and curcumin ameliorate ethanol-induced organ damage by suppressing oxidative stress, inflammation, apoptosis, MAPK activation, TGF-β/Smad signaling pathway, hyperlipidemia, regulating hepatic enzymes, expression of SREBP-1c and PPAR-α. However, the limited clinical evidence suggests that further research is needed to determine the efficacy and safety of turmeric and curcumin in human subjects. In conclusion, the available evidence supports the potential use of turmeric and curcumin as alternative treatments for ethanol toxicity, but further high-quality studies are needed to firmly establish the clinical efficacy of the plant.

Independent and additive effects of binge drinking and obesity on liver enzymes: a cross-sectional analysis using the Korean National Health Insurance Service data

Background

Binge drinking (BD) has been associated with elevated liver enzymes, but the joint association of BD and adiposity with liver enzymes is understudied. We aimed to examine the combined association of BD and obesity with elevated liver enzymes.

Methods

Data were obtained from 285,600 patients in the Korean National Health check-up program during 2009-2015. Level I BD (BD I) was defined as alcohol consumption of >60 g (men) or >40 g (women) on one occasion in the previous year. High-intensity BD (HIBD) corresponded to at least two times the BD I levels. General and abdominal obesity were defined by body mass index and waist circumference. Logistic regression was used to examine the independent and joint associations of BD and obesity with elevated alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transferase (GGT) levels. Relative excess risk (RERI), attributable proportion (AP), and synergy index (SI) were calculated to estimate the additive interaction effects.

Results

The mean age was 42.1 ± 0.03 years and 50.2% were women. Elevated ALT [odds ratio (OR) 1.09, 95% confidence interval (CI) 1.02-1.16], AST (OR 1.16, 95% CI 1.11-1.23), and GGT (OR 1.84, 95% CI 1.05-1.94) were associated with HIBD. Higher odds of elevated ALT (OR 3.57, 95% CI 3.43-3.71), AST (OR 3.47, 95% CI 3.37-3.58), and GGT (OR 2.10, 95% CI 1.98-2.12) were observed in individuals with general obesity. A similar trend was observed for abdominal obesity. The RERI, AP, and SI for the interaction effect of BD and general obesity were 23%, 7%, and 13% for elevated AST levels, and 67%, 24%, and 58% for elevated GGT levels, respectively. Similar effects were observed for the interaction between BD and abdominal obesity.

Conclusions

Obesity aggravated the odds of elevated liver AST and GGT levels in HIBD.

The intersection between alcohol-related liver disease and nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) and alcohol-related liver disease (ALD) are the leading causes of chronic liver disease worldwide. NAFLD and ALD share pathophysiological, histological and genetic features and both alcohol and metabolic dysfunction coexist as aetiological factors in many patients with hepatic steatosis. A diagnosis of NAFLD requires the exclusion of significant alcohol consumption and other causes of liver disease. However, data suggest that significant alcohol consumption is often under-reported in patients classified as having NAFLD and that alcohol and metabolic factors interact to exacerbate the progression of liver disease. In this Review, we analyse existing data on the interaction between alcohol consumption and metabolic syndrome as well as the overlapping features and differences in the pathogenesis of ALD and NAFLD. We also discuss the clinical implications of the coexistence of alcohol consumption, of any degree, in patients with evidence of metabolic derangement as well as the use of alcohol biomarkers to detect alcohol intake. Finally, we summarize the evolving nomenclature of fatty liver disease and describe a recent proposal to classify patients at the intersection of NAFLD and ALD. We propose that, regardless of the presumed aetiology, patients with fatty liver disease should be evaluated for both metabolic syndrome and alcohol consumption to enable better prognostication and a personalized medicine approach.

