High serum vitamin D levels reduce the risk for nonalcoholic fatty liver disease in healthy men independent of metabolic syndrome

Essential metal mixtures exposure and NAFLD: A cohort-based case-control study in northern Chinese male adults

Epidemiologic evidence on metal mixtures and non-alcoholic fatty liver disease (NAFLD) is limited. We aimed to assess the relationship between multiple metal co-exposure and NAFLD among male adults in Northern China. We conducted a cohort-based case-control study with 648 NAFLD and 648 non-NAFLD males. Seven metal concentrations (calcium, copper, iron, magnesium, manganese, selenium, and zinc) were determined in the blood. We used logistic regression and restricted cubic splines (RCS) to estimate the associations between the single metal and NAFLD. The impact of metal mixtures was quantified by the environmental risk score (ERS) in the adaptive elastic-net regression, and the association with NAFLD was estimated by logistic regression. Age-adjusted RCS showed linear relationships between blood calcium, selenium, and NAFLD. Blood copper, iron, magnesium, and manganese were non-linearly associated with NAFLD. Single metal analysis observed significant relationships between calcium, copper, manganese, and NAFLD, with the adjusted odds ratio (95% confidence interval) for quartile 1 vs. quartile 4 of 1.99 (1.30, 3.05), 2.36 (1.52, 3.64), and 1.77 (1.22, 2.55), respectively. However, metal mixtures analysis revealed one squared term (copper [β = -0.146]) and five metal-metal interactions (calcium × copper [β = 0.200], copper × magnesium [β = 0.188], copper × selenium [β = 0.188], iron × magnesium [β = 0.143], magnesium × selenium [β = -0.297]) except the three main effects. Higher ERS indicated a higher risk for NAFLD when exposed to metal mixtures, with an adjusted odds ratio = 6.50 (95% confidence interval: 4.36-9.69) for quartile 4 vs. quartile 1. Mediation analysis suggested that 11.66% of the effect of ERS on NAFLD was suppressed by fasting blood glucose. Our results show that exposure to metal mixtures is associated with a higher risk for NAFLD than the single metal. Interactions between metals suggest the importance of balancing the various metals for health benefits. Prospective cohorts and mechanism studies need to confirm the findings.

Association Between Blood Calcium, Magnesium, and Non-alcoholic Fatty Liver Disease in Adults: a Cohort-Based Case-Control Study

Previous studies have shown that calcium (Ca), magnesium (Mg), and Ca/Mg ratio are associated with inflammation and metabolic disorders, but their relationship with non-alcoholic fatty liver disease (NAFLD) is unclear. Thus, we aimed to explore the association between Ca, Mg, Ca/Mg ratio, and NAFLD in Chinese adults. We conducted a case-control study based on the Kailuan Cohort in China, including 1816 cases and 1111 gender- and age-matched controls. Dose-response relationships between blood Ca, Mg, Ca/Mg ratio, and NAFLD were evaluated using restricted cubic splines. Odds ratios (ORs) and their 95% confidence intervals (CIs) were estimated by logistic regression models. A negative association between blood Ca (overall association P < 0.001 and linear association P < 0.001) and NAFLD as well as Ca/Mg ratio (overall association P = 0.002 and linear association P = 0.024) and NAFLD was observed. Compared with the highest quartile, the adjusted OR (95% CI) for the lowest quartile of Ca and Ca/Mg ratio was 2.116 (1.679-2.667) and 1.358 (1.076-1.713), respectively. A U-shaped relationship was found for blood Mg and NAFLD, with the highest OR of 1.685 in the lowest quartile group when using the second quartile as a reference. Additionally, we observed the interaction between alanine aminotransferase and blood Ca (P = 0.024), total cholesterol (P = 0.017), low-density lipoprotein-cholesterol (P = 0.013), and blood Mg, as well as total cholesterol and Ca/Mg ratio (P = 0.014). Lower blood Ca and Ca/Mg ratio were significantly associated with the risk of NAFLD. Liver function or lipid metabolism parameters may modify their association, suggesting an individualized prevention strategy for NAFLD.

Non-Alcoholic Fatty Liver Disease and Vitamin D in the UK Biobank: A Two-Sample Bidirectional Mendelian Randomisation Study

Evidence for a role for vitamin D in non-alcoholic fatty liver disease (NAFLD) pathogenesis is conflicting. As Mendelian randomisation (MR) avoids many limitations of conventional observational studies, this two-sample bidirectional MR analysis was conducted to determine the following: (i) whether genetically predicted 25-hydroxyvitamin D [25(OH)D] levels are a risk factor for NAFLD, and (ii) whether genetic risk for NAFLD influences 25(OH)D levels. Single-nucleotide polymorphisms (SNPs) associated with serum 25(OH)D levels were obtained from the European ancestry-derived SUNLIGHT consortium. SNPs associated with NAFLD or NASH (p-value < 1 × 10−5) were extracted from previous studies and supplemented by genome-wide association studies (GWASs) performed in the UK Biobank. These GWASs were done both without (primary analysis) and with (sensitivity analysis) the population-level exclusion of other liver diseases (e.g., alcoholic liver diseases, toxic liver diseases, viral hepatitis, etc.). Subsequently, MR analyses were performed to obtain effect estimates using inverse variance weighted (IVW) random effect models. Cochran’s Q statistic, MR-Egger regression intercept, MR pleiotropy residual sum and outlier (MR-PRESSO) analyses were used to assess pleiotropy. No causal association of genetically predicted serum 25(OH)D (per standard deviation increase) with risk of NAFLD was identified in either the primary analysis: n = 2757 cases, n = 460,161 controls, odds ratio (95% confidence interval): 0.95 (0.76, −1.18), p = 0.614; or the sensitivity analysis. Reciprocally, no causal association was identified between the genetic risk of NAFLD and serum 25(OH)D levels, OR = 1.00 (0.99, 1.02, p = 0.665). In conclusion, this MR analysis found no evidence of an association between serum 25(OH)D levels and NAFLD in a large European cohort.

Vitamin D and nonalcoholic fatty liver disease in children: a randomized controlled clinical trial

Vitamin D is reported to have anti-inflammatory and insulin-sensitizing effects, yet vitamin D effects on hepatic fat content in children with nonalcoholic fatty liver disease (NAFLD) are not studied sufficiently. We aimed to evaluate the role of vitamin D supplementation on the hepatic fat content and NAFLD progression in children. This randomized controlled clinical trial was performed on 109 children with biopsy-proven NAFLD; only 100 patients completed the study. Patients were randomly assigned into two groups: the treatment group who received 2000 IU/day vitamin D for 6 months and the control group who received a placebo. Anthropometric measurements, vitamin D levels, aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol (TC), serum triglyceride (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), fasting blood glucose (FBG), fasting blood insulin level (FBI), homeostasis model assessment of insulin resistance (HOMA-IR), and serum calcium level were measured at the beginning and the end of the study. Liver biopsy was taken before and at the end of the study for all included children. There was a significant improvement of the hepatic steatosis and lobular inflammation by liver biopsy in the treatment group after treatment. However, there was no significant effect on the hepatocyte ballooning or hepatic fibrosis. There were significant decrease of AST, ALT, TG, LDL, FBG, FBI, and HOMA-IR and significant increase of vitamin D levels and HDL in the treatment group compared to the placebo group (P < 0.05).Conclusion: Vitamin D supplementation was found to be beneficial in the treatment of NAFLD in children.Trial registration: www.pactr.org , PACTR201710002634203. What is Known: • Nonalcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease in pediatrics. • Several studies reported a negative association between low serum vitamin D level and grades of NAFLD. What is New: • Vitamin D supplementation has significantly decreased hepatic steatosis and lobular inflammation and improved the grades of NAFLD in children, confirmed by liver biopsy, but no effect on hepatocyte ballooning or fibrosis was observed. • Adjuvant vitamin D supplementation is recommended in children with NAFLD.

Calcipotriol attenuates liver fibrosis through the inhibition of vitamin D receptor-mediated NF-κB signaling pathway

Liver fibrosis is an inevitable stage in the development of chronic liver disease to cirrhosis. Nonetheless, the interventional treatment and achieving control over the disease at this stage can substantially reduce the incidence of liver cirrhosis. To demonstrate these aspects, liver pathological sections of 18 patients with chronic liver disease are collected for research according to the degree of fibrosis. Further, the expressions of related proteins in each group are studied by the Western blot method. The cell proliferation and apoptosis are detected by CKK-8 and flow cytometry analyses. Further, a rat model with carbon tetrachloride (CCl₄)-induced liver fibrosis is employed to verify the effect and mechanism of VDR on the process of liver fibrosis in vivo. The expression of VDR in liver tissues of patients with liver fibrosis is negatively correlated with α-smooth muscle actin (α-SMA), Col-1, and liver fibrosis stages. Moreover, the tumor necrosis factor (TNF)-α stimulation could increase the proliferation of LX-2, up-regulate the expression of α-SMA, Col-1, NF-κB, p-IκBα, p-IKKβ, p-p65m, and some fibrosis factors, as well as down-regulate the expressions of VDR and matrix metalloproteinase-1 (MMP-1). Considering the protective actions of VDR, calcipotriol, a VDR agonist, effectively reduced the degree of liver fibrosis in a rat model of liver fibrosis by inhibiting the deposition of extracellular (ECM) and activation of hepatic stellate cells (HSCs), which is negatively correlated with the degree of liver fibrosis. Together, these shreds of evidence demonstrated that the calcipotriol showed great potential in effectively attenuating liver fibrosis.

