Low 25-hydroxyvitamin D level is not an independent risk factor for hepatosteatosis in obese children

Calcium signalling in hepatic metabolism: Health and diseases

The flexibility between the wide array of hepatic functions relies on calcium (Ca2+) signalling. Indeed, Ca2+ is implicated in the control of many intracellular functions as well as intercellular communication. Thus, hepatocytes adapt their Ca2+ signalling depending on their nutritional and hormonal environment, leading to opposite cellular functions, such as glucose storage or synthesis. Interestingly, hepatic metabolic diseases, such as obesity, type 2 diabetes and non-alcoholic fatty liver diseases, are associated with impaired Ca2+ signalling. Here, we present the hepatocytes' toolkit for Ca2+ signalling, complete with regulation systems and signalling pathways activated by nutrients and hormones. We further discuss the current knowledge on the molecular mechanisms leading to alterations of Ca2+ signalling in hepatic metabolic diseases, and review the literature on the clinical impact of Ca2+-targeting therapeutics.

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The burden and sexual dimorphism with nonalcoholic fatty liver disease in Asian children: A systematic review and meta-analysis

BACKGROUND

Despite substantial attention paid to the epidemic of nonalcoholic fatty liver disease (NAFLD) in adults, data on the burden and sexual dimorphism of NAFLD in Asian children have not yet been synthesized.

METHODS

We conducted a literature search of 735 references up to April 2021. Pooled analyses, stratified analyses and meta-regression were all performed.

RESULTS

Thirty-three study populations were finally included. Nine of them comprising 20 595 children showed an overall NAFLD prevalence of 5.53% (95% CI 3.46%-8.72%), in which, 36.64% (95% CI, 27.99%-46.26%) NAFLD subjects had elevated levels of ALT. The prevalence rate of NAFLD increased about 1.6-fold from 2004 to 2010 to the last decade. Male predominant trends were observed in paediatric NAFLD (boys: 8.18%, 95% CI 4.93%-13.26%; girls: 3.60%, 95% CI 1.60%-7.87%). Moreover, meta-analysis showed that after 10 years of age, boys were more prone to have NAFLD than girls (OR = 1.75; P = .0012). In addition, the pooled prevalence of NAFLD increased sequentially in normal-weight (1.49%, 95% CI 0.88%-2.51%, n = 2610), overweight (16.72%, 95% CI 7.07%-34.65%, n = 1265) and obese children (50.13%, 95% CI 41.99%-58.27%, n = 6434 individuals). After full covariate adjustment, the multivariate meta-regression also showed that boy percentage (P = .0396) and body mass index (P < .0001) were positively correlated with prevalent NAFLD.

CONCLUSIONS

In Asia, paediatric NAFLD is becoming prevalent over the recent decades, particularly among obese children and boys after 10 years old. The hormonal and chromosomal origins of paediatric NAFLD dimorphism need further investigation.

Relationship of Vitamin D Deficiency and Fatty Liver in Children as Defined by Multiple Imaging and Histologic Endpoints

Objectives

The relationship between vitamin D deficiency (VDD) and pediatric nonalcoholic fatty liver disease (NAFLD) remains uncertain due to conflicting results and few studies with histologic endpoints. We therefore used multiple imaging and histologic NAFLD endpoints to more comprehensively assess the association between VDD and NAFLD in a large pediatric population.

Methods

Data were obtained from an ongoing pediatric NAFLD study in Bronx, NY. Briefly, overweight and obese children aged 2-18 years with alanine aminotransferase (ALT) levels ≥ 35 U/L were serially enrolled. Liver biopsy was obtained in accordance with clinical guidelines. All participants had liver imaging, namely, controlled attenuation parameter (CAP; Echosens, France) to assess steatosis and, to assess fibrosis, vibration controlled transient elastography (VCTE; FibroScan™, Echosens, France) and acoustic radiation force impulse (ARFI; Philips, Netherlands) imaging. Levels of 25-hydroxyvitamin D were measured serologically.

Results

N=276 (88%) of 315 participants had 25-OH vitamin D results, of whom 241 (87%) were Hispanic, 199 (72%) were male, and 92 (33%) underwent liver biopsy. VDD was univariately associated with high waist circumference (p=0.004), high-density lipoprotein level (p=0.01), season (p=0.009), and CAP score (p=0.01). In multivariate analysis, only waist circumference (p=0.0002) and biopsy inflammation grade (p=0.03) were associated with VDD, though the latter had not approximated statistical significance in univariate analysis (p=0.56). There was no association between VDD and hepatic steatosis, ballooning, NAFLD Activity Score, ARFI or VCTE elasticity scores.

Conclusions

VDD was not associated with NAFLD defined by imaging and histologic endpoints, except for a possible relation with histologic inflammation grade.

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

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

The Level of Vitamin D in Children and Adolescents with Nonalcoholic Fatty Liver Disease: A Meta-Analysis

Background

The relationship between vitamin D level and NAFLD has not been investigated in children and adolescents. We performed a meta-analysis of published observational studies to assess this association between vitamin D levels (measured as serum 25-hydroxy vitamin D [25(OH)D]) and NAFLD in this age group.

Methods

Relevant studies conducted before May 20, 2018, were identified from the following electronic databases: PubMed, the Cochrane Library, Embase, and the Chinese CNKI databases. The quality of the included studies was evaluated using the Newcastle Ottawa Scale, and associations between vitamin D levels and NAFLD were estimated using standardised mean differences (SMD) and 95% confidence interval (CI). Subgroup and sensitivity analysis were used to identify sources of heterogeneity, and publication bias was evaluated using funnel plots.

Results

Eight articles were included in this meta-analysis. A significant difference was observed between low 25(OH)D levels and NAFLD in children and adolescents (SMD = -0.59, 95%CI = -0.98, -0.20, P <  0.01). Subgroup analysis revealed no differences in the study type, geographic location, BMI, and age subgroups.

Conclusions

Low vitamin D levels were associated with NAFLD in children and adolescents.

Vitamin D Deficiency is not Associated with Fatty Liver in a Mexican Population

INTRODUCTION AND AIM

Association of vitamin D deficiency (VDD) with fatty liver (FL) disease is controversial. The purpose of this study was to analyze the association of VDD with FL.

MATERIAL AND METHODS

Cross-sectional study. Data on cardiovascular risk factors, medications, alcohol intake, smoking, diet, and physical activity were obtained. Biochemical, anthropometric, and blood pressure variables were measured. The 25-hydroxyvitamin D (25(OH)D) was quantified through chemoluminescence. The presence of FL, defined as a liver/spleen attenuation index lower than 1.0, was identified through computed axial tomography (CAT).

RESULTS

The study included 1,467 subjects (49.7% men) with a mean age of 53.3 ± 9.3 years and BMI of 28.3 ± 4.0 kg/m2. Only 11% had optimum values of vitamin D, and 25(OH)D concentration was lower in participants with FL. Multivariate logistic regression models, adjusted for age, gender, BMI, sampling season, glucose, total cholesterol, triglycerides, HOMA-IR, hs-CRP, ALT, AST, and elevated VAT, revealed an association between FL and vitamin D (VD) insufficiency (RM 1.61 [0.99-2.61]) and with VDD (RM 1.68 [1.02-2.77]); however, statistical significance was lost when including caloric consumption and physical activity in the model.

CONCLUSIONS

In Mexican adults, deficient VD concentration and FL were not independently associated of caloric consumption and physical activity.

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.