Relationship between iron status markers and insulin resistance: an exploratory study in subjects with excess body weight

Mendelian randomization study highlights the role of hematological traits on Type-2 diabetes mellitus in African ancestry individuals

Introduction

Observational studies have identified associations between hematological traits and type-2 diabetes mellitus (T2D). However, it is difficult to infer causal effects due to the potential of confounding. Our study utilizes the Mendelian randomization (MR) approach to address the above limitation and investigate the causal effect of hematological traits such as white blood cell (WBC), platelets (PLT), and red blood cell (RBC) on T2D in individuals of African ancestry.

Methods

The participating cohorts included participants of African ancestry in the Blood Cell consortium and the Million Veteran Program dataset. Using GWAS summary statistics, we applied a univariable and multivariable Two-sample MR to estimate the causal relationship between hematological traits and T2D.

Results

In the main IVW MR estimates, genetically predicted levels of mean corpuscular hemoglobin concentration (MCHC), mean corpuscular hemoglobin (MCH), and mean corpuscular volume (MCV) were associated with decreased risk of T2D. We also observed a decreased risk of T2D with genetically predicted total WBC count and neutrophil count (NEU), for the WBC traits. The multivariable analysis further supported the direct associations of genetically predicted MCH, MCHC, and MCV levels with a decreased risk of T2D. For the European ancestry, a similar pattern of association was observed for MCH and MCV.

Discussion

These findings indicate that hematological traits may differentially play a role in the development of T2D and be affected by T2D. However, further research is needed to validate and explore the biological pathways and mechanisms involved in these associations.

The Interplay Between Iron Metabolism and Insulin Resistance: A Key Factor in Optimizing Obesity Management in Children and Adolescents

Iron plays a vital role in insulin signaling, regulating molecular mechanisms that influence cellular insulin responses. This review explores the link between iron metabolism and insulin resistance (IR) in children and adolescents with obesity. A connection between iron metabolism, iron deficiency (ID), and IR is well-documented, but further longitudinal studies are needed to better understand how iron metabolism influences insulin resistance during childhood and adolescence. This connection warrants attention due to its significant public health implications, as optimizing obesity management could help prevent both ID and metabolic complications in children. Current evidence does not suggest that dietary factors are primary contributors to ID in children. However, there is scientific evidence that weight reduction can restore iron homeostasis in people with obesity. Therefore, efforts should focus on improving dietary habits, increasing awareness of iron's importance, and implementing strategies to address both ID and obesity.

Iron Status Correlates Strongly to Insulin Resistance Among US Adults: A Nationwide Population-Based Study

CONTEXT

Evidence on the link between iron status markers and insulin resistance (IR) is limited.

OBJECTIVE

We aimed to explore the relationship between iron status and IR among US adults.

METHODS

This study involved 2993 participants from the National Health and Nutrition Examination Survey (NHANES) 2003-2006, 2017-2020. IR is characterized by a homeostatic model assessment (HOMA)-IR value of ≥2.5. Weighted linear and multivariable logistic regression analyses were used to examine the linear relationships between iron status and IR. Furthermore, restricted cubic splines (RCS) were used to identify the nonlinear dose-response associations. Stratified analyses by age, sex, body mass index, and physical activity were also performed. Last, a receiver operating characteristic (ROC) curve was used to evaluate the predictive value of iron status in IR.

RESULTS

In weighted linear analyses, serum iron (SI) exhibited a negative correlation with HOMA-IR (β -0.03, 95% CI -0.05, -0.01, P = .01). In weighted multivariate logistic analyses, iron intake and the serum transferrin receptor (sTfR) were positively correlated with IR (OR 1.02, 95% CI 1.00-1.04, P = .04; OR 1.07, 95% CI 1.02-1.13, P = .01). Also, SI and transferrin saturation (TSAT) were negatively correlated with IR (OR 0.96, 95% CI 0.94-0.98, P < .0001; OR 0.98, 95% CI 0.97-0.99, P < .001) after adjusting for confounding factors. RCS depicted a nonlinear dose-response relationship between sTfR and TSAT and IR. This correlation remained consistent across various population subgroups. The ROC curve showed that TSAT performed better than iron intake, SI and sTfR in ROC analyses for IR prediction.

CONCLUSION

All biomarkers demonstrated significantly lower risk of IR with increasing iron levels, which will contribute to a more comprehensive and in-depth understanding of the relationship between the 2 and provide a solid foundation for future exploration of the mechanisms underlying their relationship.