The Association Between Vitamin D and Type 2 Diabetes Mellitus Complicated with Non-Alcoholic Fatty Liver Disease: An Observational Cross-Sectional Study

OBJECTIVE

To investigate the association between vitamin D deficiency and NAFLD risk in patients with type 2 diabetes mellitus (T2DM).

METHODS

Overall, 434 patients with T2DM admitted to Hebei General Hospital from January 2019 to December 2019 were selected as the study subjects. According to abdominal ultrasound findings, patients were divided into the NAFLD group and the non-NAFLD group. Participants were divided into two study groups according to the 25-hydroxyvitamin D [25(OH)D] level. 25(OH)D deficiency was defined if 25(OH)D vitamin levels were <20 ng/mL. Chi-square test and one-way analysis of variance were used to compare groups. The relationship between 25(OH)D and NAFLD risk was analyzed using correlation and regression analyses. Furthermore, subgroup analyses were performed to verify the robustness of the results.

RESULTS

The 25(OH)D level in patients with T2DM complicated by NAFLD was significantly lower than in patients with T2DM only. Vitamin D deficiency was highly prevalent among T2DM patients with NAFLD. This study suggested that vitamin D deficiency was an independent factor for developing NAFLD in patients with T2DM. T2DM patients with vitamin D deficiency had 2.045 times higher risk of developing NAFLD than those without vitamin D deficiency. Vitamin D deficiency was associated with high NAFLD preference in T2DM patients with BMI >23kg/m², but not those with BMI ≤23kg/m². The significant correlation between vitamin D deficiency and NAFLD was found in participants with BMI >23kg/m², age ≤65 years, without hypertension, TG <1.7mmol/l, HDL ≥1 mmol/l in men, ≥1.3 mmol/l in women, HBA1C ≤7%, or females.

CONCLUSION

This study suggests that T2DM people with BMI >23kg/m² were more susceptible to NAFLD by vitamin D deficiency and that it is necessary to maintain optimal serum vitamin D levels in this population.

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 Association between Vitamin D and Nonalcoholic Fatty Liver Disease Assessed by Controlled Attenuation Parameter

BACKGROUND

An association between nonalcoholic fatty liver disease (NAFLD) and low vitamin D levels has been suggested. We investigated the relationship between vitamin D and NAFLD assessed by controlled attenuation parameter (CAP).

METHODS

We conducted a retrospective cohort study of apparently healthy subjects who underwent Fibroscan during health screening tests. NAFLD was diagnosed using CAP values.

RESULTS

Among the 1202 subjects (mean age 57.2 years, 60.6% male), 630 (52.4%) subjects had NAFLD with CAP ≥ 248 dB/m. Multivariable analysis was conducted after adjusting for metabolic risk factors including diabetes, hypertension, hypercholesterolemia, body mass index, high-density lipoprotein cholesterol, triglyceride and smoking. Higher vitamin D levels showed a lower risk of NAFLD compared to the lowest quartile of vitamin D in a dose-dependent manner (OR 0.68, 95% CI 0.47-1.00 in Q2 vs. Q1; OR 0.65, 95% CI 0.44-0.94 in Q3 vs. Q1; and OR 0.64, 95% CI 0.44-0.94 in Q4 vs. Q1). The highest quartile of vitamin D showed a decreased risk of a severe grade of steatosis (CAP ≥ 302 dB/m) compared to the lowest quartile (OR 0.52, 95% CI 0.31-0.87 in Q4 vs. Q1).

CONCLUSIONS

Higher levels of serum vitamin D were associated with a decreased risk of CAP-defined NAFLD, compared to low levels of serum vitamin D. The association between NAFLD and vitamin D suggests that vitamin D may exert a protective role against NAFLD.

Low serum vitamin D concentrations are associated with obese but not lean NAFLD: a cross-sectional study

Background

A low serum vitamin D concentration has been reported to be associated with an increased risk of non-alcoholic fatty liver disease (NAFLD); however, whether lean or obese individuals show a similar association between vitamin D and NAFLD remains speculative. This study aimed to explore the relationship between serum vitamin D concentration and NAFLD in lean and obese Chinese adults.

Methods

This cross-sectional study included 2538 participants (1360 men and 1178 women) who underwent health checkups at the First Affiliated Hospital, Zhejiang University School of Medicine in 2019. NAFLD was diagnosed by liver ultrasound excluding other causes. The association of serum vitamin D concentration with NAFLD was analyzed in lean and obese participants.

Results

The overall prevalence of NAFLD was 33.61% (13.10% in lean and 53.32% in obese) in this study population. The serum vitamin D levels of obese NAFLD patients were lower than those of obese NAFLD-free controls. However, the serum vitamin D levels of lean NAFLD patients were comparable to those of lean NAFLD-free controls. Serum vitamin D level was negatively correlated with the prevalence of NAFLD in obese but not lean participants. Serum vitamin D level was independently associated with the risk of NAFLD in obese participants, with an adjusted odds ratio (95% CI) of 0.987 (0.981–0.993). However, serum vitamin D level was not related to the risk of NAFLD in lean participants.

Conclusions

A low serum vitamin D level is associated with NAFLD in obese but not lean participants.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12937-021-00690-9.

Vitamin D Effect on Ultrasonography and Laboratory Indices and Biochemical Indicators in the Blood: an Interventional Study on 12 to 18-Year-Old Children with Fatty Liver

PURPOSE

The rising prevalence of childhood obesity in the past decades has caused non-alcoholic fatty liver disease (NAFLD) to become the most common cause of pediatric chronic liver disease worldwide. This study was aimed at determining the effect of vitamin D (Vit D) on ultrasonography and laboratory indices of NAFLD and some blood biochemical indicators in children.

METHODS

In this interventional study liver ultrasonography was performed in 200 children with overweight and obesity. A 108 had fatty liver among which 101 were randomly divided into two groups of study (n=51) and control (n=50). The study group was treated with Vit D, 50000 U once a week whereas the control group received placebo with the same dose and package, both for 12 weeks. At the end of the intervention lab tests and ultrasound study was performed once again to evaluate the response to treatment.

RESULTS

It was found out that Vit D supplementation improved the fatty liver grade in the study group. The mean changes in hemoglobin (Hb), uric acid, highdensity lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), insulin, albumin and alanine aminotransferase (ALT) was significantly higher in the study group compared to controls (p<0.05). After the intervention and means adjustment, a significant difference was obtained in HDL-C, insulin, LDL-C and homeostasis model assessment of insulin resistance (HOMA-IR) between the two groups.

CONCLUSION

Vit D supplementation in addition to improving the fatty liver grade in ultrasonography and increasing the blood Vit D level, increases the HDL and Hb level besides decreasing uric acid, LDL, HOMA-IR, insulin and ALT levels.

Association of vitamin D status with liver and kidney disease: A systematic review of clinical trials, and cross-sectional and cohort studies

Abstract. Background: Vitamin D deficiency (VDD) is a major public health problem. There are few comprehensive systematic reviews about the relationship between Vitamin D status and liver and renal disease in Iran.

Methods: We systemically searched the following databases: Web of Science; PubMed; Cochrane Library; Scopus; Science Direct; Google Scholar and two Iranian databases (Scientific Information Database (SID) and IranMedex) up until November 2017 to identify all randomized control trials (RCTs), case control, cross-sectional and cohort studies investigating the association between vitamin D and any form of liver or kidney disease.

Results: Vitamin D insufficiency, or deficiency (VDD), is highly prevalent in Iran, reports varying between 44.4% in Isfahan to 98% in Gorgan. There is also a high prevalence of VDD among patients with liver or kidney disease, and the administration of vitamin D supplements may have beneficial effects on lipid profile, blood glucose, liver function and fatty liver disease, and bone health. Low serum vitamin D levels are related with abnormalities in these laboratory and clinical parameters.

Conclusion: VDD is prevalent in patients with chronic liver or renal disease in Iran. There appear to be several beneficial effects of vitamin D supplementation in vitamin D deficient patients with liver or kidney disease.