Dynamic Alterations to Hepatic MicroRNA-29a in Response to Long-Term High-Fat Diet and EtOH Feeding

MicroRNA-29a (miR-29a) is a well characterized fibro-inflammatory molecule and its aberrant expression is linked to a variety of pathological liver conditions. The long-term effects of a high-fat diet (HFD) in combination with different levels of EtOH consumption on miR-29a expression and liver pathobiology are unknown. Mice at 8 weeks of age were divided into five groups (calorie-matched diet plus water (CMD) as a control group, HFD plus water (HFD) as a liver disease group, HFD plus 2% EtOH (HFD + 2% E), HFD + 10% E, and HFD + 20% E as intervention groups) and fed for 4, 13, 26, or 39 weeks. At each time point, analyses were performed for liver weight/body weight (BW) ratio, AST/ALT ratio, as well as liver histology assessments, which included inflammation, estimated fat deposition, lipid area, and fibrosis. Hepatic miR-29a was measured and correlations with phenotypic traits were determined. Four-week feeding produced no differences between the groups on all collected phenotypic traits or miR-29a expression, while significant effects were observed after 13 weeks, with EtOH concentration-specific induction of miR-29a. A turning point for most of the collected traits was apparent at 26 weeks, and miR-29a was significantly down-regulated with increasing liver injury. Overall, miR-29a up-regulation was associated with a lower liver/BW ratio, fat deposition, inflammation, and fibrosis, suggesting a protective role of miR-29a against liver disease progression. A HFD plus increasing concentrations of EtOH produces progressive adverse effects on the liver, with no evidence of beneficial effects of low-dose EtOH consumption. Moreover, miR-29a up-regulation is associated with less severe liver injury.

Prevention of colitis-induced liver oxidative stress and inflammation in a transgenic mouse model with increased omega-3 polyunsaturated fatty acids

Inflammatory bowel disease (IBD) is an immune-mediated gut dysfunction, which might also be associated with an inflammatory phenotype in the liver. It is known that the nutritional intake of omega-3 polyunsaturated fatty acids (n-3 PUFA) is inversely correlated to the severity and occurrence of IBD. In order to investigate whether n-3 PUFA can also reduce liver inflammation and oxidative liver damage due to colon inflammation, we explored the dextran sulfate sodium (DSS)-induced colitis model in wild-type and fat-1 mice with endogenously increased n-3 PUFA tissue content. Besides confirming previous data of alleviated DSS-induced colitis in the fat-1 mouse model, the increase of n-3 PUFA also resulted in a significant reduction of liver inflammation and oxidative damage in colitis-affected fat-1 mice as compared to wild-type littermates. This was accompanied by a remarkable increase of established inflammation-dampening n-3 PUFA oxylipins, namely docosahexaenoic acid-derived 19,20-epoxydocosapentaenoic acid and eicosapentaenoic acid-derived 15-hydroxyeicosapentaenoic acid and 17,18-epoxyeicosatetraenoic acid. Taken together, these observations demonstrate a strong inverse correlation between the anti-inflammatory lipidome derived from n-3 PUFA and the colitis-triggered inflammatory changes in the liver by reducing oxidative liver stress.

Mitochondrial Dysfunction: At the Nexus between Alcohol-Associated Immunometabolic Dysregulation and Tissue Injury

Alcohol misuse, directly or indirectly as a result of its metabolism, negatively impacts most tissues, including four with critical roles in energy metabolism regulation: the liver, pancreas, adipose, and skeletal muscle. Mitochondria have long been studied for their biosynthetic roles, such as ATP synthesis and initiation of apoptosis. However, current research has provided evidence that mitochondria participate in myriad cellular processes, including immune activation, nutrient sensing in pancreatic β-cells, and skeletal muscle stem and progenitor cell differentiation. The literature indicates that alcohol impairs mitochondrial respiratory capacity, promoting reactive oxygen species (ROS) generation and disrupting mitochondrial dynamics, leading to dysfunctional mitochondria accumulation. As discussed in this review, mitochondrial dyshomeostasis emerges at a nexus between alcohol-disrupted cellular energy metabolism and tissue injury. Here, we highlight this link and focus on alcohol-mediated disruption of immunometabolism, which refers to two distinct, yet interrelated processes. Extrinsic immunometabolism involves processes whereby immune cells and their products influence cellular and/or tissue metabolism. Intrinsic immunometabolism describes immune cell fuel utilization and bioenergetics that affect intracellular processes. Alcohol-induced mitochondrial dysregulation negatively impacts immunometabolism in immune cells, contributing to tissue injury. This review will present the current state of literature, describing alcohol-mediated metabolic and immunometabolic dysregulation from a mitochondrial perspective.