Association Between Dietary Inflammatory Index and Triglyceride Glucose-Body Mass Index with Iron Deficiency in Reproductive Age Women: Evidence from NHANES 2005-2018

Background & Aims

There is a growing focus on the role of dietary factors and metabolic conditions in the evolution and progression of iron deficiency (ID), yet few studies have examined the underlying mechanisms. Dietary Inflammatory Index (DII) is a metric that gauges the inflammatory potential of an overall diet. This study explores the association between DII and triglyceride glucose-body mass index (TyG-BMI) with ID in reproductive-age women.

Methods

This analysis utilized data from 2311 reproductive-age women in the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2018. ID was identified using serum ferritin and transferrin receptor (TfR). The association between DII, TyG-BMI and ID was assessed using weighted logistic regression, linear regression and restricted cubic spline (RCS) models, with receiver operating characteristic (ROC) curve analysis for diagnostic power. Mediation effects of TyG-BMI were further explored by causal mediation analysis.

Results

Among reproductive-age women, both DII and TyG-BMI were significantly positively associated with ID (DII: OR = 1.32, 95% CI 1.19, 1.48; TyG-BMI: OR = 1.13, 95% CI 1.02, 1.35). There is a close relationship between the DII index and TfR (β= 1.17, 95% CI 1.03, 1.13). RCS analysis indicated that the relationships were mostly linear (P-overall < 0.05, P-nonlinear > 0.05). Furthermore, TyG-BMI mediated 5.19%, 12.83%, and 5.63% of the associations between DII and ID, Ferritin, and transferrin receptor (TfR), respectively.

Conclusion

The findings suggest that targeted interventions to enhance dietary practices, nutritional intake, and overall metabolic well-being may result in substantial amelioration of ID among reproductive women.

Iron homeostasis and insulin sensitivity: unraveling the complex interactions

Diabetes has arisen as a noteworthy global health issue, marked by escalating incidence and mortality rates. Insulin, crucial for preserving euglycemia, acts as a vital energy provider for various tissues. Iron metabolism notably plays a significant role in the development of insulin resistance, a key factor in the onset of various metabolic disorders. The intricate interaction between iron and insulin signaling encompasses complex regulatory mechanisms at the molecular level, thereby impacting cellular reactions to insulin. The intricate interplay between insulin and glucagon, essential for precise regulation of hepatic glucose production and systemic glucose levels, may be influenced by certain microelements for instance zinc, copper, iron, boron, calcium, cobalt, chromium, iodine, magnesium and selenium. While significant progress has been achieved in elucidating the pathophysiological connections between iron overload and glucose metabolism, our understanding of the involvement of the Fenton reaction and oxidative stress in insulin resistance influencing many chronical conditions remains limited. Furthermore, the exploration of the multifaceted roles of insulin in the human body continues to be a subject of active investigation by numerous scientific researchers. This review comprehensively outlines the potential adverse impact of iron overload on insulin function and glucose metabolism. Additionally, we provide a synthesis of findings derived from various research domains, encompassing population studies, animal models, and clinical investigations, to scrutinize the multifaceted relationship between iron and insulin sensitivity. Moreover, we delineate instances of correlations between serum iron levels and various medical conditions, including the diabetes also gestational diabetes and obesity.

Iron Homeostasis-Related Parameters and Hepcidin/Ferritin Ratio: Emerging Sex-Specific Predictive Markers for Metabolic Syndrome

