Vitamin D: A new player in non-alcoholic fatty liver disease?

Vitamin D and Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD): Novel Mechanistic Insights

Metabolic dysfunction-associated steatotic liver disease (MASLD) is an increasingly prevalent condition characterized by abnormal fat accumulation in the liver, often associated with metabolic disorders. Emerging evidence suggests a potential link between vitamin D deficiency and the development and progression of MASLD. The current review provides a concise overview of recent studies uncovering novel mechanistic insights into the interplay between vitamin D and MASLD. Several epidemiological studies have highlighted a significant association between low vitamin D levels and an increased risk of MASLD. Vitamin D, traditionally known for its role in bone health, has now been recognized as a key player in various physiological processes, including immune regulation and inflammation. Experimental studies using animal models have demonstrated that vitamin D deficiency exacerbates liver steatosis and inflammation, suggesting a potential protective role against MASLD. Mechanistically, vitamin D appears to modulate MASLD through multiple pathways. Firstly, the vitamin D receptor (VDR) is abundantly expressed in liver cells, indicating a direct regulatory role in hepatic function. Activation of the VDR has been shown to suppress hepatic lipid accumulation and inflammation, providing a mechanistic basis for the observed protective effects. Additionally, vitamin D influences insulin sensitivity, a critical factor in MASLD pathogenesis. Improved insulin sensitivity may mitigate the excessive accumulation of fat in the liver, thus attenuating MASLD progression. In parallel, vitamin D exhibits anti-inflammatory properties by inhibiting pro-inflammatory cytokines implicated in MASLD pathophysiology. Experimental evidence suggests that the immunomodulatory effects of vitamin D extend to the liver, reducing inflammation and oxidative stress, key drivers of MASLD, and the likelihood of hepatocyte injury and fibrosis. Understanding the complex interplay between vitamin D and MASLD provides a basis for exploring targeted therapeutic strategies and preventive interventions. As vitamin D deficiency is a modifiable risk factor, addressing this nutritional concern may prove beneficial in mitigating the burden of MASLD and associated metabolic disorders.

The contribution of vitamin D insufficiency to the onset of steatotic liver disease among individuals with metabolic dysfunction

The interplay between fatty liver disease (FLD) and metabolic dysfunction has given rise to the concept of metabolic associated fatty liver disease (MAFLD). With vitamin D insufficiency frequently co-occurring with FLD and linked to metabolic abnormalities, this study investigates the potential role of vitamin D in the development of MAFLD. In this cross-sectional analysis, 22,476 participants with baseline metabolic dysfunction and known serum 25-OH-vitamin D3 levels were examined. The fatty liver index (FLI) was utilized to predict FLD, dividing subjects into MAFLD and non-MAFLD groups. Further stratification by vitamin D levels (sufficient vs. insufficient) and gender provided a detailed assessment through binary logistic regression to determine the association of vitamin D status with MAFLD incidence. Vitamin D insufficiency correlated with a higher MAFLD incidence in metabolically impaired individuals. Post-adjustment, the correlation was stronger (men: aOR = 1.32, 95% CI = 1.22-1.43, P < 0.001; women: aOR = 1.53, 95% CI = 1.18-1.98, P = 0.001). Lower serum 25-OH-vitamin D3 levels were found in MAFLD patients across genders (men: P = 0.003; women: P = 0.014), with a higher prevalence of insufficiency in MAFLD cases (men: P = 0.007; women: P = 0.003). The vitamin D-MAFLD link was stable across subgroups and using varying FLI criteria. Our findings indicate a clear association between vitamin D insufficiency and increased MAFLD incidence, underscoring the potential of vitamin D as an anti-lipogenic and anti-fibrotic agent.

Effects of dietary supplementation of fish oil plus vitamin D3 on gut microbiota and fecal metabolites, and their correlation with nonalcoholic fatty liver disease risk factors: a randomized controlled trial

We previously reported that fish oil plus vitamin D3 (FO + D) could ameliorate nonalcoholic fatty liver disease (NAFLD). However, it is unclear whether the beneficial effects of FO + D on NAFLD are associated with gut microbiota and fecal metabolites. In this study, we investigated the effects of dietary supplementation of FO + D on gut microbiota and fecal metabolites and their correlation with NAFLD risk factors. Methods: A total of 61 subjects were randomly divided into three groups: FO + D group (2.34 g day-1 of eicosatetraenoic acid (EPA) + docosahexaenoic acid (DHA) + 1680 IU vitamin D3), FO group (2.34 g day-1 of EPA + DHA), and corn oil (CO) group (1.70 g d-1 linoleic acid). Blood and fecal samples were collected at the baseline and day 90. Gut microbiota were analyzed through 16S rRNA PCR analysis, and fecal co-metabolites were determined via untargeted ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). Results: The relative abundance of Eubacterium (p = 0.03) and Lactobacillus (p = 0.05) increased, whereas that of Streptococcus (p = 0.02) and Dialister (p = 0.04) decreased in the FO + D group compared with the CO group. Besides, changes in tetracosahexaenoic acid (THA, C24:6 n-3) (p = 0.03) levels were significantly enhanced, whereas 8,9-DiHETrE levels (p < 0.05) were reduced in the FO + D group compared with the CO group. The changes in 1,25-dihydroxyvitamin D3 levels in the fecal samples were inversely associated with insulin resistance, which was determined using the homeostatic model assessment model (HOMA-IR, r = -0.29, p = 0.02), and changes in 8,9-DiHETrE levels were positively associated with adiponectin levels (r = -0.43, p < 0.05). Conclusion: The present results indicate that the beneficial effects of FO + D on NAFLD may be partially attributed to the impact on gut microbiota and fecal metabolites.

Exploring Promising Therapies for Non-Alcoholic Fatty Liver Disease: A ClinicalTrials.gov Analysis

Background

Non-alcoholic fatty liver disease (NAFLD) is a common disease and has been increasing in recent years. To date, no FDA-approved drug specifically targets NAFLD.

Methods

The terms "Non-alcoholic Fatty Liver Disease" and "NAFLD" were used in a search of ClinicalTrials.gov on August 24, 2023. Two evaluators independently examined the trials using predetermined eligibility criteria. Studies had to be interventional, NAFLD focused, in Phase IV, and completed to be eligible for this review.

Results

The ClinicalTrials.gov database was searched for trials examining pharmacotherapeutics in NAFLD. The search revealed 1364 trials, with 31 meeting the inclusion criteria. Out of these, 19 were finalized for evaluation. The dominant intervention model was Parallel. The most prevalent studies were in Korea (26.3%) and China (21.1%). The most common intervention was metformin (12.1%), with others like Exenatide and Pioglitazone accounting for 9.1%.

Conclusion

Therapeutics used to manage NAFLD are limited. However, various medications offer potential benefits. Further investigations are definitely warranted.

Vitamin D ameliorates age-induced nonalcoholic fatty liver disease by increasing the mitochondrial contact site and cristae organizing system (MICOS) 60 level

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease. Despite intensive research, considerable information on NAFLD development remains elusive. In this study, we examined the effects of vitamin D on age-induced NAFLD, especially in connection with mitochondrial abnormalities. We observed the prevention of NAFLD in 22-month-old C57BL/6 mice fed a vitamin D3-supplemented (20,000 IU/kg) diet compared with mice fed a control (1000 IU/kg) diet. We evaluated whether vitamin D3 supplementation enhanced mitochondrial functions. We found that the level of mitochondrial contact site and cristae organizing system (MICOS) 60 (Mic60) level was reduced in aged mice, and this reduction was specifically restored by vitamin D3. In addition, depletion of Immt, the human gene encoding the Mic60 protein, induced changes in gene expression patterns that led to fat accumulation in both HepG2 and primary hepatocytes, and these alterations were effectively prevented by vitamin D3. In addition, silencing of the vitamin D receptor (VDR) decreased the Mic60 levels, which were recovered by vitamin D treatment. To assess whether VDR directly regulates Mic60 levels, we performed chromatin immunoprecipitation and reporter gene analysis. We discovered that VDR directly binds to the Immt 5' promoter region spanning positions -3157 to -2323 and thereby upregulates Mic60. Our study provides the first demonstration that a reduction in Mic60 levels due to aging may be one of the mechanisms underlying the development of aging-associated NAFLD. In addition, vitamin D3 could positively regulate Mic60 expression, and this may be one of the important mechanisms by which vitamin D could ameliorate age-induced NAFLD.

A cross-ancestry genome-wide meta-analysis, fine-mapping, and gene prioritization approach to characterize the genetic architecture of adiponectin

Previous genome-wide association studies (GWASs) for adiponectin, a complex trait linked to type 2 diabetes and obesity, identified >20 associated loci. However, most loci were identified in populations of European ancestry, and many of the target genes underlying the associations remain unknown. We conducted a cross-ancestry adiponectin GWAS meta-analysis in ≤46,434 individuals from the Metabolic Syndrome in Men (METSIM) cohort and the ADIPOGen and AGEN consortiums. We combined study-specific association summary statistics using a fixed-effects, inverse variance-weighted approach. We identified 22 loci associated with adiponectin (p < 5×10-8), including 15 known and seven previously unreported loci. Among individuals of European ancestry, Genome-wide Complex Traits Analysis joint conditional analysis (GCTA-COJO) identified 14 additional distinct signals at the ADIPOQ, CDH13, HCAR1, and ZNF664 loci. Leveraging the cross-ancestry data, FINEMAP + SuSiE identified 45 causal variants (PP > 0.9), which also exhibited potential pleiotropy for cardiometabolic traits. To prioritize target genes at associated loci, we propose a combinatorial likelihood scoring formalism (Gene Priority Score [GPScore]) based on measures derived from 11 gene prioritization strategies and the physical distance to the transcription start site. With GPScore, we prioritize the 30 most probable target genes underlying the adiponectin-associated variants in the cross-ancestry analysis, including well-known causal genes (e.g., ADIPOQ, CDH13) and additional genes (e.g., CSF1, RGS17). Functional association networks revealed complex interactions of prioritized genes, their functionally connected genes, and their underlying pathways centered around insulin and adiponectin signaling, indicating an essential role in regulating energy balance in the body, inflammation, coagulation, fibrinolysis, insulin resistance, and diabetes. Overall, our analyses identify and characterize adiponectin association signals and inform experimental interrogation of target genes for adiponectin.