Vitamin D supplementation for nonalcoholic fatty liver disease in type 2 diabetes mellitus: A protocol for a systematic review and meta-analysis

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is strongly associated with type 2 diabetes mellitus (T2DM), and low vitamin D levels are positively associated with NAFLD and T2DM. But there is absence of convincing evidence-based medicine to confirm the efficacy of vitamin D supplementation for T2DM with NAFLD. Thus, we aimed to conduct this meta-analysis to summarize the efficacy of vitamin D supplementation for T2DM combined with NAFLD, and help to further clarify its beneficial action on diabetic patients with NAFLD.

METHODS

The study only selects clinical randomized controlled trials of vitamin D supplementation for T2DM combined with NAFLD. We will search each database from the built-in until July 2020. The English literature mainly searches Cochrane Library, Pubmed, EMBASE, and Web of Science. While the Chinese literature comes from CNKI, CBM, VIP, and Wangfang database. Meanwhile, we will retrieve clinical trial registries and grey literature. Two researchers worked independently on literature selection, data extraction, and quality assessment. The dichotomous data is represented by relative risk (RR), and the continuous is expressed by mean difference (MD) or standard mean difference (SMD), eventually the data is synthesized using a fixed effect model (FEM) or a random effect model (REM) depending on the heterogeneity. The imaging markers of liver, biomarkers of hepatic steatosis, serological indexes of hepatic fibrosis, serum NAFLD liver fat score were evaluated as the main outcomes. While several secondary outcomes were also evaluated in this study. The statistical analysis of this meta-analysis was conducted by RevMan software version 5.3.

RESULTS

This meta-analysis will further determine the beneficial efficacy of vitamin D supplementation for T2DM combined with NAFLD.

CONCLUSION

This study determines the positive efficacy of vitamin D supplementation for diabetic patients with NAFLD.

Association of nonalcoholic fatty liver disease with serum vitamin D levels in combination of physical fitness in korean older adults

The prevalence of non-alcoholic fatty liver disease (NAFLD) tends to increase with age, but little is known regarding relations between the risk of NAFLD in older adults and serum vitamin D (25-hydroxyvitamin D) and physical fitness levels. The aim of this study was to investigate the relationship between NAFLD risk and serum vitamin D levels combined with physical fitness in elderly adults using a non-invasive diagnostic approach. We enrolled 533 Korean older adults (80.8 % women), aged 65 years or older in this cross-sectional study. NAFLD in absence of another cause of liver disease was defined according to the ZJU and NAFLD liver fat (LFS) score. Physical fitness was assessed using a senior fitness test protocol. Logistic regression analysis was used to estimate odds ratios (ORs) and 95 % confidence intervals (CIs) of NAFLD for different combinations of serum vitamin D and physical fitness levels. According to the ZJU (OR: 3.073, CI: 1.285-7.350, p = 0.012) and LFS (OR = 2.443, CI = 1.071-5.572, p = 0.034), individuals with serum vitamin D < 30 ng/ml and poor physical fitness had a significantly higher risk of NAFLD than individuals with serum vitamin D ≥ 30 ng/ml and high fitness (reference, OR = 1), even after adjustments for age, sex, smoking, alcohol consumption and physical inactivity. However, there was no significant association after adjustment for additional metabolic diseases. Our findings suggest that the maintenance of appropriate levels of serum vitamin D and/or high physical fitness and the monitoring metabolic diseases can help reduce the risk of NAFLD in older adults.

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.

Serum 25-hydroxyvitamin-D and nonalcoholic fatty liver disease: Does race/ethnicity matter? Findings from the MESA cohort

BACKGROUND AND AIMS

Low serum 25-hydroxyvitamin D (25(OH)D) is associated with higher nonalcoholic fatty liver disease (NAFLD) risk in studies of mainly white participants. Significant racial/ethnic differences exist in serum 25(OH)D and NAFLD prevalence questioning extending this association to other racial/ethnic groups. We tested whether the association between serum 25(OH)D and NAFLD vary by race/ethnicity.

METHODS AND RESULTS

This was a cross-sectional analysis from the Multi-Ethnic Study of Atherosclerosis (MESA) that included 3484 participants (44% male; 38.4% Whites, 27.8% African-Americans, 23.5% Hispanics, and 10.3% Chinese-Americans) who had serum 25(OH)D and upper abdominal CT images available at baseline. Serum 25(OH)D was measured by high-performance liquid chromatography-tandem mass spectrometry. NAFLD was identified if liver-to-spleen Hounsfield-Unit ratio was <1. Whites had the highest 25(OH)D level and African-Americans had the lowest level (mean ± SD: 29.5 ± 10.4 vs.19.9 ± 9.1, respectively). Six hundred and eleven (17.5%) participants had NAFLD; Hispanics had the highest prevalence (26.2%) followed by Chinese-Americans (19.8%), Whites (15.8%) and African-Americans (11.7%), P < 0.0001. In adjusted model, the association of 25(OH)D with NAFLD differed by race/ethnicity (P < 0.0001). Negative association was only evident in Causations (OR (95% CI):1.23 (1.03, 1.47) per 1 SD lower serum 25(OH)D). For other racial/ethnic groups, BMI, triglycerides, diabetic status and/or smoking, but not serum 25(OH)D, were common independent risk factors for NAFLD.

CONCLUSIONS

The negative association between serum 25(OH)D and NAFLD in Whites may not be broadly generalizable to other racial/ethnic groups. Modifiable risk factors including BMI, triglycerides, diabetic status and/or smoking associate with NAFLD risk in non-white racial/ethnic groups beyond 25(OH)D.

Overview of studies of the vitamin D/vitamin D receptor system in the development of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the world. NAFLD is known to be associated with obesity, type 2 diabetes, metabolic syndrome and increased cardiovascular events: for these reasons, it is becoming a global public health problem and represents an important challenge in terms of prevention and treatment. The mechanisms behind the pathogenesis of NAFLD are multiple and have not yet been completely unraveled; consequently, at moment there are not effective treatments. In the past few years a large body of evidence has been assembled that attributes an important role in hepatic aberrant fat accumulation, inflammation and fibrosis, to the vitamin D/vitamin D receptor (VD/VDR) axis, showing a strong association between hypovitaminosis D and the diagnosis of NAFLD. However, the data currently available, including clinical trials with VD supplementation, still provides a contrasting picture. The purpose of this editorial is to provide an overview of recent advances in the pathogenesis of NAFLD in relation to VD/VDR. Based on recent data from literature, we focused in particular on the hypothesis that VDR itself, independently from its traditional ligand VD, may have a crucial function in promoting hepatic fat accumulation. This might also offer new possibilities for future innovative therapeutic approaches in the management of NAFLD.

Low vitamin D level was associated with metabolic syndrome and high leptin level in subjects with nonalcoholic fatty liver disease: a community-based study

Background

This study aimed to evaluate the association between serum vitamin D levels and nonalcoholic fatty liver disease (NAFLD) parameters, such as metabolic syndrome (MS), inflammatory cytokines (tumor necrosis factor, high sensitive C-reactive protein) and adipokines (adiponectin, leptin).

Methods

From August 2013 to August 2016, a community-based study was performed in the north-eastern region of Taiwan. All subjects received a demographic survey, blood testing and abdominal ultrasonography (US). The vitamin D level was evaluated by quartile divide or used the classification of deficiency (< 20 ng/ml), insufficiency (20–30 ng/ml) and sufficiency (> 30 ng/ml).

Results

Subjects were divided into NAFLD group and normal control (subjects number = 564 in each group) following abdominal US study and matching age and gender. The mean age was 57.1 years in NAFLD group and 57.5 in control group. Subjects in NAFLD group had a lower mean vitamin D than those in the control group (28.5 ± 9.5 ng/ml vs. 29.9 ± 10.2 ng/ml, P = 0.018). Subjects with serum vitamin D deficiency or insufficiency had higher odds for MS than those with sufficient vitamin D levels [deficiency vs. sufficiency, adjusted odds ratio (aOR) =1.860 (95% CI = 1.234–2.804), P = 0.003; insufficiency vs. sufficiency, aOR = 1.669 (95% CI = 1.237–2.251), P = 0.001]. Similarly, subjects in the lowest quartile of vitamin D had higher odds for MS than those in the highest quartile of vitamin D (aOR = 2.792, 95% CI = 1.719–4.538, P < 0.001). Vitamin D level was positively correlated with age and male, but negatively correlated with serum leptin level.

Conclusion

Subjects with low vitamin D level had higher odds for MS, but higher levels of leptin, compared to those with high vitamin D levels.

Association Between Vitamin D Deficiency and Suspected Nonalcoholic Fatty Liver Disease in an Adolescent Population

PURPOSE

Vitamin D deficiency is a condition widespread throughout the world. Recent studies have suggested that vitamin D deficiency was associated with obesity and metabolic syndrome. The purpose of the study was to examine the relationship between vitamin D deficiency and nonalcoholic fatty liver disease (NAFLD) in adolescents.