Metabolic syndrome (MetS) is a worldwide public health challenge. Accumulating evidence implicates elevated serum ferritin and disruptions in iron metabolism as potential elements linked to an increased risk of MetS. This study investigates the relationship between iron homeostasis-including hepcidin levels, serum iron concentration, unsaturated iron-binding capacity (UIBC), and the hepcidin/ferritin (H/F) ratio-and MetS. In this descriptive cross-sectional study, 209 participants aged 24-70 were categorized into two groups: 103 with MetS and 106 without MetS. All participants underwent medical assessment, including anthropometric measures, indices of glycemic control, lipid profiles, and iron-related parameters. Participants were further stratified by the Homeostasis Model Assessment-Insulin Resistance index into three subgroups: insulin-sensitive (IS) (<1.9), early insulin resistance (EIR) (>1.9 to <2.9), and significant insulin resistance (SIR) (>2.9). Notable increments in serum ferritin and hepcidin were observed in the SIR group relative to the IS and EIR groups, with a significant association between metabolic parameters. The UIBC and serum ferritin emerged as significant predictors of MetS, particularly in men, with an area under the curve (AUC) of 0.753 and 0.792, respectively (p ≤ 0.001). In contrast, hepcidin was notably correlated with MetS in women, with an AUC of 0.655 (p = 0.007). The H/F ratio showed superior predictive capability for MetS across both sexes (at cutoff level = 0.67). Among women, this ratio had an AUC of 0.639 (p = 0.015), and for men, it had an AUC of 0.792 (p < 0.001). Hypertension proved an independent risk factor for MetS, affirming its role in metabolic dysregulation. The findings highlight a significant interconnection between iron homeostasis parameters and MetS, with sex-specific variations underscoring the importance of personalized diagnostic criteria. The crucial role of the H/F ratio and the UIBC as emerging predictive markers for MetS indicates their potential utility in identifying at-risk individuals. Further longitudinal research is essential to establish causality and explore the interplay between these biomarkers and MetS.

Association between iron metabolism markers and triglyceride-glucose index: A cross-sectional study in China Health and Nutrition Survey

Iron metabolism plays an important role in insulin resistance, and the triglyceride-glucose (TyG) index has been proposed in recent years as a more accessible and cost-effective marker for insulin resistance. This study aims to evaluate the association between iron metabolism markers, including ferritin (FER), transferrin (TRF), and transferrin receptor (TFR), and the TyG index. A total of 6524 Chinese individuals aged between 18 and 75 years were included in this study. Multivariable linear models were used to investigate the association between FER, TRF, and TFR levels, and the TyG index. Further subgroup analyses stratified by age and sex were also performed. There was a positive association between FER and TRF levels and the TyG index in all 3 multivariable linear regression models, regardless of stratification by sex and age. Additionally, TFR was positively associated with the TyG index among females and those aged ≥45 years, but not among males and those aged <45 years. Our findings reveal a positive association between FER and TRF levels and the TyG index in a Chinese population, while the association between TFR levels and the TyG index showed different patterns depending on age and gender.

Potential Mediating Role of Iron Biomarkers in the Association of Sex With Glucose, Insulin, and Type 2 Diabetes

Context

Sex-specific prevalence and incidence of type 2 diabetes (T2D) have been reported, but the underlying mechanisms are uncertain.

Objective

In this study, we aimed to investigate whether iron biomarkers mediate the association between biological sex and glucose metabolism and the incidence of T2D.

Methods

We used data from the general population enrolled in the prospective Prevention of REnal and Vascular ENd-stage Disease study in Groningen, The Netherlands. We measured ferritin, transferrin saturation (TSAT), hepcidin, soluble transferrin receptor (sTfR), fasting plasma glucose (FPG), fasting plasma insulin (FPI) levels, and incidence of T2D. We used multivariable regression and mediation analyses to investigate our hypothesis. All iron biomarkers, FPG, and FPI were log-transformed.

Results

The mean (SD) age of the 5312 (51.3% female) individuals was 52.2 (11.6) years. Compared with males, females had lower FPG (β = -.01; 95% CI -0.02, -0.01) and FPI (β = -.03; 95% CI -0.05, -0.02) levels. Ferritin, hepcidin, and sTfR showed potential mediating effects on the association between sex and FPG, 21%, 5%, and 7.1%, respectively. Furthermore, these variables mediated 48.6%, 5.7%, and 3.1% of the association between sex and FPI, respectively. Alternatively, TSAT had a suppressive mediating role in the association of sex with FPG and FPI. The incidence of T2D was lower in females than in males (hazard ratio 0.58; 95% CI 0.44, 0.77), with 19.2% of this difference being mediated by ferritin.

Conclusion

Iron biomarkers may partially mediate the association between sex and glucose homeostasis. Future studies addressing the causality of our findings are needed.

Dietary and Lifestyle Factors of Brain Iron Accumulation and Parkinson's Disease Risk

Purpose

Iron is an essential nutrient which can only be absorbed through an individual's diet. Excess iron accumulates in organs throughout the body including the brain. Iron dysregulation in the brain is commonly associated with neurodegenerative diseases like Alzheimer's disease and Parkinson's Disease (PD). Our previous research has shown that a pattern of iron accumulation in motor regions of the brain related to a genetic iron-storage disorder called hemochromatosis is associated with an increased risk of PD. To understand how diet and lifestyle factors relate to this brain endophenotype and risk of PD we analyzed the relationship between these measures, estimates of nutrient intake, and diet and lifestyle preference using data from UK Biobank.

