Association between osteocalcin and metabolic syndrome in postmenopausal women

The role of bone in energy metabolism: A focus on osteocalcin

Understanding the mechanisms involved in whole body glucose regulation is key for the discovery of new treatments for type 2 diabetes (T2D). Historically, glucose regulation was largely focused on responses to insulin and glucagon. Impacts of incretin-based therapies, and importance of muscle mass, are also highly relevant. Recently, bone was recognized as an endocrine organ, with several bone proteins, known as osteokines, implicated in glucose metabolism through their effects on the liver, skeletal muscle, and adipose tissue. Research efforts mostly focused on osteocalcin (OC) as a leading example. This review will provide an overview on this role of bone by discussing bone turnover markers (BTMs), the receptor activator of nuclear factor kB ligand (RANKL), osteoprotegerin (OPG), sclerostin (SCL) and lipocalin 2 (LCN2), with a focus on OC. Since 2007, some, but not all, research using mostly OC genetically modified animal models suggested undercarboxylated (uc) OC acts as a hormone involved in energy metabolism. Most data generated from in vivo, ex vivo and in vitro models, indicate that exogenous ucOC administration improves whole-body and skeletal muscle glucose metabolism. Although data in humans are generally supportive, findings are often discordant likely due to methodological differences and observational nature of that research. Overall, evidence supports the concept that bone-derived factors are involved in energy metabolism, some having beneficial effects (ucOC, OPG) others negative (RANKL, SCL), with the role of some (LCN2, other BTMs) remaining unclear. Whether the effect of osteokines on glucose regulation is clinically significant and of therapeutic value for people with insulin resistance and T2D remains to be confirmed.

PIVKA‑II is associated with liver function, bone metabolism, and muscle function in patients with liver disease

Protein induced by vitamin K (VK) absence-II (PIVKA-II) is a sensitive marker for diagnosing hepatoma but is occasionally detected in patients without hepatoma Here, the clinical significance of serum PIVKA-II levels in patients who were not administered warfarin and did not have hepatoma or liver disease were evaluated. As VK is related to muscle and bone metabolism, PIVKA-II and clinical factors related to bone and muscle were compared. A total of 441 patients with various liver diseases were evaluated. Of these, 236 patients were female. Clinical factors and anthropometric measurements were obtained for each participant during outpatient visits. Among the clinical factors, type I procollagen N-propeptide (P1NP), a low titer of undercarboxylated osteocalcin (ucOC), and 25(OH) vitamin D (VD) were used as bone metabolic markers, and SARC-F and grip strength were used as muscle-related markers. Serum PIVKA-II levels above the upper limit were associated with Child B/C (Child-Pugh score), high titers of total P1NP, and low titers of ucOC in females, and alcohol-related liver disease and low VD in males. The titer of PIVKA-II were associated with immunoglobulin (Ig) A and prothrombin time (PT)-international normalized ratio (INR) in females, and fibrosis-4-4, IgG, total bilirubin, PT-INR, and SARC-F in males. Elevated PIVKA-II levels were associated with abnormal bone physiology in females, weak muscles in males, and severe liver disease in both sexes. Assessing PIVKA-II may assist in evaluating the clinical and bone-muscle metabolic stages in liver disease. Nutrition and supplementation with fat-soluble vitamins, including VK and VD may thus serve as a potential method to alleviate or prevent bone-muscle pathophysiology in patients with liver disease.

Determinants of bone mass in older adults with normal- and overweight derived from the crosstalk with muscle and adipose tissue

Lower bone mass in older adults may be mediated by the endocrine crosstalk between muscle, adipose tissue and bone. In 150 community-dwelling adults (59-86 years, BMI 17-37 kg/m²; 58.7% female), skeletal muscle mass index, adipose tissue and fat mass index (FMI) were determined. Levels of myokines, adipokines, osteokines, inflammation markers and insulin were measured as potential determinants of bone mineral content (BMC) and density (BMD). FMI was negatively associated with BMC and BMD after adjustment for mechanical loading effects of body weight (r-values between -0.37 and -0.71, all p < 0.05). Higher FMI was associated with higher leptin levels in both sexes, with higher hsCRP in women and with lower adiponectin levels in men. In addition to weight and FMI, sclerostin, osteocalcin, leptin × sex and adiponectin were independent predictors of BMC in a stepwise multiple regression analysis. Muscle mass, but not myokines, showed positive correlations with bone parameters that were weakened after adjusting for body weight (r-values between 0.27 and 0.58, all p < 0.01). Whereas the anabolic effect of muscle mass on bone in older adults may be partly explained by mechanical loading, the adverse effect of obesity on bone is possibly mediated by low-grade inflammation, higher leptin and lower adiponectin levels.

