The association of liver fat content and serum alanine aminotransferase with bone mineral density in middle-aged and elderly Chinese men and postmenopausal women

The role of lipid metabolism in osteoporosis: Clinical implication and cellular mechanism

In recent years, researchers have become focused on the relationship between lipids and bone metabolism balance. Moreover, many diseases related to lipid metabolism disorders, such as nonalcoholic fatty liver disease, atherosclerosis, obesity, and menopause, are associated with osteoporotic phenotypes. It has been clinically observed in humans that these lipid metabolism disorders promote changes in osteoporosis-related indicators bone mineral density and bone mass. Furthermore, similar osteoporotic phenotype changes were observed in high-fat and high-cholesterol-induced animal models. Abnormal lipid metabolism (such as increased oxidized lipids and elevated plasma cholesterol) affects bone microenvironment homeostasis via cross-organ communication, promoting differentiation of mesenchymal stem cells to adipocytes, and inhibiting commitment towards osteoblasts. Moreover, disturbances in lipid metabolism affect the bone metabolism balance by promoting the secretion of cytokines such as receptor activator of nuclear factor-kappa B ligand by osteoblasts and stimulating the differentiation of osteoclasts. Conclusively, this review addresses the possible link between lipid metabolism disorders and osteoporosis and elucidates the potential modulatory mechanisms and signaling pathways by which lipid metabolism affects bone metabolism balance. We also summarize the possible approaches and prospects of intervening lipid metabolism for osteoporosis treatment.

Anti-osteoporotic treatments in the era of non-alcoholic fatty liver disease: friend or foe

Over the last years non-alcoholic fatty liver disease (NAFLD) has grown into the most common chronic liver disease globally, affecting 17-38% of the general population and 50-75% of patients with obesity and/or type 2 diabetes mellitus (T2DM). NAFLD encompasses a spectrum of chronic liver diseases, ranging from simple steatosis (non-alcoholic fatty liver, NAFL) and non-alcoholic steatohepatitis (NASH; or metabolic dysfunction-associated steatohepatitis, MASH) to fibrosis and cirrhosis with liver failure or/and hepatocellular carcinoma. Due to its increasing prevalence and associated morbidity and mortality, the disease-related and broader socioeconomic burden of NAFLD is substantial. Of note, currently there is no globally approved pharmacotherapy for NAFLD. Similar to NAFLD, osteoporosis constitutes also a silent disease, until an osteoporotic fracture occurs, which poses a markedly significant disease and socioeconomic burden. Increasing emerging data have recently highlighted links between NAFLD and osteoporosis, linking the pathogenesis of NAFLD with the process of bone remodeling. However, clinical studies are still limited demonstrating this associative relationship, while more evidence is needed towards discovering potential causative links. Since these two chronic diseases frequently co-exist, there are data suggesting that anti-osteoporosis treatments may affect NAFLD progression by impacting on its pathogenetic mechanisms. In the present review, we present on overview of the current understanding of the liver-bone cross talk and summarize the experimental and clinical evidence correlating NAFLD and osteoporosis, focusing on the possible effects of anti-osteoporotic drugs on NAFLD.

Association of chronic liver disease with bone diseases and muscle weakness

The liver is a vital organ involved in nutrient metabolism, hormone regulation, immunity, cytokine production, and gut homeostasis. Impairment in liver function can result in malnutrition, chronic inflammation, decreased anabolic hormone levels, and dysbiosis. These conditions eventually cause an imbalance in osteoblast and osteoclast activities, resulting in bone loss. Osteoporosis is a frequent complication of chronic liver disease (CLD) that adversely affects quality of life and increases early mortality. Sarcopenia is another common complication of CLD characterized by progressive loss of skeletal muscle mass and function. Assessment criteria for sarcopenia specific to liver disease have been established, and sarcopenia has been reported to be associated with an increase in the risk of liver disease-related events and mortality in patients with CLD. Owing to their similar risk factors and underlying pathophysiological mechanisms, osteoporosis and sarcopenia often coexist (termed osteosarcopenia), progress in parallel, and further exacerbate the conditions mentioned above. Therefore, comprehensive management of these musculoskeletal disorders is imperative. This review summarizes the clinical implications and characteristics of osteoporosis, extending to sarcopenia and osteosarcopenia, in patients with CLD caused by different etiologies.

Association between the fatty liver index and the risk of fracture among individuals over the age of 50 years: a nationwide population-based study

Background and purpose

The association between fatty liver and fracture risk has not been firmly established. In this study, we investigated the relationship between the fatty liver index (FLI) and the incidence of fractures among individuals ≥50 years of age, using a nationwide population-based cohort.

Methods

Data from the Korean National Health Insurance System between January 2009 and December 2019 were analyzed using the Cox proportional hazards model. Fatty liver status was defined using FLI. Newly diagnosed fractures were identified based on insurance claim data.

Results

Among the 3,384,457 individuals who met our inclusion criteria over the study period, 444,203 cases of incident fractures were identified over a median follow-up of 10.3 years. On multivariate analysis, the risk of fracture was significantly higher among individuals with a higher FLI score compared to those with an FLI<30, with adjusted hazard ratio [aHR] and 95% confidence interval [CI] as follows: FLI 30-59 group, aHR 1.04 and 95% CI 1.03-1.05; and FLI ≥60 group, aHR 1.12 and 95% CI 1.10-1.13. A higher FLI was associated with a greater risk of hip (aHR 1.23 and 1.52 for the FLI 30-59 and FLI ≥60 group, respectively) and vertebral fracture (aHR 1.08 and 1.16 for the FLI 30-59 and FLI≥60 group, respectively). The association between the risk for fracture and FLI ≥60 was prominent for non-obese than obese individuals (aHR 1.25 and 95% CI, 1.22-1.27 versus 1.06 and 1.05-1.08, respectively).

