Shedding new light on vitamin D and fatty liver disease

The effect of high oral loading dose of cholecalciferol in non-alcoholic fatty liver disease patients. A randomized placebo controlled trial

Background and Aim: Non-alcoholic fatty liver (NAFLD) is one of the most common progressive metabolic disorders worldwide. There are increasing scientific interests nowadays for the association between vitamin D status and Non-alcoholic fatty liver. Earlier studies have revealed that vitamin D deficiency is highly prevalent in Non-alcoholic fatty liver patients that contributes to poor outcomes. Hence, the present study aimed to assess the efficacy and safety of oral cholecalciferol on Non-alcoholic fatty liver patients.

Subjects and Methods: This study was conducted on 140 patients that were randomized either to group 1 that received the standard conventional therapy in addition to placebo or group 2 that received the standard conventional therapy in addition to cholecalciferol during the 4 months study period.

Results: At the end of the study group 2 revealed significant decrease (p < 0.05) in the mean serum level of TG, LDL-C, TC, hsCRP as compared to their baseline results and group 1 results. Additionally, a significant improvement in the serum levels of ALT (p = 0.001) was seen in group 2 at the end of the study when compared to group 1. Whereas group 1 did not show any change in these parameters when compared to group 2 and their baseline results.

Conclusion: Cholecalciferol was shown to have beneficial effects on serum ALT levels, hsCRP levels and lipid profile of NAFLD patients.

Clinical Trial Registration:https://prsinfo.clinicaltrials.gov/prs-users-guide.html, identifier NCT05613192

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.

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.

Vitamin D deficiency: prevalence and association with liver disease severity in pediatric nonalcoholic fatty liver disease

BACKGROUND/OBJECTIVES

To determine associations between serum 25-hydroxyvitamin D (25(OH)-D) concentrations and histologic nonalcoholic fatty liver disease (NAFLD) severity.

SUBJECTS/METHODS

Clinical, laboratory, and histology data were collected retrospectively in a pediatric cohort with biopsy-confirmed NAFLD. Serum 25(OH)-D concentrations were used to define vitamin D deficiency (≤20 ng/ml), insufficiency (21-30 ng/ml), and sufficiency (≥31 ng/ml).

RESULTS

In all, 234 patients (78% non-Hispanic, median age 14 years) were included. The majority (n = 193) were either vitamin D insufficient (50%) or deficient (32%). Eighty-four patients (36%) reported taking vitamin D supplements at the time of biopsy; serum 25(OH)-D concentrations were not higher in those supplemented. There were no differences in the demographic, clinical, and laboratory characteristics of the three vitamin D status groups. Severity of steatosis, ballooning, lobular/portal inflammation, and NAFLD activity score were also not different between the groups. The proportion of patients with significant fibrosis (stage ≥ 2) was higher in those with insufficiency (29%) compared to those who were sufficient (17%) or deficient (15%, p = 0.04). After controlling for important covariates selected from age, body mass index, ethnicity, vitamin D supplementation, and season, the insufficient group had increased odds of a higher fibrosis score compared to the sufficient group (adjusted OR, 2.04; 95%CI, 1.02-4.08).

CONCLUSIONS

Vitamin D deficiency and insufficiency are common in children with NAFLD, but not consistently related with histologic disease severity. Prospective longitudinal studies are needed to determine optimal dosing strategies to achieve sufficiency and to determine whether adequate supplementation has an impact on histology.

Creatinine-to-bodyweight ratio is a predictor of incident non-alcoholic fatty liver disease: A population-based longitudinal study

AIM

Serum creatinine (Cre) is used as a surrogate marker of muscle mass. We investigated the impact of the Cre-to-bodyweight (BW) ratio (Cre/BW) on incident non-alcoholic fatty liver disease (NAFLD).

METHODS

Fatty liver disease was diagnosed by abdominal ultrasonography. In this historical cohort study of 13 728 participants (6397 men and 7331 women), we divided the participants into two groups by sex and into quartiles according to Cre (mg/dL)/BW (kg; Q1-4). We carried out Cox proportional hazard models, adjusting for age, alanine aminotransferase, fasting plasma glucose, systolic blood pressure, alcohol consumption, smoking status, and exercise.

