Sex-Specific Predictors of Metabolic Syndrome Independent of Its Components:

The association of selenium exposure with the odds of metabolic syndrome: a dose-response meta-analysis

BACKGROUND

Selenium is a key regulator of metabolic homeostasis. It has been proposed that exposure to selenium might be associated with metabolic syndrome (MetS). However, the results are contradictory. This meta-analysis was carried out to analyze the relationships between selenium levels in biological samples and odds of Mets.

METHODS

We searched Scopus and PubMed databases up until September 2024 to identify relevant studies. Odds ratio (OR) and 95% confidence interval was used to pool the data using a random effects model.

RESULTS

The meta-analysis encompassed 18 observational studies involving 21,481 participants. It found that higher selenium exposure was related to an elevated likelihood of MetS (OR = 1.30, 95% CI = 1.12-1.51), even after controlling for covariates, such as smoking, age, alcohol consumption, and physical activity. Heterogeneity was significant among the studies (I² = 88.9%, P = 0.001). While elevated serum selenium levels linked to a higher odds of MetS, no such relationship was observed for selenium in urine or toenails. Subgroup analyses indicated that this association was evident only in females (OR = 2.0, 95% CI = 1.17-1.43) and particularly pronounced in individuals aged ≥ 50 years. A dose-response relationship was identified, showing a 6% increase in MetS odds for each additional 10 µg/L of serum selenium, with the odds rising non-linearly when serum levels surpassed 80 µg/L.

CONCLUSIONS

This study suggests that selenium may associated with the odds of MetS, following a dose-response relationship.

Sex-Based Differences and Risk Factors for Comorbid Nonalcoholic Fatty Liver Disease in Patients with Bipolar Disorder: A Cross-Sectional Retrospective Study

Purpose

Sex-based differences in patients with bipolar disorders (BD) are well recognized, and it is well known that the prevalence and severity of nonalcoholic fatty liver disease (NAFLD) are both higher in men than in women. Although metabolic disorders such as NAFLD are common in patients with BD, sex differences and risk factors for NAFLD comorbidity in these patients have not been thoroughly explored. This study aimed to investigate sex differences in patients with comorbid NAFLD and BD and associated risk factors.

Methods

This retrospective cross-sectional study included 710 patients with BD. Clinical data of patients with BD, including information on fasting glucose, liver function-related enzymes, relevant lipid data, uric acid, the triglyceride-glucose index (TyG), and demographics, were derived from the hospital electronic medical record system from June 2020 to July 2022. We performed logistic regression analysis and calculated the odds ratios with 95% confidence intervals of factors using t-tests, χ²-tests, and receiver operating characteristic. NAFLD was diagnosed using liver ultrasonography.

Results

The prevalence of NAFLD was higher in male patients with BD than in female patients (50.9% vs 38.5%), and there were significant differences in the years of education and marital status (all P<0.05). Regression analysis showed that the risk factors for comorbidities were the body mass index (BMI), fasting glucose, and apolipoprotein B levels in male patients and the BMI, bipolar disease course, glutamine transpeptidase levels, and the TyG in female patients.

Conclusion

Sex-based differences exist in risk factors and in the prevalence of comorbid NAFLD among patients with BD. BMI is a sex-independent risk factor, and clinical attention should be targeted to risk factors associated with comorbid NAFLD related to sex, especially in female patients with BD who presenting a high TyG index.

Association between metabolic syndrome and uric acid: a systematic review and meta-analysis

This systematic review and meta-analysis aim to provide the best evidence on the association between metabolic syndrome (MetS) and uric acid (UA) by determining the size of the effect of this biomarker on MetS. The review protocol is registered with PROSPERO (CRD42021231124). The search covered the PubMed and Scopus databases. Methodological quality was assessed with the STROBE tool, overall risk of bias with RevMan (Cochrane Collaboration) and quality of evidence with Grade Pro. Initially, 1582 articles were identified. Then, after excluding duplicates and reviewing titles and abstracts, 1529 articles were excluded from applying the eligibility criteria. We included 43 papers (56 groups) comparing UA concentrations between subjects 91,845 with MetS and 259,931 controls. Subjects with MetS had a higher mean UA of 0.57 mg/dl (95% CI 0.54-0.61) (p < 0.00001). Given the heterogeneity of the included studies, the researchers decided to perform subgroups analysis. Men with MetS have a higher UA concentration mg/dl 0.53 (95% CI 0.45-0.62, p < 0.00001) and women with MetS 0.57 (95% CI 0.48-0.66, p < 0.00001) compared to subjects without MetS. Assessment of UA concentration could provide a new avenue for early diagnosis of MetS, as a new biomarker and the possibility of new therapeutic targets.