Premorbid Steatohepatitis Increases the Seriousness of Dextran Sulfate Sodium-induced Ulcerative Colitis in Mice

BACKGROUND AND AIMS

The concurrence of nonalcoholic steatohepatitis (NASH) and ulcerative colitis (UC) is increasingly seen in clinical practice, but the underlying mechanisms remain unclear. This study aimed to develop a mouse model of the phenomenon by combining high-fat high-cholesterol diet (HFHCD)-induced NASH and dextran sulfate sodium (DSS)-induced UC, that would support mechanistic studies.

METHODS

Male C57BL/6 mice were randomly assigned to two groups receiving either a chow diet or HFHCD for 12 weeks of NASH modeling. The mice were the divided into four subgroups for UC modeling: (1) A control group given a chow diet with normal drinking water; (2) A colitis group given chow diet with 2% DSS in drinking water; (3) A steatohepatitis group given HFHCD with normal drinking water; and (4) A steatohepatitis + colitis group given HFHCD with 2% DSS in drinking water.

RESULTS

NASH plus UC had high mortality (58.3%). Neither NASH nor UC alone were fatal. Although DSS-induced colitis did not exacerbate histological liver injury in HFHCD-fed mice, premorbid NASH significantly increased UC-related gut injury compared with UC alone. It was characterized by a significantly shorter colon, more colonic congestion, and a higher histopathological score (p<0.05). Inflammatory (tumor necrosis factor-alpha, interleukin 1 beta, C-C motif chemokine ligand 2, and nuclear factor kappa B) and apoptotic (Bcl2, Bad, Bim, and Bax) signaling pathways were significantly altered in distal colon tissues collected from mice with steatohepatitis + colitis compared with the other experimental groups.

CONCLUSIONS

Premorbid steatohepatitis significantly aggravated DSS-induced colitis and brought about a lethal phenotype. Potential links between NASH and UC pathogeneses can be investigated using this model.

Natural History of Alcohol-Associated Liver Disease: Understanding the Changing Landscape of Pathophysiology and Patient Care

Alcohol use and consequent liver disease are major burdens that have worsened during the COVID-19 pandemic. There are several facets to the pathophysiology and clinical consequences of alcohol-use disorder (AUD) and progression to alcohol-associated liver disease (ALD) that require a concerted effort by clinicians and translational and basic science investigators. Several recent advances from bedside to bench and bench to bedside have been made in ALD. We focused this review on a case-based approach that provides a human context to these important advances across the spectrum of ALD.

Alcoholic liver disease: a new insight into the pathogenesis of liver disease

Excessive alcohol consumption contributes to a broad clinical spectrum of liver diseases, from simple steatosis to end-stage hepatocellular carcinoma. The liver is the primary organ that metabolizes ingested alcohol and is exquisitely sensitive to alcohol intake. Alcohol metabolism is classified into two pathways: oxidative and non-oxidative alcohol metabolism. Both oxidative and non-oxidative alcohol metabolisms and their metabolites have toxic consequences for multiple organs, including the liver, adipose tissue, intestine, and pancreas. Although many studies have focused on the effects of oxidative alcohol metabolites on liver damage, the importance of non-oxidative alcohol metabolites in cellular damage has also been discovered. Furthermore, extrahepatic alcohol effects are crucial for providing additional information necessary for the progression of alcoholic liver disease. Therefore, studying the effects of alcohol-producing metabolites and interorgan crosstalk between the liver and peripheral organs that express ethanol-metabolizing enzymes will facilitate a comprehensive understanding of the pathogenesis of alcoholic liver disease. This review focuses on alcohol-metabolite-associated hepatotoxicity due to oxidative and non-oxidative alcohol metabolites and the role of interorgan crosstalk in alcoholic liver disease pathogenesis.