RESULTS

During the 5.1-year follow up for men and 6.0-year follow up for women, 2497 participants (1696 men, 801 women) developed NAFLD. The 4000-days cumulative incidence rates of FLD for men and women were 29.6% and 16.6% in Q1, 28.2% and 10.6% in Q2, 25.5% and 8.8% in Q3, and 22.7% and 7.7% in Q4, respectively. The hazard ratios of incident NAFLD in Q1 (Cre/BW [×100]: men <1.28; women <1.17) were 1.89 (95% confidence interval 1.64-2.17, P < 0.001) in men and 2.96 (2.42-3.62, P < 0.001) in women, compared with Q4 (Cre/BW [×100]: men ≥1.61; women ≥1.51).

CONCLUSIONS

A low Cre/BW is associated with an increased risk of NAFLD. Screening Cre/BW can be used to identify individuals who are at high risk of NAFLD.

Intestinal vitamin D receptor modulates lipid metabolism, adipose tissue inflammation and liver steatosis in obese mice

OBJECTIVE

Hypovitaminosis D is common in the obese population and patients suffering from obesity-associated disorders such as type 2 diabetes and fatty liver disease, resulting in suggestions for vitamin D supplementation as a potential therapeutic option. However, the pathomechanistic contribution of the vitamin D-vitamin D receptor (VDR) axis to metabolic disorders is largely unknown.

METHODS

We analyzed the pathophysiological role of global and intestinal VDR signaling in diet-induced obesity (DIO) using global Vdr-/- mice and mice re-expressing an intestine-specific human VDR transgene in the Vdr deficient background (Vdr-/- hTg).

RESULTS

Vdr-/- mice were protected from DIO, hepatosteatosis and metabolic inflammation in adipose tissue and liver. Furthermore, Vdr-/- mice displayed a decreased adipose tissue lipoprotein lipase (LPL) activity and a reduced capacity to harvest triglycerides from the circulation. Intriguingly, all these phenotypes were partially reversed in Vdr-/- hTg animals. This clearly suggested an intestine-based VDR activity on systemic lipid homeostasis. Scrutinizing this hypothesis, we identified the potent LPL inhibitor angiopoietin-like 4 (Angptl4) as a novel transcriptional target of VDR.

CONCLUSION

Our study suggests a VDR-mediated metabolic cross-talk between gut and adipose tissue, which significantly contributes to systemic lipid homeostasis. These results have important implications for use of the intestinal VDR as a therapeutic target for obesity and associated disorders.

Beneficial Effects of Vitamin D Treatment in an Obese Mouse Model of Non-Alcoholic Steatohepatitis

Serum vitamin D levels negatively correlate with obesity and associated disorders such as non-alcoholic steatohepatitis (NASH). However, the mechanisms linking low vitamin D (VD) status to disease progression are not completely understood. In this study, we analyzed the effect of VD treatment on NASH in mice. C57BL6/J mice were fed a high-fat/high-sugar diet (HFSD) containing low amounts of VD for 16 weeks to induce obesity, NASH and liver fibrosis. The effects of preventive and interventional VD treatment were studied on the level of liver histology and hepatic/intestinal gene expression. Interestingly, preventive and to a lesser extent also interventional VD treatment resulted in improvements of liver histology. This included a significant decrease of steatosis, a trend towards lower non-alcoholic fatty liver disease (NAFLD) activity score and a slight non-significant decrease of fibrosis in the preventive treatment group. In line with these changes, preventive VD treatment reduced the hepatic expression of lipogenic, inflammatory and pro-fibrotic genes. Notably, these beneficial effects occurred in conjunction with a reduction of intestinal inflammation. Together, our observations suggest that timely initiation of VD supplementation (preventive vs. interventional) is a critical determinant of treatment outcome in NASH. In the applied animal model, the improvements of liver histology occurred in conjunction with reduced inflammation in the gut, suggesting a potential relevance of vitamin D as a therapeutic agent acting on the gut⁻liver axis.

Vitamin D Deficiency, Its Role in Health and Disease, and Current Supplementation Recommendations

Vitamin D deficiency has been identified as a common metabolic/endocrine abnormality. Despite known dietary sources of vitamin D and the role of sunlight in its production, much of the US population may have inadequate levels of serum 25-hydroxyvitamin D. Deficiency of vitamin D can be caused by a variety of health conditions, but studies on the effects of vitamin D supplements have had mixed results. This evidence-based clinical review discusses what is currently known about vitamin D and what areas need further research to clarify its role in health and disease.