METHODS

The data were obtained from the Korean National Health and Nutrition Examination Survey from 2008-2014. A total of 3,878 adolescents were included in the study. Vitamin D deficiency was defined as a 25-hydroxyvitamin D concentration <20 ng/mL and suspected NAFLD was defined as an alanine transaminase concentration >30 U/L.

RESULTS

Vitamin D deficiency was noted in 78.9% of the studied population. Age, body mass index, waist circumference, and blood pressure, glucose, cholesterol, and triglyceride levels were significantly higher in adolescents with suspected NAFLD than in adolescents without suspected NAFLD, while the mean vitamin D level was significantly lower in adolescents with suspected NAFLD. The multivariate-adjusted odds of suspected NAFLD were higher with increased age, male gender, obesity, and metabolic syndrome. Individuals with vitamin D deficiency were at higher risk of suspected NAFLD (odds ratio, 1.77; 95% confidence interval, 1.07-2.95) after adjusting for age, gender, obesity, and metabolic syndrome.

CONCLUSION

Vitamin D deficiency was associated with suspected NAFLD, independent of obesity and metabolic syndrome, in adolescents.

Avaliação da frequência de deficiência de vitamina D em pacientes com obesidade

Introdução: A obesidade é um problema de saúde pública mundial. Além das diversas alterações metabólicas encontradas em indivíduos obesos, há evidências de alterações no sistema endócrino, como observado no metabolismo da vitamina D.Objetivos:Avaliar a frequência de deficiência de vitamina D em uma amostra de pacientes adultos com obesidade.Materiais e métodos: Foi realizado um estudo transversal retrospectivo analisando 183 prontuários dos pacientes atendidos pela primeira vez buscando tratamento para obesidade. Após os fatores de exclusão, restaram 113 prontuários válidos.Resultados: O IMC variou de 30.1 a 77.1, com uma mediana de 44.5 kg/m2. Trinta pacientes (26,55 %) tinham a Vitamina D abaixo de 20 ng/ml, sendo considerados com diagnóstico de Deficiência de Vitamina D. Nenhum correlação foi encontrada entre os níveis de Vitamina D e os parâmetros antropométricos. Houve associação significativa estatística dos níveis de Vitamina D com colesterol total (r=-0.26; p=0.0053), LDL-colesterol (r=-0.25; p=0.0071), além de uma tendência à significância com os níveis de TGP (r=0.16; p=0.088).Conclusão: Houve uma elevada frequência de deficiência de vitamina D em pacientes obesos. Não houve correlação entre os níveis de vitamina D e os marcadores antropométricos, porém foi encontrada uma correlação inversa de vitamina D com níveis de colesterol total e LDL-colesterol, mostrando a relação com a dislipidemia. Também, houve uma tendência à significância com os níveis de TGP, o que provavelmente remete à esteatose hepática, comum em obesos.

Strong association between serum Vitamin D and Vaspin Levels, AIP, VAI and liver enzymes in NAFLD patients

Some studies indicated poor vitamin D level in NAFLD which is independently correlated with severity of steatosis. Low 25(OH) D3 levels are associated with an impaired lipid profile. Impaired levels and function of vaspin and omentin, which are adipokines, have been demonstrated in NAFLD patients. This study determined the relationship between vitamin D and serum liver enzymes, ultrasound findings, some adipokines, atherogenic index of plasma (AIP) and visceral adiposity index (VAI) in patients with NAFLD in a cross-sectional study. This study was a cross-sectional study in eighty-three NAFLD patients (57 males and 26 females). Plasma levels of omentin-1e-1, vaspin were measured. Anthropometric indices metabolic status was assessed. Visceral adiposity index and atherogenic index of plasma were calculated according to suggested formula. Anthropometric indices, lipid profiles, liver enzymes as well as abdominal ultrasonography and the status of vitamin D were assessed. The results showed that aspartate aminotransferase (AST) (44.22 ± 8.5 IU/L vs. 40.19 ± 8.75 IU/L, p-value = 0.039) AIP (0.767 ± 0.142 vs. 0.6417 ± 0.139, p < 0.001) and VAI (9.28 ± 3.25 vs. 7.048 ± 2.415, p = 0.001) were significantly higher in patients with vitamin D deficiency compared to those with vitamin D sufficiency. The positive correlations between Vaspin levels and vitamin D were found to be remarkably significant in both males and females (r = 0.437; P = 0.004; P < 0.001, r = -0.709, respectively. In both males and females serum vitamin D concentrations were negatively associated with AIP. Partial correlations controlling for age and sex showed that vitamin D is significantly and inversely associated with AIP, VAI, AST, and ALT. Additionally, vitamin D levels correlated directly with vaspin.

Association between Vitamin D Levels and Nonalcoholic Fatty Liver Disease: Potential Confounding Variables

Nonalcoholic fatty liver disease (NAFLD), historically considered to be the hepatic component of the metabolic syndrome, is a spectrum of fat-associated liver conditions, in the absence of secondary causes, that may progress to nonalcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. Disease progression is closely associated with body weight or fatness, dyslipidemia, insulin resistance, oxidative stress, and inflammation. Recently, vitamin D deficiency has been linked to the pathogenesis and severity of NAFLD because of vitamin D "pleiotropic" functions, with roles in immune modulation, cell differentiation and proliferation, and regulation of inflammation. Indeed, several studies have reported an association between vitamin D and NAFLD/NASH. However, other studies have failed to find an association. Therefore, we sought to critically review the current evidence on the association between vitamin D deficiency and NAFLD/NASH, and to analyze and discuss some key variables that may interfere with this evaluation, such as host-, environment-, and heritability-related factors regulating vitamin D synthesis and metabolism; definitions of deficient or optimal vitamin D status with respect to skeletal and nonskeletal outcomes including NAFLD/NASH; methods of measuring 25(OH)D; and methods of diagnosing NAFLD as well as quantifying adiposity, the cardinal link between vitamin D deficiency and NAFLD.

Nonalcoholic fatty liver disease in obese and nonobese pediatric patients

Purpose

Obesity is risk factor for nonalcoholic fatty liver disease (NAFLD). However, nonobese patients are also increasingly susceptible to NAFLD. The aim of this study was to compare the clinical characteristics of obese and nonobese pediatric patients with NAFLD.

Methods

We retrospectively studied 68 patients who were diagnosed with NAFLD between January 2010 and October 2016 at 10–18 years of age. Body mass index ≥95th percentile for age and sex was defined as obesity. Abdominal ultrasonography and laboratory, anthropometrics measurements were evaluated.

Results

Among the 68, 26 (38.2%) were nonobese patients. The ratio of male to female was 5.8:1, and the median age at diagnosis was 13 years (range, 10–17 years). Significant higher triglyceride (223.0 mg/dL vs. 145.9 mg/dL, P=0.047) and total cholesterol levels (211.6 mg/dL vs. 173.2 mg/dL, P=0.011) were shown in nonobese than obese patients. High-density lipoprotein cholesterol level <40 mg/dL (hazard ratio [HR], 6.5; 95% confidence interval [CI], 2.13–7.10; P=0.048), total cholesterol level >200mg/dL (HR, 5.6; 95% CI, 1.23–15.31; P=0.038) and abdominal obesity (HR, 2.53; 95% CI, 1.22–4.68; P=0.013) were significant risk factors for NAFLD in nonobese patients.

Conclusion

Nonobese patients present a substantial proportion of pediatric NAFLD cases. Significant abnormal lipid concentrations were found in nonobese and abdominal obesity was important risk factor for nonobese NAFLD.

Vitamin D supplementation for the treatment of non-alcoholic fatty liver disease: A randomized double blind placebo controlled trial

BACKGROUND

Low serum vitamin D has been associated with metabolic syndrome and Non-alcoholic fatty liver disease (NAFLD). This study aimed to investigate the impact of vitamin D supplementation in treatment of patients with NAFLD.

METHODS

In a double blind, randomized, placebo controlled trial patients with NAFLD were randomized to receive one weekly pearl of placebo, 50,000 U vitamin D3 (cholecalciferol) pearl per week and 0.25 mg calcitriol (1,25 dihydroxycholecalciferol) pearl per day for 3 months.

RESULTS

106 NAFLD patients were randomized to receive calcitriol, vitamin D3 and placebo pearls for 12 weeks and data for 91 patients were analyzed. After 12 weeks of treatment, serum alkaline phosphatase levels was significantly decreased from baseline levels in vitamin D and calcitriol treated groups (P < 0.05). Serum and gamma glutamyl transferase (GGT) level was also significantly decreased compared to the baseline levels after 12 weeks of treatment with vitamin D. There was no statistically significant difference between placebo, calcitriol, vitamin D groups in terms of serum aminotransferase, alkaline phosphatase, serum GGT and lipid profile (P > 0.05).

CONCLUSION

While significant reduction of serum alkaline phosphatase and GGT were seen with vitamin D and calcitriol supplementation from baseline levels, no beneficial effects was seen when comparing vitamin D, calcitriol and placebo groups at the end of trial.