Maternal Vitamin D Deficiency in Mice Sex-Dependently Affects Hepatic Lipid Accumulation in Offspring

SCOPE

Vitamin D deficiency (VDD) is becoming a global issue and low 25-hydroxyvitamin D (25(OH)D) plasma levels have been linked to hepatic steatosis in adulthood. Nevertheless, the impact of maternal VDD on lipid metabolism and hepatic steatosis remains poorly documented, especially under obesogenic condition. The goal of this study is to assess the effects of maternal VDD on hepatic lipid accumulation in adult offspring fed a normal or obesogenic diet.

METHODS AND RESULTS

Several approaches are implemented including histology and lipidomics on the liver in both males and females. No major impact of high-fat (HF) or VDD is observed at histological level in both males and females. Nevertheless, in males born from VDD mice and fed an HF diet, an increase of total lipids and modulation of the relative lipid species distribution characterized by a decrease of triglycerides and increase of phospholipids is observed. In female no major lipid profile is noticed.

CONCLUSION

Maternal VDD combined with a HF diet in male may predispose to hepatic hypertrophia, with a specific lipid profile. Such observations reinforce our knowledge of the impact of maternal VDD on hepatic programming in the offspring.

Steatosis regression assessed by cap after Vitamin 'D' supplementation in NAFLD patients with Vitamin 'D' deficiency

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease, and previous studies suggested a relationship between vitamin D deficiency and NAFLD. It is suggested that vitamin D supplementation may have significant beneficial effect on liver biochemistry and histology.

OBJECTIVE

This study aims to assess the degree of possible steatosis regression using controlled attenuation parameter (CAP) in NAFLD patients with vitamin D deficiency after vitamin D supplementation and evaluating its effect on lipid profile and transaminases.

PATIENTS AND METHODS

This study was conducted on 100 NAFLD patients with vitamin D deficiency. They received 10000 IU/week of vitamin D orally for 3 months. CAP was used to assess hepatic steatosis and fibrosis before/after intervention. Transaminases, lipid profile, and vitamin D levels were evaluated before/after treatment.

RESULTS

Serum AST, ALT, cholesterol, TG, LDL and HDL showed a significant reduction posttreatment in patients with both normal and elevated baseline levels ( P < 0.001). The posttreatment mean CAP showed a significant reduction (300.44 ± 37.56 vs. 265 ± 36.19 dB/ml) ( P  < 0.001), and there was a significant improvement in the mean fibrosis values by LSM (5.32 ± 1.53 vs. 4.86 ± 1.28 KPa) ( P  = 0.001). After supplementation, serum vitamin D level was raised significantly in the majority of patients ( P  < 0.001); however, only 13% of them reached sufficient levels (>30 ng/ml), insufficient levels (20-29 ng/ml) was reached in 83% and 5% showed vitamin D deficiency (<20 ng/ml).

CONCLUSION

A significant improvement was detected in hepatic steatosis (by CAP); mean values of LSM, transaminases and lipid profile after three months of oral vitamin D supplementation.

Serum vitamin D is associated with ultrasound-defined hepatic fibrosis

BACKGROUND

Evidences from population-based investigations on the exact relationship between vitamin D and the severity of liver fibrosis remain debated and conflicting. Here, we aim to explore the relationship between serum vitamin D and ultrasound-defined advanced hepatic fibrosis in the US participants with nonalcoholic fatty liver disease (NAFLD).

METHODS

In the retrospective study, individuals with intact information on interesting variables from the 2017-2018 National Health and Nutrition Examination Survey (NHANES) were included. NAFLD was diagnosed on the basis of controlling attenuation parameter (CAP) value≥ 274 dB/m without causes of other chronic hepatic diseases. We identified advanced fibrosis grades (F2) by liver stiffness measurement (LSM) score of ≥ 8.2 kPa in NAFLD patients. The impact of elevated serum vitamin D on the prevalence of hepatic fibrosis was assessed by multivariate logistic regression models on the basis of the NHANES recommended weights.

RESULTS

The study involved 1624 subjects with NAFLD in total, and 305 (18.28 %, weighted%) of whom were diagnosed with advanced hepatic fibrosis according to the definition based on parameters obtained from vibration controlled transient elastography (VCTE). In the multivariate logistic regression analysis, serum vitamin D presented a negative relationship to hepatic fibrosis with lower odds in patients with hepatic steatosis after being adjusted for potential confounding factors (fully adjusted: OR=0.47, 95 % CI: 0.24-0.90, p = 0.034). Our subgroup analysis revealed that the inverse relationship was still existed in males (fully adjusted: OR = 0.34, 95 % CI: 0.17-0.70, p = 0.014), non-obese subjects (fully adjusted: OR = 0.20, 95 % CI: 0.04-0.89, p = 0.042) and participants below 60 years (fully adjusted: OR = 0.43, 95 % CI: 0.21-0.90, p = 0.033), whereas in models adjusted for the potential confounding factors, no statistically significant correlation was noted in females, obese subjects or subjects with age≥ 60 years.

CONCLUSIONS

This large population-based investigation indicated that elevated serum vitamin D reduced the onset of advanced fibrosis diagnosed by ultrasound in males, non-obese subjects and younger participants with NAFLD.

The effects of low-fat dairy products fortified with 1500 IU vitamin D3 on serum liver function biomarkers in adults with abdominal obesity: a randomized controlled trial

INTRODUCTION

Vitamin D deficiency has been reported to affect liver function biomarkers. This study was aimed to investigate the effect of consuming vitamin D fortified low-fat dairy products on liver function tests in adults with abdominal obesity.

METHODS

This total blinded randomized controlled trial was undertaken on otherwise healthy abdominally obese adults living in Mashhad, Iran. Milk and yogurt were fortified with 1500 IU vitamin D3 nano-capsules. Participants were randomized to receive fortified milk (n = 73), plain milk (n = 73), fortified yogurt (n = 69), and plain yogurt (n = 74) for 10 weeks. Blood samples were taken at baseline and at the end of the study to assess serum levels of vitamin D, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase (ALP), and Gamma glutamyl transferase.

RESULTS

A total of 289 participants completed the study (54% female). The groups were homogenous in terms of age, sex, weight, energy intake, and physical activity level (p-value > 0.05). After the trial, vitamin D serum levels were significantly increased in both groups receiving fortified products (both p < 0.001). There was a significant time*group effect only in serum ALP (p < 0.001).

CONCLUSION

Consumption of dairy products fortified by 1500 IU vitamin D3 might have detrimental effects on serum levels of some liver enzymes in individuals with abdominal obesity. Further studies needed to determine these effects and underlying mechanisms.

TRIAL REGISTRATION

IRCT20101130005280N27 .

High parathyroid hormone level as a marker of non-alcoholic fatty liver disease and non-alcoholic steatohepatitis: A systematic review and meta-analysis

BACKGROUND AND AIMS

Studies have suggested that high parathyroid hormone (PTH) was associated with non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH), although the results from existing studies are inconsistent. Using systematic review and meta-analysis, we aimed to determine the association of PTH with NAFLD and NASH.

METHODS

Potentially eligible studies were identified from Embase and Medline databases from using search strategy consisting of terms for "NAFLD/NASH", and "PTH". Eligible study must consist of one group of patients with NAFLD/NASH and another group without NAFLD/NASH. The study must provide mean ± SD PTH in both groups. We extracted such data to calculate mean difference (MD). Pooled MD was then calculated by combining MDs of each study using random-effects model. Funnel plot was used to assess for the presence of publication bias.

RESULTS

A total of 388 articles were identified. After systematic review, 12 studies fulfilled the eligibility criteria and were included into the meta-analysis. The meta-analysis of 10 studies revealed the significant association between high PTH and NAFLD, with the pooled MD of 5.479 (95%CI 0.947-10.011, I2 82.4%). The funnel plot was symmetric and did not suggest publication bias. The meta-analysis of 4 studies revealed the non-significant association between high PTH and NASH, with the pooled MD of 11.955 (95%CI -4.703 - 28.614, I2 81.0%).

CONCLUSIONS

High PTH level is significantly associated with NAFLD and can be used as a marker of NAFLD. However, high PTH level is non-significantly associated with NASH. Further studies are needed to increase the sample size and eliminate the confounding factors.

