Non-alcoholic fatty liver disease is associated with low bone mineral density in obese children

An international multidisciplinary consensus on pediatric metabolic dysfunction-associated fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is highly prevalent in children and adolescents, particularly those with obesity. NAFLD is considered a hepatic manifestation of the metabolic syndrome due to its close associations with abdominal obesity, insulin resistance, and atherogenic dyslipidemia. Experts have proposed an alternative terminology, metabolic dysfunction-associated fatty liver disease (MAFLD), to better reflect its pathophysiology. This study aimed to develop consensus statements and recommendations for pediatric MAFLD through collaboration among international experts.

METHODS

A group of 65 experts from 35 countries and six continents, including pediatricians, hepatologists, and endocrinologists, participated in a consensus development process. The process encompassed various aspects of pediatric MAFLD, including epidemiology, mechanisms, screening, and management.

FINDINGS

In round 1, we received 65 surveys from 35 countries and analyzed these results, which informed us that 73.3% of respondents agreed with 20 draft statements while 23.8% agreed somewhat. The mean percentage of agreement or somewhat agreement increased to 80.85% and 15.75%, respectively, in round 2. The final statements covered a wide range of topics related to epidemiology, pathophysiology, and strategies for screening and managing pediatric MAFLD.

CONCLUSIONS

The consensus statements and recommendations developed by an international expert panel serve to optimize clinical outcomes and improve the quality of life for children and adolescents with MAFLD. These findings emphasize the need for standardized approaches in diagnosing and treating pediatric MAFLD.

FUNDING

This work was funded by the National Natural Science Foundation of China (82070588, 82370577), the National Key R&D Program of China (2023YFA1800801), National High Level Hospital Clinical Research Funding (2022-PUMCH-C-014), the Wuxi Taihu Talent Plan (DJTD202106), and the Medical Key Discipline Program of Wuxi Health Commission (ZDXK2021007).

Effects of Metabolic Dysfunction-Associated Steatotic Liver Disease on Bone Density and Fragility Fractures: Associations and Mechanisms

Metabolic dysfunction-associated steatotic liver disease (MASLD) has profound adverse effects on bone health and homeostasis. MASLD appears to be associated with changes in bone mineral density (BMD) and fracture rate. However, the data are ambiguous and conflicting. Although several studies have shown that children and adolescents with MASLD have decreased BMD, the data on the prevalence of fragility fractures among children are scarce. In adults, increasing evidence suggests that MASLD decreases BMD and increases the risk of fragility fractures, which appears to be due to deterioration of bone architecture in addition to a decrease in BMD. Effects of MASLD on bone health may also be age- and race-specific. MASLD does not seem to increase fracture risk in children and adolescents but increases the risk of fractures in elderly men, especially those of Asian origin. From a mechanistic perspective, bone remodeling is a continuous process between osteoblasts (bone-forming) and osteoclasts (bone-resorbing), with any imbalance resulting in metabolic bone disease. In individuals with MASLD, loss of anabolic insulin receptor signaling (insulin resistance) in osteoblasts and increased receptor activator of nuclear factor κB (RANK)/RANK ligand signaling in osteoclasts (proinflammatory cytokines) swings the pendulum toward accelerated bone loss. These processes are further complicated by the concomitant presence of obesity, type 2 diabetes mellitus, or sarcopenia in individuals with MASLD. This study reviews the current literature associated with the effects of MASLD on BMD and fragility fractures in children/adolescents and adults. This review also discusses the pathomechanisms that link MASLD with changes in BMD and fragility fractures.

Linking Non-alcoholic Fatty Liver Disease Severity With Metabolic Syndrome Features: An Integrative Study on Clinical and Radiological Fronts

Introduction Non-alcoholic fatty liver disease (NAFLD) has become a widespread cause of chronic liver disease, ranging from simple steatosis to severe conditions like non-alcoholic steatohepatitis (NASH) and cirrhosis. Despite its similarity to alcohol-induced liver damage, NAFLD affects individuals with no significant alcohol consumption. This study explores the association between NAFLD, bone mineral density (BMD), insulin resistance, and subclinical inflammation, focusing on the Asian Indian population. The primary objective was to investigate the relationship between NAFLD and BMD, insulin levels, and markers of subclinical inflammation, hypothesizing that patients with NAFLD exhibit lower BMD, possibly linked to insulin resistance and inflammation. Methodology A cross-sectional study with 100 subjects aged 18-50 years (50 cases with NAFLD and 50 controls) was conducted. Exclusion criteria included excessive alcohol consumption, drug-induced fatty liver, severe organ dysfunction, infections, pregnancy, and acute or chronic illness. Data were collected through clinical examinations, anthropometric measurements, biochemical investigations, ultrasound diagnosis of NAFLD, and dual-energy X-ray absorptiometry (DEXA) scans for BMD assessment. Statistical analysis employed the chi-squared tests, t-tests, and Wilcoxon rank-sum tests. Results NAFLD patients had higher body mass index (BMI), waist-to-hip ratio, and markers of insulin resistance and inflammation compared to non-NAFLD controls. DEXA scans revealed significantly lower BMD in NAFLD cases, along with a higher prevalence of osteopenia. Positive correlations were observed between BMD and insulin resistance. The study contributes to understanding the link between NAFLD and lower BMD in the Asian Indian population, emphasizing the impact of insulin resistance and inflammation on bone health. The literature review supports the relevance of exploring NAFLD as an independent risk factor for low BMD. Conclusion This case-control study underscores the significant association between NAFLD and lower BMD in the Asian Indian population. Despite limitations, the findings highlight the importance of further research with larger samples and comprehensive assessments to elucidate the interplay between NAFLD, metabolic factors, and bone health.

Mendelian-randomization study revealed causal relationship between nonalcoholic fatty liver disease and osteoporosis/fractures

BACKGROUND

Patients with nonalcoholic fatty liver disease (NAFLD) are reported to have a higher risk of osteoporosis/fractures; however, the causal relationship remains unclear.

METHODS

Publicly available genome-wide association studies (GWASs) were used for Mendelian randomization (MR) analysis. GWASs of NAFLD and fractures were obtained from the FinnGen Consortium. GWASs of bone mineral density (BMD) were derived from a meta-analysis. GWASs of obesity, diabetes, liver function, and serum lipid-related metrics were used to clarify whether the accompanying NAFLD symptoms contributed to fractures. Moreover, two additional GWASs of NAFLD were applied.

RESULTS

A causal association was not observed between NAFLD and BMD using GWASs from the FinnGen Consortium. However, a causal relationship between NAFLD and femoral neck-BMD (FN-BMD), a suggestive relationship between fibrosis and FN-BMD, and between NAFLD and osteoporosis were identified in replication GWASs. Genetically proxied body mass index (BMI), high-density lipoprotein (HDL), and hip circumference increased the likelihood of lower limb fractures. The waist-to-hip ratio decreased, whereas glycated hemoglobin (HbA1C) and homeostasis model assessment of β-cell function (HOMA-B) increased the risk of forearm fractures. Low-density lipoprotein (LDL) reduced, whereas HbA1C increased the incidence of femoral fractures. Alkaline phosphatase (ALP) raised the risk of foot fractures. However, after a multivariate MR analysis (adjusted for BMI), all the relationships became insignificant.

CONCLUSIONS

NAFLD caused reduced BMD, and genetically predicted HDL, LDL, HbA1C, HOMA-B, ALP, hip circumference, and waist-to-hip ratio causally increased the risk of fractures. BMI may mediate causal relationships. Larger GWASs are required to verify this finding.

The association of Neuromedin U levels and non-alcoholic fatty liver disease: A comparative analysis

This comprehensive study delves into the potential link between Neuromedin U (NmU) serum levels and the development of non-alcoholic fatty liver disease (NAFLD), a condition of increasing global prevalence and significant public health concern. The research provides a nuanced understanding of the disease's etiology by examining a cohort of 112 participants, including individuals with and without NAFLD. The study meticulously considers a spectrum of variables such as demographic factors, body composition metrics, and blood parameters. Advanced diagnostic tools like Fibroscan® are employed to ascertain NAFLD presence, ensuring accurate and reliable results. The investigation reveals a noteworthy correlation between NAFLD and several risk factors, notably obesity, increased waist and neck circumferences, hypertriglyceridemia, and insulin resistance. These findings underscore the multifactorial nature of NAFLD and its intricate connection with metabolic syndromes. Intriguingly, the study observes lower NmU levels in individuals diagnosed with NAFLD. However, the role of NmU as an independent risk factor for NAFLD remains inconclusive, warranting further investigation. Although triglyceride level was observed to be an independent risk factor for NAFLD, this relationship was not associated with NmU. This research contributes significantly to the existing knowledge on NAFLD, highlighting the disease's complexity and the interplay of various risk factors. It also opens up new avenues for future research, particularly in exploring the role of NmU within the metabolic pathways associated with NAFLD. The insights gained from this study could guide the development of novel diagnostic and therapeutic strategies for NAFLD, addressing a crucial need in contemporary healthcare. In conclusion, the findings of this study not only enhance the understanding of NAFLD's pathophysiology but also emphasize the importance of comprehensive risk factor analysis in the management and prevention of this growing health concern.

Low bone mineral density is associated with fatty liver disease and respiratory illness in a pediatric mortality sample

This study finds that fatty liver disease is associated with low bone density in a pediatric mortality sample. Since non-alcoholic fatty liver disease has increased in prevalence over the past few decades among children, a better understanding of the disease's impacts on bone health is of significance to clinicians.