The relationship between estimated glucose disposal rate and bone turnover markers in type 2 diabetes mellitus

PURPOSE

To investigate the relationship between estimated glucose disposal rate (eGDR) and bone turnover markers in patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

This is a cross-sectional study, which recruited 549 patients with T2DM. The eGDRs of patients were calculated based on the presence of hypertension, glycated hemoglobin, and body mass index. All patients were divided into high-eGDR group and low-eGDR group using the median of eGDR as the boundary. The patients were further divided into two subgroups: males and postmenopausal females.

RESULTS

The lower the eGDR, the more severe was insulin resistance. The levels of osteocalcin (OC), type I collagen carboxyl-terminal peptide (β-CTX), and type I procollagen amino-terminal peptide (PINP) were significantly lower in the low-eGDR group than those in the high-eGDR group. The eGDR was positively correlated with OC, β-CTX, and PINP in all patients, and in the male subgroups. In the postmenopausal female subgroup, there was no correlation between eGDR and OC, β-CTX, or PINP. In addition, this positive correlation remained after adjusting for other factors in multilinear regression analysis.

CONCLUSION

Our study was the first to demonstrate that eGDR is positively correlated with bone turnover markers in patients with T2DM. This correlation was observed among the male patients with T2DM but not among postmenopausal female patients with T2DM.

The Association of Serum Osteocalcin Levels with Metabolic Parameters and Inflammation in Postmenopausal Women with Metabolic Syndrome

Introduction: Although adipose tissue largely plays a role in the etiopathogenesis of metabolic syndrome (MS), which is an inflammatory process, the skeleton may also contribute to this process through osteocalcin (OC), which is a bone-derived protein. In this study, we aimed to evaluate OC levels in postmenopausal women with MS and to investigate the association of OC levels with the metabolic and inflammatory parameters. Methods: Thirty-five postmenopausal women diagnosed with MS were recruited for the study. Sixteen postmenopausal women without any of the MS criteria formed the control group. Body weight, height, and waist and hip circumference of all of the subjects were measured and body mass indices (BMIs) were calculated. Levels of serum glucose, insulin, C-peptide, triglyceride, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, albumin, creatinine, calcium, phosphorus, total alkaline phosphatase, parathormone, and as inflammatory parameters, erythrocyte sedimentation rate, fibrinogen, and high-sensitive C-reactive protein (hsCRP) were studied from fasting venous blood samples of all the subjects. Homeostatic model assessment for insulin resistance (HOMA-IR) was calculated. Serum total OC levels were studied from all of the subjects. Bone mineral densities were also measured. Results: Serum OC levels of the group with MS median (5.37 ng/mL) were lower than the OC levels of the group without MS (P < 0.01). Serum OC levels significantly and negatively correlated with fasting blood glucose (r = -0.310, P < 0.05), insulin (r = -0.343, P < 0.05), and HOMA-IR (r = -0.384, P < 0.01) values. Serum OC levels showed a significant and negative correlation with body weight (r = -0.293, P < 0.05), BMI (r = -0.333, P < 0.05), and waist-to-hip ratio (r = -0.384, P < 0.05). The inflammatory markers in the patient group were significantly higher than the control group. We found a negative association between serum OC levels and hsCRP levels in all cases (r = -0.283, P < 0.05). Conclusion: In the presence of MS, OC levels are significantly low and display a close association with glucose metabolism and adipose tissue. In addition, OC may play a regulatory role in subclinical systematic inflammatory response.