Xenobiotic-Induced Aggravation of Metabolic-Associated Fatty Liver Disease

Metabolic-associated fatty liver disease (MAFLD), which is often linked to obesity, encompasses a large spectrum of hepatic lesions, including simple fatty liver, steatohepatitis, cirrhosis and hepatocellular carcinoma. Besides nutritional and genetic factors, different xenobiotics such as pharmaceuticals and environmental toxicants are suspected to aggravate MAFLD in obese individuals. More specifically, pre-existing fatty liver or steatohepatitis may worsen, or fatty liver may progress faster to steatohepatitis in treated patients, or exposed individuals. The mechanisms whereby xenobiotics can aggravate MAFLD are still poorly understood and are currently under deep investigations. Nevertheless, previous studies pointed to the role of different metabolic pathways and cellular events such as activation of de novo lipogenesis and mitochondrial dysfunction, mostly associated with reactive oxygen species overproduction. This review presents the available data gathered with some prototypic compounds with a focus on corticosteroids and rosiglitazone for pharmaceuticals as well as bisphenol A and perfluorooctanoic acid for endocrine disruptors. Although not typically considered as a xenobiotic, ethanol is also discussed because its abuse has dire consequences on obese liver.

Crosstalk between Oxidative Stress and Inflammatory Liver Injury in the Pathogenesis of Alcoholic Liver Disease

Alcoholic liver disease (ALD) is characterized by the injury, inflammation, and scarring in the liver owing to excessive alcohol consumption. Currently, ALD is a leading cause for liver transplantation. Therefore, extensive studies (in vitro, in experimental ALD models and in humans) are needed to elucidate pathological features and pathogenic mechanisms underlying ALD. Notably, oxidative changes in the liver have been recognized as a signature trait of ALD. Progression of ALD is linked to the generation of highly reactive free radicals by reactions involving ethanol and its metabolites. Furthermore, hepatic oxidative stress promotes tissue injury and, in turn, stimulates inflammatory responses in the liver, forming a pathological loop that promotes the progression of ALD. Accordingly, accumulating further knowledge on the relationship between oxidative stress and inflammation may help establish a viable therapeutic approach for treating ALD.

Host Factors in Dysregulation of the Gut Barrier Function during Alcohol-Associated Liver Disease

Chronic alcohol consumption and alcohol-associated liver disease (ALD) represent a major public health problem worldwide. Only a minority of patients with an alcohol-use disorder (AUD) develop severe forms of liver disease (e.g., steatohepatitis and fibrosis) and finally progress to the more advanced stages of ALD, such as severe alcohol-associated hepatitis and decompensated cirrhosis. Emerging evidence suggests that gut barrier dysfunction is multifactorial, implicating microbiota changes, alterations in the intestinal epithelium, and immune dysfunction. This failing gut barrier ultimately allows microbial antigens, microbes, and metabolites to translocate to the liver and into systemic circulation. Subsequent activation of immune and inflammatory responses contributes to liver disease progression. Here we review the literature about the disturbance of the different host defense mechanisms linked to gut barrier dysfunction, increased microbial translocation, and impairment of liver and systemic inflammatory responses in the different stages of ALD.