Conclusions

A high FLI is associated with an increased risk of hip and vertebral fractures among individuals ≥50 years of age, suggestive of an association between a higher FLI and osteoporotic fractures.

Non-alcoholic fatty liver disease is associated with decreased bone mineral density in upper Egyptian patients

Nonalcoholic fatty liver disease (NAFLD) has been linked with a number of extra hepatic diseases and could be a potential risk factor of decreasing bone mineral density. To determine whether Upper Egyptian patients with NAFLD are at risk of developing osteoporosis. Cross sectional study was done on a total 100 individuals; 50 patients diagnosed with NAFLD (based on ultrasound imaging) crossed-matched with 50 individuals without NAFLD based on age, sex and body mass index. Bone mineral density, serum calcium and phosphorus levels, serum parathyroid hormone, serum vitamin D and fasting insulin level were assessed. Osteoporosis was prevalent in NAFLD patients versus to controls (19/50 vs. 0/50; P < 0.001). There was significant decrease in bone mineral density in NAFLD patients than controls (- 2.29 ± 0.4 vs. - 1.53 ± 0.1; P < 0.001). There was a statistical significance decrease in serum vitamin D and calcium levels in NAFLD patients than controls. Furthermore, vitamin D levels in the NAFLD group was a predictor for osteoporosis (OR 0.614; 95% CI 0.348-0.825). Patients with NAFLD tend to have a significant decrease in bone density, vitamin D, and serum calcium levels than controls.

2019 Global NAFLD Prevalence: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

The increasing rates of obesity and type 2 diabetes mellitus may lead to increased prevalence of nonalcoholic fatty liver disease (NAFLD). We aimed to determine the current and recent trends on the global and regional prevalence of NAFLD.

METHODS

Systematic search from inception to March 26, 2020 was performed without language restrictions. Two authors independently performed screening and data extraction. We performed meta-regression to determine trends in NAFLD prevalence.

RESULTS

We identified 17,244 articles from literature search and included 245 eligible studies involving 5,399,254 individuals. The pooled global prevalence of NAFLD was 29.8% (95% confidence interval [CI], 28.6%-31.1%); of these, 82.5% of included articles used ultrasound to diagnose NAFLD, with prevalence of 30.6% (95% CI, 29.2%-32.0%). South America (3 studies, 5716 individuals) and North America (4 studies, 18,236 individuals) had the highest NAFLD prevalence at 35.7% (95% CI, 34.0%-37.5%) and 35.3% (95% CI, 25.4%-45.9%), respectively. From 1991 to 2019, trend analysis showed NAFLD increased from 21.9% to 37.3% (yearly increase of 0.7%, P < .0001), with South America showing the most rapid change of 2.7% per year, followed by Europe at 1.1%.

CONCLUSIONS

Despite regional variation, the global prevalence of NAFLD is increasing overall. Policy makers must work toward reversing the current trends by increasing awareness of NAFLD and promoting healthy lifestyle environments.

Relationship between nonalcoholic fatty liver disease and bone mineral density in adolescents

Liver metabolism is strongly linked to bone metabolism, and a significant correlation between nonalcoholic fatty liver disease (NAFLD) and bone mineral density (BMD) in adults has been demonstrated. However, the current relationship between NAFLD and BMD in the adolescent population remains controversial. The purpose of this study was to investigate the specific relationship between NAFLD and BMD in adolescents aged 12 to 19 years in the United States. The quantitative relationship between NAFLD and total BMD was investigated using multivariate logistic regression and smoothed fitted curve curves based on multiperspective data from the National Health and Nutrition Examination Survey (NHANES). A total of 740 adolescents were included in this study after excluding unusable samples. The results showed that NAFLD was positively associated with total BMD in adolescents. The results of the subgroup analysis showed that this positive association was mainly found in boys, whites and blacks. The association was not significant in girls, Mexican Americans and other racial groups. Among US adolescents, there was a significant positive association between NAFLD and total BMD, and this relationship varied by gender and race.

Nonalcoholic fatty liver disease and osteoporosis: A potential association with therapeutic implications

Nonalcoholic fatty liver disease (NAFLD) and osteoporosis are two highly prevalent metabolic diseases. Increasing experimental evidence supports a pathophysiological link between NAFLD and osteoporosis. A key feature could be chronic, low-grade inflammation, which characterizes NAFLD and possibly affects bone metabolism. In this context, several factors, including but not limited to receptor activator of nuclear factor kappa-B ligand, osteoprotegerin, osteopontin and osteocalcin, may serve as mediators. In the clinical setting, most but not all epidemiological evidence indicates that NAFLD is associated with lower bone mineral density or osteoporosis in adults. Although an association between NAFLD and osteoporosis has not yet been established, and thus remains speculative, pharmacological considerations already exist. Some of the current and emerging pharmacological options for NAFLD have shown possible anti-osteoporotic properties (eg, vitamin E, obeticholic acid, semaglutide), while others (eg, pioglitazone, canagliflozin) have been associated with increased risk of fractures and may be avoided in patients with NAFLD and concomitant osteoporosis, especially those at high fracture risk. Conversely, some anti-osteoporotic medications (denosumab) might benefit NAFLD, while others (raloxifene) might adversely affect it and, consequently, may be avoided in patients with osteoporosis and NAFLD. If an association between NAFLD and osteoporosis is established, a medication that could target both diseases would be a great advancement. This review summarizes the main experimental and clinical evidence on the potential association between NAFLD and osteoporosis and focuses on treatment considerations derived from this potential association.