PURPOSE

Chronic illness leads to decreased bone modeling and remodeling. This can be especially problematic during childhood and adolescence, since the majority of an individual's peak bone mass is achieved by the age of 20. In this study, we examine relationships between chronic illness and low bone mineral density (BMD) in a pediatric mortality sample (aged 0.5 to 20.9 years) from New Mexico. We also test whether low BMD is related to decelerated linear growth by examining its relationship to growth stunting and arrest (Harris lines).

METHODS

Hounsfield units (HU), a proxy for trabecular BMD, were obtained at the fourth lumbar vertebra and the femoral neck from postmortem CT scans. Linear regression was used to examine associations between z-standardized HU and age, sex, medical conditions, Harris lines, and growth stunting.

RESULTS

We find that lumbar HU is significantly lower for individuals with fatty liver disease and respiratory illness; femoral HU is significantly lower in individuals with Harris lines.

CONCLUSION

The mechanisms of low BMD in individuals with fatty liver disease and respiratory illness are likely multifactorial and involve vitamin D deficiency (malnutrition, malabsorption), systemic inflammation, and sedentary lifestyles. However, better awareness of this relationship can provide clinicians with the ability to introduce nutritional and behavioral interventions early to mitigate deleterious effects on bone. Harris lines, on the other hand, mark temporary growth cessation due to physiological stress followed by a rapid resumption of growth. Low BMD in these individuals may be due to bone mineralization lagging behind relatively rapid linear growth.

Are Nonalcoholic Fatty Liver Disease and Bone Mineral Density Associated? - A Cross-Sectional Study Using Liver Biopsy and Dual-Energy X-Ray Absorptiometry

There is controversy regarding the association between nonalcoholic fatty liver disease (NAFLD) and osteoporosis. Our study aim was to assess bone mineral density (BMD) in patients with biopsy-proven NAFLD and examine if the severity of NAFLD affects BMD. A total of 147 adult women (n = 108) and men (n = 39) aged 18-76 years (mean ± standard deviation [SD] age 45.3 ± 12.5) were recruited in this cross-sectional study and underwent a liver biopsy and dual-energy X-ray absorptiometry (DXA). NAFLD activity score (NAS) based on the degree of steatosis, lobular inflammation and hepatocellular ballooning was used to assess NAFLD severity. The majority of subjects, 53%, had steatosis, 25% had nonalcoholic steatohepatitis (NASH) whereas 23% served as control subjects with no evidence of NAFLD. There were no significant differences in the lumbar spine (1.09 ± 0.12, 1.11 ± 0.18, and 1.12 ± 0.15 g/cm², p = 0.69, in controls, steatosis, and NASH, respectively) or hip BMD (1.10 ± 0.15, 1.12 ± 0.13, and 1.09 ± 0.13 g/cm², p = 0.48, in controls, steatosis, and NASH, respectively) between the groups. Adjusting for age, gender, body mass index, and diabetes in multiple regression models did not alter the results. There was no correlation between NAS and neither lumbar spine BMD (r = 0.06, p = 0.471), nor hip BMD (r = -0.03, p = 0.716). In conclusion, BMD was similar across the spectrum of NAFLD in both genders and not related to the severity of the underlying histological lesions, suggesting that neither steatosis nor NASH exerts a detrimental effect on BMD in these relatively young patients. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Histologic Severity of Nonalcoholic Fatty Liver Disease Associates with Reduced Bone Mineral Density in Children

BACKGROUND

Lower whole body bone mineral density (BMD) has been reported in children with nonalcoholic fatty liver disease (NAFLD), but potential mediators remain uncertain.

AIMS

To assess BMD at multiple skeletal sites in children with confirmed NAFLD and controls with obesity, adjusting for known determinants of BMD, and examine potential mediators.

METHODS

We assessed age-, sex-, and race-specific, and height-adjusted BMD z-scores of whole body, lumbar spine, hip, femoral neck and forearm by dual-energy-x-ray absorptiometry in 79 children, 8-19 years old: 46 with biopsy-confirmed NAFLD [29 steatohepatitis (NASH)/17 fatty liver (NAFL)] and 33 controls without liver disease. We compared BMD z-scores by multivariable regression, adjusting for known BMD determinants and potential mediators (inflammatory and insulin resistance measures).

RESULTS

Unadjusted mean BMD z-scores in NAFLD were similar to controls, but significantly lower in NASH vs. NAFL at all sites. After covariate adjustment, mean forearm BMD z-score was higher in NAFL (β 0.60 ± SE 0.30, p < 0.05) and lower in NASH (β - 0.49 ± SE 0.26, p = 0.06) vs. controls (p = 0.002 for group), with similar trends at whole body and total hip; hs-CRP negatively associated with whole body and forearm BMD z-scores (p < 0.05), while visceral fat area negatively associated with femoral neck (p < 0.05). Only three children had clinically low whole body BMD z-scores (< - 2), one per group (control, NAFL and NASH).

CONCLUSIONS

NASH, but not NAFL, may be associated with increased risk of reduced BMD in children. Systemic inflammation, independent of body composition and load bearing, may mediate reduction in BMD in NASH.

Bone disease in patients with cirrhosis of different etiology and severity; are Klotho protein and osteoprotegerin potential biomarkers?

BACKGROUND AND AIMS

Cirrhosis is associated with increased risk for osteoporosis and osteopenia. This study aims to further investigate this relationship by examining if etiology and severity of cirrhosis are independent predictors of bone mineral density (BMD) loss. Furthermore we examined the serum levels of osteoprotegerin (OPG) and Klotho proteins that have been involved in bone metabolism.

METHODS

Seventy-four patients with cirrhosis of different etiology and 25 matched healthy controls were included in this study. Bone mineral densitometry at both lumbar spine and femoral neck was measured. Serum total OPG, Klotho protein and vitamin D levels were also determined. Comparisons were performed according to etiology and severity of cirrhosis.

RESULTS

Decreased bone density was observed in cirrhotic patients compared to healthy controls with T = -1.46 and T = -1.37 in lumbar spine and femoral bone respectively compared to T = -0.396 and T = -0.672 in the control group. In the cirrhotic group, osteopenia was observed in 46% in lumbar spine and 51% in femoral bone whereas osteoporosis was observed in 20% in lumbar spine and 9% in femoral bone. Decreased bone density was confirmed, regardless of cirrhosis etiology or stage of liver function. Patients were found to have higher levels of OPG than the control group (136 pg/ml vs. 67 pg/ml, p < 0.001), but lower levels of Klotho protein (1051 pg/ml vs. 1842 pg/ml, p < 0.001) regardless etiology and severity of cirrhosis. High OPG levels were found to be associated with low femoral bone density.

CONCLUSIONS

BMD is lower in cirrhotic patients regardless etiology and severity of liver disease with osteopenia and osteoporosis be present in 50% and 20%, respectively. Higher levels of OPG and lower levels of Klotho protein were observed in cirrhotic patients regardless etiology and severity in comparison to matched healthy group.

The Diverse Roles of 17β-Estradiol in Non-Gonadal Tissues and Its Consequential Impact on Reproduction in Laying and Broiler Breeder Hens

Estradiol-17β (E2) has long been studied as the primary estrogen involved in sexual maturation of hens. Due to the oviparous nature of avian species, ovarian production of E2 has been indicated as the key steroid responsible for activating the formation of the eggshell and internal egg components in hens. This involves the integration and coordination between ovarian follicular development, liver metabolism and bone physiology to produce the follicle, yolk and albumen, and shell, respectively. However, the ability of E2 to be synthesized by non-gonadal tissues such as the skin, heart, muscle, liver, brain, adipose tissue, pancreas, and adrenal glands demonstrates the capability of this hormone to influence a variety of physiological processes. Thus, in this review, we intend to re-establish the role of E2 within these tissues and identify direct and indirect integration between the control of reproduction, metabolism, and bone physiology. Specifically, the sources of E2 and its activity in these tissues via the estrogen receptors (ERα, ERβ, GPR30) is described. This is followed by an update on the role of E2 during sexual differentiation of the embryo and maturation of the hen. We then also consider the implications of the recent discovery of additional E2 elevations during an extended laying cycle. Next, the specific roles of E2 in yolk formation and skeletal development are outlined. Finally, the consequences of altered E2 production in mature hens and the associated disorders are discussed. While these areas of study have been previously independently considered, this comprehensive review intends to highlight the critical roles played by E2 to alter and coordinate physiological processes in preparation for the laying cycle.

Research status and progress of metabolic associated fatty liver disease

Metabolic associated fatty liver disease (MAFLD) is a more appropriate general predicate to describe non-alcoholic fatty liver disease. The new definition lists metabolic dysfunction as an important cause of liver disease, demonstrates the high heterogeneity of this condition, and speeds up the transformation path to new treatment. The incidence of extrahepatic complications and related diseases of MAFLD far exceed that of the liver disease itself, which seriously threatens human health. In view of the current insufficient understanding of its severity, and the imperfect understanding of the disease scope, pathogenesis, and diagnosis of extrahepatic complications, especially the lack of effective drug treatment, this paper introduces and reviews the research status and progress of extrahepatic complications of MAFLD.