VITAMIN D DEFICIENCY, A NONINVASIVE MARKER OF STEATOHEPATITIS IN PATIENTS WITH OBESITY AND BIOPSY PROVEN NONALCOHOLIC FATTY LIVER DISEASE

CONTEXT

Nonalcoholic fatty liver disease (NAFLD) includes simple steatosis, steatohepatitis (NASH) which can evolve with progressive fibrosis, cirrhosis and hepatocellular carcinoma. As liver biopsy cannot be used as a screening method, noninvasive markers are needed.

OBJECTIVE

The aim of this study was to test if there is a significant association between vitamin D deficit and the severity of NAFLD.

DESIGN

The patients were divided into two groups (vitamin D insufficiency/deficiency) and statistical analyses were performed on the correlation of clinical and biochemical characteristics with histopathological hepatic changes.

SUBJECTS AND METHODS

We prospectively studied 64 obese patients referred for bariatric surgery between 2014 and 2016 to our Surgical Unit. Anthropometric, clinical measurements, general and specific biological balance were noted. NAFLD diagnosis and activity score (NAS) were evaluated on liver biopsies.

RESULTS

Increased serum fibrinogen was correlated with NASH (p=0.005) and higher NAS grade. T2DM was positively correlated with liver fibrosis (p=0.002). 84.37% of the patients had vitamin D deficit and 15.62% were vitamin D insufficient. Lobular inflammation correlated with vitamin D deficit (p=0.040). Fibrosis (p=0.050) and steatohepatitis (p=0.032) were independent predictors of low vitamin D concentration.

CONCLUSIONS

Vitamin D status in conjunction with other parameters - such as T2DM - or serum biomarkers - namely fibrinogen level and PCR level - may point out the aggressive forms of NAFLD and the need for liver biopsy for appropriate management.

Lifestyle predictors of obese and non-obese patients with nonalcoholic fatty liver disease: A cross-sectional study

BACKGROUND & AIMS

Most people with nonalcoholic fatty liver disease (NAFLD) are obese, and they usually eat more while being less physically active as compared to healthy individuals. However, little is known about the lifestyle patterns of non-obese or obese patients with NAFLD. The aim of this study was to investigate nutrition components and behavioral differences between non-obese and obese patients with NAFLD.

METHODS

This is a cross-sectional study comprising of 209 patients. Nutritional components and physical activity status were compared in obese and non-obese subjects with NAFLD against healthy controls. Dietary intake was assessed using the 5-day food diary. Physical activity was measured using the protocol of Korea Health and Nutrition Examination Survey. Total and regional body composition analysis was conducted using anthropometry and tetrapolar multi-frequency bio-impedance. Visceral adipose tissue, total abdominal adipose tissue, abdominal subcutaneous adipose tissue as well as liver fat were measured using abdomen tomography.

RESULTS

Non-obese subjects with NAFLD had higher levels of ALT, AST, GGT, triglyceride, fasting glucose; higher carbohydrate energy ratio; higher visceral fat area, subcutaneous area, body muscle mass, fat free mass and body fat compared to subjects without NAFLD. Subjects with obesity and NAFLD had higher ALT, AST, visceral fat, fasting glucose and HOMA-IR (homeostatic model assessment-insulin resistance), and less moderate-level physical activity compared to those with obesity who do not have NAFLD. Obese subjects with NAFLD also had higher blood pressure, visceral fat area, subcutaneous fat area, body fat, body fat percent and GGT compared to non-obese subjects with NAFLD. In multivariate analysis, carbohydrate energy ratio and physical activity less than moderate-level (<2 h/week) were predictors of NAFLD in non-obese subjects independent of the visceral fat, body muscle index, total energy intake, age and sex. Physical activity less than moderate-level was a predictor of NAFLD in obese subjects with NAFLD, independent of the HOMA-IR, visceral fat, total energy intake, fat energy percent, age and sex.

CONCLUSIONS

Percentage of carbohydrate intake percent and physical activity, less than moderate-level were independent predictors of NAFLD in non-obese subjects. Meanwhile, physical activity, less than moderate-level, was an independent predictor in obese subjects.

Is Vitamin D an Independent Risk Factor of Nonalcoholic Fatty Liver Disease?: a Cross-Sectional Study of the Healthy Population

The association between vitamin D levels and nonalcoholic fatty liver disease (NAFLD) has been recognized. However, few studies showed independent associations between vitamin D deficiency and NAFLD after a sex-related adjustment for metabolic factors. We aimed to study whether vitamin D deficiency is an independent risk factor of NAFLD even after controlling for metabolic syndrome and visceral fat in both sexes. In this cross-sectional study, 7,514 Korean adults (5,278 men, 2,236 women) participated in a health check-up program. They underwent blood tests, abdominal computed tomography (CT) of the visceral fat area, and ultrasonography for NAFLD screening. Multiple logistic regression analysis was used to investigate the association of vitamin D deficiency with NAFLD according to the sex differences. Vitamin D deficiency is associated with NAFLD. The adjusted odds ratio (aOR) for NAFLD increased sequentially with decreasing vitamin D level, even after adjusting for metabolic syndrome and visceral fat. The subjects in the vitamin D sufficiency group (20-30 ng/mL) had an aOR for NAFLD of 1.18 (95% CI, 1.00-1.39), whereas the deficiency group (< 20 ng/mL) had an aOR of 1.29 (95% CI, 1.10-1.52). However, we have detected a significant sex-related interaction when analyzing the results. A significant relationship between vitamin D deficiency and NAFLD was found in men (aOR, 1.33; 95% CI, 1.11-1.60) but not in women.

Immune Imbalances in Non-Alcoholic Fatty Liver Disease: From General Biomarkers and Neutrophils to Interleukin-17 Axis Activation and New Therapeutic Targets

Non-alcoholic fatty liver disease (NAFLD) is an increasing problem worldwide and is associated with negative outcomes such as cirrhosis, hepatocellular carcinoma, insulin resistance, diabetes, and cardiovascular events. Current evidence shows that the immune response has an important participation driving the initiation, maintenance, and progression of the disease. So, various immune imbalances, from cellular to cytokines levels, have been studied, either for better compression of the disease pathophysiology or as biomarkers for severity assessment and outcome prediction. In this article, we performed a thorough review of studies that evaluated the role of inflammatory/immune imbalances in the NAFLD. At the cellular level, we gave special focus on the imbalance between neutrophils and lymphocytes counts (the neutrophil-to-lymphocyte ratio), and that which occurs between T helper 17 (Th17) and regulatory T cells as emerging biomarkers. By extension, we reviewed the reflection of these imbalances at the molecular level through pro-inflammatory cytokines including those involved in Th17 differentiation (IL-6, IL-21, IL-23, and transforming growth factor-beta), and those released by Th17 cells (IL-17A, IL-17F, IL-21, and IL-22). We gave particular attention to the role of IL-17, either produced by Th17 cells or neutrophils, in fibrogenesis and steatohepatitis. Finally, we reviewed the potential of these pathways as new therapeutic targets in NAFLD.

Serum 25-Hydroxyvitamin D Concentration Is Independently Inversely Associated with Insulin Resistance in the Healthy, Non-Obese Korean Population

BACKGROUND

We evaluated the associations between 25-hydroxyvitamin D (25(OH)D) concentrations in serum and insulin resistance in the healthy Korean population.

METHODS

We conducted this cross-sectional analysis in 1,807 healthy Korean people (628 men and 1,179 women) aged 30 to 64 years in the Cardiovascular and Metabolic Disease Etiologic Research Center study. All participants were assessed for 25(OH)D, fasting glucose, and insulin levels, and completed a health examination and lifestyle questionnaire according to standard procedures. Insulin resistance was defined as the homeostasis model assessment insulin resistance higher than the 75 percentile.

RESULTS

Compared to those in the highest tertile (≥14.3 ng/mL), the odds ratio (OR) for insulin resistance was 1.37 (95% confidence interval [CI], 1.01 to 1.86) for the 1st tertile (<9.7 ng/mL) and 1.19 (95% CI, 0.08 to 1.62) for the 2nd tertile (9.7 to 14.3 ng/mL) after adjusting for age, gender, waist circumference, alcohol consumption, smoking status, physical exercise, season, and cohort. After stratification of the subjects by adiposity, these associations remained only in non-obese subjects (lowest tertile vs. highest tertile, multivariable OR, 1.64; 95% CI, 1.05 to 2.56).

CONCLUSION

Serum 25(OH)D has an independent inverse association with insulin resistance in the healthy, non-obese Korean population, even among people with vitamin D insufficiency.