Risk of fractures and subsequent mortality in non-alcoholic fatty liver disease: A nationwide population-based cohort study

BACKGROUND

Studies suggest an association between osteoporosis and non-alcoholic fatty liver disease (NAFLD), but whether patients with NAFLD are at increased risk of fractures is unknown.

OBJECTIVES

The aim was to determine the rate and risk of fractures and the mortality rate after fracture in patients with NAFLD compared to the general population.

METHODS

This was a nationwide population-based cohort study using data from the Swedish National Patient Registry on 10,678 patients with NAFLD from 1987 to 2016. Patients were matched for sex, age, and municipality with 99,176 controls from the Swedish Total Population Registry. Cox regression was used to estimate fracture rates. The risk of fractures was assessed while accounting for competing risks (death and liver transplantation).

RESULTS

A total of 12,312 fractures occurred during 761,176 person-years of follow-up. Patients with NAFLD (17.5 per 1000 person-years) had a slightly higher fracture rate than controls (16.1 per 1000 person-years; adjusted hazard ratio 1.11, 95% confidence interval [CI] 1.05-1.19), although the 5-year risk of fractures was similar (8.0%, 95% CI 7.4-8.6 versus 7.3%, 95% CI 7.2-7.5). Additionally, 1-year mortality after fracture was similar in NAFLD and controls.

CONCLUSIONS

Patients with NAFLD have a slightly higher rate of fractures but long-term risk of fractures comparable to the general population. This suggests that broad surveillance of risk factors for fractures in patients with NAFLD is not motivated.

The cortical bone metabolome of C57BL / 6J mice is sexually dimorphic

Cortical bone quality, which is sexually dimorphic, depends on bone turnover and therefore on the activities of remodeling bone cells. However, sex differences in cortical bone metabolism are not yet defined. Adding to the uncertainty about cortical bone metabolism, the metabolomes of whole bone, isolated cortical bone without marrow, and bone marrow have not been compared. We hypothesized that the metabolome of isolated cortical bone would be distinct from that of bone marrow and would reveal sex differences. Metabolite profiles from liquid chromatography–mass spectrometry (LC‐MS) of whole bone, isolated cortical bone, and bone marrow were generated from humeri from 20‐week‐old female C57Bl/6J mice. The cortical bone metabolomes were then compared for 20‐week‐old female and male C57Bl/6J mice. Femurs from male and female mice were evaluated for flexural material properties and were then categorized into bone strength groups. The metabolome of isolated cortical bone was distinct from both whole bone and bone marrow. We also found sex differences in the isolated cortical bone metabolome. Based on metabolite pathway analysis, females had higher lipid metabolism, and males had higher amino acid metabolism. High‐strength bones, regardless of sex, had greater tryptophan and purine metabolism. For males, high‐strength bones had upregulated nucleotide metabolism, whereas lower‐strength bones had greater pentose phosphate pathway metabolism. Because the higher‐strength groups (females compared with males, high‐strength males compared with lower‐strength males) had higher serum type I collagen cross‐linked C‐telopeptide (CTX1)/procollagen type 1 N propeptide (P1NP), we estimate that the metabolomic signature of bone strength in our study at least partially reflects differences in bone turnover. These data provide novel insight into bone bioenergetics and the sexual dimorphic nature of bone material properties in C57Bl/6 mice. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Metabolic-associated Fatty Liver Disease (MAFLD): A Multi-systemic Disease Beyond the Liver

Nonalcoholic fatty liver disease (NAFLD) is a multisystemic clinical condition that presents with a wide spectrum of extrahepatic manifestations, such as obesity, type 2 diabetes mellitus, metabolic syndrome, cardiovascular diseases, chronic kidney disease, extrahepatic malignancies, cognitive disorders, and polycystic ovarian syndrome. Among NAFLD patients, the most common mortality etiology is cardiovascular disorders, followed by extrahepatic malignancies, diabetes mellitus, and liver-related complications. Furthermore, the severity of extrahepatic diseases is parallel to the severity of NAFLD. In clinical practice, awareness of the associations of concomitant diseases is of major importance for initiating prompt and timely screening and multidisciplinary management of the disease spectrum. In 2020, a consensus from 22 countries redefined the disease as metabolic (dysfunction)-associated fatty liver disease (MAFLD), which resulted in the redefinition of the corresponding population. Although the patients diagnosed with MAFLD and NAFLD mostly overlap, the MAFLD and NAFLD populations are not identical. In this review, we compared the associations of key extrahepatic diseases between NAFLD and MAFLD.

Nonalcoholic Fatty Liver Disease and Endocrine Axes—A Scoping Review

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

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.

Hepatic fibrosis is associated with an increased rate of decline in bone mineral density in men with nonalcoholic fatty liver disease

BACKGROUND

There is still controversy about the association between nonalcoholic fatty liver disease (NAFLD) and bone mineral density (BMD). The aim of this study was to clarify the association between NAFLD and the decline in BMD in healthcare examinees.

