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

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.

Liver Fat, Bone Marrow Adipose Tissue, and Bone Mineral Density in Children With Overweight

CONTEXT

Hepatic steatosis is associated with decreased bone mineral density (BMD). Bone marrow fat fraction (BMFF) could play a role in this relationship in children with obesity.

OBJECTIVE

The objectives of this work were (i) to examine the relationship between the lumbar spine (LS) BMFF and BMD, and (ii) to explore the mediating role of LS-BMFF on the relationship between percentage hepatic fat with LS-BMD in preadolescent children with overweight/obesity.

METHODS

Hepatic fat and LS-BMFF (magnetic resonance imaging) and areal LS-BMD (LS-aBMD, dual-energy x-ray absorptiometry) were measured in 106 children (aged 10.6 ± 1.1 years, 53.8% girls) with overweight/obesity.

RESULTS

LS-BMFF was inversely associated with LS-aBMD (r = -0.313; P = .001) and directly related with percentage hepatic fat (r = 0.276; P = .005). LS-BMFF was significantly greater in children with than without hepatic steatosis (P = .003; Cohen's d: 0.61; 95% CI, -0.21 to 1.0), while no significant difference was seen between children with overweight and those with obesity (P = .604; Cohen's d: 0.16; 95% CI, -0.21-0.55). Mediating analysis indicated that LS-BMFF is an important mediator (50%) in the association of hepatic fat with lower LS-aBMD (indirect effect: β = -.076; 95% CI, -0.143 to -0.015).

CONCLUSION

These findings suggest that hepatic steatosis, rather than overall excess adiposity, is associated with greater bone marrow adipose tissue in preadolescent children with overweight/obesity, which in turn, is related to lower BMD. Hepatic steatosis could be a potential biomarker of osteoporosis risk, and a therapeutic target for interventions that aim to reduce not only hepatic steatosis, but for those designed to improve bone health in such children.

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.

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.

Adequacy of calcium intake in Spanish population according age groups

This review shows the estimated calcium intake in Spain in recent years. Our results indicate that adolescents and the elderly are at risk of insufficient calcium intake. By using the national and the European recommendations, this work contributes to map and compare population's dietary calcium intake in the European countries. PURPOSE AND METHODS : The present work aims to examine calcium intake in the healthy Spanish population of any age and analyze its adequacy to the calcium Recommended Dietary Intake (RDI) for different groups in Spanish population, as well to the Adequate Intake (AI) or Population Reference Intake (PRI) estimated by European Food Safety Authority (EFSA). Forty-three studies published in the last 5 years were eligible for review. RESULTS AND CONCLUSIONS: The results show that infants and children exceed Spanish and EFSA dietary recommendations, adults meet more that 80% of the RDI and EFSA recommendations, and the estimated average calcium intake in the adolescent and elderly groups does not reach 75% of the recommended intake. Representative national studies with a common methodology to estimate calcium intake are needed.

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.

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.