Relationship Between Non-Alcoholic Fatty Liver Disease and Degree of Hepatic Steatosis and Bone Mineral Density

BACKGROUND

The liver and bones are both active endocrine organs that carry out several metabolic functions. However, the link between non-alcoholic fatty liver disease (NAFLD) and bone mineral density (BMD) is still controversial. The goal of this study was to discover if there was a link between non-alcoholic fatty liver disease and bone mineral density in US persons aged 20 to 59 years of different genders and races.

METHODS

Using data from the National Health and Nutrition Examination Survey (NHANES) 2017-2018, multivariate logistic regression models were utilized to investigate the association between NAFLD and lumbar BMD. Fitted smoothing curves and generalized additive models were also used.

RESULTS

The analysis included a total of 1980 adults. After controlling for various variables, we discovered that NAFLD was negatively linked with lumbar BMD. The favorable connection of NAFLD with lumbar BMD was maintained in subgroup analyses stratified by sex, race and age in men, other race and aged 20-29 years. The relationship between NAFLD and lumbar BMD in blacks and people aged 40-49 years was a U-shaped curve with the inflection point: at 236dB/m and 262dB/m. Furthermore, we discovered that liver advanced fibrosis and liver cirrhosis were independently connected with higher BMD, while no significant differences were detected in severe liver steatosis and BMD.

CONCLUSIONS

Our study found an independently unfavorable relationship between NAFLD and BMD in persons aged 20 to 59. We also discovered a positive link between BMD and advanced fibrosis and cirrhosis. More research is needed to back up the findings of this study and to look into the underlying issues.

Association of Metabolic Dysfunction-Associated Fatty Liver Disease and Liver Stiffness With Bone Mineral Density in American Adults

CONTEST

The relationship between metabolic dysfunction-associated fatty liver disease (MAFLD) and liver stiffness and bone mineral density (BMD) remains unclear.

OBJECTIVES

We aimed to investigate the association between MAFLD and liver stiffness and BMD in the United States population.

METHODS

A cross-sectional study among 2031 participants over 50 years old in the National Health and Nutrition Examination Survey (NHANES) 2017-2018 was performed. All patients underwent vibration controlled transient elastography (VCTE) and dual-energy x-ray absorptiometry (DXA). The linear and logistic regression model were used to analyze the association between the MAFLD and liver stiffness and osteoporosis, with adjustments for known covariates. Furthermore, the sensitive analyses were conducted to explore the relationship between MAFLD and liver stiffness and whole osteoporosis (include femoral and lumbar osteoporosis).

RESULTS

MAFLD was prevalent in the study population, with a prevalence of 50.9% for men and 40.7% for women. The multiple linear models demonstrated positive associations between MAFLD and liver stiffness and total femur BMD, femur neck BMD, trochanter BMD, intertrochanter BMD. In multiple logistic regression models, both MAFLD and significant liver fibrosis were negatively associated with femoral osteoporosis (OR=0.41, 95% CI: 0.27 to 0.63; OR=0.67, 95% CI: 0.33-1.37, respectively). Nonetheless, when BMI was adjusted, the association between MAFLD and liver stiffness and osteoporosis became insignificant. Besides, as showed in the sensitive analyses, the relationship between MAFLD and liver stiffness and whole osteoporosis were stable.

CONCLUSIONS

These results suggest that MAFLD and liver stiffness were associated with higher femoral and lumbar bone mineral density in individuals aged over 50 years. But the results may be confounded by BMI.

Τhe anthropometric and biochemical profile of pediatric non-alcoholic fatty liver disease: A systematic review and a meta-analysis

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in children and one of the leading indications for liver transplantation in adults. However, current screening methods are inadequate and are accompanied by several disadvantages. This meta-analysis aims to identify the anthropometrical and biochemical characteristics most commonly appearing in pediatric NAFLD that could contribute to the diagnosis of the disease in the every-day clinical setting.

METHODS

A systematic search was conducted in major electronic databases (MEDLINE, Scopus and Embase) up to 15th of August 2021. Primary outcome was the comparison of the anthropometric characteristics, whereas secondary outcomes were the comparisons of biochemical profile, lipid profile, and metabolic parameters in children with NAFLD compared with age-matched healthy controls. Quality assessment was performed with Newcastle-Ottawa Scale (NOS) and results were expressed as mean differences with 95% confidence intervals.

RESULTS

Sixty-four studies were included. Two different comparisons were designed regarding the body mass status. Statistically significant differences were demonstrated by comparing children with NAFLD vs lean/normal weighted controls in body weight (23.0 kg, 95% CI: 14.0-31.8, P < 0.00001), height (3.07 cm, 95% CI: 0.21-5.94, P = 0.04), ΒΜΙ (10 kg/m², 95% CI: 8.36-11.7, P < 0.00001) and waist circumference 25.8 cm (95% CI: 20.6-30.9, P < 0.00001) and by comparing children with NAFLD vs overweight/obese controls in weight (6.81 kg, 95% CI: 3.81-9.81), height (3.18 cm, 95% CI: 1.24 to 5.13, P = 0.001), BMI (2.19 kg/m², 95% CI: 1.76-2.62, P < 0.00001) and WC (7.35 cm, 95% CI: 6.20-8.49, P < 0.00001).

CONCLUSIONS

Anthropometrical and biochemical characteristics of children and adolescents with NAFLD are statistically significantly different compared to age-matched controls; these characteristics could be used to identify individuals at risk of developing NAFLD and related comorbidities.

Decreased Sclerostin Secretion in Humans and Mice With Nonalcoholic Fatty Liver Disease

Objectives

Growing evidence argues for a relationship between liver and bone metabolisms. Sclerostin is a secreted glycoprotein and could antagonize osteoblast-mediated bone formation. Previous studies indicated that circulating sclerostin levels may be associated with metabolic parameters with inconsistent results. This study was designed to evaluate serum sclerostin in patients with or without nonalcoholic fatty liver disease (NAFLD) and to analyze its relationship with metabolic parameters in different populations.

Methods

A cross-sectional study was designed and 168 NAFLD subjects and 85 control subjects were included in this study. Serum sclerostin and metabolic parameters were measured. Mouse models of NAFLD were also induced by high-fat diet. Bone structural parameters were determined using microCT and mRNA expression levels of sclerostin in bone and liver tissues were measured.

Results

Our study suggested that circulating sclerostin levels were significantly lower in NAFLD subjects compared with normal controls. In NAFLD subjects, sclerostin was negatively correlated with multiple metabolic parameters, including waist circumference, urea, hepatic enzyme, gamma-glutamyl transpeptidase, and triglyceride, while such correlation was not significant in control subjects. Circulating sclerostin was also negatively correlated with fatty liver index in NAFLD subjects but not in control subjects. Mice fed on a high-fat diet had reduced bone mass and lower sclerostin expression levels in both the bone and liver tissues.

Conclusions

Our study suggested that the liver-lipid-bone interactions may play a key role in the abnormal bone metabolism in NAFLD, and circulating sclerostin may be a surrogate marker to reflect bone metabolism status in NAFLD subjects.

Hepatic Steatosis is Negatively Associated with Bone Mineral Density in Children

OBJECTIVE

To evaluate the relationship between hepatic steatosis and bone mineral density (BMD) in children. In addition, to assess 25-hydroxyvitamin D levels in the relationship between hepatic steatosis and BMD.

STUDY DESIGN

A community-based sample of 235 children was assessed for hepatic steatosis, BMD, and serum 25-hydroxyvitamin D. Hepatic steatosis was measured by liver magnetic resonance imaging proton density fat fraction (MRI-PDFF). BMD was measured by whole-body dual-energy x-ray absorptiometry.

RESULTS

The mean age of the study population was 12.5 years (SD 2.5 years). Liver MRI-PDFF ranged from 1.1% to 40.1% with a mean of 9.3% (SD 8.5%). Across this broad spectrum of hepatic fat content, there was a significant negative relationship between liver MRI-PDFF and BMD z score (R = -0.421, P < .001). Across the states of sufficiency, insufficiency, and deficiency, there was a significant negative association between 25-hydroxyvitamin D and liver MRI-PDFF (P < .05); however, there was no significant association between vitamin D status and BMD z score (P = .94). Finally, children with clinically low BMD z scores were found to have higher alanine aminotransferase (P < .05) and gamma-glutamyl transferase (P < .05) levels compared with children with normal BMD z scores.

CONCLUSIONS

Across the full range of liver MRI-PDFF, there was a strong negative relationship between hepatic steatosis and BMD z score. Given the prevalence of nonalcoholic fatty liver disease and the critical importance of childhood bone mineralization in protecting against osteoporosis, clinicians should prioritize supporting bone development in children with nonalcoholic fatty liver disease.