METHODS

Participants who underwent regular health check-ups with BMD and hepatic ultrasonography from 2006 to 2015 with more than one follow-up until 2020 were included. Propensity score matching was performed between the NAFLD group and the control group, and mixed linear regression models were used for the longitudinal analysis.

RESULTS

Of 2623 eligible participants (mean age 58.7 ± 7.3 years; males 31.3%), 888 (33.9%) had NAFLD. At baseline, the NAFLD group had a higher total hip BMD than the non-NAFLD group in men (0.988 vs. 1.015 g/cm², p = 0.007); however, there was no difference in baseline BMD in women (p = 0.253). In longitudinal analysis during a follow-up period of 7.1 years, there was no significant difference in the BMD decline rate between the two groups in the PS-matched cohort (p = 0.816 in men and p = 0.827 in women). However, among men with NAFLD, those with a high and intermediate probability of advanced fibrosis by the FIB-4 showed a significantly increased rate of decline in total hip BMD compared to those with low scores (0.01 vs. - 0.19% change/year, p = 0.011).

CONCLUSIONS

NAFLD was not associated with the total hip BMD decline rate. However, hepatic fibrosis was significantly associated with an increased rate of decline in total hip BMD in men with NAFLD.

CLINICAL TRIAL REGISTRATION

This study is a retrospective observational study and is not a drug trial. There was no need for clinical trial registration.

Bone Marrow Fat Measured by a Chemical Shift-Encoded Sequence (IDEAL-IQ) in Patients With and Without Metabolic Syndrome

BACKGROUND

Metabolic syndrome increases the risk of chronic diseases such as cardiovascular disease and diabetes. Metabolic syndrome also has an impact on bone mineral density. However, the relationship between metabolic syndrome and bone marrow fat is unclear.

PURPOSE

To determine factors associated with bone marrow fat concentration in subjects with and without metabolic syndrome.

STUDY TYPE

Retrospective.

POPULATION

One hundred and one women with metabolic syndrome (31.0 years ±5.1) and 96 female living liver transplant donors (32.0 years ±3.7). Our institutional review board approved the study. Each subject signed written informed consent.

FIELD STRENGTH/SEQUENCE

3.0 T MRI system and a commercially available chemical shift-encoded 3D sequence (Iterative Decomposition of water and fat with Echo asymmetry and Least Square Estimation).

ASSESSMENT

Proton density fat fraction (PDFF) in liver, vertebral body, and paraspinal muscle (erector spinae) were measured from a single acquisition by a 15-year-experience orthopedic radiologist. The factors associated with PDFF were acquired.

STATISTICAL TESTS

The analysis of covariance test, after adjustment for body mass index and age, was used to analyze the differences between metabolic syndrome and non-metabolic syndrome groups. A stepwise multiple regression analysis was used to determine which variables were independently associated with PDFF.

RESULTS

Mean vertebral PDFF and alanine aminotransferase (ALT) were significantly lower in donors than subjects with metabolic syndrome (both P < 0.05). Serum vitamin D concentration, ferritin, and high-density lipoprotein (HDL) cholesterol were significantly higher in donors than subjects with metabolic syndrome (all P < 0.05). Multiple regression analysis revealed antidiabetic medicine, higher serum vitamin D concentration, lower waist circumference, lower ferritin, lower HDL, absence of metabolic syndrome, and lower ALT were significantly associated with lower vertebral PDFF (all P < 0.05).

DATA CONCLUSION

Multiple factors affect bone marrow fat concentration in subjects with metabolic syndrome. Serum vitamin D concentration and antidiabetic medicine are associated with low bone marrow fat, whereas waist circumference, serum ferritin, metabolic syndrome, imbalanced lipid metabolism, and abnormal liver function are associated with high bone marrow fat.

LEVEL OF EVIDENCE LEVEL

3 TECHNICAL EFFICACY STAGE: 1.

The different correlations between obesity and osteoporosis after adjustment of static mechanical loading from weight and fat free mass

OBJECTIVES

To explore complex correlations between obesity (OB) and osteoporosis (OP) after adjustment of static mechanical loading from weight and fat free mass (FFM).

METHODS

A total of 3749 Chinese aged ≥65 years were selected from our ongoing cohort study. OB indices and bone mineral density (BMD) were measured for each subject. Linear regression analyses were performed to explore the correlations between OB indices and OP under three adjustment models (unadjusted, adjusted with weight and adjusted with FFM).

RESULTS

Under no adjustment, three general obesity indices (body mass index: BMI, fat mass: FM, and percentage FM: PFM) were positively associated with BMD at three skeletal sites (P<0.001) in the regression analyses. However, after the adjustment with weight, these associations were mostly significant but reverse i.e., negatively in direction. After adjustment with FFM, the three indices were still positively and significantly (P<0.001) associated with BMD but regression coefficients were smaller compared to the unadjusted associations. Similar associations were observed for central adiposity and lower limb adiposity indices.

CONCLUSIONS

The combined relation of OB to OP due to the physiological factors secreted from adipose tissues and the static mechanical loading from FM is positive in direction.

Serum Fibroblast Growth Factor 23 Level and Liver Fat Content in MAFLD: A Community-Based Cohort

PURPOSE

Although fibroblast growth factor-23 (FGF23) is involved in the development of metabolic diseases, its association with metabolic-associated fatty liver disease (MAFLD) remains unknown. We explored the relationship between serum fibroblast growth factor-23 level, metabolic associated fatty liver disease, and liver fat content.