Vitamin D3 alleviates nonalcoholic fatty liver disease in rats by inhibiting hepatic oxidative stress and inflammation via the SREBP-1-c/ PPARα-NF-κB/IR-S2 signaling pathway

Introduction: Nonalcoholic fatty liver disease (NAFLD) is a chronic disease characterized by fat deposits in liver cells, which can lead to hepatitis and fibrosis. This study attempted to explore the protective effect of vitamin D3 (VitD) against NAFLD. Methods: Adult male albino rats were randomized into four separate groups: the negative control group was fed a standard rat chow; the positive group received a high-fat diet (20%) and 25% fructose water (NAFLD); the VitD control group was intramuscularly treated with VitD (1,000 IU/kg BW) 3 days per week for 10 weeks; and the NAFLD group was treated with VitD therapy. Biochemical and hepatic histological analyses were performed. Hepatic oxidative stress and inflammatory conditions were also studied. Hepatic expression of sterol regulatory element-binding protein 1-c (SREBP-1-c), peroxisome proliferator-activated receptor alpha (PPAR-α), and insulin receptor substrate-2 was analyzed by quantitative real-time polymerase chain reaction. Results and discussion: The NAFLD rats exhibited elevated terminal body weight, hepatic injury markers, dyslipidemia, glucose intolerance, and insulin resistance. Moreover, the NAFLD rats had increased SREBP-1-c expression and reduced PPAR-α and IRS-2 expressions. Histological analysis showed hepatic steatosis and inflammation in the NAFLD group. In contrast, VitD administration improved the serum biochemical parameters and hepatic redox status in NAFLD rats. Also, VitD treatment ameliorated hepatic inflammation and steatosis in the NAFLD group by decreasing the expression of SREBP-1-c and increasing the expression of PPAR-α. Overall, these results suggest that VitD could have a protective effect against NAFLD and its associated complication.

Nutritional and Lifestyle Therapy for NAFLD in People with HIV

HIV infection and nonalcoholic fatty liver disease (NAFLD) are two major epidemics affecting millions of people worldwide. As people with HIV (PWH) age, there is an increased prevalence of metabolic comorbidities, along with unique HIV factors, such as HIV chronic inflammation and life-long exposure to antiretroviral therapy, which leads to a high prevalence of NAFLD. An unhealthy lifestyle, with a high dietary intake of refined carbohydrates, saturated fatty acids, fructose added beverages, and processed red meat, as well as physical inactivity, are known to trigger and promote the progression of NAFLD to nonalcoholic steatohepatitis, liver fibrosis, and hepatocellular carcinoma. Furthermore, with no currently approved pharmacotherapy and a lack of clinical trials that are inclusive of HIV, nutritional and lifestyle approaches still represent the most recommended treatments for PWH with NAFLD. While sharing common features with the general population, NAFLD in PWH displays its own peculiarities that may also reflect different impacts of nutrition and exercise on its onset and treatment. Therefore, in this narrative review, we aimed to explore the role of nutrients in the development of NAFLD in PWH. In addition, we discussed the nutritional and lifestyle approaches to managing NAFLD in the setting of HIV, with insights into the role of gut microbiota and lean NAFLD.

1,25-Dihydroxycholecalciferol down-regulates 3-mercaptopyruvate sulfur transferase and caspase-3 in rat model of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the commonest cause of liver morbidity and mortality and has multiple unclear pathogenic mechanisms. Vitamin D deficiency was associated with increased incidence and severity of NAFLD. Increased hepatic expression of 3-mercaptopyruvate sulfur transferase (MPST) and dysregulated hepatocyte apoptosis were involved in NAFLD pathogenesis. We aimed to explore the protective effect of 1,25-Dihydroxycholecalciferol (1,25-(OH)₂ D3) against development of NAFLD and the possible underlying mechanisms, regarding hepatic MPST and caspase-3 expression. 60 male adult rats were divided into 4 and 12 week fed groups; each was subdivided into control, high-fat diet (HFD), and HFD + VD. Serum levels of lipid profile parameters, liver enzymes, insulin, glucose, C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), and hepatic levels of malondialdehyde (MDA), total antioxidant capacity (TAC), and reactive oxygen species (ROS) were measured. BMI and HOMA-IR were calculated, and liver tissues were processed for histopathological and immunohistochemical studies. The present study found that 1,25-(OH)₂ D3 significantly decreased BMI, HOMA-IR, serum levels of glucose, insulin, liver enzymes, lipid profile parameters, CRP, TNF-α, hepatic levels of MDA, ROS, hepatic expression of MPST, TNF-α, 8-hydroxy-2'-deoxyguanosine (8-OHdG), and caspase-3; and significantly increased hepatic TAC in both HFD-fed groups. In conclusion: Administration of 1,25-(OH)₂ D3 with HFD abolished the NAFLD changes associated with HFD in 4-week group, and markedly attenuated the changes in 12-week group. The anti-apoptotic effect via decrement of caspase-3 and MPST expression are novel mechanisms suggested to be implicated in the protective effect of 1,25-(OH)₂ D3.

Nutraceutical approaches to non-alcoholic fatty liver disease (NAFLD): A position paper from the International Lipid Expert Panel (ILEP)

Non-Alcoholic Fatty Liver Disease (NAFLD) is a common condition affecting around 10-25% of the general adult population, 15% of children, and even > 50% of individuals who have type 2 diabetes mellitus. It is a major cause of liver-related morbidity, and cardiovascular (CV) mortality is a common cause of death. In addition to being the initial step of irreversible alterations of the liver parenchyma causing cirrhosis, about 1/6 of those who develop NASH are at risk also developing CV disease (CVD). More recently the acronym MAFLD (Metabolic Associated Fatty Liver Disease) has been preferred by many European and US specialists, providing a clearer message on the metabolic etiology of the disease. The suggestions for the management of NAFLD are like those recommended by guidelines for CVD prevention. In this context, the general approach is to prescribe physical activity and dietary changes the effect weight loss. Lifestyle change in the NAFLD patient has been supplemented in some by the use of nutraceuticals, but the evidence based for these remains uncertain. The aim of this Position Paper was to summarize the clinical evidence relating to the effect of nutraceuticals on NAFLD-related parameters. Our reading of the data is that whilst many nutraceuticals have been studied in relation to NAFLD, none have sufficient evidence to recommend their routine use; robust trials are required to appropriately address efficacy and safety.

Inverse Association Between Serum 25-Hydroxyvitamin D and Nonalcoholic Fatty Liver Disease

BACKGROUND & AIMS

Serum 25-hydroxyvitamin D [S-25(OH)D] and nonalcoholic fatty liver disease (NAFLD) are correlated in many observational studies, whereas the causality of this association is uncertain, especially in European populations. We conducted a bidirectional Mendelian randomization study to determine the association between S-25(OH)D and NAFLD.

METHODS

Seven and 6 independent genetic variants associated with S-25(OH)D and NAFLD at the genome-wide-significance level, respectively, were selected as instrumental variables. Summary-level data for S-25(OH)D were obtained from the Study of Underlying Genetic Determinants of Vitamin D and Highly Related Traits consortium including 79,366 individuals. Summary-level data for NAFLD were available from a genome-wide association meta-analysis (1483 cases and 17,781 controls), the FinnGen consortium (894 cases and 217,898 controls), and the UK Biobank study (275 cases and 360,919 controls). Summary-level data for 4 liver enzymes were obtained from the UK Biobank.

RESULTS

There were genetic correlations of S-25(OH)D with NAFLD and certain liver enzymes. Genetically predicted higher levels of S-25(OH)D were consistently associated with a decreased risk of NAFLD in the 3 sources. For a 1-SD increase in genetically predicted S-25(OH)D levels, the combined odds ratio of NAFLD was 0.78 (95% confidence interval [CI], 0.69 to 0.89). Genetically predicted higher levels of S-25(OH)D showed a borderline association with aspartate aminotransferase levels (change -1.17; 95% CI, -1.36 to 0.01). Genetic predisposition to NAFLD was not associated with S-25(OH)D (change 0.13; 95% CI, -1.26 to 0.53).

CONCLUSIONS

Our findings have clinical implications as they suggest that increased vitamin D levels may play a role in NAFLD prevention in European populations.

Regulation of Cholesterol Metabolism by Phytochemicals Derived from Algae and Edible Mushrooms in Non-Alcoholic Fatty Liver Disease

Cholesterol synthesis occurs in almost all cells, but mainly in hepatocytes in the liver. Cholesterol is garnering increasing attention for its central role in various metabolic diseases. In addition, cholesterol is one of the most essential elements for cells as both a structural source and a player participating in various metabolic pathways. Accurate regulation of cholesterol is necessary for the proper metabolism of fats in the body. Disturbances in cholesterol homeostasis have been linked to various metabolic diseases, such as hyperlipidemia and non-alcoholic fatty liver disease (NAFLD). For many years, the use of synthetic chemical drugs has been effective against many health conditions. Furthermore, from ancient to modern times, various plant-based drugs have been considered local medicines, playing important roles in human health. Phytochemicals are bioactive natural compounds that are derived from medicinal plants, fruit, vegetables, roots, leaves, and flowers and are used to treat a variety of diseases. They include flavonoids, carotenoids, polyphenols, polysaccharides, vitamins, and more. Many of these compounds have been proven to have antioxidant, anti-inflammatory, antiobesity and antihypercholesteremic activity. The multifaceted role of phytochemicals may provide health benefits to humans with regard to the treatment and control of cholesterol metabolism and the diseases associated with this disorder, such as NAFLD. In recent years, global environmental climate change, the COVID-19 pandemic, the current war in Europe, and other conflicts have threatened food security and human nutrition worldwide. This further emphasizes the urgent need for sustainable sources of functional phytochemicals to be included in the food industry and dietary habits. This review summarizes the latest findings on selected phytochemicals from sustainable sources-algae and edible mushrooms-that affect the synthesis and metabolism of cholesterol and improve or prevent NAFLD.