Associations of Osteocalcin Forms With Metabolic Syndrome and Its Individual Components in Older Men: The Health In Men Study

CONTEXT

The osteoblast-derived polypeptide, osteocalcin (OC), has been associated with lower risk of type 2 diabetes and metabolic syndrome (MetS) in several epidemiological studies. Animal studies have indicated the undercarboxylated form of OC (ucOC) drives its association with metabolic outcomes.

OBJECTIVE

We compared associations of ucOC and carboxylated OC (cOC) with MetS and its components in older men.

METHODS

A cross-sectional analysis of 2575 men aged ≥70 years and older resident in Perth, Western Australia. ucOC was assayed using a hydroxyapatite-binding method, and cOC calculated by subtracting ucOC from total OC. Main outcome measures were MetS and its components.

RESULTS

Both lower serum ucOC and cOC levels, and the proportion of cOC (%cOC) were associated with less favorable metabolic parameters (higher waist circumference, triglyceride, glucose, blood pressure, and lower high-density lipoprotein cholesterol), whereas inverse associations were found with %ucOC. Men in the lowest quintile of ucOC had higher risk of MetS compared to men in the highest quintile (Q1 ≤ 7.7 vs Q5 > 13.8 ng/mL; OR = 2.4; 95% CI, 1.8-3.2). Men in the lowest quintile of cOC had higher risk of MetS compared to those in the highest quintile (≤ 5.8 vs > 13.0 ng/mL; OR = 2.4; 95% CI, 1.8-3.2).

CONCLUSION

Lower concentrations of serum ucOC or cOC were associated with less favorable metabolic parameters and a higher risk of MetS. In contrast, a lower proportion of ucOC was associated with better metabolic parameters and lower MetS risk. Further research is warranted to determine whether ucOC and cOC are suitable biomarkers for cardiometabolic risk in men.

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 Serum Osteocalcin Levels and Metabolic Syndrome according to the Menopausal Status of Korean Women

BACKGROUND

Osteocalcin is known to regulate energy metabolism. Recently, metabolic syndrome (MetS) has been found to be associated with reduced levels of osteocalcin in men, as well as in postmenopausal women. The aim of this study was to investigate the association between serum osteocalcin and MetS in premenopausal women, compared with that in postmenopausal women.

METHODS

This cross-sectional study was based on 5,896 participants who completed a health screening examination. They were classified according to their menopausal status. Each group was subdivided into non-MetS and MetS groups according to the modified National Cholesterol Education Program-Adult Treatment Panel III criteria. Serum osteocalcin levels were measured using the electrochemiluminescence immunoassay.

RESULTS

Serum osteocalcin level was significantly lower in women with MetS than in those without MetS, after adjusting for confounders (14.12 ± 0.04 vs. 13.17 ± 0.13 [P = 0.004] in premenopausal women, and 20.34 ± 0.09 vs. 19.62 ± 0.21 [P < 0.001] in postmenopausal women), regardless of their menopausal status. Serum osteocalcin levels decreased correspondingly with an increasing number of MetS elements (P for trend < 0.001). Multiple regression analysis demonstrated that waist circumference (β = -0.085 [P < 0.001] and β = -0.137 [P < 0.001]) and hemoglobin A1c (β = -0.09 [P < 0.001] and β = -0.145 [P < 0.001]) were independent predictors of osteocalcin in premenopausal and postmenopausal women. Triglyceride levels were also independently associated with osteocalcin levels in premenopausal women (β = -0.004 [P < 0.013]). The odds ratio (OR) for MetS was significantly higher in the lowest quartile than in the highest quartile of serum osteocalcin levels after adjusting for age, alkaline phosphatase, uric acid, high sensitivity C-reactive protein, and body mass index in all women (OR, 2.00; 95% confidence interval [CI], 1.49-2.68) as well as in premenopausal (OR, 2.23; 95% CI, 1.39-3.58) and postmenopausal (OR, 2.01; 95% CI, 1.26-3.23) subgroups.

CONCLUSION

Lower serum osteocalcin concentrations were significantly associated with MetS in both premenopausal and postmenopausal women and were therefore independent of menopausal status.