The Common Mechanisms of Sarcopenia and NAFLD

Current studies have shown that sarcopenia and nonalcoholic fatty liver disease (NAFLD) have similar pathophysiological profiles. The cooccurrence of sarcopenia and NAFLD has been observed in elderly patients. The actions of these conditions are linked, and their treatments are similar. Therefore, studies should be conducted on NAFLD-sarcopenia rather than on NAFLD or sarcopenia.

Vitamin D supplementation and non-alcoholic fatty liver disease: A critical and systematic review of clinical trials

Previous observational studies have found a relationship between vitamin D deficiency and non-alcoholic fatty liver disease (NAFLD). However, this type of study could not show the causal relationship between these two conditions. Therefore, we systematically and critically reviewed the available clinical trials to elucidate such relationship. We searched databases such as Medline, Scopus and Cochrane to identify the clinical trials that assessed the effects of vitamin D supplementation in adults with NAFLD. The outcome variables of interest were indicators of hepatic steatosis, liver enzymes, insulin resistance, inflammation and oxidative stress. A total of 6 studies were included in the qualitative analysis. Only in two studies the grade of hepatic steatosis decreased significantly after vitamin D supplementation. The changes in insulin resistance parameters were reported significant only in one. Of the 3 included studies that measured biomarkers of inflammation and oxidative stress, one revealed a significant decrease in these biomarkers after vitamin D supplementation. Findings from current review study provided new insight into the factors that could affect the therapeutic role of vitamin D in NAFLD. Factors such as gender differences, baseline serum status of vitamin D, co-supplementation with calcium and gene polymorphism should be considered when designing future clinical trials.

Vitamin D supplementation for chronic liver diseases in adults

BACKGROUND

Vitamin D deficiency is often reported in people with chronic liver diseases. Therefore, improving vitamin D status could have a beneficial effect on people with chronic liver diseases.

OBJECTIVES

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

SEARCH METHODS

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Science Citation Index Expanded, and Conference Proceedings Citation Index - Science. We also searched databases of ongoing trials and the World Health Organization International Clinical Trials Registry Platform. We scanned bibliographies of relevant publications and asked experts and pharmaceutical companies for additional trials. All searches were up to January 2017.

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 The Cochrane Collaboration. We contacted authors of the trials to ask for missing information. We conducted random-effects and fixed-effect meta-analyses. For dichotomous outcomes, we calculated risk ratios (RRs), and for continuous outcomes, we calculated mean differences (MD), both with 95% confidence intervals (CI) and Trial Sequential Analyses-adjusted CIs. We calculated Peto odds ratio (OR) for rare events. We considered risk of bias in domains to assess the risk of systematic errors. We conducted Trial Sequential Analyses to control the risk of random errors. We assessed the quality of the evidence with GRADE.

MAIN RESULTS

We included 15 randomised clinical trials with 1034 participants randomised. All trials had a parallel group design. Nine trials were conducted in high-income countries and six trials in middle-income countries. All trials were at high risk of bias. Six trials included participants with chronic hepatitis C, four trials included participants with liver cirrhosis, four trials included participants with non-alcoholic fatty liver disease, and one trial included liver transplant recipients. All included trials reported the baseline vitamin D status of participants. Participants in six trials had baseline 25-hydroxyvitamin D levels at or above vitamin D adequacy (20 ng/mL), while participants in the remaining nine trials were vitamin D insufficient (less than 20 ng/mL). All trials administered vitamin D orally. Mean duration of vitamin D supplementation was 0.5 years and follow-up was 0.6 years. Eleven trials (831 participants; 40% women; mean age 52 years) tested vitamin D3, one trial (18 men; mean age 61 years) with three intervention groups tested vitamin D2 and 25-dihydroxyvitamin D in separate groups, and three trials (185 participants; 55% women; mean age 55 years) tested 1,25-dihydroxyvitamin D. Seven trials used placebo, and eight trials used no intervention in the control group.The effect of vitamin D on all-cause mortality at the end of follow-up is uncertain because the results were imprecise (Peto OR 0.70, 95% CI 0.09 to 5.38; I2 = 32%; 15 trials; 1034 participants; very low quality evidence). Trial Sequential Analysis on all-cause mortality was performed based on a mortality rate in the control group of 10%, a relative risk reduction of 28% in the experimental intervention group, a type I error of 2.5%, and type II error of 10% (90% power). There was no diversity. The required information size was 6396 participants. The cumulative Z-curve did not cross the trial sequential monitoring boundary for benefit or harm after the 15th trial, and the Trial Sequential Analyses-adjusted CI was 0.00 to 2534.The effect of vitamin D on liver-related mortality (RR 1.62, 95% CI 0.08 to 34.66; 1 trial; 18 participants) and on 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), and thyroiditis (RR 0.33 95% CI 0.01 to 7.91; 1 trial; 68 participants) is uncertain because the results were imprecise. The evidence on all these outcomes is of very low quality. The effect of vitamin D3 on non-serious adverse events such as glossitis (RR 3.70, 95% CI 0.16 to 87.6; 1 trial; 65 participants; very low quality of evidence) is uncertain because the result was imprecise.Due to few data, we did not conduct Trial Sequential Analysis on liver-related mortality, and serious and non-serious adverse events.We found no data on liver-related morbidity and health-related quality of life in the randomised trials included in this review.