Higher Serum 25-Hydroxyvitamin D Is Associated with Lower All-Cause and Cardiovascular Mortality among US Adults with Nonalcoholic Fatty Liver Disease

Aims: We aimed to assess the association between serum 25-hydroxyvitamin D (25(OH)D) levels with all-cause and cardiovascular mortality in patients with nonalcoholic fatty liver disease (NAFLD). Methods: We performed a retrospective cohort study based on the US National Health and Nutrition Examination Survey 2001–2016 on adults aged ≥20 years. NAFLD was determined as a US Fatty Liver Index score ≥ 30 in the absence of other liver conditions. Weighted Cox proportional hazards regression models were applied to explore the relationship between serum 25(OH)D levels and mortality. Results: 898 all-cause deaths and 305 cardiovascular deaths were recorded over a median follow-up of 8.7 years. Compared with those in the severe deficiency group (below 25.0 nmol/L), the fully adjusted HRs and 95% CIs of NAFLD patients with sufficient serum 25(OH)D concentrations (≥75.0 nmol/L) were 0.36 (0.22, 0.60) for all-cause mortality and 0.14 (0.07, 0.29) for cardiovascular mortality. Each one-unit increase in the natural log-transformed serum 25(OH)D concentration was related to a 41% lower risk for all-cause deaths (HR = 0.59, 95% CI: 0.46, 0.77) and a 65% lower risk for cardiovascular deaths (HR = 0.35, 95% CI: 0.22, 0.58). Conclusions: Among NAFLD patients, increased serum 25(OH)D levels were independently associated with reduced risk for all-cause and cardiovascular deaths.

Vitamin D Status and Steatohepatitis in Obese Diabetic and Non-Diabetic Patients

BACKGROUND AND AIMS

The presence of steatohepatitis in obese patients can be multifactorial. The current study tries to determine the differences between diabetic and non-diabetic patients regarding the presence of steatohepatitis. We evaluated sequential liver samples and collected the times of bariatric surgery to assess the presence of NASH in patients with obesity, in the circuit of bariatric surgery.

METHODS

We performed a retrospective study of 49 patients presenting high-grade obesity in the circuit of bariatric surgery, with liver biopsy. The patients underwent bariatric surgery at a single center in France and were followed for 2 years. The liver biopsies were performed intraoperatively on all 49 patients before the bariatric surgery. The primary endpoint of the study was to evaluate the relationships between steatohepatitis/liver fibrosis and the presence of diabetes and to evaluate the current relationships between the biochemical work-ups. Special importance was accorded to the correlations between vitamin D levels and the presence of hepatic steatosis, due to the antifibrogenic pattern in the liver, as shown in many important papers in the field.

RESULTS

Significant correlations were found between the presence of liver fibrosis and the presence of diabetes (p = 0.022), but not regarding the antidiabetic treatment. An important correlation was found between the vitamin D levels and the presence of liver fibrosis, as well as with the levels of A1C hemoglobin and LDL cholesterol levels.

CONCLUSIONS

Vitamin D deficiency presents a strong correlation with hepatic steatosis in individuals with morbid obesity. Correcting vitamin D deficiency may present a beneficial role in treating hepatic steatosis, diabetes, and cardiovascular risk in patients with morbid obesity.

Association between serum 25-hydroxy vitamin D concentrations and mortality among individuals with metabolic dysfunction-associated fatty liver disease: a prospective cohort study

BACKGROUND

The association between serum 25-hydroxy vitamin D (25(OH)D) concentrations and mortality remains unclear among patients with metabolic dysfunction-associated fatty liver disease (MAFLD) or non-alcoholic fatty liver disease (NAFLD).

OBJECTIVES

To evaluate the association between serum 25(OH)D concentrations and mortality among individuals with MAFLD/NAFLD.

METHODS

The study included 4651 individuals with fatty liver disease (FLD) (3964 had MAFLD and 3968 had NAFLD) from the Third National Health and Nutrition Examination Survey. Fatty liver disease was identified by ultrasonographic detection of hepatic steatosis. Mortality was ascertained by linkage to the National Death Index up to 31 December 2019. Cox proportional hazards models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) with adjustment of potential confounders.

RESULTS

Of 4651 individuals with FLD, 3427 individuals (69.7%) had both MAFLD and NAFLD. During median follow-ups of 25.8 and 26.1 years, we identified 1809 and 1665 deaths among 3964 participants with MAFLD and 3968 participants with NAFLD, respectively. Compared with participants with serum 25(OH)D concentrations ≤30.0 nmol/L, the multivariable-adjusted HR and 95% CI of all-cause mortality were 0.62 (0.43, 0.89) for participants with MAFLD having serum 25(OH)D >75.0 nmol/L (P-trend = 0.001), and 0.63 (0.42, 0.95) for participants with NAFLD having serum 25(OH)D >75.0 nmol/L (P-trend = 0.002). A nonlinearly inverse association was observed between serum 25(OH)D concentrations and all-cause mortality among participants with MAFLD (Poverall <0.001; Pnonlinear = 0.003) or NAFLD (Poverall <0.001; Pnonlinear = 0.009), with a threshold effect at around 50.0 nmol/L. The inverse association was stronger among participants with MAFLD aged <60 years (P-interaction = 0.001).

CONCLUSIONS

This study suggested a nonlinearly inverse association between serum 25(OH)D concentrations and all-cause mortality among patients with MAFLD/NAFLD, with a threshold effect at around 50.0 nmol/L of serum 25(OH)D.

Vitamin D–VDR Novel Anti-Inflammatory Molecules—New Insights into Their Effects on Liver Diseases

There is consistent evidence that vitamin D deficiency is strongly associated with liver dysfunction, disease severity, and poor prognosis in patients with liver disease. Vitamin D and its receptor (VDR) contribute to the regulation of innate and adaptive immune responses. The presence of genetic variants of vitamin D- and VDR-associated genes has been associated with liver disease progression. In our recent work, we summarized the progress in understanding the molecular mechanisms involved in vitamin D–VDR signaling and discussed the functional significance of VDR signaling in specific cell populations in liver disease. The current review focuses on the complex interaction between immune and liver cells in the maintenance of liver homeostasis and the development of liver injury, the interplay of vitamin D and VDR in the development and outcome of liver disease, the role of vitamin D- and VDR-associated genetic variants in modulating the occurrence and severity of liver disease, and the therapeutic value of vitamin D supplementation in various liver diseases. The association of the vitamin D–VDR complex with liver dysfunction shows great potential for clinical application and supports its use as a prognostic index and diagnostic tool.

Nonalcoholic Fatty Liver Disease and Endocrine Axes—A Scoping Review

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease. NAFLD often occurs associated with endocrinopathies. Evidence suggests that endocrine dysfunction may play an important role in NAFLD development, progression, and severity. Our work aimed to explore and summarize the crosstalk between the liver and different endocrine organs, their hormones, and dysfunctions. For instance, our results show that hyperprolactinemia, hypercortisolemia, and polycystic ovary syndrome seem to worsen NAFLD’s pathway. Hypothyroidism and low growth hormone levels also may contribute to NAFLD’s progression, and a bidirectional association between hypercortisolism and hypogonadism and the NAFLD pathway looks likely, given the current evidence. Therefore, we concluded that it appears likely that there is a link between several endocrine disorders and NAFLD other than the typically known type 2 diabetes mellitus and metabolic syndrome (MS). Nevertheless, there is controversial and insufficient evidence in this area of knowledge.

The Predictive Role of Parathyroid Hormone for Nonalcoholic Fatty Liver Disease following Bariatric Surgery

Background

Morbid obesity is frequently complicated by chronic liver diseases, including nonalcoholic fatty liver disease (NAFLD), nonalcoholic steatohepatitis (NASH), and fibrosis. Parathyroid hormone (PTH) is found to be elevated in morbid obesity due to the defective hepatic metabolism of vitamin D. Bariatric surgery is performed to help patients with BMI>40 kg/m² to effectively lose weight, particularly in patients with obesity who are afflicted with complications such as NAFLD/NASH.

Objective

This study aimed to evaluate the PTH level as a predictor of hepatic function in individuals with morbid obesity who have undergone bariatric surgery.

Methods

Ninety subjects with morbid obesity referred for Roux en-Y gastric bypass surgery were recruited. After IRB approval, demographic profiles, anthropometric factors, liver biopsy, and laboratory tests were obtained. The two-dimensional shear wave elastography (2D-SWE) technique was applied to assess hepatic stiffness.

Results

A significant reduction occurred six months after bariatric surgery in the anthropometric indices (p < 0.001), hepatic elasticity (p=0.002), alanine aminotransferase (p < 0.001), serum alkaline phosphatase (p < 0.001), gamma-glutamyl transpeptidase (GGT) (p < 0.001), and nonalcoholic fatty liver disease fibrosis score (NFS) (p < 0.001). Serum PTH concentration was not predictive of postsurgical liver fibrosis and steatosis at six months but could predict weight loss success rate. No significant alteration in serum PTH levels was observed between presurgical vs. postsurgical time points.

Conclusion

A significant reduction was observed in the anthropometric parameters, liver enzymes, and hepatic elasticity after bariatric surgery. No significant effect was found on PTH levels.

Association and interaction between vitamin D level and metabolic syndrome for non-alcoholic fatty liver disease

INTRODUCTION/OBJECTIVES

Previous studies have shown conflicting results regarding the association between hypovitaminosis D and non-alcoholic fatty liver disease (NAFLD). The aim of this study is to explore the individual and combined effect of hypovitaminosis D and metabolic syndrome (MS) on NAFLD.

MATERIALS AND METHODS

In this cross-sectional study, 874 subjects were enrolled. 25(OH)D was assessed by a sequential competitive immuno-fluoro-assay method. The Fatty Liver Index (FLI) was used for NAFLD screening. Binary logistic regression and additive interaction were performed to investigate the association between vitamin D status, MS and NAFLD.