On the Relationship Between Non-alcoholic Fatty Liver Disease with Body Composition and Bone Mineral Density in Overweight/Obese Adolescents

Background: Nonalcoholic fatty liver disease (NAFLD) is a health problem growing in line with the rising prevalence of obesity in children and adolescents, which may be correlated with different metabolic abnormalities such as osteoporosis. Objectives: This study aimed to evaluate the possible relationship between NAFLD with body composition and bone mineral density (BMD) in obese and overweight adolescents. Methods: This cross-sectional study encompassed 70 adolescents aged 11 - 18 years and was conducted during March 2016 and September 2016 in Mashhad, Iran. Anthropometric parameters and blood biomarkers were measured. Fat mass, fat-free mass, and BMD were determined using dual-energy X‐ray absorptiometry (DXA) scans, and NAFLD was also assessed using Fibroscan. All statistical data were analyzed using SPSS software version 21. Multivariate linear regression assessed the relationship between liver fat content with bone-related indicators, and multivariate logistic regression detected the relationship between body composition and NAFLD. Results: Total and trunk fat mass were significantly correlated with higher NAFLD even after controlling for intervening factors (total fat mass, OR = 1.27; 95% CI, 1.016 to 1.59, P = 0.036; trunk fat mass, OR = 1.35; 95% CI, 0.97 to 1.88, P = 0.045). Moreover, liver fat content was significantly correlated with lower BMD Z-score after adjusting for gender, BMI Z-score, ALT, fat mass index, total lean mass, and physical activity (β = -0.285, P = 0.048). Conclusions: The findings of the present study suggest that excess adipose tissue is correlated with higher NAFLD. Moreover, liver steatosis may be correlated with decreased BMD Z-score in overweight/obese adolescents.

Osteocalcin and Non-Alcoholic Fatty Liver Disease: Lessons From Two Population-Based Cohorts and Animal Models

Osteocalcin regulates energy metabolism in an active undercarboxylated/uncarboxylated form. However, its role on the development of non-alcoholic fatty liver disease (NAFLD) is still controversial. In the current study, we investigated the causal relationship of circulating osteocalcin with NAFLD in two human cohorts and studied the effect of uncarboxylated osteocalcin on liver lipid metabolism through animal models. We analyzed the correlations of serum total/uncarboxylated osteocalcin with liver steatosis/fibrosis in a liver biopsy cohort of 196 participants, and the causal relationship between serum osteocalcin and the incidence/remission of NAFLD in a prospective community cohort of 2055 subjects from Shanghai Changfeng Study. Serum total osteocalcin was positively correlated with uncarboxylated osteocalcin (r = 0.528, p < .001). Total and uncarboxylated osteocalcin quartiles were inversely associated with liver steatosis, inflammation, ballooning, and fibrosis grades in both male and female participants (all p for trend <.05). After adjustment for confounding glucose, lipid, and bone metabolism parameters, the male and female participants with lowest quartile of osteocalcin still had more severe liver steatosis, with multivariate-adjusted odds ratios (ORs) of 7.25 (1.07-49.30) and 4.44 (1.01-19.41), respectively. In the prospective community cohort, after a median of 4.2-year follow-up, the female but not male participants with lowest quartile of osteocalcin at baseline had higher risk to develop NAFLD (hazard ratio [HR] = 1.90; 95% confidence interval [CI] 1.14-3.16) and lower chance to achieve NAFLD remission (HR = 0.56; 95% CI 0.31-1.00). In wild-type mice fed a Western diet, osteocalcin treatment alleviated hepatic steatosis and reduced hepatic SREBP-1 and its downstream proteins expression. In mice treated with osteocalcin for a short term, hepatic SREBP-1 expression was decreased without changes of glucose level or insulin sensitivity. When SREBP-1c was stably expressed in a human SREBP-1c transgenic rat model, the reduction of lipogenesis induced by osteocalcin treatment was abolished. In conclusion, circulating osteocalcin was inversely associated with NAFLD. Osteocalcin reduces liver lipogenesis via decreasing SREBP-1c expression. © 2020 American Society for Bone and Mineral Research (ASBMR).

Association between Nonalcoholic Fatty Liver Disease and Bone Mineral Density in HIV-Infected Patients Receiving Long-term TDF-Based Antiretroviral Therapy

BACKGROUND

Tenofovir (TDF) has a detrimental effect on bone mineral density (BMD), while nonalcoholic fatty liver disease (NAFLD) is associated with a lower BMD.

OBJECTIVE

To help understand the mutual effects of NAFLD and TDF on BMD, this study was designed to explore the potential association between NAFLD and BMD in HIV-infected patients receiving long-term TDF-based antiretroviral therapy (ART).

METHODS

A total of 89 HIV-infected patients who received TDF-based ART for more than three years were enrolled in this cross-sectional study. We measured BMD using an ultrasonic bone density apparatus, and liver ultrasonography was performed to determine the severity of the fatty liver. The association of NAFLD with BMD was examined using multiple logistic regression analyses.

RESULTS

Patients with NAFLD showed a worse BMD status than those without NAFLD. The incidence rates of osteopenia (42.86% versus 25.93%) and osteoporosis (17.14% versus 3.70%) were significantly higher in HIV-infected patients with NAFLD than in those without NAFLD. After multivariate adjustment, the odds ratio (OR) for patients with NAFLD exhibiting a worse BMD status compared with those without NAFLD was 4.49 (95% confidence interval [CI] 1.42, 14.15).

CONCLUSION

Based on our results, NAFLD was significantly associated with a worse BMD status, including osteopenia and osteoporosis, in HIV patients after receiving long-term TDF-based ART. Furthermore, we may want to avoid using TDF for ART in HIV-infected patients with NAFLD.

Organ-organ communication: The liver's perspective

Communication between organs participates in most physiological and pathological events. Owing to the importance of precise coordination among the liver and virtually all organs in the body for the maintenance of homeostasis, many hepatic disorders originate from impaired organ-organ communication, resulting in concomitant pathological phenotypes of distant organs. Hepatokines are proteins that are predominantly secreted from the liver, and many hepatokines and several signaling proteins have been linked to diseases of other organs, such as the heart, muscle, bone, and eyes. Although liver-centered interorgan communication has been proposed in both basic and clinical studies, to date, the regulatory mechanisms of hepatokine production, secretion, and reciprocation with signaling factors from other organs are obscure. Whether other hormones and cytokines are involved in such communication also warrants investigation. Herein, we summarize the current knowledge of organ-organ communication phenotypes in a variety of diseases and the possible involvement of hepatokines and/or other important signaling factors. This provides novel insight into the underlying roles and mechanisms of liver-originated signal transduction and, more importantly, the understanding of disease in an integrative view.

Prevalence and Trends in Low Bone Density, Osteopenia and Osteoporosis in U.S. Adults With Non-Alcoholic Fatty Liver Disease, 2005-2014

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) is suggested to be associated with bone mineral density (BMD) alterations; however, this has not been ascertained. The current study aimed to investigate the changes in BMD and the prevalence of osteopenia/osteoporosis in US adults with or without NAFLD and to evaluate their association.

METHODS

The study was conducted based on data collected from the U.S. National Health and Nutrition Examination Survey (NHANES) during the period 2005-2014. A total of 13 837 and 6 177 participants aged > 20 years were eligible for conducting the Hepatic Steatosis Index (HSI) and the US Fatty Liver Index (USFLI) analysis, respectively.

RESULTS

From 2005-2014, a downward trend in femoral neck BMD was observed in subjects with NAFLD aged ≥ 40. After adjustment for potential confounders, an upward shift occurred in the prevalence of osteopenia/osteoporosis at the femoral neck in adults aged ≥ 40, particularly in women ≥ 60 years old and men below the age of 60. Moreover, a negative association was found between BMD and NAFLD markers (USFLI, HSI), whereas NAFLD with advanced fibrosis was positively associated with the prevalence of spine fractures.

CONCLUSIONS

There was a trend toward lower BMD and higher prevalence of osteopenia/osteoporosis at the femoral neck in US adults with NAFLD aged ≥ 40 years during the period of 2005-2014. NAFLD with advanced fibrosis was positively associated with a higher risk of spine fracture. More research is required to fully investigate the mechanism and consequence of poor bone health in NAFLD patients and consider optimum management of osteopenia/osteoporosis for this population.

Osteocalcin and osteoprotegerin levels and their relationship with adipokines and proinflammatory cytokines in children with nonalcoholic fatty liver disease

OBJECTIVES

To investigate the relationship between osteocalcin and osteoprotegerin as bone markers and inflammatory biomarkers such as adiponectin, leptin, tumor necrosis factor alpha (TNF-α), and interleukin-6 (IL-6) in children with nonalcoholic fatty liver disease (NAFLD).

METHODS

This study included 40 obese children with NAFLD as the patient group and 40 healthy obese children of matched age, sex and BMI as the control group. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), fasting blood glucose, fasting insulin, Homeostatic model assessment method of insulin resistance (HOMA-IR), lipid profile, osteocalcin, osteoprotegerin, adiponectin, leptin, TNF-α, and IL-6 were measured in all participants.

RESULTS

Children with NAFLD had a significant decrease in osteocalcin, osteoprotegerin and adiponectin level with a significant increase in TNF-α and IL-6 levels. We also found a significant positive correlation between osteocalcin level and adiponectin levels but a significant negative correlation of osteocalcin with each of leptin and TNF-α. However, there was a significant negative correlation between osteoprotegerin levels and both TNF-α and IL-6 levels. Moreover, adiponectin and TNF-α were significant predictors for osteocalcin, and IL-6 was a significant predictor for osteoprotegerin.

CONCLUSION

Adiponectin, leptin, TNF-α, and IL-6 have potential association with the changes of osteocalcin and osteoprotegerin levels in children with NAFLD.

Relationship Between Non-alcoholic Fatty Liver Disease and Decreased Bone Mineral Density: A Retrospective Cohort Study in Korea

Objectives

The aim of this retrospective cohort study was to investigate whether non-alcoholic fatty liver disease (NAFLD) was associated with incident bone mineral density (BMD) decrease.