PATIENTS AND METHODS

Participants were enrolled from communities in Shanghai. Serum fibroblast growth factor-23 level was determined using two-side sandwich enzyme-linked immunosorbent assays. MAFLD was diagnosed using the international expert consensus (2020) criteria. Liver fat content was assessed using ultrasound.

RESULTS

We enrolled 1827 individuals aged 30-80 years (mean age, 59.4±7.3 years). MAFLD was diagnosed in 445/1393 (31.9%) non-diabetic participants and 245/434 (56.5%) diabetic participants. After adjusting for confounders, one standard deviation increase in serum FGF23 was associated with MAFLD in diabetic (odds ratio, 1.27; 95% confidence interval, 1.15-1.49; P<0.001) and non-diabetic (odds ratio, 1.28; 95% confidence interval, 1.07-1.74; P=0.030) groups. In a fully adjusted linear regression model, serum FGF23 emerged as a positive determinant of liver fat content in both diabetic and non-diabetic groups (P=0.039; P=0.034).

CONCLUSION

Participants with MAFLD had higher serum fibroblast growth factor-23 level than those without MAFLD, regardless of diabetes status. Serum fibroblast growth factor-23 was independently related to MAFLD and liver fat content.

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.

Correlation between income and non-alcoholic fatty liver disease in a Chinese population

OBJECTIVE

The aim of the study was to analyze the correlation between income and non-alcoholic fatty liver disease (NAFLD) in a Chinese population.

METHOD

subjects were divided into three groups according to liver fat content (LFC). (1) normal: LFC < 9.15%, 197 cases; (2) low LFC: LFC 9.15-20%, 532 cases; and (3) high LFC: LFC > 20%, 201 cases. Participants' clinical and social background were collected, including a routine fasting test to assess the relevant indices. Intergroup differences were compared on 1-way ANOVA, to analyze the relation between income and each index on Pearson correlation, and independent factors for LFC were identified on binary logistic regression.

RESULTS

(1) In retired persons, prevalence of NAFLD was greater in females (81.2%) than males (75%), but fell with age: the highest prevalence was between 40 and 49 years of age (87.5%), and the lowest above 70 years (68%). (2) Income correlated positively with triglyceride and serum uric acid levels and LFC (P < 0.05) and negatively with alanine aminotransferase (P = 0.01). (3) As income increased from level I to V, prevalence of NAFLD increased progressively (P < 0.05). In the study, LFC was taken as the dependent variable, and the traditional NAFLD risk factors and income level (I-V) were taken as independent variables. Income emerged as an independent risk factor for NAFLD. Risk in group V was 1.964-fold higher than in group I.

CONCLUSION

Prevalence of NAFLD was closely related to socio-economic level. Demographic risk factors include female gender, age 40-49 years, and monthly income > 5,000 RMB. Thus, if income is increased without improving educational level and health awareness, NAFLD prevalence will rise.

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.

Energy restriction in obese women suggest linear reduction of hepatic fat content and time-dependent metabolic improvements

Energy restriction reduces liver fat, improves hepatic insulin resistance and lipid metabolism. However, temporal data in which these metabolic improvements occur and their interplay is incomplete. By performing repeated MRI scans and blood analysis at day 0, 3, 7, 14 and 28 the temporal changes in liver fat and related metabolic factors were assessed at five times during a low-calorie diet (LCD, 800–1100 kcal/day) in ten obese non-diabetic women (BMI 41.7 ± 2.6 kg/m²) whereof 6 had NAFLD. Mean weight loss was 7.4 ± 1.2 kg (0.7 kg/day) and liver fat decreased by 51 ± 16%, resulting in only three subjects having NAFLD at day 28. Marked alteration of insulin, NEFA, ALT and 3-hydroxybuturate was evident 3 days after commencing LCD, whereas liver fat showed a moderate but a linear reduction across the 28 days. Other circulating-liver fat markers (e.g. triglycerides, adiponectin, stearoyl-CoA desaturase-1 index, fibroblast growth factor 21) demonstrated modest and variable changes. Marked elevations of NEFA, 3-hydroxybuturate and ALT concentrations occurred until day 14, likely reflecting increased tissue lipolysis, fat oxidation and upregulated hepatic fatty acid oxidation. In summary, these results suggest linear reduction in liver fat, time-specific changes in metabolic markers and insulin resistance in response to energy restriction.

Systematic review with meta-analysis: non-alcoholic fatty liver disease is associated with a history of osteoporotic fractures but not with low bone mineral density

BACKGROUND

Several studies have explored the effect of non-alcoholic fatty liver disease (NAFLD) on bone mineral density (BMD) and risk of osteoporotic fractures in adults. However, the extent to which NAFLD adversely affects bone health remains uncertain.

AIM

To provide a quantitative estimation of the magnitude of the association of NAFLD with BMD or history of osteoporotic fractures in adults.

METHODS

We searched PubMed, Web of Science, and Scopus using predefined keywords to identify all observational studies, published up to 31 August 2018, in which NAFLD was diagnosed by imaging or histology; BMD was measured by dual energy X-ray absorptiometry; and a self-reported history of osteoporotic fractures was collected with interviewer-assisted questionnaires. Data from selected studies were extracted, and meta-analysis was performed using random-effects modelling.