RESULTS

Severe vitamin D deficiency was found to be positively related to NAFLD, with a higher risk in women than in men (OR = 6.4, 95% CI [2.8-15], p < 0.0001 vs. OR = 5.8, 95% CI [1.9-17.7], p = 0.002). In men, this association was partially masked by obesity. The additive interaction with MS was significant in women but not in men, the relative excess risk due to interaction was of 7.2, 95% CI [1.3-12.9], p = 0.02), the attributable proportion due to the combined effect was of 0.6, 95% CI [0.4-0.8], p < 0.0001. The interaction mechanism is synergistic; the synergy index: was of 2.9, 95% CI [1.6-5.3], p = 0.0006.

CONCLUSION

A positive association has been found between severe vitamin D deficiency and NAFLD. Moreover, an excess risk in women combining both MS and severe vitamin D deficiency was quantified.

Real-world Comorbidity Burden, Health Care Utilization, and Costs of Nonalcoholic Steatohepatitis Patients With Advanced Liver Diseases

GOALS

This study evaluates the real-world comorbidity burden, health care resource utilization (HRU), and costs among nonalcoholic fatty liver disease/nonalcoholic steatohepatitis (NAFLD/NASH) patients with advanced liver diseases [compensated cirrhosis (CC), decompensated cirrhosis (DCC), liver transplantation (LT), hepatocellular carcinoma (HCC)].

BACKGROUND

NAFLD/NASH is a leading cause of liver diseases.

MATERIALS AND METHODS

Adult NAFLD/NASH patients were identified retrospectively from MarketScan Commercial claims (2006-2016). Following initial NAFLD/NASH diagnosis, advanced liver diseases were identified using the first diagnosis as their index date. Mean annual all-cause HRU and costs (2016 USD) were reported. Adjusted costs were estimated through generalized linear models. Cumulative costs were illustrated for patient subsets with variable follow-up for each stage.

RESULTS

Within the database, 485,774 NAFLD/NASH patients met eligibility criteria. Of these, 93.4% (453,564) were NAFLD/NASH patients without advanced liver diseases, 1.6% (7665) with CC, 3.3% (15,833) with DCC, 0.1% (696) with LT, and 0.1% (428) with HCC. Comorbidity burden was high and increased as patients progressed through liver disease severity stages. Compared with NAFLD/NASH without advanced liver diseases (adjusted costs: $23,860), the annual cost of CC, DCC, LT, and HCC were 1.22, 5.64, 8.27, and 4.09 times higher [adjusted costs: $29,078, $134,448, $197,392, and $97,563 (P<0.0001)]. Inpatient admissions significantly drove increasing HRU.

CONCLUSION

Study findings suggest the need for early identification and effective management of NAFLD/NASH patients to minimize comorbidity burden, HRU, and costs in the privately insured US population.

Associations of Nutritional, Lifestyle, and Metabolic Factors With Non-alcoholic Fatty Liver Disease: An Umbrella Review With More Than 380,000 Participants

Background & Aims: Nonalcoholic fatty liver disease (NAFLD) is the most common liver injury. We performed this umbrella review of meta-analyses to summarize the evidence on the associations of nutritional, lifestyle, and metabolic factors with NAFLD.

Methods: We searched the PubMed, Embase, and Web of Science databases from inception until July 2, 2020, to identify meta-analyses of observational studies which explored the associations of nutritional, lifestyle, and metabolic factors with NAFLD. Evidence levels were assessed using summary effect sizes, 95% prediction intervals, between-study heterogeneity, evidence of small-study effects, and evidence of excess significance bias for each meta-analysis. (No. of PROSPERO, CRD42020200124).

Results: Twenty two risk or protective factors from 10 published meta-analyses were included and studied. Three risk factors (sugar-sweetened beverage consumption, serum fetuin-A, and waist circumference) with highly suggestive levels of evidence and three risk factors (soft drink consumption, former smoking, and body mass index) with suggestive levels of evidence were identified. Only two protective factors (physical activity and serum vitamin D level [among adults in Western countries]) with suggestive levels of evidence were identified. Furthermore, other six risk factors and two protective factors with weak levels of evidence were identified.

Conclusions: We found varying levels of evidence of associations of nutritional, lifestyle, and metabolic factors and NAFLD. The results suggest that nutritional and lifestyle management should be considered as a major primary preventive strategy for NAFLD. Moreover, considering the low quality of included meta-analyses and limited area of research topics, future high-quality original studies and meta-analyses should be performed to study these associations.

Role of fatty liver in coronavirus disease 2019 patients' disease severity and hospitalization length: a case-control study

Background and purpose

Fatty liver is one of the most common pre-existing illnesses; it can cause liver injury, leading to further complications in coronavirus disease 2019 patients. Our goal is to determine if pre-existing fatty liver is more prevalent in hospitalized COVID-19 patients compared to patients admitted before the SARS-CoV-2 pandemic and determine the disease severity among fatty liver patients.

Experimental approach

This retrospective study involves a case and a control group consisting of 1162 patients; the case group contains hospitalized COVID-19 patients with positive PCR tests and available chest CT-scan; the control group contains patients with available chest CT-scan previous to the COVID-19 pandemic. Patients’ data such as liver Hounsfield unit, hospitalization length, number of affected lobes, and total lungs involvement score were extracted and compared between the patients.

Results

The findings indicate that 37.9% of hospitalized COVID-19 patients have a pre-existing fatty liver, which is significantly higher (P < 0.001) than the prevalence of pre-existing fatty liver in control group patients (9.02%). In comparison to hospitalized non-fatty liver COVID-19 patients, data from hospitalized COVID-19 patients with fatty liver indicate a longer hospitalization length (6.81 ± 4.76 P = 0.02), a higher total lungs involvement score (8.73 ± 5.28 P < 0.001), and an increased number of affected lobes (4.42 ± 1.2 P < 0.001).

Conclusion

The statistical analysis shows fatty liver is significantly more prevalent among COVID-19 against non-COVID-19 patients, and they develop more severe disease and tend to be hospitalized for more extended periods.

Vitamin D supplementation for chronic liver diseases in adults

BACKGROUND

Vitamin D deficiency is often reported in people with chronic liver diseases. Improving vitamin D status could therefore be beneficial for people with chronic liver diseases.

OBJECTIVES

To assess the beneficial and harmful effects of vitamin D supplementation in adults with chronic liver diseases.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, CENTRAL, MEDLINE Ovid, Embase Ovid, LILACS, Science Citation Index Expanded, and Conference Proceedings Citation Index-Science. We also searched ClinicalTrials.gov  and the World Health Organization International Clinical Trials Registry Platform. We scanned bibliographies of relevant publications and enquired experts and pharmaceutical companies as to additional trials. All searches were up to November 2020.

SELECTION CRITERIA

Randomised clinical trials that compared vitamin D at any dose, duration, and route of administration versus placebo or no intervention in adults with chronic liver diseases. Vitamin D could have been administered as supplemental vitamin D (vitamin D₃ (cholecalciferol) or vitamin D₂ (ergocalciferol)), or an active form of vitamin D (1α-hydroxyvitamin D (alfacalcidol), 25-hydroxyvitamin D (calcidiol), or 1,25-dihydroxyvitamin D (calcitriol)).

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We used GRADE to assess the certainty of evidence.

MAIN RESULTS

We included 27 randomised clinical trials with 1979 adult participants. This review update added 12 trials with 945 participants. We assessed all trials as at high risk of bias. All trials had a parallel-group design. Eleven trials were conducted in high-income countries and 16 trials in middle-income countries. Ten trials included participants with chronic hepatitis C, five trials participants with liver cirrhosis, 11 trials participants with non-alcoholic fatty liver disease, and one trial liver transplant recipients. All of the included trials reported the baseline vitamin D status of participants. Participants in nine trials had baseline serum 25-hydroxyvitamin D levels at or above vitamin D adequacy (20 ng/mL), whilst participants in the remaining 18 trials were vitamin D insufficient (less than 20 ng/mL). Twenty-four trials administered vitamin D orally, two trials intramuscularly, and one trial intramuscularly and orally. In all 27 trials, the mean duration of vitamin D supplementation was 6 months, and the mean follow-up of participants from randomisation was 7 months. Twenty trials (1592 participants; 44% women; mean age 48 years) tested vitamin D₃ (cholecalciferol); three trials (156 participants; 28% women; mean age 54 years) tested vitamin D₂; four trials (291 participants; 60% women; mean age 52 years) tested 1,25-dihydroxyvitamin D; and one trial (18 participants; 0% women; mean age 52 years) tested 25-hydroxyvitamin D. One trial did not report the form of vitamin D. Twelve trials used a placebo, whilst the other 15 trials used no intervention in the control group. Fourteen trials appeared to be free of vested interest. Eleven trials did not provide any information on clinical trial support or sponsorship. Two trials were funded by industry. We are very uncertain regarding the effect of vitamin D versus placebo or no intervention on all-cause mortality (risk ratio (RR) 0.86, 95% confidence interval (CI) 0.51 to 1.45; 27 trials; 1979 participants). The mean follow-up was 7 months (range 1 to 18 months). We are very uncertain regarding the effect of vitamin D versus placebo or no intervention on liver-related mortality (RR 1.62, 95% CI 0.08 to 34.66; 1 trial; 18 participants) (follow-up: 12 months); serious adverse events such as hypercalcaemia (RR 5.00, 95% CI 0.25 to 100.8; 1 trial; 76 participants); myocardial infarction (RR 0.75, 95% CI 0.08 to 6.81; 2 trials; 86 participants); thyroiditis (RR 0.33, 95% CI 0.01 to 7.91; 1 trial; 68 participants); circular haemorrhoidal prolapse (RR 3.00, 95% CI 0.14 to 65.9; 1 trial; 20 participants); bronchopneumonia (RR 0.33, 95% CI 0.02 to 7.32; 1 trial 20 participants); and non-serious adverse events. The certainty of evidence for all outcomes is very low. We found no data on liver-related morbidity such as gastrointestinal bleeding, hepatic encephalopathy, hepatorenal syndrome, ascites, or liver cancer. There were also no data on health-related quality of life. The evidence is also very uncertain regarding the effect of vitamin D versus placebo or no intervention on rapid, early, and sustained virological response in people with chronic hepatitis C.