Effect of daily calcitriol supplementation with and without calcium on disease regression in non-alcoholic fatty liver patients following an energy-restricted diet: Randomized, controlled, double-blind trial

BACKGROUND & AIMS

Despite evidence for beneficial effects of vitamin D, to our knowledge, no study has compared the effects of calcium supplementation with vitamin D on non-alcoholic fatty liver disease (NAFLD) regression during a hypo-energetic program. We compared the effect of the vitamin D supplementation with and without calcium on anthropometric measures and biochemical parameters in NAFLD patients during a weight-loss program.

METHODS

A 12-week, randomized, controlled, double-blind trial was conducted in 120 NAFLD patients randomly assigned to receive 25 μg calcitriol (n = 37), 500 mg calcium carbonate + 25 μg calcitriol (n = 37), or placebo (n = 36) every day with their lunch meals while following a weight-loss program.

RESULTS

Weight, BMI and fat mass reduction were significant in each group after 12 wk of intervention (p < 0.001), but differences among the groups was not significant after 12 wk of the study, adjusted to the baseline measurements. Significant reduction in fasting plasma glucose (FPG), insulin, insulin resistance (by HOMA-IR) and TG concentrations and an increase in HDL.C was seen over the 12 wk of study in each group (p < 0.001). Adjusting to the baseline measurements, there was significant difference in FPG (p < 0.001), HOMA-IR (p < 0.001), serum insulin (p = 0.01), TG (p = 0.01) and HDL.C (p < 0.001) among the groups after 12 wk of the study. The calcium plus calcitriol group showed a significant decrease in ALT and FPG and increase in HDL.C level compared with the calcitriol group, adjusted to the baseline measures (p < 0.001).

CONCLUSIONS

Our results suggest that calcium plus calcitriol supplementation for 12 weeks may be potentially effective for biochemical parameters in NAFLD patients. Further additional larger controlled trials are needed to confirm these findings.

REGISTRATION

Registered under ClinicalTrials.gov Identifier no. IRCT201408312709N29.

Micronutrient Antioxidants and Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is one of the most important chronic liver diseases worldwide and has garnered increasing attention in recent decades. NAFLD is characterized by a wide range of liver changes, from simple steatosis to nonalcoholic steatohepatitis, cirrhosis, and hepatocellular carcinoma. The blurred pathogenesis of NAFLD is very complicated and involves lipid accumulation, insulin resistance, inflammation, and fibrogenesis. NAFLD is closely associated with complications such as obesity, diabetes, steatohepatitis, and liver fibrosis. During the progression of NAFLD, reactive oxygen species (ROS) are activated and induce oxidative stress. Recent attempts at establishing effective NAFLD therapy have identified potential micronutrient antioxidants that may reduce the accumulation of ROS and finally ameliorate the disease. In this review, we present the molecular mechanisms involved in the pathogenesis of NAFLD and introduce some dietary antioxidants that may be used to prevent or cure NAFLD, such as vitamin D, E, and astaxanthin.

Assessment of Vitamin D status in a group of Egyptian children with non alcoholic fatty liver disease (multicenter study)

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is one of the health problems with great burden on the liver that may end with liver cirrhosis and hepatocellular carcinoma. The aim of this work was to assess serum vitamin D level in nonalcoholic fatty liver disease children.

METHODS

This cross sectional case control study involved 47 patients with nonalcoholic fatty liver disease selected while recruiting the pediatric hepatology clinics. Their ages ranged from 5-15 years and were compared with 23 healthy age and sex matched children. All involved patients were subjected to careful history taking, clinical examination and for patients and control, anthropometric measures for body mass index (BMI) calculation (plotted on WHO percentile growth charts), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma glutamyl transferase (GGT), bilirubin (total and direct), serum albumin, creatinine, triglycerides, cholesterol, high density lipoprotein (HDL),low density lipoprotein (LDL), fasting blood glucose and fasting insulin (for calculation of insulin resistance), C reactive protein and serum vitamin D all were assayed. NAFLD was detected by ultrasonography and graded as absent, mild, moderate and severe.

RESULTS

Ninety-three percent of NAFLD patients were obese. Significant differences were found between patients and control regarding AST, ALT, ALP, GGT, total and direct bilirubin, serum albumin, creatinine, triglycerides, cholesterol, HDL, fasting blood glucose, fasting insulin, the homeostatic model assessment for insulin resistance (HOMA-IR) and serum vitamin D levels. Significant negative correlation was found between serum vitamin D level and grades of steatosis.

CONCLUSIONS

Serum vitamin D level decreases in children with NAFLD. This low serum vitamin D level is associated with higher stages of steatosis but not with BMI.

Panhypopituitarism due to Absence of the Pituitary Stalk: A Rare Aetiology of Liver Cirrhosis

Studies have established a relationship between hypothalamic-pituitary dysfunction and the onset of liver damage, which may occasionally progress to cirrhosis. Patients with hypopituitarism can develop a metabolic syndrome-like phenotype. Insulin resistance is the main pathophysiological axis of metabolic syndrome and is the causal factor in the development of nonalcoholic fatty liver disease (NAFLD). We present the case of a young patient with liver cirrhosis of unknown aetiology that was finally attributed to panhypopituitarism.

The serum vitamin D level is inversely correlated with nonalcoholic fatty liver disease

Background/Aims:

A low vitamin D level has been associated with metabolic syndrome and diabetes. However, an association between a low vitamin D level and nonalcoholic fatty liver disease (NAFLD) has not yet been definitively established. This study aimed to characterize the relationship between a vitamin D level and NAFLD in Korea.

Methods:

A cross-sectional study involving 6,055 health check-up subjects was conducted. NAFLD was diagnosed on the basis of typical ultrasonographic findings and a history of alcohol consumption.

Results:

The subjects were aged 51.7±10.3 years (mean±SD) and 54.7% were female. NAFLD showed a significant inverse correlation with the vitamin D level after adjusting for age and sex [odds ratio (OR)=0.85, 95% confidence interval (CI)=0.75–0.96]. The age- and sex-adjusted prevalence of NAFLD decreased steadily with increasing vitamin D level [OR=0.74, 95% CI=0.60–0.90, lowest quintile (≤14.4 ng/mL) vs highest quintile (≥28.9 ng/mL), p for trend <0.001]. Multivariate regression analysis after adjusting for other metabolic factors revealed that NAFLD showed a significant inverse correlation with both the vitamin D level (>20 ng/mL) [OR=0.86, 95% CI=0.75-0.99] and the quintiles of the vitamin D level in a dose-dependent manner (p for trend=0.001).

Conclusions:

The serum level of vitamin D, even when within the normal range, was found to be inversely correlated with NAFLD in a dose-dependent manner. Vitamin D was found to be inversely correlated with NAFLD independent of known metabolic risk factors. These findings suggest that vitamin D exerts protective effects against NAFLD.

Low vitamin D levels and non-alcoholic fatty liver disease, evidence for their independent association in men in East China: a cross-sectional study (Survey on Prevalence in East China for Metabolic Diseases and Risk Factors (SPECT-China))

Recent studies have suggested an association between vitamin D and non-alcoholic fatty liver disease (NAFLD); however, some results are subject to debate. This study was carried out to evaluate the correlation between NAFLD and vitamin D in men and women in East China. The data were obtained from a cross-sectional study that focused on the health and metabolic status of adults in sixteen areas of East China. According to ultrasonic assessments, the patients were divided into normal and NAFLD groups. Demographic characteristics and biochemical measurements were obtained. Binary logistic regression analysis was used to explore the association. In total, 5066 subjects were enrolled, and 2193 (43·3 %) were diagnosed with NAFLD; 84·56 % of the subjects showed vitamin D deficiency. Subjects with high vitamin D levels had a lower prevalence of NAFLD, particularly male subjects. Within the highest quartile of vitamin D levels, the prevalence of NAFLD was 40·8 %, whereas the lowest quartile of vitamin D levels showed a prevalence of 62·2 %, which was unchanged in women across the vitamin D levels. Binary logistic analysis showed that decreased vitamin D levels were associated with an increased risk of NAFLD (OR 1·54; 95 % CI 1·26, 1·88). This study suggests that vitamin D levels are significantly associated with NAFLD and that vitamin D acts as an independent factor for NAFLD prevalence, particularly in males in East China. Vitamin D interventional treatment might be a new target for controlling NAFLD; elucidating the mechanism requires further research.