Methods

This study included 4536 subjects with normal BMD at baseline. NAFLD was defined as the presence of fatty liver on abdominal ultrasonography without significant alcohol consumption or other causes. Decreased BMD was defined as a diagnosis of osteopenia, osteoporosis, or BMD below the expected range for the patient’s age based on dual-energy X-ray absorptiometry. Cox proportional hazards models were used to estimate the hazard ratio of incident BMD decrease in subjects with or without NAFLD. Subgroup analyses were conducted according to the relevant factors.

Results

Across 13 354 person-years of total follow-up, decreased BMD was observed in 606 subjects, corresponding to an incidence of 45.4 cases per 1000 person-years (median follow-up duration, 2.1 years). In the model adjusted for age and sex, the hazard ratio was 0.65 (95% confidence interval, 0.51 to 0.82), and statistical significance disappeared after adjustment for body mass index (BMI) and cardiometabolic factors. In the subgroup analyses, NAFLD was associated with a lower risk of incident BMD decrease in females even after adjustment for confounders. The direction of the effect of NAFLD on the risk of BMD decrease changed depending on BMI category and body fat percentage, although the impact was statistically insignificant.

Conclusions

NAFLD had a significant protective effect on BMD in females. However, the effects may vary depending on BMI category or body fat percentage.

Association between non-alcoholic fatty liver disease-associated hepatic fibrosis and bone mineral density in postmenopausal women with type 2 diabetes or impaired glucose regulation

INTRODUCTION

To evaluate the association of non-alcoholic fatty liver disease (NAFLD)-associated hepatic fibrosis with bone mineral density (BMD) in postmenopausal women with type 2 diabetes mellitus (T2DM) or impaired glucose regulation (IGR).

RESEARCH DESIGN AND METHODS

Two cohorts including 46 subjects with biopsy-proven NAFLD and 445 subjects with proton magnetic resonance spectrum-proven NAFLD were enrolled in this study. All subjects were postmenopausal women with T2DM or IGR. BMD at the lumbar spine L1-L4 and hip was measured using dual-energy X-ray absorptiometry. NAFLD fibrosis stage and NAFLD fibrosis score were used to evaluate the severity of liver fibrosis.

RESULTS

In subjects with liver biopsy-proven NAFLD, BMD (T-score, Z-score and BMD value) in the advanced fibrosis group were significantly lower than that in the non-advanced fibrosis group (p<0.05). Fibrosis stage was negatively associated with T-score, Z-score and BMD value after adjusting for age, body mass index (BMI) and fasting plasma glucose (FPG). Additionally, fibrosis stage was independently associated with T-score, Z-score and BMD value after adjusting for age, BMI and FPG. These results were validated in a large cohort of 445 subjects. Additionally, bone metabolism-associated factors, including calcium and phosphate, were associated with liver fibrosis, indicating that bone metabolism may play a critical role in the association between liver fibrosis and BMD. Mechanically, parathyroid hormone and biomarkers of bone formation (osteocalcin and procollagen type 1 N-terminal propeptide) and bone resorption (procollagen type I carboxy terminal peptide β special sequence) were increased in subjects with advanced liver fibrosis than in subjects without advanced liver fibrosis, indicating that liver fibrosis decreased BMD probably via increasing bone turnover.

CONCLUSIONS

NAFLD-associated hepatic fibrosis was negatively associated with decreased BMD in postmenopausal women with T2DM or IGR. Liver fibrosis decreased BMD probably via increasing bone turnover. Severe liver fibrosis may represent high risk for osteoporosis in postmenopausal women with T2DM or IGR.

Bone marrow fat change in pediatric patients with non-alcoholic fatty liver disease

Objectives

To investigate changes of fat in bone marrow (BM) and paraspinal muscle (PSM) associated with the degree of fatty liver in pediatric patients with non-alcoholic fatty liver disease (NAFLD) in consideration of age and body mass index (BMI).

Methods

Hepatic fat, BM fat, and PSM fat from proton density fat fraction of liver MRI between June 2015 and April 2019 were quantitatively evaluated on axial images of the fat map at the mid-level of T11-L2 vertebral bodies for BM fat and at the mid-level of L2 for PSM fat. Age, height, and weight at the time of MRI were recorded and BMI was calculated. Correlation analysis was performed.

Results

A total of 147 patients (114 male) were included with a mean age of 13.3 ± 2.9 years (range 7–18 years). The mean fat fractions were 24.3 ± 13.0% (2–53%) in liver, 37.4 ± 8.6% (17.3–56%) in vertebral BM, and 2.7 ± 1.1% (1.0–6.9%) in PSM. Age, height, weight, and BMI were not correlated with liver fat or BM fat. However, weight (ρ = 0.174, p = 0.035) and BMI (ρ = 0.247, p = 0.003) were positively correlated with PSM fat. Liver fat showed positive correlation with BM fat when adjusting age and BMI (ρ = 0.309, p<0.001), but not with PSM fat.

Conclusions

BM fat positively correlates with liver fat, but not with age or BMI in pediatric NAFLD patients.

Bone Health in Patients With Liver Diseases

Osteoporosis is the most common bone disease in chronic liver disease (CLD) resulting in frequent fractures and leading to significant morbidity in this population. In addition to patients with cirrhosis and chronic cholestasis, patients with CLD from other etiologies may be affected in the absence of cirrhosis. The mechanism of osteoporosis in CLD varies according to etiology, but in cirrhosis and cholestatic liver disease it is driven primarily by decreased bone formation, which differs from the increased bone resorption seen in postmenopausal osteoporosis. Direct toxic effects from iron and alcohol play a role in hemochromatosis and alcoholic liver disease, respectively. Chronic inflammation also has been proposed to mediate bone disease in viral hepatitis and nonalcoholic fatty liver disease. Treatment trials specific to osteoporosis in CLD are small, confined to primary biliary cholangitis and post-transplant patients, and have not consistently demonstrated a benefit in this population. As it stands, prevention of osteoporosis in CLD relies on the mitigation of risk factors such as smoking and alcohol use, treatment of underlying hypogonadism, and encouraging a healthy diet and weight-bearing exercise. The primary medical intervention for the treatment of osteoporosis in CLD remains bisphosphonates though a benefit in terms of fracture reduction has never been shown. This review outlines what is known regarding the pathogenesis of bone disease in CLD and summarizes current and emerging therapies.

NAFLD and Extra-Hepatic Comorbidities: Current Evidence on a Multi-Organ Metabolic Syndrome

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide and its incidence is definitely increasing. NAFLD is a metabolic disease with extensive multi-organ involvement, whose extra-hepatic manifestations include type 2 diabetes mellitus, cardiovascular disease, obstructive sleep apnea, chronic kidney disease, osteoporosis, and polycystic ovarian syndrome. Recently, further evidence has given attention to pathological correlations not strictly related to metabolic disease, also incorporating in this broad spectrum of systemic involvement hypothyroidism, psoriasis, male sexual dysfunction, periodontitis, and urolithiasis. The most common cause of mortality in NAFLD is represented by cardiovascular disease, followed by liver-related complications. Therefore, clinicians should learn to screen and initiate treatment for these extra-hepatic manifestations, in order to provide appropriate multidisciplinary assessments and rigorous surveillance. This review evaluates the current evidence regarding extra-hepatic associations of NAFLD, focusing on the pathogenic hypothesis and the clinical implications.

Association Between Nonalcoholic Fatty Liver Disease and Reduced Bone Mineral Density in Children: A Meta-Analysis

Recent cross-sectional studies have examined the association between nonalcoholic fatty liver disease (NAFLD) and bone mineral density (BMD) in children or adolescents, but these have produced conflicting results. We performed a systematic review and meta-analysis of these published studies to quantify the magnitude of the association, if any, between NAFLD and BMD. We searched publication databases from January 2000 to September 2018, using predefined keywords to identify relevant observational studies conducted in children or adolescents in whom NAFLD was diagnosed either by imaging or by histology and BMD Z score was measured by dual-energy X-ray absorptiometry. Data from selected studies were extracted, and a meta-analysis was performed using random-effects modeling. A total of eight observational cross-sectional or case-control studies enrolling 632 children and adolescents (mean age 12.8 years), 357 of whom had NAFLD, were included in the final analysis. Meta-analysis showed significant differences in whole-body or lumbar BMD Z scores between children/adolescents with and without NAFLD (n = 6 studies; pooled weighted mean difference [WMD], -0.48; 95% confidence interval [CI], -0.74 to -0.21; I² = 55.5%), as well as between those with biopsy-confirmed nonalcoholic steatohepatitis (NASH) and those with no-NASH (n = 4 studies; pooled WMD, -0.27; 95% CI, -0.40 to -0.13; I² = 0%). The aforementioned WMDs in BMD Z scores were independent of common clinical risk factors, such as age, sex, race/ethnicity, and body mass index. Sensitivity analyses did not modify these findings. Funnel plot and Egger test did not reveal significant publication bias. Conclusion: This meta-analysis shows that the presence and severity of NAFLD are significantly associated with reduced whole-body BMD Z scores in children and adolescents; however, the observational design of the studies included does not allow for proving causality.