The roles of osteocalcin in lipid metabolism in adipose tissue and liver

Bone provides skeletal support and functions as an endocrine organ by producing osteocalcin, whose uncarboxylated form (GluOC) increases the metabolism of glucose and lipid by activating its putative G protein-coupled receptor (family C group 6 subtype A). Low doses (≤10 ng/ml) of GluOC induce the expression of adiponectin, adipose triglyceride lipase and peroxisome proliferator-activated receptor γ, and promote active phosphorylation of lipolytic enzymes such as perilipin and hormone-sensitive lipase via the cAMP-PKA-Src-Rap1-ERK-CREB signaling axis in 3T3-L1 adipocytes. Administration of high-dose (≥20 ng/ml) GluOC induces programmed necrosis (necroptosis) through a juxtacrine mechanism triggered by the binding of Fas ligand, whose expression is induced by forkhead box O1, to Fas that is expressed in adjacent adipocytes. Furthermore, expression of adiponectin and adipose triglyceride lipase in adipocytes is triggered in the same manner as following low-dose GluOC stimulation; these effects protect mice from diet-induced accumulation of triglycerides in hepatocytes and consequent liver injury through the upregulation of nuclear translocation of nuclear factor-E2-related factor-2, expression of antioxidant enzymes, and inhibition of the c-Jun N-terminal kinase pathway. Evaluation of these molecular mechanisms leads us to consider that GluOC might have potential as a treatment for lipid metabolism disorders. Indeed, there have been many reports demonstrating the negative correlation between serum osteocalcin levels and obesity or non-alcoholic fatty liver disease, a common risk factor for which is dyslipidemia in humans. The present review summarizes the effects of GluOC on lipid metabolism as well as its possible therapeutic application for metabolic diseases including obesity and dyslipidemia.

Osteocalcin and measures of adiposity: a systematic review and meta-analysis of observational studies

Osteocalcin, the osteoblast-derived protein, has been shown to be modulated in patients with problematic glucose metabolism. Our systematic review and meta-analysis found that in humans, higher blood osteocalcin level is associated with lower body indices of fat.

PURPOSE/INTRODUCTION

Osteocalcin (OC) was found to be inversely correlated with measures of glucose and energy metabolism, with some groups suggesting the undercarboxylated form (ucOC) to be metabolically active, although the link is not clear, especially in humans. Given obesity is a major risk factor for metabolic disorders, we aimed to assess the correlation between OC and two measures of body weight: body mass index (BMI) and percentage body fat (%BF).

METHODS

MEDLINE and EMBASE were searched to identify observational studies in adult populations that reported the crude correlation coefficients (r) between OC and BMI and %BF. Pool r were obtained using random-effects models.

RESULTS

Fifty-one publications were included in this analysis. Both total OC (TOC) (pooled r = - 0.151, 95% CI - 0.17, - 0.130; I² = 52%) and ucOC (pooled r = - 0.060, 95% CI - 0.103, - 0.016; I² = 54%) were inversely correlated with BMI. The pooled r between TOC and BMI in Caucasian-and-other-regions (r = - 0.187) were stronger than those in Asian populations (r = - 0.126; intra-group p = 0.002; R² = 0.21). The mean/median BMI of the reported cohort was the major contributor to between-study heterogeneity in correlation between TOC/ucOC and BMI (R² = 0.28 and 0.77, respectively). Both TOC and ucOC were also inversely correlated with %BF (TOC: pooled r = - 0.185, 95% CI - 0.257 to - 0.112; ucOC: pooled r = - 0.181, 95% CI - 0.258 to - 0.101).

CONCLUSION

Higher OC and ucOC were correlated with lower BMI and %BF. The inverse correlations between TOC/ucOC and BMI appear to be affected by ethnicity and obesity status.

Is oxidative stress of adipocytes a cause or a consequence of the metabolic syndrome?