AUTHORS' CONCLUSIONS

Given the high risk of bias and insufficient power of the included trials and the very low certainty of the available evidence, vitamin D supplementation versus placebo or no intervention may increase or reduce all-cause mortality, liver-related mortality, serious adverse events, or non-serious adverse events in adults with chronic liver diseases. There is a lack of data on liver-related morbidity and health-related quality of life. Further evidence on clinically important outcomes analysed in this review is needed.

Inverse Association between Serum 25-hydroxyvitamin D Levels and Risk of Suspected Non-Alcoholic Fatty Liver Disease in Obese Population

BACKGROUND

Worldwide, vitamin D deficiency is a public health issue and the prevalence of obesity and non-alcoholic fatty liver disease (NAFLD) are rapidly increasing. There are a limited number of studies assessing the association between serum levels of 25-hydroxyvitamin D (25(OH)D) and NAFLD risk in obese population.

OBJECTIVE

We evaluated the associations between serum 25(OH)D levels and risk of suspected NAFLD after stratification by obesity using data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2008-2014.

METHODS

This study included 25,755 subjects without significant alcohol consumption for the serum alanine aminotransferase (ALT) and hepatic steatosis index (HSI) analyses (8922 subjects for the serum gamma-glutamyl transferase (GGT) and fatty liver index (FLI) analyses), based on a cross-sectional study design. Serum 25(OH)D levels were measured using a Gamma counter with radioimmunoassay. A survey logistic regression model was applied to estimate ORs and 95% CIs. Restricted cubic smoothing splines were applied to evaluate nonlinear associations.

RESULTS

The risk of suspected NAFLD was reduced per unit of natural log-transformed serum 25(OH)D concentration in obese individuals (OR [95% (CI)]; for ALT, 0.80 [0.67, 0.96]; for GGT, 0.70 [0.49, 0.99; for FLI, 0.68 [0.47, 1.01]; for HSI, 0.70 [0.56, 0.87]). The ORs [95% CI] of suspected NAFLD changed across the quartiles: for serum ALT, from 1.02 [0.85, 1.23] to 0.72 [0.59, 0.87]; for serum GGT, from 0.79 [0.56, 1.13] to 0.64 [0.44, 0.92]; for FLI, from 0.98 [0.67, 1.44] to 0.70 [0.48, 1.02]; and for HSI, from 0.91 [0.73, 1.14] to 0.65 [0.52, 0.81] with dose-response relationships (all p for trend < 0.01).

CONCLUSIONS

This study suggests that vitamin D sufficiency for public health should be emphasized in order to prevent adverse health effects in obese populations.

The effect of 1,25-dihydroxyvitamin D3 on liver damage, oxidative stress, and advanced glycation end products in experimental nonalcoholic- and alcoholic- fatty liver disease

Background/aim

Oxidative stress and advanced glycation end products (AGEs) formation are proposed as effective mechanisms in the pathogenesis of nonalcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD). 1,25(OH)2D3 was proposed to have antioxidant, antiinflammatory and antiglycation properties. In this study, the effect of 1,25(OH)2D3 treatment on oxidative stress parameters and AGEs levels together with hepatic histopathology was investigated in high fructose (HFr) or ethanol (EtOH)-treated rats.

Materials and methods

Rats were treated with fructose (30%) or ethanol (5-20%) in drinking water with and without 1,25(OH)2D3 treatment (5 µg/kg two times a week) for 8 weeks. Insulin resistance (IR), oxidative stress parameters, AGEs, triglyceride (TG), and hydroxyproline (Hyp) levels together with histopathology were investigated in the liver.

Results

1,25(OH)2D3 decreased hepatic reactive oxygen species, lipid and protein oxidation products together with histopathological improvements in HFr- and EtOH-treated rats. 1,25(OH)2D3 treatment was observed to decrease significantly serum and hepatic AGEs in HFr group, and hepatic AGEs in EtOH group.

Conclusion

Our results clearly show that 1,25(OH)2 D3 treatment may be useful in the alleviation of hepatic lesions by decreasing glycooxidant stress in both NAFLD and ALD models created by HFr- and EtOH-treated rats, respectively.

Role of Steroid Hormones in the Pathogenesis of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease and may progress to cirrhosis or even hepatocellular carcinoma. A number of steroid hormones are important regulators of lipid homeostasis through fine tuning the expression of genes related to lipid synthesis, export, and metabolism. Dysregulation of such pathways has been implicated in the pathogenesis of NAFLD. The aim of this review is to clarify the potential impact of steroid hormones on NAFLD. We also highlight potential interventions through modulating steroid hormone levels or the activities of their cognate receptors as therapeutic strategies for preventing NAFLD.

Vitamin D and non-alcoholic fatty liver disease: a meta-analysis of randomized controlled trials

The results of randomized controlled trials (RCTs) investigating supplemental vitamin D on aminotransferases and cardio-metabolic risk factors in subjects with non-alcoholic fatty liver disease (NAFLD) have been inconsistent. The present study aimed to quantitatively evaluate whether supplementation with vitamin D has beneficial effects in treatment of NAFLD. A systematical literature search was performed with Cochrane Library, PubMed, Scopus databases and Web of Science up to June 2020. The mean changes in alanine aminotransferase (ALT), aspartate aminotransferase (AST), fasting glucose, insulin, homeostasis model assessment of insulin resistance (HOMA-IR), total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), and triglyceride (TAG) were calculated as standard mean difference (SMD) using a random-effects model. Pre-specified subgroup and univariate meta-regression analyses were performed to identify the sources of heterogeneity. Ten trials with a total of 544 NAFLD subjects were included for data synthesis. The summary estimates indicated that supplemental vitamin D significantly reduced the levels of serum/plasma fasting glucose (-0.22; 95%CI: -0.39, -0.04), insulin (-0.68; 95%CI: -1.22, -0.14) and HOMA-IR (-1.32; 95%CI: -2.30, -0.34), and marginally reduced the ALT (-0.18; 95%CI: -0.39, 0.04) and TAG (-10.38; 95%CI: -21.09, 0.34) levels. However, the pooled effect did not support that supplemental vitamin D was beneficial for concentrations of AST, TC, HDL-C and LDL-C. The present study provides substantial evidence that supplemental vitamin D has favorable effects on glycemic control and insulin sensitivity in NAFLD patients. Vitamin D could be as an adjuvant pharmacotherapy of NAFLD.

Vitamin D deficiency in patients with chronic intestinal failure on home parenteral nutrition

BACKGROUND & AIMS

Vitamin D deficiency is an important complication of chronic intestinal failure (CIF). Liver steatosis is a known late complication of long-term home parenteral nutrition (HPN) therapy in patients with CIF, which can progress to intestinal failure-associated liver disease (IFALD). The aim of this study was to determine the prevalence of vitamin D deficiency among Slovene HPN patients and determine any potential correlation between serum vitamin D levels and liver steatosis associated with IFALD in adult patients with CIF on HPN therapy.

METHODS

Adult patients, diagnosed with CIF, receiving long term HPN therapy, were included in a cross-sectional study. Vitamin D status was determined by measuring serum levels of 25-hydroxyvitamin D. The presence of liver steatosis was diagnosed using 3 T S MRI scanner. The association between serum vitamin D levels and liver steatosis was calculated using univariate logistic regression.

RESULTS

We included 63 adult patients with CIF on HPN therapy in the study. The median duration of HPN therapy was 70 weeks. The average serum concentration of 25-hydroxyvitamin D was 41.3 nmol/l. Insufficient vitamin D levels were found in 45 (73%) patients. Liver steatosis was present in 18 (28.6%) patients. No statistically significant association between serum vitamin D levels and liver steatosis in the study population was found.

CONCLUSION

The results of this study have shown a high prevalence of vitamin D deficiency in adult patients with CIF on HPN. We failed to demonstrate an association between serum vitamin D levels and the prevalence of liver steatosis.

Vitamin D Metabolites and Sex Steroid Indices in Postmenopausal Women with and without Low Bone Mass

While the independent roles of vitamin D and sex hormones in skeletal health are well established, the associations of vitamin D and its metabolites to sex hormones and their indices are less investigated. In this observational study, clinical information of 189 Saudi postmenopausal women aged ≥50 years old [N = 80 with normal bone mineral density (BMD), aged 53.3 ± 7.7 years with body mass index (BMI)= 34.1kg/m² ± 5.8, and N = 109 with low BMD (T-score −1.0 to −2.5), aged 57.0 ± 8.2 years, BMI = 32.4kg/m² ± 6.2] was extracted from an existing capital-wide osteoporosis registry in Riyadh, Saudi Arabia. Data included were BMD scores, serum total 25(OH)D, sex hormones, and bone turnover markers which were measured using commercially available assays. Age- and BMI-adjusted comparisons revealed significantly higher parathyroid hormone (PTH) levels as well as significantly lower testosterone and bioavailable testosterone in the low BMD group than the normal BMD group (p-values 0.04, 0.02, and 0.03, respectively). Stepwise linear regression showed that circulating testosterone levels accounted for 9.7% and 8.9% of the variances perceived in bioavailable 25(OH)D and free 25(OH)D, respectively (p < 0.01), independent of other sex hormones, sex hormone indices, and bone turnover markers. Our study suggests that androgens are significantly associated with non-conventional vitamin D metabolites and these associations may have clinical relevance in assessing risk for low BMD and osteoporosis in Arab postmenopausal women.