AUTHORS' CONCLUSIONS

We are uncertain as to whether vitamin D supplements in the form of vitamin D3, vitamin D2, 1,25-dihydroxyvitamin D, or 25-dihydroxyvitamin D have important effect on all-cause mortality, liver-related mortality, or on serious or non-serious adverse events because the results were imprecise. There is no evidence on the effect of vitamin D supplementation on liver-related morbidity and health-related quality of life. Our conclusions are based on few trials with an insufficient number of participants and on lack of data on clinically important outcomes. In addition, the analysed trials are at high risk of bias with significant intertrial heterogeneity. The overall quality of evidence is very low.

Vitamin D supplementation in patients with nonalcoholic fatty liver disease: A randomized controlled trial

Background and Aim

Deficiency of vitamin D may be related to the pathogenesis of nonalcoholic fatty liver disease (NAFLD). The aim of the present study was to evaluate the effect of vitamin D supplementation in patients with NAFLD.

Methods

A total of 81 patients with NAFLD with normal or raised (n = 47) serum alanine aminotransferase (ALT) having vitamin D deficiency were randomized prospectively. Group 1 (n = 51) received lifestyle modifications and a single injection of vitamin D (600 000 U) (standard medical treatment [SMT] + vitamin D) and group 2 (n = 30) received lifestyle modifications (SMT) for 6 months. The primary objective of this study was to assess the improvement in insulin resistance (IR) and serum ALT (in patients with raised ALT) and the secondary objective was to assess the change in cytokine profile in the SMT + vitamin D group.

Results

After 6 months, significant improvement in serum levels of ALT was observed in the SMT + vitamin D group when compared to the SMT group (ALT [87 ± 48 and 59 ± 32 IU/mL, P < 0.001] vs [64 ± 35 and 62 ± 24 IU/mL, P = 0.70]). Mean insulin levels and homeostasis model assessment‐IR remained unchanged at 6 months in the SMT + vitamin D group while there was a significant increase in mean insulin and homeostasis model assessment‐IR in the SMT group. SMT + vitamin D group had significant increase in mean serum levels of adiponectin (836 ± 309 and 908 ± 312 (pg/mL), P = 0.018) compared with the baseline; tumor necrosis factor‐α levels decreased from baseline but the change was not significant.

Conclusion

Patients with NAFLD given vitamin D in addition to lifestyle modifications have significant improvement in serum ALT and serum adiponectin levels.

Non-alcoholic fatty liver disease: epidemiology, clinical course, investigation, and treatment

BACKGROUND

The global obesity epidemic has increased the prevalence of fatty liver disease. At present, 14% to 27% of the general population in the industrialized world has non-alcoholic fatty liver disease (NAFLD).

METHOD

We review pertinent publications retrieved by a selective search of the PubMed database for the years 1995 to 2013.