Metabolic syndrome is accompanied by oxidative stress in animals and humans. The main source of ROS in experimental metabolic syndrome is NADPH oxidase and possibly adipocyte mitochondria. It is now documented that oxidative stress induces insulin resistance of adipocytes and increases secretion of leptin, MCP-1, IL-6, and TNF-α by adipocytes. It was established that oxidative stress induces a decrease in adiponectin production by adipocytes. It has also been shown that obesity itself can induce oxidative stress. Oxidative stress can cause an alteration of intracellular signaling in adipocytes that apparently leads to the formation of insulin resistance of adipocytes. Chronic stress, glucocorticoids, mineralocorticoids, angiotensin-II, TNF-α also play an important role in the pathogenesis of oxidative stress of adipocytes. Oxidative stress is not only a consequence of metabolic syndrome, but also a reason and a foundational link in the pathogenesis of the metabolic syndrome.

Complex interplay among adiposity, insulin resistance and bone health

Obesity and osteoporosis are common public health problems. Paradoxically, while obesity is associated with higher bone density, type 2 diabetic obese individuals have an increased fracture risk. Although obesity and insulin resistance co-exist, some obese individuals remain insulin-sensitive. We suggest that the apparent paradox relating obesity, bone density and fracture risk in type 2 diabetes may be at least partly influenced by differences in bone strength and quality between insulin-resistant and insulin-sensitive obese individuals. In this review, we focus on the complex interplay between, adiposity, insulin resistance and osteoporotic fracture risk and suggest that this is an important area of study that has implications for individually tailored and targeted treatment to prevent osteoporotic fracture in obese type 2 diabetic individuals.

Association between serum osteocalcin and body mass index: a systematic review and meta-analysis

PURPOSE

Osteocalcin is considered as a bone-derived hormone affecting on the body fat distribution and body mass index. Several cross-sectional studies have investigated the association between serum osteocalcin and body mass index. The aim of this study was to summarize the evidence on the relationship between serum osteocalcin and body mass index.

METHODS

We conducted a complete search up to November 2016 in PubMed and SCOPUS and reviewed reference list of all relevant articles and reviews. The DerSimonian-Laird method were used to pool effect sizes of eligible studies. The potential sources of heterogeneity were assessed using the standard χ 2 test.To find possible the sources of between-study heterogeneity, we carried out subgroup analyses based on sex, and type of study population.

RESULTS

There was a significant inverse association in the overall result of this study between serum osteocalcin levels and BMI(r = -0.161; 95% CI: -0.197, -0.124, p < 0.000). In the subgroup analysis to find the sources of significant heterogeneity between-study, we observed that the type of the study population may be the source of between-study heterogeneity and the most correlation was seen in metabolic syndrome studies (r = -0.265; p = 0.000).

CONCLUSION

Findings from the available data indicated an overall significant inverse association between serum osteocalcin and body mass index. Further studies based on the type of study population are needed to better clarify these associations.

[Osteocalcin and glucose metabolism: assessment of human studies]

Osteocalcin, a protein secreted by osteoblasts, is recognized as a biomarker of bone mineralization. Besides, animal experimental studies have shown that osteocalcin could play an important role in glucose metabolism. Over the course of the last decade, this theory has been investigated in several human studies. Most of the results obtained from these reports support a positive correlation between total and undercarboxylated osteocalcin and insulin secretion/sensitivity. Studies also corroborate a reverse association with glycemic parameters such as fasting glucose and glycated hemoglobin. Nevertheless, because most of the studies published are observational, it is not possible to yet confirm a direct cause-effect relationship. Research in the field will surely contribute to the development of new pharmacological strategies for the treatment of endocrine diseases.

Osteocalcin, a bone-derived hormone with important andrological implications

Increasing evidence disclosed the existence of a novel multi-organ endocrine pathway, involving bone, pancreas and testis, of high penetrance in energy metabolism and male fertility. The main mediator of this axis is undercarboxylated osteocalcin (ucOC), a bone-derived protein-exerting systemic effects on tissues expressing the metabotropic receptor GPRC6A. The recognized effects of ucOC are the improvement of insulin secretion from the pancreas, the amelioration of systemic insulin sensitivity, in particular in skeletal muscle, and the stimulation of the global endocrine activity of the Leydig cell, including vitamin D 25-hydroxylation and testosterone production. The supporting evidence of this circuit in both animal and human models is here reviewed, with particular emphasis on the role of ucOC on testis function. The possible pharmacological modulation of this hormonal circuit for therapeutic aims is also discussed.