RESULTS

Twelve cross-sectional or case-control studies with aggregate data on 30 041 adults of predominantly Asian ethnicity (30% with NAFLD) were included in the final analysis. No significant differences in BMD at different skeletal sites (whole body, lumbar spine, or femur) were observed between individuals with and without NAFLD. Conversely, NAFLD was associated with increased odds of osteoporotic fractures, especially in older Chinese men (n = 2 studies; random-effects odds ratio 2.10, 95% CI 1.36-3.25; I²  = 0%). Sensitivity analyses did not alter these findings. The funnel plot and Egger test did not reveal significant publication bias.

CONCLUSIONS

This meta-analysis suggests that imaging-defined or biopsy-proven NAFLD is associated with a self-reported history of osteoporotic fractures (principally in Chinese men), but not with low BMD, in middle-aged and elderly individuals.

Clinical and body composition predictors of bone turnover and mineral content in obese postmenopausal women

The purpose of this study was to determine the predictors of bone mineral density (BMD), bone mineral content (BMC), and bone turnover markers in obese postmenopausal women. In this cross-sectional study, 81 postmenopausal women aged 58.40 ± 6.08 years were analyzed. Anthropometric parameters were recorded. Serum glucose parameters, serum lipid profiles, adipokines, renal, hepatic parameters, and bone markers concentrations were determined by well-validated laboratory routine methods. BMD, BMC, and body composition were measured by Dual X-ray Absorptiometry. We found a significant correlation of BMD with age, years since menopause, anthropometric parameters, glycemia, alkaline phosphatase, fat mass, and lean mass. Multiple regression analysis demonstrated that years since menopause, waist circumference, alkaline phosphatase, trunk fat, and lean mass were independently associated to BMD. Also, age, years since menopause, anthropometric parameters, total cholesterol, alkaline phosphatase, fat mass, and lean mass were correlated to BMC. However, only waist circumference and trunk fat were independently related to BMC. Bone turnover markers were significantly correlated to the age, glycemia, HbA1c, adipokines, hepatic parameters, and lean mass. Nevertheless, only adipokines, gamma glutamyl transferase (GGT), and alkaline phosphatase were independently associated to bone turnover markers. These observations suggest that number of years since menopause, waist circumference, alkaline phosphatase, trunk fat, and lean mass were the only significant predictors of BMD. However, waist circumference seems to be a stronger predictor than trunk fat for BMC. Moreover, adiponectin, resistin, GGT, and alkaline phosphatase were significant predictors of the bone resorption (CTX-I) and the bone formation (P1NP) markers.

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.

The Combined Effect of Nonalcoholic Fatty Liver Disease and Metabolic Syndrome on Osteoporosis in Postmenopausal Females in Eastern China

The present study evaluated the potential combined effects of NAFLD and MetS on the development of osteoporosis. The relationship between NAFLD and MetS and osteoporosis was assessed in 938 postmenopausal female participants. Moderate and severe NAFLDs were combined as significant NAFLD (SNAFLD). All the subjects were divided into 4 subgroups based on the status of SNAFLD and MetS. Relative excess risk of interaction (RERI), attributable proportion (AP) of interaction, and synergy index (SI) were used to investigate the additive interaction of those two factors. NAFLD, SNAFLD, and MetS were independent factors for osteoporosis with the adjustment of age and other confounders. The incidence of osteoporosis in MetS (+) SNAFLD (+) group was significantly higher than that in other three groups. RERI was 2.556 (95% CI = 0.475-4.636), AP was 0.454 (95% CI = 0.201-0.706), and SI was 2.231 (95% CI = 1.124 to 4.428), indicating the significant combined interaction of SNAFLD and MetS on the development of osteoporosis. SNAFLD and MetS are independent risk factors for osteoporosis in postmenopausal females, respectively. Moreover, SNAFLD and MetS have an additive effect on the development of osteoporosis.

Metformin attenuates triglyceride accumulation in HepG2 cells through decreasing stearyl-coenzyme A desaturase 1 expression

BACKGROUND

The prevalence of nonalcoholic fatty liver disease (NAFLD) has increased worldwide. Metformin decreases triglyceride (TG) accumulation in hepatocytes in vivo and in vitro. Stearyl-coenzyme A desaturase 1 (SCD1) knockout mice also show decreased liver TG accumulation; however, whether SCD1 plays a role in the effect of metformin on TG accumulation is unknown. Therefore, the aim of this study was to investigate whether SCD1 mediated the effect of metformin on TG accumulation.

METHODS

HepG2 and AML12 cells were exposed to high glucose and high insulin with or without metformin. An adenovirus was used for the SCD1 knockdown and overexpression. The triglyceride level in cells was detected. The expression of related genes was detected by Western blot and quantitative real-time PCR. A dual-luciferase reporter assay was used to determine the effect of metformin on the transcriptional activity of the SCD1 promoter.

RESULTS

Metformin decreased TG accumulation to normal level in HepG2 cells exposed to high glucose and high insulin. The expression of SCD1 and fatty acid synthetase (FAS) was also decreased to normal level by metformin. Knockdown of SCD1 mimicked the effect of metformin on decreasing TG levels in AML12 cells, and the overexpression of SCD1 attenuated the effect of metformin on decreasing TG accumulation in HepG2 cells. The dual-luciferase reporter assay showed that the transcriptional activity of the SCD1 promoter (- 550/+ 199) after metformin treatment was 2-fold lower compared to control group in HepG2 cells. Additionally, the phosphorylation of AMPK after metformin treatment was 2-fold higher, and the expression of sterol regulatory element-binding protein-1c (SREBP-1c) after metformin treatment was about 2-fold lower compared to high glucose and high insulin group in HepG2 cells.