RESULTS

The term "non-alcoholic fatty liver disease" covers cases of a wide spectrum of severity, ranging from bland fatty liver without any inflammation and with little or no tendency to progress all the way to non-alcoholic steato-hepatitis (NASH) with inflammatory reactions and hepatocyte damage, with or without fibrosis. Some 5% to 20% of patients with NAFLD develop NASH, which undergoes a further transition to higher-grade fibrosis in 10% to 20% of cases. In fewer than 5% of cases, fibrosis progresses to cirrhosis. These approximate figures lead to an estimate of 0.05% to 0.3% for the prevalence of cirrhosis in the general population. About 2% of all cirrhosis patients per year develop hepatocellular carcinoma. The diagnosis of fatty liver disease can be suspected initially on the basis of abnormally high aspartate aminotransferase (ASAT) and/or alanine aminotransferase (ALAT) levels and abnormal ultrasonographic findings. The positive predictive value of an ultrasonographic study for mild steatosis is 67% at most. The NAFLD fibrosis score, which is computed on the basis of multiple parameters (age, body-mass index, diabetes status, ASAT, ALAT, platelet count, and albumin level), has a positive predictive value of 82% to 90% and a negative predictive value of 88% to 93%. Liver biopsy is the gold standard for diagnosis but should be performed sparingly in view of its rare but sometimes life-threatening complications, such as hemorrhage. The treatment of NAFLD and NASH consists mainly of changes in lifestyle and nutrition.

CONCLUSION

NAFLD can, in principle, be reversed. This is only possible with weight reduction by at least 3% to 5%.

Relation between vitamin D status and nonalcoholic fatty liver disease in children

OBJECTIVES

In adults, vitamin D deficiency is common in patients with nonalcoholic fatty liver disease (NAFLD) and has been associated with the severity of histology. There are known differences between adult and pediatric NAFLD, with little data regarding the relation between vitamin D and pediatric NAFLD. The aim of the present study was to examine the relation between vitamin D levels and NAFLD in children.

METHODS

Clinical and histological data were used from children ages 2 to 18 years with biopsy-proven NAFLD enrolled in the Nonalcoholic Steatohepatitis Clinical Research Network studies. 25(OH) vitamin D levels were measured from serum. Data examined included demographics, anthropometrics, laboratory markers, and liver histology. Data were analyzed using 3 categories of vitamin D level: deficient (≤ 20 ng/mL), insufficient (21-29 ng/mL), and sufficient (≥ 30 ng/mL).

RESULTS

A total of 102 children were studied. There was a high prevalence (80/102, 78%) of vitamin D deficiency or insufficiency; however, there were no significant associations between vitamin D level and the histological characteristics or severity of NAFLD. Significantly higher levels of triglycerides were found in those with vitamin D deficiency (P = 0.004), but there was no association with other features of the metabolic syndrome.

CONCLUSIONS

There is a high prevalence of vitamin D deficiency and insufficiency in children with biopsy-proven NAFLD; however, no association was found between vitamin D deficiency and the severity of disease on biopsies. This differs from adult NAFLD studies in which vitamin D deficiency correlates with histological severity, suggesting differences in the risk factors for or consequences of pediatric NAFLD.

Association between serum vitamin D and severity of liver fibrosis in chronic hepatitis C patients: a systematic meta-analysis

To conduct a systematic review of group studies assessing the association of serum vitamin D status with the severity of liver fibrosis in chronic hepatitis C patients using meta-analysis. The relevant research literatures were identified by searching PubMed and EMBASE databases prior to October 2013 with no restrictions. We included group studies that reported odds ratio (OR) estimates with 95% confidence intervals (CIs) or a mean with standard deviation (SD) for the association between serum vitamin D status and the severity of liver fibrosis in chronic hepatitis C patients. Approximately 8321 participants from several countries were included in this analysis. Six studies on serum vitamin D status and the severity of liver fibrosis were included in this meta-analysis. ORs with 95% CIs were extracted from four studies and the pooled ORs were 0.866 (95% CI, 0.649 to 1.157). The means with SDs were extracted from three studies and the pooled means were -0.487 (95% CI, -0.659 to -0.315). There was statistically significant heterogeneity among the mean data extracted studies (P=0.029; I(2)=71.8%) but not among the OR data extracted studies (P=0.061; I(2)=55.6%). Finally, results from the mean data extracted studies suggest that lower serum vitamin D is a risk factor for the severity of liver fibrosis in chronic hepatitis C patients. However, there is no conclusive evidence on this association because of inconsistencies between the OR data extracted studies and the mean data extracted studies.