A Systematic Review of NAFLD-Associated Extrahepatic Disorders in Youths

Background: There is growing evidence that non-alcoholic fatty liver disease (NAFLD) is a disease affecting not only the liver but also extrahepatic organs. Aim: To investigate whether in youths NAFLD is associated with extrahepatic complications such as subclinical atherosclerosis, cardiac abnormalities, hypertension, type 2 diabetes, decreased bone mineral density, renal dysfunction, obstructive sleep apnea, and polycystic ovary syndrome. Methods: We systematically reviewed PubMed; Scopus; Embase; and the Cochrane Library databases up to 28 February 2019 and assessed the quality of studies using the Newcastle-Ottawa Scale. Results: Thirty-five articles were selected for this systematic review: fifteen (4627 participants) evaluated the association of NAFLD with subclinical atherosclerosis; four (969 participants) with cardiac abnormalities; two (550 participants) with hypertension; four (1328 participants) with diabetes; six (523 participants) with low bone mineral density; two (865 participants) with renal dysfunction; one with obstructive sleep apnea; and one with polycystic ovary syndrome. Most studies found that youths with NAFLD have increased features of subclinical atherosclerosis; as well as of cardiac alterations. Limited data were available to endorse a solid estimate of the prevalence of diabetes; low mineral density and renal dysfunction in the pediatric NAFLD population. Conclusion: NAFLD-related intermediate CVD outcomes can occur and be detected early in young populations.

Hepatic Osteodystrophy-Molecular Mechanisms Proposed to Favor Its Development

Almost all patients with chronic liver diseases (CLD) show altered bone metabolism. Depending on the etiology, this manifests in a severe osteoporosis in up to 75% of the affected patients. Due to high prevalence, the generic term hepatic osteodystrophy (HOD) evolved, describing altered bone metabolism, decreased bone mineral density, and deterioration of bone structure in patients with CLD. Once developed, HOD is difficult to treat and increases the risk of fragility fractures. Existing fractures affect the quality of life and, more importantly, long-term prognosis of these patients, which presents with increased mortality. Thus, special care is required to support the healing process. However, for early diagnosis (reduce fracture risk) and development of adequate treatment strategies (support healing of existing fractures), it is essential to understand the underlying mechanisms that link disturbed liver function with this bone phenotype. In the present review, we summarize proposed molecular mechanisms favoring the development of HOD and compromising the healing of associated fractures, including alterations in vitamin D metabolism and action, disbalances in transforming growth factor beta (TGF-β) and bone morphogenetic protein (BMP) signaling with histone deacetylases (HDACs) as secondary regulators, as well as alterations in the receptor activator of nuclear factor kappa B ligand (RANKL)–osteoprotegerin (OPG) system mediated by sclerostin. Based on these mechanisms, we give an overview on the limitations of early diagnosis of HOD with established serum markers.

Relationship between nonalcoholic fatty liver disease and bone mineral density in adolescents with obesity: a meta-analysis

PURPOSE

Many studies have reported the relationship between nonalcoholic fatty liver disease (NAFLD) and bone mineral density (BMD) among adults. However, fewer studies on this topic have been reported in adolescents. We thus conducted a meta-analysis to show the association between NAFLD and BMD in adolescents with obesity.

MATERIALS AND METHODS

Computer retrieval was carried out via PubMed, Embase, Cochrane Library and the Cochrane Central Register of Controlled Trials from inception to September 2018. Six published case-control studies that assessed the relationship between NAFLD and BMD were included.

RESULTS

The six studies included 217 obese adolescents with NAFLD and 236 controls. The meta-analysis indicated that obese children with NAFLD had a lower BMD and Z-score than the control group (weighted mean difference [WMD]-0.03, 95% CI [-0.05, -0.02], P=0.000; [WMD] -0.26, 95% CI [-0.37, -0.14], P=0.000). However, we analyzed the factor of bone mineral content, and there was no correlation between the two groups ([WMD]-55.99, 95% CI [-132.16, 20.18], P=0.150).

CONCLUSION

Obese children with NAFLD are more susceptible to osteoporosis than children with only obesity. Because of the limitations related to the quantity and quality of the included literature, further studies are still needed.

Relationship between non-alcoholic steatohepatitis, PNPLA3 I148M genotype and bone mineral density in adolescents

BACKGROUND & AIMS

It is uncertain whether non-alcoholic steatohepatitis (NASH) is a risk factor for low bone mineral density (BMD). Our aim was to investigate: (a) associations between NASH and BMD values and (b) associations between PNPLA3 I148M genotypes and BMD, in children with histologically proven non-alcoholic fatty liver disease (NAFLD).

METHODS

BMD area (g/cm² ) was measured using dual-energy X-ray absorptiometry (DEXA). NASH was diagnosed by a Steatosis, Activity and Fibrosis (SAF) score and FLIP algorithm. Genotyping for patatin-like phospholipase domain containing-3 (PNPLA3) I148M genotype (rs738409) (CC, CG and GG) was undertaken using the TaqMan SNP genotyping allelic discrimination method. Logistic regression was used to test associations [OR (95% CIs)] between low BMD, and both NASH and PNPLA3 I148M genotypes.

RESULTS

Thirty-four adolescents (mean age 13.8 ± 1.1 years) with histologically confirmed NAFLD were studied. Subjects with NASH (n = 25) had a lower BMD (means (SDs) 0.87 ± 0.06 vs 0.97 ± 0.12, P = 0.005), compared to subjects without NASH. Subjects with PNPLA3 CG+GG genotypes had a lower BMD compared with subjects with PNPLA3-CC genotype (means (SDs) 0.79 ± 0.20 vs 0.92 ± 0.10, P = 0.009). PNPLA3 CG+GG genotypes were independently associated with NASH [OR (95% CIs 1.78, 1.24, 2.99)], and low BMD was associated with both PNPLA3 CG+GG (OR 3.62 (95% CIs 1.21, 5.53), P = 0.028) and with SAF score (OR 2.76 (95% CIs 1.12, 5.41), P = 0.045).

CONCLUSIONS

Taken together the independent associations between: (a) low BMD and PNPLA3 CG+GG genotype; (b) low BMD and NASH; and (c) PNPLA3 CG+GG genotype and NASH, provide support for a causal relationship between NASH and low BMD.

Hepatic fat content and bone mineral density in children with overweight/obesity

OBJECTIVES

To examine the influence of non-alcoholic fatty liver disease (NAFLD) and hepatic fat content on bone mineral density (BMD), and to investigate whether the relationship between NAFLD and BMD is independent of lifestyle factors related to BMD.

METHODS

Hepatic fat content (magnetic resonance imaging), BMD, lean mass index, total and abdominal fat mass (dual-energy-X-ray absorptiometry), moderate to vigorous physical activity (MVPA) (accelerometry), and calcium and vitamin D intake (two 24 h recalls) were measured in 115 children with overweight/obesity aged 10.6 ± 1.1 years old.

RESULTS

Children with NAFLD had lower BMD than children without NAFLD regardless of sex, puberty stage, lean mass index, fat mass, MVPA, and calcium and vitamin D intake (0.89 ± 0.01 vs. 0.93 ± 0.01 g/cm² for NAFLD and non-NAFLD, respectively, P < 0.01). Higher hepatic fat content was significantly associated with lower BMD regardless of confounders (adjusted P < 0.05).

CONCLUSIONS

Findings of the current study suggest that hepatic fat accumulation is associated with decreased BMD independently of adiposity, and regardless of those lifestyle factors closely related to bone mineral accrual in children. These results may have implication in the clinical management of children with overweight/obesity given the high prevalence of pediatric NAFLD.

Novel insights into the relationship between nonalcoholic fatty liver disease and osteoporosis

Excess fat deposition and insulin resistance are considered the main risk factors for nonalcoholic fatty liver disease (NAFLD), and therefore, not surprisingly, the global prevalence of NAFLD increases in parallel with both obesity and type 2 diabetes. Although deterioration of bone homeostasis in patients with NAFLD is commonly observed, its etiology has not been fully elucidated yet. It was shown in several studies that bone tissue seems to be independently associated with NAFLD. A mechanistic perspective puts the liver at the center of mutual interdependencies obviously involving adipose tissue and muscles and also the bone matrix and bone cells, which are relatively novel. In this review, various pathophysiological mechanisms and possible mediating molecules that may interplay between NAFLD and bone tissue are described. Chronic inflammation, vitamin D3, growth hormone, insulin-like growth factor 1, osteopontin, fetuin-A, irisin, osteocalcin, and osteoprotegerin from osteoblasts have been proposed as mediators of mutual interactions among the skeleton, fatty tissue, and liver. Although to date there are still many issues that have not been elucidated, growing evidence suggests that screening and surveillance of bone mineral density in patients with NAFLD should be considered in future strategies and guidelines for NAFLD management.

Nonalcoholic Fatty Liver Disease in Children: Not a Small Matter

The prevalence of nonalcoholic fatty liver disease (NAFLD) has increased substantially in the past two decades and NAFLD has now become the most common cause of chronic liver disease in children and adolescents. NAFLD is a broad clinicopathologic spectrum ranging from simple steatosis to varying degrees of necroinflammation called nonalcoholic steatohepatitis (NASH), leading to fibrosis and subsequently to cirrhosis. Despite the increasing prevalence and progressive nature of NAFLD even among children, therapy for NAFLD in both adults and children are limited. Weight loss remains the only consistently effective therapy for NAFLD. Pharmacologic options are even more limited in children than in adults with NAFLD. Vitamin E has been shown to be effective in improving histology in children with NASH. Few pharmacologic options such as metformin, probiotics, omega-3 fatty acids, and cysteamine bitartrate have been studied in children, with limited beneficial effects. However, these studies are limited by small sample size and heterogeneity of outcome assessment after treatment. Recent studies show promising results with bariatric surgery with regards to weight loss and improvement in liver histology in adolescents with NAFLD. In this review article, we discuss epidemiology, pathophysiology, and extrahepatic comorbidities of pediatric NAFLD and review existing therapeutic options for children with NAFLD. We also review novel therapeutic strategies studied in adults that could potentially be studied in children in the future.