Probiotic Yogurt Fortified with Vitamin D Can Improve Glycemic Status in Non-Alcoholic Fatty Liver Disease Patients: a Randomized Clinical Trial

Non-alcoholic fatty liver disease (NAFLD) is a significant public health problem globally and the most notable chronic liver disease in Asian countries. Various dietary supplements have been assessed as potential methods to alleviate the metabolic damages related to NAFLD, but the results of these works have been equivocal. This study aimed to evaluate the effects of probiotic yogurt fortified with vitamin D (Pro-YFD) on glycemic and anthropometric indices in patients with NAFLD. One hundred and four NAFLD patients of both sexes were randomly allocated to 2 groups: group A (Pro-YFD) and group B (unfortified yogurt). The intervention period was 3 months. Fasting blood samples were obtained for measuring fasting blood sugar (FBS) and insulin level. Food intake was measured using a validated food frequency questionnaire. Body composition was estimated by bio-impedance. Eighty-eight patients completed the study. The mean serum level of 25(OH)D₃ was elevated significantly (p < 0.001), while insulin level decreased significantly (p < 0.003) in group A at the end of the study. FBS levels showed no significant differences between the groups at the end of the trial. Also, there were no significant changes in diet caloric intake, physical activity, or anthropometric indices in the 2 groups during the interventions. Pro-YFD in the diets of patients with NAFLD may attenuate insulin resistance and improve serum level of 25(OH)D₃.

Efficacy of vitamin D supplementation on adult patients with non-alcoholic fatty liver disease: a single-center experience

AIM

The aim of this study was to determine the efficacy of a 6-month intramuscular vitamin D supplementation in improving the liver parameters in adult patients with non-alcoholic fatty liver disease (NAFLD).

BACKGROUND

The association between vitamin D level and NAFLD has not been determined.

METHODS

A single-blinded non-randomized controlled trial was conducted in 80 NAFLD patients assigned to receive a monthly single intramuscular dose of 200,000 IU cholecalciferol/vitamin D3 (n= 40), or placebo (n= 40) for six months. Transient elastography for the measurement of controlled attenuation parameter (CAP) and liver stiffness measurements (LSM), as well as fibrosis 4 score (FIB4) and NAFLD fibrosis score (NFS) were performed.

RESULTS

The mean serum 25(OH)D was significantly increased after six months of vitamin D treatment (16.31±10.23 Vs 39.37±11.99 ng/ml). In the vitamin D group, most vitamin D deficiency patients (70% deficiency, 10% insufficiency, and 20% sufficiency) had changed to be sufficient (7.5% deficiency, 5% insufficiency, and 87.5% sufficiency). On the other hand, the values of CAP (311.9±42.2 dB/m) and LSM (6.8±2 kPa) had significantly reduced after six months of supplementation (287.0 ±44.3dB/m and 6.1 ±1.1 kPa, respectively) with significantly higher mean CAP and LSM change from baseline in vitamin D group compared to the placebo group. Furthermore, the ALT and AST levels were significantly improved in Vitamin D group compared to the placebo group (P<0.05). Multivariate regression analysis showed that lower serum 25(OH)D level was the only significant predictor for NAFLD (OR=0.89, p=0.001) in this study.

CONCLUSION

A monthly single intramuscular dose of 200,000 IU cholecalciferol is effective in improving the laboratory and fibroscan parameters of the liver disease in NAFLD patients, which confirm a significant relationship between vitamin D deficiency and the risk of NAFLD.

The Impact of Vitamin D in Non-Alcoholic Fatty Liver Disease: A Cross-Sectional Study in Patients with Morbid Obesity

PURPOSE

We aimed to evaluate the association between vitamin D status and hepatic function parameters and scores: Fatty Liver Index (FLI, predictor of hepatic steatosis) and BARD (BMI, AST/ALT ratio and DM, predictor of hepatic fibrosis) in patients with morbid obesity.

PATIENTS AND METHODS

Cross-sectional study including patients with morbid obesity followed in our centre between January 2010 and July 2018. Patients with missing vitamin D levels or hepatic profile parameters were excluded. We divided the population according to two cut-offs of vitamin D levels (12ng/mL and 20ng/mL).

RESULTS

The included population (n=1124) had an average age of 43.3±10.7 years and 84.3% were female. Seventy-point eight percent of the population had vitamin D levels lower than 20ng/mL and 34.8% lower than 12ng/dL. Patients with lower vitamin D levels (<12ng/mL) had higher BMI, hip and waist circumferences and higher prevalence of hypertension. Higher FLI scores [OR= 0.77 (0.07), p<0.01] and ALP levels [β= -0.03 (-0.06, -0.01), p<0.01] associated to lower vitamin D levels.

CONCLUSION

Vitamin D deficiency is associated with a higher risk of hepatic steatosis in individuals with morbid obesity. Correction of vitamin D deficiency may have a beneficial role in the management of NAFLD in patients with morbid obesity.

The role of the gut microbiome and diet in the pathogenesis of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease, with a prevalence that is increasing in parallel with the global rise in obesity and type 2 diabetes mellitus. The pathogenesis of NAFLD is complex and multifactorial, involving environmental, genetic and metabolic factors. The role of the diet and the gut microbiome is gaining interest as a significant factor in NAFLD pathogenesis. Dietary factors induce alterations in the composition of the gut microbiome (dysbiosis), commonly reflected by a reduction of the beneficial species and an increase in pathogenic microbiota. Due to the close relationship between the gut and liver, altering the gut microbiome can affect liver functions; promoting hepatic steatosis and inflammation. This review summarises the current evidence supporting an association between NAFLD and the gut microbiome and dietary factors. The review also explores potential underlying mechanisms underpinning these associations and whether manipulation of the gut microbiome is a potential therapeutic strategy to prevent or treat NAFLD.

Association of vitamin D supplementation with serum leptin and metabolic parameters in Egyptian patients with non-alcoholic steatohepatitis: a prospective study

Background

Nonalcoholic steatohepatitis (NASH) is the progressive form of NAFLD, a common cause of liver disease, with increased chance of progression to liver fibrosis, cirrhosis, and hepatocellular carcinoma. Circulating leptin is increased in patients with NASH. It is an independent positive predictor of the severity of hepatic steatosis. Vitamin D is a lipophilic molecule essential to maintain calcium and phosphate balance. Moreover, it has antifibrotic, antiproliferative, and anti-inflammatory effects on the liver. Vitamin D deficiency is a worldwide condition and very common in patients with NASH. Low serum vitamin D has been shown to predispose to intrahepatic lipid accumulation leading to NAFLD. The aim of this study was to investigate the association of vitamin D supplementation with serum leptin and metabolic parameters in Egyptian patients with non-alcoholic steatohepatitis

Results

Patients with NASH group had statistically significant higher values of diastolic blood pressure (94.3 ± 11.9 mmHg, p < 0.0001), glycated hemoglobin (8.0 ± 2.4%, p < 0.0001), fasting blood sugar (165.6 ± 62.0 mg/dL, p < 0.0001), fasting insulin level (24.2 ± 3.0 μU/ml, p < 0.0001), homeostatic model assessment of insulin resistance (HOMA-IR) (1.8 ± 0.7, p < 0.0001), alanine transferase (ALT) (78.2 ± 36.7 U/L, p < 0.0001), aspartate transferase (AST) (108.6 ± 85.6 U/L, p < 0.0001), NAFLD fibrosis score (− 0.78 ± 0.9, p < 0.0001), total cholesterol (233.0 ± 40.9 mg/dL, p = 0.0011), low-density lipoprotein (117.5 ± 41.6 mg/dL, p = 0.0084), and triglycerides (229.7 ± 62.1 mg/dL, p < 0.0001) than the control group. Moreover, they had lower serum vitamin D level (15.6 ± 6.6 ng/ml, p = 0.0004) and higher serum leptin level (35.9 ± 28.4 ng/ml, p < 0.0001) than the control group. Following vitamin D supplementation, there was a statistically significant reduction in HbA1c (6.8 ± 1.3%, p = 0.0055), fasting blood sugar (136.1 ± 32.7 mg/dL, p = 0.0094), fasting insulin level (22.9 ± 1.8 μU/ml, p = 0.0236), HOMA-IR (1.4 ± 0.4, p = 0.0026), ALT (55.3 ± 21.3 U/L, p = 0.0010), AST (73.1 ± 54.2 U/L, p = 0.0297), and triglycerides (203.6 ± 49.8 mg/dL, p = 0.0415) in patients with NASH. There was a statistically significant increase in serum vitamin D level (33.0 ± 7.6 ng/ml, p < 0.0001) and decrease in serum leptin level (23.5 ± 12.9 ng/ml, p = 0.0140) after treatment.

Conclusions

Vitamin D supplementation in patients with NASH in a dose of 4000 IU/day for 12 weeks improves severity of hepatic inflammation, decreases insulin resistance, improves glycemic control, corrects dyslipidemia, and protects against lipotoxicity by inhibition of serum leptin.