Does vitamin D improve liver enzymes, oxidative stress, and inflammatory biomarkers in adults with non-alcoholic fatty liver disease? A randomized clinical trial

The aim of this study was to investigate the effects of vitamin D supplementation on serum aminotransferases, insulin resistance, oxidative stress, and inflammatory biomarkers in adult patients with non-alcoholic fatty liver disease (NAFLD). Fifty-three patients with NAFLD were enrolled in a parallel, double-blind, placebo-controlled study. The patients were randomly allocated to receive either one oral pearl consisting of 50,000 IU vitamin D3 (n = 27) or a placebo (n = 26), every 14 days for 4 months. Serum aminotransferases, high-sensitive C-reactive protein (hs-CRP), tumor necrosis factor α, malondialdehyde (MDA), total antioxidant capacity, transforming growth factor β1, as well as grade of hepatic steatosis and homeostasis model assessment of insulin resistance were assessed pre- and post-intervention. In patients who received vitamin D supplement compared to the controls, the median of serum 25(OH)D3 significantly increased (16.2 vs. 1.6 ng/ml, P < 0.001). This increase accompanied by significant decrease in serum MDA (-2.09 vs. -1.23 ng/ml, P = 0.03) and near significant changes in serum hs-CRP (-0.25 vs. 0.22 mg/l, P = 0.06). These between-group differences remained significant even after controlling for baseline covariates. Other variables showed no significant changes. Improved vitamin D status led to amelioration in serum hs-CRP and MDA in patients with NAFLD. This might be considered as an adjunctive therapy to attenuate systemic inflammation and lipid peroxidation alongside other treatments for NAFLD patients.

Low serum 25-hydroxyvitamin D concentrations associate with non-alcoholic fatty liver disease in adolescents independent of adiposity

BACKGROUND AND AIMS

Non-alcoholic fatty liver disease (NAFLD) and serum 25-hydroxyvitamin D (s25[OH]D) concentrations are both associated with adiposity and insulin resistance (IR) and thus may be pathogenically linked. We aimed to determine the prevalence of vitamin D deficiency in adolescents with NAFLD and to investigate the prospective and cross-sectional associations between s25[OH]D concentrations and NAFLD.

METHODS

Participants in the population-based West Australian Pregnancy (Raine) Cohort had seasonally adjusted s25(OH)D concentrations determined at ages 14 and then 17 years. NAFLD was diagnosed at 17 years using liver ultrasonography. Associations were examined after adjusting for potential confounders. Odds ratios (ORs) and confidence intervals (CIs) are reported per standard deviation in s25(OH)D concentrations.

RESULTS

NAFLD was present in 16% (156/994) of adolescents. The majority of participants with NAFLD had either insufficient (51%) or deficient (17%) vitamin D status. s25(OH)D concentrations at 17 years were inversely associated with risk of NAFLD (OR 0.74, 95% CI 0.56, 0.97; P = 0.029), after adjusting for sex, race, physical activity, television/computer viewing, body mass index, and IR. The effect of s25(OH)D concentrations at 17 years was minimally affected after further adjusting for s25(OH)D concentrations at 14 years (OR 0.76, 95% CI 0.56, 1.03; P = 0.072).

CONCLUSIONS

Lower s25(OH)D concentrations are significantly associated with NAFLD, independent of adiposity and IR. Screening for vitamin D deficiency in adolescents at risk of NAFLD is appropriate, and clinical trials investigating the effect of vitamin D supplementation in the prevention and treatment of NAFLD may be warranted.

No significant association between vitamin D and nonalcoholic fatty liver disease in a Chinese population

BACKGROUND

Some research evidence from Western populations suggests that lower vitamin D is associated with the prevalence and histologically assessed severity of nonalcoholic fatty liver disease (NAFLD).

AIMS

To investigate the associations of serum 25-hydroxyvitamin D [25(OH)D] concentrations and vitamin D status (deficiency <20 ng/ml; insufficiency 20-30 ng/ml; sufficiency >30 ng/ml) with the prevalence of NAFLD in study population of Chinese.

METHODS

Serum 25(OH)D, parathyroid hormone, lipids, liver enzymes, and anthropometric characteristics were measured in 1,248 subjects aged ≥ 20 years. NAFLD was diagnosed using abdominal ultrasound examination.

RESULTS

The prevalence of NAFLD was 30.3 % in the total study population, 37.9 % in the male subjects, and 20.8 % in the female subjects (P < 0.0001). Subjects with NAFLD had a significantly higher body mass index, higher levels of fasting blood glucose and liver enzymes, and a more atherogenic lipid profile. However, serum 25(OH)D concentrations were not significantly different between subjects with and without NAFLD (22.1 vs. 22.8 ng/ml, respectively; P = 0.21). In addition, a 10 ng/ml higher serum 25(OH)D concentrations [odds ratio (OR) 1.02, 95 % confidence interval (CI) 0.84-1.25, P = 0.82] or vitamin D status (vs. sufficiency: deficiency OR 0.86, 95 % CI 0.54-1.37, P = 0.52; insufficiency OR 0.96, 95 % CI 0.61-1.52, P = 0.87) were not significantly associated with the presence of NAFLD in the multivariate logistic regression analyses.