Combined Association of Vitamin D and Sex Hormone Binding Globulin With Nonalcoholic Fatty Liver Disease in Men and Postmenopausal Women: A Cross-Sectional Study

This study aimed to explore the combined associations of 25(OH)-vitamin D and sex hormone binding globulin (SHBG) with nonalcoholic fatty liver disease (NAFLD) in men and postmenopausal women. Our data, which were based on the population, were collected from 16 sites in East China in 2014. There were 2700 men with a mean age of 53 years and 1461 women over 55 who were considered postmenopausal enrolled in the study. Levels of 25(OH)D and SHBG were measured using chemiluminescence assay. NAFLD was measured using liver ultrasound. Multivariable-adjusted logistic regression models examined associations of 25(OH)D and SHBG tertiles with odds of mild and moderate-severe NAFLD. Both the low 25(OH)D and low SHBG groups were significantly associated with higher odds of mild NAFLD (men: OR 1.37, 95% CI 1.05, 1.78 in low 25(OH)D group; OR 1.73, 95% CI 1.23, 2.45 in low SHBG group; women: OR 1.51, 95% CI 1.08, 2.12 in low 25(OH)D group; OR 2.16, 95% CI 1.48, 3.14 in low SHBG group) and moderate-severe NAFLD (men: OR 1.61, 95% CI 1.24, 2.10 in low 25(OH)D group; OR 3.42, 95% CI 2.41, 4.87 in low SHBG group; women: OR 1.66, 95% CI 1.14, 2.42 in low 25(OH)D group; OR 6.84, 95% CI 4.31, 10.84 in low SHBG group). However, the combined association of low 25(OH)D and low SHBG was much larger, especially in moderate-severe NAFLD (men: OR 6.57, 95% CI 3.87, 11.18; women: OR 8.16, 95% CI 3.98, 16.73). The associations were independent of age, total testosterone, abdominal obesity, diabetes, and lipid profile. The negative associations of 25(OH)D and SHBG levels with NAFLD are strongest when viewed in combination in men and postmenopausal women. Further studies should determine the cause-effect relationship and investigate the underlying mechanisms of this finding.

[Vitamin D deficiency in chronic liver disease, clinical-epidemiological analysis and report after vitamin d supplementation]

INTRODUCTION

Vitamin D (VD) is known to have multiple extra-skeletal health functions. There is emerging interest in exploring the relationship between vitamin D and chronic liver disease (CLD).

OBJECTIVES

To determine the prevalence of VD deficiency in patients with CLD in our setting and to assess whether VD supplementation influences plasma levels and is associated with improved liver function.

MATERIAL AND METHODS

We conducted a study in 2 phases. First, we analysed clinical and epidemiological characteristics in 94 patients with CLD; second, different doses of calcifediol (25-OH-VD) were administered to patients with VD deficiency (<20ng/mL) and insufficiency (20-30ng/mL). Plasma concentrations and liver function (Child-Pugh and MELD) at the end of treatment were compared with baseline data.

RESULTS

Deficient or insufficient VD levels were found in 87% of the patients, with an average concentration of 18.8ng/mL. Levels were lower in patients with cirrhosis (15.9ng/mL) (P=.002) and in alcoholic liver disease. VD levels were inversely proportional to the degree of liver function: Child A (16.52ng/mL) vs C (7.75ng/mL). After VD supplementation, optimal serum levels were achieved in 94% of patients and significant improvements were observed in platelet count, albumin levels (P<.05) and functional status assessed by the Child-Pugh scale (P<.05).

CONCLUSION

Given the high prevalence of VD deficiency or insufficiency, the need for screening should be considered in the population with CLD. VD supplementation could be safe and effective.

Interactions of Hepatitis B Virus Infection with Nonalcoholic Fatty Liver Disease: Possible Mechanisms and Clinical Impact

Hepatitis B virus (HBV) infection is a major etiology of chronic liver disease worldwide. In the past decade, nonalcoholic fatty liver disease (NAFLD) has emerged as a common liver disorder in general population. Accordingly, the patient number of chronic hepatitis B (CHB) concomitant with NAFLD grows rapidly. The present article reviewed the recent studies aiming to explore the relationship between CHB and NAFLD from different aspects, including the relevant pathogenesis of CHB and NAFLD, the intracellular molecular mechanisms overlaying HBV infection and hepatic steatosis, and the observational studies with animal models and clinical cohorts for analyzing the coincidence of the two diseases. It is concluded that although numerous cross-links have been suggested between the molecular pathways in HBV infection and NAFLD pathogenesis, regarding whether HBV infection can substantially interfere with the occurrence of NAFLD or vice versa in the patients, there is still far from a conclusive agreement.

1,25(OH)2D3 downregulates the Toll-like receptor 4-mediated inflammatory pathway and ameliorates liver injury in diabetic rats

BACKGROUND

Fatty acid deposition in the liver can activate a number of pro-inflammatory signaling pathways such as the Toll-like receptor 4 (TLR4) pathway, which may be important in the pathogenesis of nonalcoholic steatohepatitis. 1,25(OH)2D3 downregulates the expression of TLR4 and may represent a novel treatment strategy for reducing hepatocyte injury. Therefore, in this study, we investigated the protective effects of 1,25(OH)2D3 on diabetic liver injury in vivo.

METHODS

Streptozotocin (STZ)-induced diabetic rats were randomly divided into five groups and treated with low-dose 1,25(OH)2D3 (0.025 μg/kg/day), medium-dose 1,25(OH)2D3 (0.15 μg/kg/day), high-dose 1,25(OH)2D3 (0.3 μg/kg/day), insulin (protamine zinc insulin 16 U/kg/day, subcutaneous injection), or no intervention (the control group). Sixteen weeks later, the rats were killed, and blood samples were obtained to test lipid profiles and hepatic function. The infiltration of inflammatory cells, the level of fibrosis, and the expression levels of TLR4, nuclear factor-kappa B (NF-κB), and tumor necrosis factor-α (TNF-α) in the liver were analyzed. The hepatocytes were treated with vehicle control, LPS (100 ng), high fat [DMEM + FFA (0.1 mM: palmitic acid, oleic acid, 1:2)], LPS + high fat, vehicle + 1,25(OH)2D3 (10(-7) M), LPS + 1,25(OH)2D3, high fat + 1,25(OH)2D3, or LPS + high fat + 1,25(OH)2D3. RNA and protein were extracted to detect the expression of TLR4 and downstream inflammatory factors such as NF-ΚB, TNF-α, and IL-6. Groups of data were compared by single factor variance analysis.

RESULTS

High-dose 1,25(OH)2D3 administration for 16 weeks downregulated the expression of TLR4, NF-κB, and TNF-α in the liver tissue of diabetic rats and attenuated hepatic inflammation and fibrosis, as shown by immunohistochemical staining, hematoxylin and eosin staining, Masson's trichrome staining, reverse transcription polymerase chain reaction (RT-PCR), and western blotting. In vitro, hepatocytes treated with high fat or LPS exhibited significantly increased expression of TLR4, NF-κB, and downstream inflammatory factors (P < 0.05). Intervention with 1,25(OH)2D3 decreased the expression of TLR4, NF-κB, and inflammatory factors (P < 0.05).

CONCLUSIONS

1,25(OH)2D3 exhibited protective effects against diabetes-related liver injury, possibly through downregulation of components of the TLR4 signaling pathway.

Serum vitamin D levels are inversely related with non-alcoholic fatty liver disease independent of visceral obesity in Chinese postmenopausal women

The aim of the present study was to investigate the association between serum vitamin D levels and both visceral adipose and with non-alcoholic fatty liver disease (NAFLD) in Chinese postmenopausal women. Four hundred and fifty-one postmenopausal women between 45 and 74 years of age (mean (± SD) age 57.3 ± 4.6 years) were enrolled in the study. All subjects participated in the Shanghai Obesity Study between June and August 2011 and underwent abdominal magnetic resonance imaging and an abdominal ultrasonography. Patients with a visceral fat area (VFA) ≥ 80 cm(2) were classified as abdominally obese. Serum 25-hydroxyvitamin D3 (25(OH)D3 ) levels were measured with an electrochemiluminescence immunoassay. The prevalence of NAFLD in the study population was 34.8% (n = 157). Women with abdominal obesity had significantly lower serum 25(OH)D3 levels than those without abdominal obesity (median (interquartile range) 11.23 (8.64-14.12) vs 12.56 (9.41-15.98) ng/mL, respectively; P < 0.01). Regardless of abdominal obesity status, serum 25(OH)D3 levels in patients with NAFLD were lower than those without non-NAFLD (11.14 (8.63-13.81) vs 12.92 (9.48-16.37) ng/mL (P < 0.05) for those without abdominal obesity; 10.86 (8.61-13.56) vs 11.55 (8.82-16.38) ng/mL (P < 0.05) for those with abdominal obesity). Partial correlation analyses demonstrated a negative correlation between serum 25(OH)D3 levels and VFA (P < 0.05). Logistic regression analysis revealed that high serum 25(OH)D3 levels were a protective factor against NAFLD after adjusting for risk factors such as VFA. In conclusion, independent of visceral obesity, vitamin D is inversely correlated with NAFLD in Chinese postmenopausal women.

Can skin exposure to sunlight prevent liver inflammation?