Vitamin D and Metabolic Dysfunction-Associated Fatty Liver Disease (MAFLD): An Update

Non-alcoholic fatty liver disease (NAFLD) is the first cause of chronic liver disease worldwide; it ranges from simple steatosis to steatohepatitis (NASH) and, potentially, cirrhosis and hepatocarcinoma. NAFLD is also an independent risk factor for type 2 diabetes, cardiovascular diseases, and mortality. As it is largely associated with insulin resistance and related disorders, NAFLD has been recently re-named as Metabolic dysfunction-Associated Fatty Liver Disease (MAFLD). At present, there are no approved pharmacological treatments for this condition. Vitamin D is a molecule with extensive anti-fibrotic, anti-inflammatory, and insulin-sensitizing properties, which have been proven also in hepatic cells and is involved in immune-metabolic pathways within the gut–adipose tissue–liver axis. Epidemiological data support a relationship hypovitaminosis D and the presence of NAFLD and steatohepatitis (NASH); however, results from vitamin D supplementation trials on liver outcomes are controversial. This narrative review provides an overview of the latest evidence on pathophysiological pathways connecting vitamin D to NAFLD, with emphasis on the effects of vitamin D treatment in MAFLD by a nonsystematic literature review of PubMed published clinical trials. This article conforms to the Scale for Assessment of Narrative Review Articles (SANRA) guidelines. Evidence so far available supports the hypothesis of potential benefits of vitamin D supplementation in selected populations of NAFLD patients, as those with shorter disease duration and mild to moderate liver damage.

Correlating Circulating Vitamin D3 with Aspects of the Metabolic Syndrome and Nonalcoholic Fatty Liver Disease in Healthy Female Volunteers

Background: Significant inverse correlations between circulating vitamin D3 and the presence and strength of common clinical entities influenced by insulin resistance (IR) have been reported. Among these entities are common maladies such as the metabolic syndrome (MS) and nonalcoholic fatty liver disease (NAFLD). Since hypovitaminosis D3 is considered a common worldwide health disturbance, the consequences emanating from such relationships once soundly established might reasonably be ameliorated by vitamin replacement. Accordingly, a need exists for definitive confirmatory support for the existence of these linkages particularly in ordinary, relatively healthy individuals.Methodology: Many aspects of MS and NAFLD were examined in healthy females via linear regression analyses to determine significant correlations mainly using vitamin D3 and fasting blood glucose (FBG), the latter a surrogate for IR, as independent variables.Results: A descending linear regression between vitamin D3 and FBG did not reach full statistical significance, but a negative correlation of vitamin D3 with HbA1C was statistically significant and that with circulating insulin concentrations showed a downward statistical trend. These findings are consistent with previous ones by others suggesting an ameliorating effect of vitamin D3 on IR. Body weight, body mass index (BMI), and body fat correlated statistically significantly with vitamin D3 levels, as did systolic blood pressure. Again, these correlations were negative instead of positive unlike the case when FBG was the independent variable. The significant negative correlation of ALT with vitamin D3 was also consistent with previous reports that higher circulating vitamin D3 favorably influences the extent and intensity of NAFLD.Conclusions: Employing FBG as a surrogate for IR and ALT for status of NAFLD, linear correlations reasonably suggest that increasing circulating vitamin D3 can favorably influence the initial development of and/or strength of risk factors for MS including NAFLD in relatively fit females.

Active vitamin D impedes the progression of non-alcoholic fatty liver disease by inhibiting cell senescence in a rat model

OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD) refers to an accumulation of excess fat in liver due to causes other than alcohol use. The relationship between vitamin D (VD) and NAFLD has been previously studied. Therefore, we aimed to explore the mechanism involved active VD regulating the progression of NAFLD by inhibiting cell senescence and to provide a potential approach for further nutritional treatment of NAFLD.

METHODS

Following the induction with high-fat diet and intraperitoneal injection of corn oil, the successfully established NAFLD rat models were treated with 1,25(OH)₂D₃ at 1μg/kg, 5μg/kg or 10μg/kg. Meanwhile, the levels of factors related to oxidative stress, cell senescence, the p53-p21 signaling pathway and inflammation in liver were determined. Then, cell senescence was also measured by using senescence-associated β-galactosidase (SAβ-gal) staining.

RESULTS

It was also found that active VD increased the concentration of VD in serum and VDR in liver of NAFLD rats, and alleviated hepatic fibrosis. Besides, treatment of 1,25(OH)₂D₃ at 1μg/kg, 5μg/kg or 10μg/kg reduced oxidative stress and inflammation, inhibited the p53-p21 signaling pathway and consequent cell senescence. Furthermore, treatment of 1,25(OH)₂D₃ at a dosage of 5μg/kg made the most impact on these factors.

CONCLUSION

Collectively, the evidences from this study demonstrated that active VD could alleviate the development of NAFLD through blocking the p53-p21 signaling pathway, which provided a novel nutritional therapeutic insight for NAFLD.

Vitamin D levels are not associated with non-alcoholic fatty liver disease severity in a Brazilian population

Some epidemiological evidence suggests an inverse correlation between non-alcoholic fatty liver disease (NAFLD) frequency and vitamin D levels. Likewise, a beneficial effect of vitamin D on diabetes mellitus (DM) and insulin resistance has been observed, but this is an unsolved issue. Thus, we aimed to investigate the prevalence of hypovitaminosis D in a NAFLD Brazilian population and its association with disease severity and presence of comorbidities. In a cross-sectional study, the clinical, biochemical and histological parameters of 139 NAFLD patients were evaluated according to two different cut-off points of serum 25-hydroxyvitamin D levels (20 ng/mL and 30 ng/mL). The mean age of the population was 56 ± 16 years, most patients were female (83%), 72% had hypertension, 88% dyslipidemia, 46% DM, 98% central obesity, and 82% metabolic syndrome. Serum vitamin D levels were < 30 ng/mL in 78% of the patients, and < 20 ng/mL in 35%. The mean vitamin D level was 24.3 ± 6.8 ng/mL. The comparison between the clinical, biochemical and histological characteristics of the patients according to the levels of vitamin D showed no significant difference. Most patients with NAFLD had hypovitaminosis D, but low vitamin D levels were not related to disease severity and the presence of comorbidities.

Psoriasis and fatty liver: a harmful synergy

Numerous epidemiology studies confirm the increasing prevalence of non-alcoholic fatty liver disease in severe psoriasis, with more than double the risk reported for patients without psoriasis (odds ratio [OR] 2.15). Liver disease is more severe in patients with psoriasis than in controls without psoriasis and is associated with the severity. Similarly, patients with fatty liver disease have more severe psoriasis. This harmful synergy has a common pathogenic origin, resulting from the frequent association between both diseases, insulin resistance and the metabolic syndrome. The disease manifests with a greater intensity when both conditions co-occur than when each manifests separately. Furthermore, psoriasis and fatty liver also have a common cytokine-mediated inflammatory background, which involves an imbalance between pro-inflammatory and anti-inflammatory cytokines. In fact, each disease plays a role in the course of the other. The dermatologist should usually detect liver disease after a specific assessment of patients who present with the metabolic syndrome. The hepatologist should be aware of the more severe condition of these patients. Various medications, such as acitretin, cyclosporine and methotrexate may prove harmful for patients with liver disease. Biologics have proven to be safe in patients with chronic liver disease. Hepatologists and dermatologists should work together to ensure the careful evaluation of the optimal therapy for each patient depending on the severity of both diseases, taking care to avoid, where possible, hepatotoxic drugs and select options that may even have a shared benefit for both diseases.

A Potential Linking between Vitamin D and Adipose Metabolic Disorders

Vitamin D has been discovered centuries ago, and current studies have focused on the biological effects of vitamin D on adipogenesis. Besides its role in calcium homeostasis and energy metabolism, vitamin D is also involved in the regulation of development and process of metabolic disorders. Adipose tissue is a major storage depot of vitamin D. This review summarized studies on the relationship between vitamin D and adipogenesis and furthermore focuses on adipose metabolic disorders. We reviewed the biological roles and functionalities of vitamin D, the correlation between vitamin D and adipose tissue, the effect of vitamin D on adipogenesis, and adipose metabolic diseases. Vitamin D is associated with adipogenesis, and vitamin D supplements can reduce the burden caused by metabolic diseases. The review provides new insights and basis for medical therapy on adipose metabolic diseases.

Association of serum vitamin D level and nonalcoholic fatty liver disease: a meta-analysis

We aimed to explore the potential link of serum vitamin D level with nonalcoholic fatty liver disease (NAFLD). PubMed, Embase and the Cochrane Library database were searched until the end of February 2018. Clinical studies with sufficient data investigating the relationship between serum vitamin D and NAFLD were included. The outcome data were processed to make an overall estimate of combined standardized mean differences (SMD) and pooled odds ratio (OR)/hazard ratios with 95% confidence intervals (CIs). Of the 309 initially retrieved studies, 15 studies of high quality involving a total of 20 096 participants (including 7803 NAFLD patients) were included in this meta-analysis. Meta-analysis of continuous data indicated that NAFLD patients had averagely 0.90 ng/ml lower levels of 25-hydroxyvitamin D compared with the non-NAFLD subjects (SMD -0.90; 95% CI: -1.29 to -0.52). Parallelly, pooled dichotomous data revealed that serum vitamin D level is negatively associated with NAFLD (OR = 0.64, 95% CI = 0.54-0.77), albeit with substantial heterogeneity. Next, subgroup analysis showed that Western NAFLD patients were more likely to be vitamin D deficient (OR = 0.60, 95% CI = 0.46-0.78). Finally, meta-regression showed that sample size, ethnic background, and diagnosis of NAFLD were possible sources of heterogeneity in the meta-analysis. Our results revealed that serum vitamin D level was inversely associated with an increased risk of NAFLD. Patients with hypovitaminosis D might benefit from extra supplement of vitamin D against the risk of NAFLD.