The Role of Epigenetic Changes in the Progression of Alcoholic Steatohepatitis

Alcoholic steatohepatitis (ASH) is a progression hepatitis with severe fatty liver and its mortality rate for 30-days in patients are over 30%. Additionally, ASH is well known for one-fifth all alcoholic related liver diseases in the world. Excessive chronic alcohol consumption is one of the most common causes of the progression of ASH and is associated with poor prognosis and liver failure. Alcohol abuse dysregulates the lipid homeostasis and causes oxidative stress and inflammation in the liver. Consequently, metabolic pathways stimulating hepatic accumulation of excessive lipid droplets are induced. Recently, many studies have indicated a link between ASH and epigenetic changes, showing differential expression of alcohol-induced epigenetic genes in the liver. However, the specific mechanisms underlying the pathogenesis of ASH remain elusive. Thus, we here summarize the current knowledge about the roles of epigenetics in lipogenesis, inflammation, and apoptosis in the context of ASH pathophysiology. Especially, we highlight the latest findings on the roles of Sirtuins, a conserved family of class-III histone deacetylases, in ASH. Additionally, we discuss the involvement of DNA methylation, histone modifications, and miRNAs in ASH as well as the ongoing efforts for the clinical translation of the findings in ASH-related epigenetic changes.

Alcohol Consumption Is Associated with Poor Prognosis in Obese Patients with COVID-19: A Mendelian Randomization Study Using UK Biobank

BACKGROUND

Acute and chronic alcohol abuse has adverse impacts on both the innate and adaptive immune response, which may result in reduced resistance to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection and promote the progression of coronavirus disease 2019 (COVID-19). However, there are no large population-based data evaluating potential causal associations between alcohol consumption and COVID-19.

METHODS

We conducted a Mendelian randomization study using data from UK Biobank to explore the association between alcohol consumption and risk of SARS-CoV-2 infection and serious clinical outcomes in patients with COVID-19. A total of 12,937 participants aged 50-83 who tested for SARS-CoV-2 between 16 March to 27 July 2020 (12.1% tested positive) were included in the analysis. The exposure factor was alcohol consumption. Main outcomes were SARS-CoV-2 positivity and death in COVID-19 patients. We generated allele scores using three genetic variants (rs1229984 (Alcohol Dehydrogenase 1B, ADH1B), rs1260326 (Glucokinase Regulator, GCKR), and rs13107325 (Solute Carrier Family 39 Member 8, SLC39A8)) and applied the allele scores as the instrumental variables to assess the effect of alcohol consumption on outcomes. Analyses were conducted separately for white participants with and without obesity.

RESULTS

Of the 12,937 participants, 4496 were never or infrequent drinkers and 8441 were frequent drinkers. Both logistic regression and Mendelian randomization analyses found no evidence that alcohol consumption was associated with risk of SARS-CoV-2 infection in participants either with or without obesity (All q > 0.10). However, frequent drinking, especially heavy drinking (HR = 2.07, 95%CI 1.24-3.47; q = 0.054), was associated with higher risk of death in patients with obesity and COVID-19, but not in patients without obesity. Notably, the risk of death in frequent drinkers with obesity increased slightly with the average amount of alcohol consumed weekly (All q < 0.10).

CONCLUSIONS

Our findings suggest that alcohol consumption has adverse effects on the progression of COVID-19 in white participants with obesity, but was not associated with susceptibility to SARS-CoV-2 infection.

The interplay of Western diet and binge drinking on the onset, progression, and outlook of liver disease

Non-alcoholic fatty liver disease and alcoholic liver disease, the two most prevalent liver diseases worldwide, share a common pathology but have largely been considered disparate diseases. Liver diseases are widely underestimated, but their prevalence is increasing worldwide. The Western diet (high-fat, high-sugar) and binge drinking (rapid consumption of alcohol in a short period of time) are two highly prevalent features of standard life in the United States, and both are linked to the development and progression of liver disease. Yet, few studies have been conducted to elucidate their potential interactions. Data shows binge drinking is on the rise in several age groups, and poor dietary trends continue to be prevalent. This review serves to summarize the sparse findings on the hepatic consequences of the combination of binge drinking and consuming a Western diet, while also drawing conclusions on potential future impacts. The data suggest the potential for a looming liver disease epidemic, indicating that more research on its progression as well as its prevention is needed on this critical topic.