Liver inflammation contributes towards the pathology of non-alcoholic fatty liver disease (NAFLD). Here we discuss how skin exposure to sunlight may suppress liver inflammation and the severity of NAFLD. Following exposure to sunlight-derived ultraviolet radiation (UVR), the skin releases anti-inflammatory mediators such as vitamin D and nitric oxide. Animal modeling studies suggest that exposure to UVR can prevent the development of NAFLD. Association studies also support a negative link between circulating 25-hydroxyvitamin D and NAFLD incidence or severity. Clinical trials are in their infancy and are yet to demonstrate a clear beneficial effect of vitamin D supplementation. There are a number of potentially interdependent mechanisms whereby vitamin D could dampen liver inflammation, by inhibiting hepatocyte apoptosis and liver fibrosis, modulating the gut microbiome and through altered production and transport of bile acids. While there has been a focus on vitamin D, other mediators induced by sun exposure, such as nitric oxide may also play important roles in curtailing liver inflammation.

Lipid metabolism and inflammation modulated by Vitamin D in liver of diabetic rats

Background

In recent years, much evidence suggested that vitamin D plays an important role in decreasing the risk of type 2 diabetes. The purpose of this study was to investigate whether 1, 25 (OH) ₂D₃ can modulate inflammation and lipid metabolism in type 2 diabetic rat liver.

Methods

Type 2 diabetes was induced in SD rat with high-fat and high-sugar diets and multiple low-dose streptozotocin. The levels of serum calcium, phosphorus, glucose, TC, TG, AST, ALT and hepatic TG were determined. H & E staining were performed to assess the effects of vitamin D treatment on pathological changes in the liver tissues. Immunohistology, real-time PCR and Western blot were used to evaluate the expressions of NF-κ B, MCP-1, ICAM-1, TGF-β1, PPAR-α and CPT-1.

Results

The administration of 1, 25 (OH) ₂D₃ reduced liver weight. Compared to DM rats, 1, 25 (OH) ₂D₃-treated DM rats had lower liver weight. Moreover, compared to healthy or 1, 25 (OH) ₂D₃-treated DM rats, DM rats had increased hepatic transcription factors (NF-κ B), monocyte chemoattractant protein −1 (MCP-1), intercellular adhesion molecule −1 (ICAM-1), transforming growth factor-β1 (TGF-β1) expressions, but had fewer hepatic PPAR- α and CPT-1 expressions.

Conclusions

1, 25 (OH) ₂D₃ significantly modulated the liver inflammation and lipid metabolism in diabetic rat models, which may be caused by its regulations on hepatic signaling NF-κ B pathway and PPAR- α.

Recent advances in dietary supplementation, in treating non-alcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is currently known as the most common liver problem, characterized by excessive lipid accumulation in hepatocytes, which may progress to other liver diseases such as nonalcoholic steatohepatitis, hepatic tissue fibrosis, liver cirrhosis, and failure or hepatocellular carcinoma. Since NAFLD is positively associated with the development of obesity, insulin resistance, and ultimately type 2 diabetes mellitus, it is often regarded as the hepatic manifestation of the metabolic syndrome. No pharmacologic treatment has yet been proven for this disease. For most patients with presumed or confirmed NAFLD, the only proven strategy is to offer lifestyle advice that can lead to sustained weight loss. Since insulin resistance, oxidative stress, inflammation, and necro-apoptosis are involved in NAFLD pathogenesis, it seems that every potential therapeutic agent should target one or some of these pathologic events. There are many well known anti-oxidants, anti-inflammatory, and insulin sensitizer dietary supplements which have shown beneficial effects on NAFLD improvement in animal and human studies. The purpose of this review is to explore the existing evidences on dietary supplements considered to have hepatoprotective properties, and to present some proposed mechanisms by which they may protect against NAFLD.

Vitamin D inhibits development of liver fibrosis in an animal model but cannot ameliorate established cirrhosis

1,25(OH)2D3, the active form of vitamin D, has an antiproliferative and antifibrotic effect on hepatic stellate cells. Our aim was to investigate the potential of 1,25(OH)2D3 to inhibit the development of liver fibrosis and to ameliorate established fibrosis in vivo. The antifibrotic effect of 1,25(OH)2D3 was investigated in a thioacetamide (TAA) model (as a preventive treatment and as a remedial treatment) and in a bile duct ligation model. In the preventive model, rats received simultaneously intraperitoneum injection of TAA and/or 1,25(OH)2D3 for 10 wk. In the remedial model, rats were treated with TAA for 10 wk and then received 1,25(OH)2D3 or saline for 8 wk. Fibrotic score was determined by Masson staining. Collagen I, α-smooth muscle actin (α-SMA), tissue inhibitor of metalloproteinase-1 (TIMP1), platelet-derived growth factor (PDGF), and transforming growth factor-β (TGF-β) expression were measured by Western blot analysis and real-time PCR. Hypercalemia was detected by chemistry measurements. Preventive treatment of 1,25(OH)2D3 significantly suppressed liver fibrosis both macroscopically and microscopically and significantly lowered the fibrotic score of the TAA + 1,25(OH)2D3 group compared with the TAA group. 1,25(OH)2D3 significantly inhibited expression of PDGF and TGF-β by ∼50% and suppressed the expression of collagen Iα1, TIMP1, and α-SMA by approximately three-, two-, and threefold, respectively. In contrast, 1,25(OH)2D3 was inefficient in amelioration of established liver fibrosis. Administration of 1,25(OH)2D3 to bile duct ligation rats led to a high mortality rate probably caused by hypercalcemia. We conclude that 1,25(OH)2D3 may be considered as a potential preventive treatment in an in vivo model but failed to ameliorate established cirrhosis.

Comparison of serum ferritin and vitamin d in association with the severity of nonalcoholic Fatty liver disease in korean adults

BACKGROUND

Increased serum ferritin and decreased vitamin D levels associated with nonalcoholic fatty liver disease (NAFLD). However, their association with the severity of NAFLD has not been fully evaluated. The aim of this study was to compare the association of serum ferritin and 25(OH)D₃ levels with the severity of ultrasonographically detected NAFLD (US-NAFLD) and hepatic steatosis defined by fatty liver index (FLI) in Korean adults.

METHODS

A cross-sectional analysis of clinical and anthropometric data, including serum ferritin and 25(OH)D₃, from men (n=295) and women (n=263) who underwent a routine health check-up in 2012.

RESULTS

In men, with an increase in the quartile of serum ferritin level, the incidences of subjects with metabolic syndrome (P=0.002), US-NAFLD (P=0.041), and FLI ≥60 (P=0.010) were significantly elevated. In women, the incidence of subjects with US-NAFLD was also significantly elevated with increases in the serum ferritin quartile (P=0.012). Regarding 25(OH)D₃, no statistical differences were observed among the different quartiles in either gender. Serum ferritin level significantly increased as the severity of US-NAFLD increased (P<0.001); however, no significant differences in 25(OH)D₃ level were observed in men. No significant differences in either serum ferritin or 25(OH)D₃ level were observed among women with different levels of severity of US-NAFLD.

CONCLUSION

Increased serum ferritin level showed a closer association with severity of NAFLD compared with level of serum vitamin D, suggesting that serum ferritin level may be a better marker than vitamin D level for predicting the severity of US-NAFLD and hepatic steatosis in a clinical setting.

Serum vitamin D is associated with non-alcoholic fatty liver disease in Chinese males with normal weight and liver enzymes

AIM

Considering the characterization of vitamin D deficiency as a risk factor of ectopic fat deposition, the association of serum 25-hydroxy vitamin D3 [25(OH)D3] levels with non-alcoholic fatty liver disease (NAFLD) was evaluated in Chinese men with normal body mass index (BMI) and enzyme markers of liver function.

METHODS

A total of 514 participants (22 to 79 years old) with normal BMI and liver enzymes were identified for analysis. Abdominal ultrasound was performed to diagnose NAFLD, and the fatty liver index (FLI) was calculated to quantify liver steatosis. Serum 25(OH)D3 levels were determined by an electrochemiluminescence immunoassay.

RESULTS

Among the entire study population, the mean levels of serum 25(OH)D3 were 15.32±5.77 ng/mL. However, when serum 25(OH)D3 levels were compared between non-NAFLD subjects (n=438) and NAFLD subjects (n=76), the latter showed significantly lower levels (15.65±5.89 ng/mL vs 13.46±4.65 ng/mL, P=0.002). In addition, serum 25(OH)D3 levels were found to be significantly correlated with FLI after adjustment for age and BMI (r=-0.108, P=0.014). Logistic regression showed that serum 25(OH)D3 levels were independently correlated with NAFLD (OR: 0.937, 95% CI: 0.884-0.993, P=0.028). Furthermore, stepwise regression analysis revealed that serum 25(OH)D3 levels were inversely associated with FLI (β=-0.055, P=0.040).

CONCLUSION

The present study demonstrated that serum 25(OH)D3 levels were inversely associated with NAFLD, even in subjects with normal total body fat, suggesting a potential role of lower levels of vitamin D in the occurrence and development of NAFLD.