CONCLUSIONS

Together, these results reveal that metformin reduces TG accumulation in HepG2 cells via inhibiting the expression of SCD1.

Bone Turnover Markers in Patients With Nonalcoholic Fatty Liver Disease and/or Type 2 Diabetes During Oral Glucose and Isoglycemic Intravenous Glucose

CONTEXT

Nonalcoholic fatty liver disease (NAFLD) is associated with type 2 diabetes (T2D) and vice versa, and both conditions are associated with an increased risk of fractures and altered bone turnover. Although patients with NAFLD typically suffer from decreased bone mineral density (BMD), T2D is associated with normal to high BMD. The pathophysiology is uncertain but may involve the gut-bone axis.

OBJECTIVE

We investigated the influence of the gut on glucose-induced changes in plasma bone turnover markers in healthy controls and patients with T2D and/or biopsy-verified NAFLD.

DESIGN

Cross-sectional cohort study.

PATIENTS

Patients with NAFLD with normal glucose tolerance, patients with NAFLD and T2D, patients with T2D without liver disease, and healthy controls.

INTERVENTIONS

Four-hour 50-g oral glucose tolerance test (OGTT) and an isoglycemic intravenous glucose infusion (IIGI).

MAIN OUTCOME MEASURES

Collagen type 1 C-telopeptide (CTX), osteocalcin, procollagen type 1 N-terminal propeptide (P1NP), and parathyroid hormone.

RESULTS

Plasma glucose levels achieved during OGTTs were successfully matched on corresponding IIGI days. Patients with NAFLD and T2D exhibited similar CTX suppression during the two glucose challenges (P = 0.46) and pronounced suppression of P1NP during IIGI compared with OGTT. Conversely, remaining groups showed greater (P < 0.05) CTX suppression during OGTT and similar suppression of bone formation markers during IIGI and OGTT.

CONCLUSIONS

OGTT-induced CTX suppression seems to be impaired in patients with NAFLD and T2D, but preserved in patients with either NAFLD or T2D, suggesting that coexistence of T2D and NAFLD may affect gut-bone axis.

A circulating microRNA signature as noninvasive diagnostic and prognostic biomarkers for nonalcoholic steatohepatitis

BACKGROUND

Noninvasive biomarkers are urgently needed for patients with nonalcoholic steatohepatitis (NASH) to assist in diagnosis, monitoring disease progression and assessing treatment response. Recently several exploratory studies showed that circulating level of microRNA is associated with NASH and correlated with disease severity. Although these data were encouraging, the application of circulating microRNA as biomarkers for patient screening and stratification need to be further assessed under well-controlled conditions.

RESULTS

The expression of circulating microRNAs were profiled in diet-induced NASH progression and regression models to assess the diagnostic and prognostic values and the translatability between preclinical mouse model and men. Since these mice had same genetic background and were housed in the same conditions, there were minimal confounding factors. Histopathological lesions were analyzed at distinct disease progression stages along with microRNA measurement which allows longitudinal assessment of microRNA as NASH biomarkers. Next, differentially expressed microRNAs were identified and validated in an independent cohorts of animals. Thirdly, these microRNAs were examined in a NASH regression model to assess whether they would respond to NASH treatment. MicroRNA profiling in two independent cohorts of animals validated the up-regulation of 6 microRNAs (miR-122, miR-192, miR-21, miR-29a, miR-34a and miR-505) in NASH mice, which was designated as the circulating microRNA signature for NASH. The microRNA signature could accurately distinguish NASH mice from lean mice, and it responded to chow diet treatment in a NASH regression model. To further improve the performance of microRNA-based biomarker, a new composite biomarker was proposed, which consists of miR-192, miR-21, miR-505 and ALT. The new composite biomarker outperformed the microRNA signature in predicting NASH mice which had NAS > 3, and deserves further validations in large scale studies.

CONCLUSION

The present study supported the translation of circulating microRNAs between preclinical models and humans in NASH pathogenesis and progression. The microRNA-based composite biomarker may be used for non-invasive diagnosis, clinical monitoring and assessing treatment response for NASH.

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.

Danshen (Salvia miltiorrhiza) protects ovariectomized rats fed with high-saturated fat-sucrose diet from bone loss

Dietary patterns may interfere with the efficacy of herbal intervention. Our results demonstrated the protective effects of Salvia miltiorrhiza aqueous extract (SMA) on bone metabolism were influenced by levels of dietary fat and sucrose in ovariectomized (OVX) rats through its actions on attenuating lipid deposition and oxidative stress in rats.

INTRODUCTION

Salvia miltiorrhiza (SM), also known as Danshen, has been tested as an osteoporosis treatment in a series of small, short human trials that generally report improvements in bone property. However, dietary patterns may interfere with the effects of herbal intervention. We hypothesized that dietary fat and sucrose levels could influence the effects of SM supplementation on bone in estrogen-deficient animals.

METHODS

Six-month-old Sprague-Dawley sham or OVX rats were fed either a low-saturated fat-sucrose (LFS, a diet that was similar in composition to normal rat chow) or a high-fat-sucrose (HFS) diet and OVX rats were treated (8 rats/group) with SM aqueous extract (SMA, 600 mg/kg/day), 17β-estradiol (1 mg/kg/day), or vehicle for 12 weeks.