A two-hit model of alcoholic liver disease that exhibits rapid, severe fibrosis

Alcoholic liver disease (ALD) is responsible for an average of 50.4% and 44.2%of liver disease deaths among males and females respectively. Driven by alcohol misuse, ALD is often reversible by cessation of consumption. However, abstinence programs can have limited success at curtailing abuse, and the loss of life. ALD, therefore, remains a significant clinical challenge. There is a need for effective treatments that prevent or reverse alcohol-induced liver damage to complement or supplant behavioral interventions. Metabolic syndrome, which is disproportionally prevalent in ALD patients, accelerates the progression of ALD and increases liver disease mortality. Current rodent models of ALD unfortunately do not account for the contribution of the western diet to ALD pathology. To address this, we have developed a rodent model of ALD that integrates the impact of the western diet and alcohol; the WASH-diet model. We show here that the WASH diet, either chronically or in small time-restricted bouts, accelerated ALD pathology with severe steatohepatitis, elevated inflammation and increased fibrosis compared to mice receiving chronic alcohol alone. We also validated our WASH-diet model as an in vivo system for testing the efficacy of experimental ALD treatments. The efficacy of the inverse-agonist SR9238, previously shown to inhibit both non-alcohol and alcohol-induced steatohepatitis progression, was conserved in our WASH-diet model. These findings suggested that the WASH-diet may be useful for in vivo pre-clinical assessment of novel therapies.

Alcohol Consumption is Associated with Poor Prognosis in Obese Patients with COVID-19: a Mendelian Randomization Study using UK Biobank

Background

Acute and chronic alcohol abuse have adverse impacts on both the innate and adaptive immune response, which may result in reduced resistance to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection and promote the progression of coronavirus disease 2019 (COVID-19). However, there are no large population-based data evaluating potential causal associations between alcohol consumption and COVID-19.

Method

We conducted a Mendelian randomization study using data from UK Biobank to explore the association between alcohol consumption and risk of SARS-CoV-2 infection and serious clinical outcomes in patients with COVID-19. A total of 12,937 participants aged 50-83 who tested for SARS-CoV-2 between 16 March to 27 July 2020 (12.1% tested positive) were included in the analysis. The exposure factor was alcohol consumption. Main outcomes were SARS-CoV-2 positivity and death in COVID-19 patients. We generated weighted and unweighted allele scores using three genetic variants (rs1229984, rs1260326, and rs13107325) and applied the allele scores as the instrumental variables to assess the effect of alcohol consumption on outcomes. Analyses were conducted separately for white participates with and without obesity.

Results

Of the 12,937 participants, 4,496 were never or infrequent drinkers and 8,441 were frequent drinkers. (including 1,156 light drinkers, 3,795 moderate drinkers, and 3,490 heavy drinkers). Both logistic regression and Mendelian randomization analyses found no evidence that alcohol consumption was associated with risk of SARS-CoV-2 infection in participants either with (OR=0.963, 95%CI 0.800-1.159; q =1.000) or without obesity (OR=0.891, 95%CI 0.755-1.053; q =.319). However, frequent drinking (HR=1.565, 95%CI 1.012-2.419; q =.079), especially heavy drinking (HR=2.071, 95%CI 1.235-3.472; q =.054), was associated with higher risk of death in patients with obesity and COVID-19, but not in patients without obesity. Notably, the risk of death in frequent drinkers with obesity increased slightly with the average amount of alcohol consumed weekly (HR=1.480, 95%CI 1.059-2.069; q =.099).

Conclusions

Our findings suggested alcohol consumption may had adverse effects on the progression of COVID-19 in white participants with obesity, but was not associate with susceptibility to SARS-CoV-2 infection.