Role of osteoprotegerin/receptor activator of nuclear factor kappa B/receptor activator of nuclear factor kappa B ligand axis in nonalcoholic fatty liver disease

Concomitantly with the increase in the prevalences of overweight/obesity, nonalcoholic fatty liver disease (NAFLD) has worldwide become the main cause of chronic liver disease in both adults and children. Patients with fatty liver display features of metabolic syndrome (MetS), like insulin resistance (IR), glucose intolerance, hypertension and dyslipidemia. Recently, epidemiological studies have linked obesity, MetS, and NAFLD to decreased bone mineral density and osteoporosis, highlighting an intricate interplay among bone, adipose tissue, and liver. Osteoprotegerin (OPG), an important symbol of the receptor activator of nuclear factor-B ligand/receptor activator of nuclear factor kappa B/OPG system activation, typically considered for its role in bone metabolism, may also play critical roles in the initiation and perpetuation of obesity-related comorbidities. Clinical data have indicated that OPG concentrations are associated with hypertension, left ventricular hypertrophy, vascular calcification, endothelial dysfunction, and severity of liver damage in chronic hepatitis C. Nonetheless, the relationship between circulating OPG and IR as a key feature of MetS as well as between OPG and NAFLD remains uncertain. Thus, the aims of the present review are to provide the existent knowledge on these associations and to discuss briefly the underlying mechanisms linking OPG and NAFLD.

Serum Osteocalcin Levels in Children With Nonalcoholic Fatty Liver Disease

OBJECTIVES

The aim of the study was to investigate the relationship between osteocalcin and nonalcoholic fatty liver disease (NAFLD) in children with obesity.

METHOD

60 obese children with NAFLD were taken as a patient group and 60 obese children and normal liver with matching age, sex, and body mass index were taken as a control group. Anthropometric measurements, abdominal ultrasonography for diagnosis and grading of NAFLD, and laboratory investigations in the form of liver function tests, lipid profile, fasting serum glucose and insulin, and serum osteocalcin levels were done for all children. Patients with NAFLD were further divided into patients with metabolic syndrome (MS) and patients without MS.

RESULTS

Age of NAFLD children was (10.55 ± 2.71), 20 boys and 40 girls, whereas age of children in control group was (10.05 ± 3.51), 24 boys and 36 girls (P > 0.05). Patients with NAFLD showed significant increase in waist and hip circumference, alanine aminotransferase, alkaline phosphatase, total cholesterol, triglycerides, insulin resistance (IR), fasting serum glucose, and insulin, but lower serum osteocalcin level than control group. Serum osteocalcin level is inversely correlated with waist circumference, triglyceride, liver enzymes, fasting serum insulin, fasting serum glucose, IR, and grades of fatty liver. Increase in alanine aminotransferase, total cholesterol, triglycerides, fasting insulin, and IR went with increase in degree of hepatic steatosis. Serum osteocalcin level <44.5 ng/mL is a good predictor for severity of hepatic steatosis with sensitivity and specificity of 80%.

CONCLUSIONS

Osteocalcin plays an important role in glucose and lipid metabolism for protection against NAFLD occurrence and progression. Moreover, it could be a useful marker for progression of NAFLD in children with obesity.

Reduced Serum IGF-1 Associated With Hepatic Osteodystrophy Is a Main Determinant of Low Cortical but Not Trabecular Bone Mass

Hepatic osteodystrophy is multifactorial in its pathogenesis. Numerous studies have shown that impairments of the hepatic growth hormone/insulin-like growth factor-1 axis (GH/IGF-1) are common in patients with non-alcoholic fatty liver disease, chronic viral hepatitis, liver cirrhosis, and chronic cholestatic liver disease. Moreover, these conditions are also associated with low bone mineral density (BMD) and greater fracture risk, particularly in cortical bone sites. Hence, we addressed whether disruptions in the GH/IGF-1 axis were causally related to the low bone mass in states of chronic liver disease using a mouse model of liver-specific GH-receptor (GHR) gene deletion (Li-GHRKO). These mice exhibit chronic hepatic steatosis, local inflammation, and reduced BMD. We then employed a crossing strategy to restore liver production of IGF-1 via hepatic IGF-1 transgene (HIT). The resultant Li-GHRKO-HIT mouse model allowed us to dissect the roles of liver-derived IGF-1 in the pathogenesis of osteodystrophy during liver disease. We found that hepatic IGF-1 restored cortical bone acquisition, microarchitecture, and mechanical properties during growth in Li-GHRKO-HIT mice, which was maintained during aging. However, trabecular bone volume was not restored in the Li-GHRKO-HIT mice. We found increased bone resorption indices in vivo as well as increased basal reactive oxygen species and increased mitochondrial stress in osteoblast cultures from Li-GHRKO and the Li-GHRKO-HIT compared with control mice. Changes in systemic markers such as inflammatory cytokines, osteoprotegerin, osteopontin, parathyroid hormone, osteocalcin, or carboxy-terminal collagen cross-links could not fully account for the diminished trabecular bone in the Li-GHRKO-HIT mice. Thus, the reduced serum IGF-1 associated with hepatic osteodystrophy is a main determinant of low cortical but not trabecular bone mass. © 2017 American Society for Bone and Mineral Research.

The relationship between fatty liver index and bone mineral density in Koreans: KNHANES 2010-2011

Analyses using a nationally representative cohort have revealed that high fatty liver index (FLI) is associated with low bone mineral density (BMD) regardless of insulin resistance in men, thereby supporting the deteriorated bone metabolism in nonalcoholic fatty liver disease (NAFLD).

INTRODUCTION

NAFLD is linked to deteriorated bone health. We investigated the association of FLI, a scoring model for NAFLD, with BMD.

METHODS

This was a population-based, cross-sectional study from the Korea National Health and Nutrition Examination Surveys including 4264 Koreans (1908 men and 2356 women). FLI was calculated using body mass index, waist circumference, serum triglyceride, and gamma-glutamyltranspeptidase level. Insulin resistance was evaluated using the homeostasis model assessment-estimated insulin resistance (HOMA-IR) index. BMD was measured using dual-energy X-ray absorptiometry at the lumbar spine, total hip, femoral neck, and whole body.

RESULTS

Men had a higher FLI than women, while the HOMA-IR index was similar between men and women. The significant association between FLI and BMD was observed only in men, but not in women. FLI was negatively correlated with total hip, femoral neck, and whole body BMD in men after adjusting for all potential confounders, including HOMA-IR (P < 0.001 to 0.010). Lumbar spine, total hip, femoral neck, and whole body BMD in men showed a decreasing trend as the FLI tertile increased after adjusting for all potential confounders, including HOMA-IR (P for trends < 0.001 to 0.034). In men aged 50 years or older, odds ratios for combined osteopenia and osteoporosis increased across increasing FLI tertiles after adjusting for confounders (P for trends < 0.011 to 0.029).

CONCLUSION

NAFLD is associated with low bone density regardless of insulin resistance in men. These findings suggest an undiscovered direct link between liver and bone that increases the risk of osteoporosis in men with NAFLD.

Causes of low peak bone mass in women

Peak bone mass is the maximum bone mass that accrues during growth and development. Consolidation of peak bone mass normally occurs during early adulthood. Low peak bone mass results from failure to achieve peak bone mass genetic potential, primarily due to bone loss caused by a variety of conditions or processes occurring at younger ages than usual. Recognized causes of low peak bone mass include genetic causes, endocrine disorders, nutritional disorders, chronic diseases of childhood or adolescence, medications, and idiopathic factors.

Nonalcoholic fatty liver disease and osteoporosis: a systematic review and meta-analysis

Several major risk factors for osteoporosis have been identified. One of these risk factors is chronic inflammation. Several recent studies have supported the association between low bone mineral density (BMD) and nonalcoholic fatty liver disease (NAFLD), which comprises a spectrum of disorders involving liver inflammation. However, conflicting evidence regarding this association has been obtained thus far. We, therefore, conducted a meta-analysis of observational studies to show the association between NAFLD and BMD. The Cochrane Central Register of Controlled Trials, Cochrane Library, Medline, and Embase were searched from database inception to November 2014 for all observational studies evaluating the association between NAFLD or nonalcoholic steatohepatitis (NASH) and bone mass, BMD, or osteoporosis. All patients were ≥18 years of age and had no other cause of liver disease, osteoporosis, or pathological bone disease at baseline. Risk factors were NAFLD and NASH; control subjects were individuals without NAFLD. Eleven articles underwent full-length review. Data were extracted from five cross-sectional studies involving 1276 participants; 638 had NAFLD. The main meta-analysis showed no significant difference in BMD between patients with fatty liver disease and controls. Among all variables analyzed, body mass index had the strongest and most significant predictive effect on the difference in BMD. Controversy exists regarding the effect of BMD on NAFLD. Further studies are required to fully show this relationship.

Significant liver fibrosis assessed using liver transient elastography is independently associated with low bone mineral density in patients with non-alcoholic fatty liver disease

Background

Metabolic bone disorders frequently occur in patients with chronic liver disease; however, the association between liver fibrosis and bone mineral density in patients with non-alcoholic fatty liver disease (NAFLD) is unclear.