Can biomarkers be used to improve diagnosis and prediction of metabolic syndrome in childhood cancer survivors? A systematic review

Childhood cancer survivors (CCS) are at increased risk to develop metabolic syndrome (MetS), diabetes, and cardiovascular disease. Common criteria underestimate adiposity and possibly underdiagnose MetS, particularly after abdominal radiotherapy. A systematic literature review and meta-analysis on the diagnostic and predictive value of nine newer MetS related biomarkers (adiponectin, leptin, uric acid, hsCRP, TNF-alpha, IL-1, IL-6, apolipoprotein B (apoB), and lipoprotein(a) [lp(a)]) in survivors and adult non-cancer survivors was performed by searching PubMed and Embase. Evidence was summarized with GRADE after risk of bias evaluation (QUADAS-2/QUIPS). Eligible studies on promising biomarkers were pooled. We identified 175 general population and five CCS studies. In the general population, valuable predictive biomarkers are uric acid, adiponectin, hsCRP and apoB (high level of evidence), and leptin (moderate level of evidence). Valuable diagnostic biomarkers are hsCRP, adiponectin, uric acid, and leptin (low, low, moderate, and high level of evidence, respectively). Meta-analysis showed OR for hyperuricemia of 2.94 (age-/sex-adjusted), OR per unit uric acid increase of 1.086 (unadjusted), and AUC for hsCRP of 0.71 (unadjusted). Uric acid, adiponectin, hsCRP, leptin, and apoB can be alternative biomarkers in the screening setting for MetS in survivors, to enhance early identification of those at high risk of subsequent complications.

Relationship between inflammatory parameters and cardiovascular and lifestyle factors in the Mugello study oldest old

AIM

To explore possible inter-relationships of various biomarkers of inflammation and lifestyle and other cardiovascular risk factors (age, gender, smoking history, hypertension, Type 2 diabetes, dyslipidemia, alteration of circadian rhythms, body mass index, calf circumference, thigh circumference, abdominal circumference) in the Mugello study oldest old.

METHODS

In 399 noninstitutionalized nonagenarians (291 women), whole blood cells, mean platelet volume, C-reactive protein, uric acid, gamma-glutamyl transferase were assessed.

RESULTS

Aging resulted as the only independent determinant for uric acid (<0.05), and abdominal circumference for C-reactive protein. Female gender (<0.01), and thigh circumference (<0.05) remained as determinants for mean platelet volume, age (<0.01), and male gender (<0.01) for gamma-glutamyl transferase, and Type 2 diabetes (≤0.01) and alteration of circadian rhythms (<0.05) for whole blood cells.

CONCLUSION

Several inflammatory parameters remain associated with adverse lifestyle and cardiovascular risk factors even among nonagenarians.

Relation of Biochemical Parameters with Flow-mediated Dilatation in Patients with Metabolic Syndrome

BACKGROUND

Metabolic syndrome (MetS) is one of the high cardiovascular (CV) situations. Endothelial dysfunction, which is a common finding in patients with MetS, is related with increased CV risk. In patients with MetS, the effect of the major CV risk factors, not included in the MetS definition, on endothelial dysfunction is not well known. The aim of this study was to determine the effect of major CV risk factors such as gender, smoking, family history, and biochemical parameters on endothelial dysfunction in patients with MetS.

METHODS

The study was performed between December 2010 and August 2014. A total of 55 patients (15 females and 40 males) with MetS and 81 healthy controls (37 females and 44 males) with a body mass index <25 kg/m2 were enrolled in the study. Endothelial dysfunction was measured by flow-mediated dilatation (FMD), oxidative stress parameters; high-sensitivity C-reactive protein (hs-CRP), oxidized low-density lipoprotein (ox-LDL), endothelial nitric oxide synthase (e-NOS), nitric oxide, and cell adhesion markers; von Willebrand factor, and e-selectin. Platelet aggregation (endothelial adenosine diphosphate), total platelet count, and mean platelet volume were additionally analyzed and demographic parameters were explored. Student's t- test, Mann-Whitney U-test, and Chi-square test were used to analyze the results.

RESULTS

The fasting blood glucose (z= 3.52, P= 0.001), hs-CRP (z = 3.23, P= 0.004), ox-LDL (z = 2.62, P= 0.013), and e-NOS (z = 2.22, P= 0.026) levels and cardiac risk score (z = 5.23, P< 0.001) were significantly higher in patients with MetS compared with the control group. Smoking was correlated with decreased FMD (χ2 = 9.26, P= 0.002) in MetS patients but not in the control group.