CONCLUSIONS

Serum 25(OH)D concentrations or vitamin D status were not significantly associated with the presence of NAFLD. More studies are needed to elucidate the relationship between vitamin D and the occurrence of NAFLD in Chinese.

Nonalcoholic fatty liver disease and reduced serum vitamin D(3) levels

Nonalcoholic fatty liver disease (NAFLD) and vitamin D3 deficiency are two highly prevalent pathologic conditions worldwide that share several cardiometabolic risk factors. In addition to its traditional calcium-related effects on the skeleton, vitamin D3 deficiency has now been recognized to exert nonskeletal adverse effects on several other organ systems. Accumulating epidemiological evidence suggests that low levels of serum 25-hydroxyvitamin D3 are associated with the presence and severity of NAFLD, independently of several potential confounders, including features of the metabolic syndrome. The molecular mechanisms of this association remain incompletely understood. A variety of biologically plausible mechanisms may mediate a hepato-protective role for the active metabolite of vitamin D3. 1α,25-dihydroxyvitamin D3 modulates the insulin signaling pathway/insulin resistance, suppresses fibroblast proliferation and collagen production, exerts anticoagulant and profibrinolytic effects, and modulates macrophage activity and inflammatory cytokine generation. Overall, the high prevalence of vitamin D3 deficiency and the plausible biological mechanisms linking this to NAFLD suggest that treatment of vitamin D3 deficiency to prevent and/or treat NAFLD is a promising field to explore. Large placebo-controlled randomized clinical trials are urgently needed to determine whether vitamin D3 supplementation could have any potential benefit in reducing the development and progression of NAFLD.

Vitamin d deficiency in patients with chronic liver disease and cirrhosis

Vitamin D is now widely recognized to have multiple extraskeletal health functions. The liver is one of the major organs involved in its metabolism. Recent studies have demonstrated a very high prevalence of vitamin D deficiency and insufficiency in patients with chronic liver disease and cirrhosis. There is an emerging interest to explore the relationship between vitamin D deficiency and prevalence and severity of non-alcoholic liver disease and response to antiviral therapy in hepatitis C. In this review, we discuss the current status of our understanding of vitamin D metabolism and vitamin D deficiency in patients with chronic liver disease and cirrhosis.

Combined effect of 25-OH vitamin D plasma levels and genetic vitamin D receptor (NR 1I1) variants on fibrosis progression rate in HCV patients

BACKGROUND

Decreased vitamin D levels have been described in various forms of chronic liver disease and associated with advanced fibrosis. Whether this association is a cause or consequence of advanced fibrosis remains unclear to date.

AIMS

To analyse combined effects of 25-OH vitamin D plasma levels and vitamin D receptor gene (VDR; NR1I1) polymorphisms on fibrosis progression rate in HCV patients.

METHODS

251 HCV patients underwent VDR genotyping (bat-haplotype: BsmI rs1544410 C, ApaI rs7975232 A and TaqI rs731236 A). Plasma 25-OH vitamin D levels were quantified in a subgroup of 97 patients without advanced fibrosis. The VDR haplotype and genotypes as well as plasma 25-OH vitamin D levels were associated with fibrosis progression.

RESULTS

The bAt[CCA]-haplotype was significantly associated with fibrosis progression >0.101 U/year (P = 0.007; OR = 2.02) and with cirrhosis (P = 0.022; OR = 1.84). Forty-five percent of bAt[CCA]-haplotype patients were rapid fibrosers, 21.1% were cirrhotic. Likewise, ApaI rs7975232 CC genotype was significantly associated with fibrosis progression and cirrhosis. Lower plasma 25-OH vitamin D levels were significantly associated with fibrosis progression >0.101 U/year in F0-2 patients (P = 0.013). Combined analysis of both variables revealed a highly significant additive effect on fibrosis progression with 45.5% rapid fibrosers for bAt[CCA]-haplotype and 25-OH vitamin D < 20 μg/L compared with only 9.1% for the most favourable combination (P = 0.006). In multivariate analysis, the bAt-haplotype was an independent risk factor for fibrosis progression (P = 0.001; OR = 2.83).