Osteocalcin as a potential risk biomarker for cardiovascular and metabolic diseases

Clear evidence supports a role for circulating and locally-produced osteocalcin (OC) in the pathophysiology of cardiovascular (CV) lesions and CV risk, also in combination with metabolic changes, including type 2 diabetes mellitus (T2DM). Reduced plasma OC levels are associated with greater incidence of pathological CV changes, like arterial and valvular calcification, coronary and carotid atherosclerosis and increased carotid intima-media thickness. The actual relationship between OC levels and incidence of major CV events is, however, still unclear. Moreover, reduced circulating OC levels have been mostly associated with insulin resistance, metabolic syndrome or T2DM, indicating relevant OC actions on pancreatic β-cells and insulin secretion and activity. Based on these observations, this review article will attempt to summarize the current evidence on the potential usefulness of circulating OC as a biomarker for CV and metabolic risk, also evaluating the currently open issues in this area of research.

Metabolic Syndrome and Menopause: Pathophysiology, Clinical and Diagnostic Significance

Menopause is a risk factor for cardiometabolic diseases, including metabolic syndrome (MetS), type 2 diabetes, and cardiovascular diseases. MetS is a constellation of interdependent factors such as insulin resistance, abdominal obesity, dyslipidemia, and hypertension. The prevalence of MetS in postmenopause is due to loss of the protective role of estrogens and increased circulating androgens resulting in changes to body fat distribution and development of abdominal obesity. Excessive visceral adipose tissue plays an important role due to synthesis and secretion of bioactive substances such as adipocytokines, proinflammatory cytokines, reactive oxygen species, prothrombotic, and vasoconstrictor factors. MetS may also impact risk assessment of breast cancer, osteoporosis and chronic kidney disease, and quality of life during the menopausal transition. Increased MetS has stimulated the exploration of new laboratory tests for early detection and therapies.

Searching for additional endocrine functions of the skeleton: genetic approaches and implications for therapeutics

Our knowledge of whole organism physiology has greatly advanced in the past decades through mouse genetics. In particular, genetic studies have revealed that most organs interact with one another through hormones in order to maintain normal physiological functions and the homeostasis of the entire organism. Remarkably, through these studies many unexpected novel endocrine means to regulate physiological functions have been uncovered. The skeletal system is one example. In this article, we review a series of studies that over the years have identified bone as an endocrine organ. The mechanism of action, pathological relevance, and therapeutic implications of the functions of the bone-derived hormone osteocalcin are discussed. In the last part of this review we discuss the possibility that additional endocrine functions of the skeleton may exist.

The Relationship of Metabolic Syndrome and Body Composition in Children with Premature Adrenarche: Is It Age Related?

BACKGROUND

Studies that evaluate both body composition and metabolic syndrome (MeS) risk in prepubertal children with premature adrenarche (PA) are limited.

METHODS

Fifty-eight prepubertal children (aged 5-9 years, 33 female and 25 male), 30 with PA and 28 controls, were evaluated for the presence of MeS as defined by age-modified National Cholesterol Education Program Adult Treatment Panel III criteria. A subset had dual-energy X-ray absorptiometry and bone markers (n = 23/58) to evaluate the effect of hyperandrogenism on metabolic abnormalities and body composition.

RESULTS

There was no difference in the prevalence of MeS between PA and controls (p = 0.138). Children with MeS were obese with an increased waist circumference (WC) and decreased high-density lipoprotein levels. Androgens were not associated with having more than one criterion for MeS (p = 0.08) but were associated with triglycerides and WC (p = 0.029 and p = 0.041, respectively). Lean mass was greater in PA subjects (p = 0.039), and androgens correlated with bone mineral density (p = 0.029) and total body fat (p = 0.008). Subjects with a higher percent of body fat were more likely to have more than one MeS risk factor (p = 0.005).

CONCLUSIONS

MeS was seen only in obese subjects whether or not they had PA. Thus, it appears that obesity drives metabolic risk in the prepubertal population rather than PA. Our findings are important in determining how the prepubertal patient with PA should be evaluated for metabolic risk.