CONCLUSIONS

Increased ox-LDL, hs-CRP, and e-NOS are likely to be a result of oxidative stress, a condition in which an imbalance occurs between the production and inactivation of reactive nitrogen and oxygen species. In addition, in patients with MetS, smoking is independently related to endothelial dysfunction.

Gender-related association between uric acid, homocysteine, γ-glutamyltransferase, inflammatory biomarkers and metabolic syndrome in subjects affected by obesity

AIM

Evaluation of gender-related differences in uric acid (UA), homocysteine and inflammatory biomarkers as metabolic syndrome (MetS) determinants.

PATIENTS & METHODS

Anthropometric and routine data were obtained from 825 obese subjects (591 F, mean age 54 ± 14 years).

RESULTS

Hyperuricemia was 24% in both genders. Waist circumference, creatinine, triglycerides, C-reactive protein and γ-glutamyltransferase were identified as UA-independent determinants in females and creatinine and insulin in males. Hyperuricemia increased MetS risk in both genders (2.8-fold and 1.5-fold in males and females).

CONCLUSION

UA and γ-glutamyltransferase positively relate to MetS in both genders, although inflammatory abnormalities are closer related to UA and MetS in females. These differences in gender physiology may account for epidemiologic gender disparities and help to develop gender-targeted clinical strategies.

Modulation of SHBG binding to testosterone and estradiol by sex and morbid obesity

OBJECTIVE

Sex hormone-binding globulin (SHBG) binds and transports testosterone and estradiol in plasma. The possibility that SHBG is a mixture of transporting proteins has been postulated. We analyzed in parallel the effects of obesity status on the levels and binding capacity of circulating SHBG and their relationship with testosterone and estradiol.

DESIGN

Anthropometric measures and plasma were obtained from apparently healthy young (i.e. 35 ± 7 years) premenopausal women (n = 32) and men (n = 30), with normal weight and obesity (BMI >30 kg/m²).

METHODS

SHBG protein (Western blot), as well as the plasma levels of testosterone, estradiol, cortisol and insulin (ELISA) were measured. Specific binding of estradiol and testosterone to plasma SHBG was analyzed using tritium-labeled hormones.

RESULTS

Significant differences in SHBG were observed within the obesity status and gender, with discordant patterns of change in testosterone and estradiol. In men, testosterone occupied most of the binding sites. Estrogen binding was much lower in all subjects. Lower SHBG of morbidly obese (BMI >40 kg/m²) subjects affected testosterone but not estradiol. The ratio of binding sites to SHBG protein levels was constant for testosterone, but not for estradiol. The influence of gender was maximal in morbid obesity, with men showing the highest binding/SHBG ratios.

CONCLUSIONS

The results reported here are compatible with SHBG being a mixture of at least two functionally different hormone-binding globulins, being affected by obesity and gender and showing different structure, affinities for testosterone and estradiol and also different immunoreactivity.

Does the low-density lipoprotein cholesterol play a key role in predicting metabolic syndrome in the Iranian adult population?

BACKGROUND

The low density lipoprotein cholestrol (LDL-C) has an important role in the pathogenesis of cardiovascular disease but its association and predictive accuracy with metabolic syndrome (MetS) remains controversial. The objective of this study was to investigate the association and predictive ability of LDL-C with MetS.

METHODS

We analyzed the data from a population-based cross-sectional study conducted on representative samples of an Iranian adult population. The demographic data, anthropometric measures and the lipid profiles were measured with standard methods, and MetS was diagnosed by ATP III criteria. Logistic regression model and ROC analysis were used to estimate the predictive accuracy of LDL-C and its association with MetS.

RESULTS

The mean age (±SD) of participants with and without MetS was 47.6±12.5 years and 39.1±12.9 years, respectively (p=0.001). All anthropometric measures (body mass index, waist circumference, waist to hip ratio, waist to height ratio), systolic blood pressure, total cholesterol, triglycerides and fasting blood glucose were significantly higher in MetS, but a significantly higher difference in LDL-C was observed only in women. Accuracy of LDL-C in predicting MetS for men and women was 0.48 (95% CI: 0.43-0.54) and 0.55 (95% CI: 0.51-0.60), respectively. The unadjusted and adjusted odds ratios of different quartiles of LDL-C compared with 1st quartile did not reach to a significant level.

CONCLUSION

Serum LDL-C level is not significantly associated with MetS but exhibits a weak ability in predicting MetS in women.