CONCLUSION

Low 25-OH vitamin D plasma levels and the unfavourable VDR bAt[CCA]-haplotype are associated with rapid fibrosis progression in chronic HCV patients. In combination, both variables exert significant additive effects on fibrosis progression.

Review article: the extra-skeletal effects of vitamin D in chronic hepatitis C infection

BACKGROUND

Recent interest has focused on the extra-skeletal effects of vitamin D, in particular, in patients with chronic hepatitis C.

AIMS

To review data in the literature regarding the extra-skeletal effects of vitamin D in patients with chronic hepatitis C, with and without liver transplantation.

METHODS

A Medline search was performed for relevant studies up to August 2011 using the terms 'vitamin D' 'chronic liver disease' and 'hepatitis C'.

RESULTS

Vitamin D deficiency is very frequent before liver transplantation ranging between 51% and 92%, whereas, in the liver transplantation setting, the prevalence of vitamin D deficiency is also high. Severe liver disease may increase the risk of vitamin D deficiency and vice versa, as there may be a relationship between vitamin D deficiency and fibrosis. In patients with chronic hepatitis C and those with recurrent of hepatitis C after liver transplantation, recent clinical data shows that a higher serum vitamin D level is an independent predictor of sustained virological response (SVR) following anti-viral therapy, and that a higher SVR is achieved with vitamin D supplementation.

CONCLUSIONS

Larger randomised clinical studies with adequate statistical power are needed to confirm these potentially very important nonskeletal effects of vitamin D in patients with chronic hepatitis C.

The vitamin D receptor gene bAt (CCA) haplotype impairs the response to pegylated-interferon/ribavirin-based therapy in chronic hepatitis C patients

BACKGROUND

Chronic hepatitis C infection is a major cause of end-stage liver disease. Therapy outcome is influenced by 25-OH vitamin D deficiency. To further address this observation, our study investigates the impact of the vitamin D receptor (NR1I1) haplotype and combined effects of plasma vitamin D levels in a well-described cohort of hepatitis C patients.

METHODS

A total of 155 chronic hepatitis C patients were recruited from the Swiss Hepatitis C Cohort Study for NR1I1 genotyping and plasma 25-OH vitamin D level measurement. NR1I1 genotype data and combined effects of plasma 25-OH vitamin D level were analysed regarding therapy response (sustained virological response).

RESULTS

A strong association was observed between therapy non-response and the NR1I1 CCA (bAt) haplotype consisting of rs1544410 (BsmI) C, rs7975232 (ApaI) C and rs731236 (TaqI) A alleles. Of the HCV patients carrying the CCA haplotype, 50.3% were non-responders (odds ratio [OR] 1.69, 95% CI 1.07, 2.67; P=0.028). A similar association was observed for the combinational CCCCAA genotype (OR 2.94, 95% CI 1.36, 6.37; P=0.007). The combinational CCCCAA genotype was confirmed as an independent risk factor for non-response in multivariate analysis (OR 2.50, 95% CI 1.07, 5.87; P=0.034). Analysing combined effects, a significant impact of low 25-OH vitamin D levels on sustained virological response were only seen in patients with the unfavourable NR1I1 CCA (bAt) haplotype (OR for non-SVR 3.55; 95% CI 1.005, 12.57; P=0.049).

CONCLUSIONS

NR1I1 vitamin D receptor polymorphisms influence response to pegylated-interferon/ribavirin-based therapy in chronic hepatitis C and exert an additive genetic predisposition to previously described low 25-OH vitamin D serum levels.

Vitamin D and the vitamin D receptor in liver pathophysiology

Vitamin D through the vitamin D nuclear receptor (VDR) plays a key role in mineral ion homeostasis. The liver is central in vitamin D synthesis, however the direct involvement of the vitamin D-VDR axis on the liver remains to be evaluated. In this review, we will describe vitamin D metabolism and the mechanisms of homeostatic control. We will also address the associations between the vitamin D-VDR axis and pathological liver entities, such as non-alcoholic fatty liver disease, autoimmune liver disease, viral hepatitis and liver cancer. The link between liver diseases and the vitamin D-VDR axis will be discussed in light of evidences arising from in vitro and in vivo studies. Finally, we will consider the therapeutic potential of the vitamin D-VDR axis in liver diseases.