RESULTS

SMA significantly improved bone properties as revealed by the increase in trabecular bone mineral density and decrease in trabecular separation at proximal metaphysis of the tibia (PT) in HFS-fed OVX rats, but not in LFS-fed OVX rats. SMA greatly reduced lipid deposition and malondialdehyde levels, improved the activities of superoxide dismutase, catalase, and glutathione peroxidase in the livers of HFS-fed OVX rats. SMA could directly improve the proliferation and differentiation in vitro in an H₂O₂-induced preosteoblast cell model by attenuating cellular reactive oxygen species levels.

CONCLUSIONS

The protective effects of SMA on bone metabolism were influenced by dietary fat and sucrose levels in OVX rats. The ability of SMA to reduce bone loss in HFS-fed OVX rats was associated with the attenuation of lipid deposition and oxidative stress levels.

Association of Nonalcoholic Fatty Liver Disease With Osteoporotic Fractures: A Cross-Sectional Retrospective Study of Chinese Individuals

Objective: Nonalcoholic fatty liver disease (NAFLD) is related to several inflammatory or metabolic diseases. However, findings of previous studies investigating the association between NAFLD and BMD are inconsistent. Only one study reported a potential association between NAFLD and osteoporotic fracture. This study investigated whether NAFLD in older participants (>55 years) was associated with osteoporotic fracture risk. Materials and Methods: This cross-sectional, observational study included 2,695 participants (35.7% men, 614 cases of NAFLD, and 383 fractures). Standardized questionnaires, laboratory tests, and physical and ultrasonic examinations were completed. Results: After adjusting for various factors including serum triglycerides (TG), high-density cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), multivariate logistic regression models revealed a marginal association between NAFLD and osteoporotic fracture risk in men (odds ratio [OR], 1.86; 95% confidence interval [CI], 1.06-3.27; P = 0.030) but no association in women (OR, 1.05; 95% CI, 0.74-1.48; P = 0.800). Further stratified analyses showed a significant association between NAFLD and osteoporotic fracture risk in men without high TG, low HDL-C, and high LDL-C. Conclusions: There was a significant association between NAFLD and osteoporotic fracture risk in older Chinese men, particularly men without dyslipidemia.

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.

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.

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.

Association between bone mineral density and nonalcoholic fatty liver disease in Korean adults

PURPOSE

Nonalcoholic fatty liver disease (NAFLD) is associated with various metabolic abnormalities that can increase the risk of an osteoporotic fracture. Across the few previous studies of the association between NAFLD and bone mineral density (BMD), the association was not consistent. We examined the association between BMD and NAFLD in generally healthy adults.

METHODS

The subjects who visited the Seoul National University Hospital for health checkup between 2005 and 2015 were included. Men aged more than 40 and postmenopausal women were included. Lumbar spine and femoral neck (FN) BMD were measured using dual-energy X-ray absorptiometry. Liver ultrasonography was conducted to evaluate the extent of fatty changes. After excluding subjects with a secondary cause of liver disease such as heavy drinking or viral hepatitis, multivariable linear regression analysis adjusted for possible cofactors was performed to investigate the association between BMD and NAFLD.

RESULTS

A total of 6634 subjects was included in this study (men:women = 3306:3328). Multivariate regression analysis revealed a significant negative association between FN BMD and NAFLD in men (β = -0.013, p = 0.029). However, there was a positive correlation between lumbar spine BMD and NAFLD in postmenopausal women (β = 0.022, p = 0.005).

CONCLUSIONS

Moderate or severe NAFLD exerted a detrimental effect on FN BMD in men. However, moderate or severe NAFLD had a positive effect on lumbar spine BMD in postmenopausal women. Potential sex-specific differences of the effect of NAFLD on BMD need to be elucidated further.

Vitamin D Levels Are Inversely Associated with Liver Fat Content and Risk of Non-Alcoholic Fatty Liver Disease in a Chinese Middle-Aged and Elderly Population: The Shanghai Changfeng Study

Background/Objectives

Vitamin D exerts metabolic activities. We investigated whether the 25-hydroxy vitamin D [25(OH)D] is associated with liver fat content (LFC) and non-alcoholic fatty liver disease (NAFLD) in a middle-aged, elderly Chinese population.

Subject/Methods

A total of 2,960 participants (954 men and 2,006 women) aged over 45 years old were enrolled. Each participant underwent a standard interview, anthropometric measurements and laboratory examinations. Vitamin D deficiency and insufficiency was diagnosed when serum 25(OH) D level was < 50 and 50–75nmol/L. An ultrasound quantitative method was used to assess the LFC.

Results

Among the 2,960 participants, 1,982 (67.0%) subjects had vitamin D deficiency, 769 (26.0%) had vitamin D insufficiency, and 209 (7%) had normal vitamin D. Male subjects with vitamin D deficiency and insufficiency had significantly higher LFC than those with normal 25(OH)D (P = 0.034), while the LFC values showed no significant difference among the female subjects with vitamin D sufficiency, insufficiency and deficiency (P = 0.396). Univariate correlation analysis showed that 25(OH)D had a significantly negative association with LFC in men (r = -0.085, P = 0.009), but not in women. After adjusting for age, cigarette smoking, examination season, serum calcium, PTH and all possible confounders that displayed significant associations with LFC in univariate correlation analysis, serum 25(OH)D remained associated with LFC in middle-aged and elderly Chinese men.

Conclusion

Serum 25(OH)D level was inversely associated with LFC in middle-aged and elderly Chinese men.