Methods

This is a cross-sectional analysis of 231 asymptomatic subjects (160 women, 61.6 years old) from a university hospital setting, between February 2012 and December 2014. Bone mineral density (BMD) was measured at the lumbar spine, femur neck, and total hip using dual-energy X-ray absorptiometry (DXA). Liver fibrosis and steatosis were assessed using transient elastography.

Results

Among a total of 231 individuals, 129 subjects (55.8%) had NAFLD. BMDs at lumbar spine, femur neck, and total hip were significantly lower in patients having NAFLD with significant fibrosis, compared with patients having NAFLD without significant fibrosis (Ps<0.005). In patients with NAFLD, significant liver fibrosis revealed marked negative correlations with BMD at the lumber spine (r = –0.19, P = 0.032), femur neck (r = –0.19, P = 0.034), and total hip (r = –0.21, P = 0.016). A multivariate linear regression analysis revealed that significant liver fibrosis was independently correlated with low BMD at the femur neck (β = –0.18, P = 0.039) and total hip (β = –0.21, P = 0.005) after adjustment for age, sex, BMI, fasting plasma glucose, alanine aminotransferase, high-density lipoprotein cholesterol, and liver steatosis among patients with NAFLD. Using multivariable logistic regression, significant liver fibrosis was independently associated with overall osteopenia and osteoporosis in subjects having NAFLD (OR = 4.10, 95% CI = 1.02–16.45).

Conclusion

The presence of significant liver fibrosis assessed via TE was independently associated with low BMD in NAFLD subjects.

Pediatric Non-Alcoholic Fatty Liver Disease

With the increase in the prevalence of obesity, non-alcoholic fatty liver disease (NAFLD) has become among the leading causes of chronic liver disease in the pediatric age group. Once believed to be a “two-hit process”, it is now clear that the actual pathophysiology of NAFLD is complex and involves multiple pathways. Moreover, NAFLD is not always benign, and patients with non-alcoholic steatohepatitis (NASH) are at increased risk of developing advanced stages of liver disease. It has also been shown that NAFLD is not only a liver disease, but is also associated with multiple extrahepatic manifestations, including cardiovascular diseases, type 2 diabetes, and low bone mineral density. Although the data is scarce in the pediatric population, some studies have suggested that long-term mortality and the requirement of liver transplantation will continue to increase in patients with NAFLD. More studies are needed to better understand the natural history of NAFLD, especially in the pediatric age group.

Nonalcoholic Fatty Liver Disease in Children: Hepatic and Extrahepatic Complications

Nonalcoholic fatty liver disease (NAFLD) is considered the hepatic manifestation of metabolic syndrome and has become the most common form of chronic liver disease in children and adolescents. The histologic spectrum of NAFLD is broad ranging, from the relatively benign form of simple steatosis to the aggressive form of nonalcoholic steatohepatitis, eventually leading to fibrosis and cirrhosis. NAFLD has also been recognized as an independent risk factor for extrahepatic complications, such as cardiovascular disease, type 2 diabetes mellitus, sleep disorders, and osteoporosis. In this review, we discuss both the hepatic and extrahepatic complications of NAFLD in children.

Non-alcoholic fatty liver disease and its relationship with cardiovascular disease and other extrahepatic diseases

Key physiological functions of the liver, including glucose and lipid metabolism, become disturbed in the setting of non-alcoholic fatty liver disease (NAFLD) and may be associated with a systemic inflammatory 'milieu' initiated in part by liver-secreted cytokines and molecules. Consequently, the pathophysiological effects of NAFLD extend beyond the liver with a large body of clinical evidence demonstrating NAFLD to be independently associated with both prevalent and incident cardiovascular disease (CVD), chronic kidney disease (CKD) and type 2 diabetes mellitus (T2DM). The magnitude of risk of developing these extrahepatic diseases parallels the underlying severity of NAFLD, such that patients with non-alcoholic steatohepatitis (NASH) appear to be at greater risk of incident CVD, CKD and T2DM than those with simple steatosis. Other modifiers of risk may include genetic variants (eg, patatin-like phospholipase domain-containing 3 and trans-membrane 6 superfamily member 2 polymorphisms), visceral adipose tissue accumulation, dietary intake and the gut microbiome. Emerging data also suggest that NAFLD may be a risk factor for colonic neoplasia and reduced bone mineral density, especially among men. Importantly, improvement/resolution of NAFLD is associated with a reduced incidence of T2DM and improved kidney function, adding weight to causality and suggesting liver focused treatments may reduce risk of extrahepatic complications. Awareness of these associations is important for the clinicians such that CVD risk factor management, screening for T2DM and CKD are part of the routine management of patients with NAFLD.

Bone marrow fat content is correlated with hepatic fat content in paediatric non-alcoholic fatty liver disease

AIM

To investigate the relationship between bone marrow fat content and hepatic fat content in children with known or suspected non-alcoholic fatty liver disease (NAFLD).

MATERIALS AND METHODS

This was an institutional review board-approved, Health Insurance Portability and Accountability Act (HIPAA)-compliant, cross-sectional, prospective analysis of data collected between October 2010 to March 2013 in 125 children with known or suspected NAFLD. Written informed consent was obtained for same-day research magnetic resonance imaging (MRI) of the lumbar spine, liver, and abdominal adiposity. Lumbar spine bone marrow proton density fat fraction (PDFF) and hepatic PDFF were estimated using complex-based MRI (C-MRI) techniques and magnitude-based MRI (M-MRI), respectively. Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SCAT) were quantified using high-resolution MRI. All images were acquired by two MRI technologists. Hepatic M-MRI images were analysed by an image analyst; all other images were analysed by a single investigator. The relationship between lumbar spine bone marrow PDFF and hepatic PDFF was assessed with and without adjusting for the presence of covariates using correlation and regression analysis.

RESULTS

Lumbar spine bone marrow PDFF was positively associated with hepatic PDFF in children with known or suspected NAFLD prior to adjusting for covariates (r=0.33, p=0.0002). Lumbar spine bone marrow PDFF was positively associated with hepatic PDFF in children with known or suspected NAFLD (r=0.24, p=0.0079) after adjusting for age, sex, body mass index z-score, VAT, and SCAT in a multivariable regression analysis.

CONCLUSION

Bone marrow fat content is positively associated with hepatic fat content in children with known or suspected NAFLD. Further research is needed to confirm these results and understand their clinical and biological implications.

Non-alcoholic fatty liver disease connections with fat-free tissues: A focus on bone and skeletal muscle

The estimates of global incidence and prevalence of non-alcoholic fatty liver disease (NAFLD) are worrisome, due to the parallel burden of obesity and its metabolic complications. Indeed, excess adiposity and insulin resistance represent two of the major risk factors for NAFLD; interestingly, in the last years a growing body of evidence tended to support a novel mechanistic perspective, in which the liver is at the center of a complex interplay involving organs and systems, other than adipose tissue and glucose homeostasis. Bone and the skeletal muscle are fat- free tissues which appeared to be independently associated with NAFLD in several cross-sectional studies. The deterioration of bone mineral density and lean body mass, leading to osteoporosis and sarcopenia, respectively, are age-related processes. The prevalence of NAFLD also increases with age. Beyond physiological aging, the three conditions share some common underlying mechanisms, and their elucidations could be of paramount importance to design more effective treatment strategies for the management of NAFLD. In this review, we provide an overview on epidemiological data as well as on potential contributors to the connections of NAFLD with bone and skeletal muscle.

Circulating sclerostin and Dickkopf-1 levels in patients with nonalcoholic fatty liver disease

There is increasing evidence for bone-liver interplay. The main aim of this study was to determine serum sclerostin and Dickkopf (DKK)-1 levels in patients with nonalcoholic fatty liver disease (NAFLD) and their association with the disease severity. Patients with biopsy-proven NAFLD, 13 with nonalcoholic simple steatosis (SS) and 14 with steatohepatitis (NASH), and 20 gender-, age-, body mass index- and waist circumference-matched controls were enrolled. Serum sclerostin, DKK-1, bone turnover markers, vitamin D, insulin and standard biochemical and hematologic parameters were measured; lumbar spinal dual-energy X-ray absorptiometry was performed. We observed that there was a progressive decline in serum sclerostin levels from the controls (76.1 ± 6.8) to SS (53.5 ± 6.4) and NASH (46.0 ± 8.1 pmol/l) patients (p = 0.009); in adjusted pairwise comparisons, sclerostin was significantly higher in the controls than in NASH patients (p = 0.012). Although serum DKK-1 did not differ between groups (p = 0.135), there was a trend toward U-shaped distribution (controls 35.8 ± 2.8; SS 27.3 ± 2.9; NASH 36.8 ± 4.4 pmol/l). Higher DKK-1 levels were independently associated with NASH. Regarding specific histological lesions, DKK-1 levels were marginally lower in NAFLD patients with lower (≤33 %) than higher (>33 %) steatosis grade (27.7 ± 3.1 and 38.8 ± 4.7 pmol/l, respectively; p = 0.049). No other significant difference was observed within histological lesions. In conclusion, serum sclerostin levels were lower in NASH patients than in controls. DKK-1 levels were independently associated with NASH in NAFLD patients. The potential importance of these findings indicates a possible bone-liver interaction and warrants further investigation.