Methods

Using distinct imaging and non-imaging samples (20,477 to 28,388 and 132,023 to 150,603 participants, respectively), we performed linear and logistic regression analyses using estimated dietary nutrient intake and food preferences to predict a) brain iron accumulation score (derived from T2-Weighted Magnetic Resonance Imaging) and b) PD risk. In addition, we performed a factor analysis of diet and lifestyle preferences to investigate if latent lifestyle factors explained significant associations. Finally, we performed an instrumental variable regression of our results related to iron accumulation and PD risk to identify if there were common dietary and lifestyle factors that were jointly associated with differences in brain iron accumulation and PD risk.

Results

We found multiple highly significant associations with measures of brain iron accumulation and preferences for alcohol (factor 7: t=4.02, pFDR=0.0003), exercise (factor 11: t=-4.31, pFDR=0.0001), and high-sugar foods (factor 2: t=-3.73, pFDR=0.0007). Preference for alcohol (factor 7: t=-5.83, pFDR<1×10-8), exercise (factor 11: t=-7.66, pFDR<1×10-13), and high sugar foods (factor 2: t=6.03, pFDR<1×10-8) were also associated with PD risk. Instrumental variable regression of individual preferences revealed a significant relationship in which dietary preferences associated with higher brain iron levels also appeared to be linked to a lower risk for PD (p=0.004). A similar relationship was observed for estimates of nutrient intake (p=0.0006). Voxel-wise analysis of i) high-sugar and ii) alcohol factors confirmed T2-weighted signal differences consistent with iron accumulation patterns in motor regions of the brain including the cerebellum and basal ganglia.

Conclusion

Dietary and lifestyle factors and preferences, especially those related to carbohydrates, alcohol, and exercise, are related to detectable differences in brain iron accumulation and alterations in risk of PD, suggesting a potential avenue for lifestyle interventions that could influence risk.

The Modulation of Euglycemic Endocrine and Exocrine Pancreatic Secretions in Iron Deficiency

OBJECTIVES

The contribution of pancreatic secretions in iron metabolism has been elucidated, but the clinical outcomes of iron deficiency on pancreatic function are debatable. This study aimed to investigate the modulation of euglycemic endocrine and exocrine pancreatic excretions in response to variations in iron availability.

SUBJECTS AND METHODS

Serum levels of insulin, glucagon, insulin-to-glucagon ratio (IGR), and amylase were determined in 170 adult subjects with variable levels of serum iron.

RESULTS

Control (n = 46) and iron-deficient (n = 124) subjects had significant differences (p < 0.001) in their average levels of insulin (68.7 ± 0.5 vs. 100.0 ± 2.0 pmol/dL), glucagon (17.9 ± 0.6 vs. 10.8 ± 0.8 pmol/dL), IGR (4.0 ± 0.1 vs. 19.5 ± 2.1), and amylase (29.7 ± 0.9 vs. 17.5 ± 0.2). The upregulation of serum insulin levels increases proportionally and gradually to the extent of iron deficiency as compared to an abrupt downregulation of serum levels of glucagon and amylase. A significant association was observed between serum iron and IGR (r = -0.645, p < 0.001) and amylase levels (r = 0.653, p < 0.001). The receiver operating characteristic curve analysis defines an excellent predictivity of the reduced serum iron level to discriminate subjects with upregulated IGR and amylase levels with area under curves of 0.938 and 0.905, respectively.

CONCLUSION

Iron deficiency is associated with an adaptive modulation of euglycemic endocrine and exocrine secretions that is consistent with a status of insulin resistance.

Association between iron profile status and insulin resistance in patients with type 2 diabetes mellitus

Introduction

Individuals' burden of insulin resistance and metabolic syndrome, such as type 2 diabetes mellitus, is increasing. This indicates to intrigue into various facets of prevention, early screening, prognostication and feasible treatment alternatives in this arena.

Aim

This study targets to evaluate iron profile status among people diagnosed with type 2 diabetes mellitus and normoglycemic in order to deduce association between iron parameters and insulin resistance, if any exist.

Methodology

A case-control study of total 123 subjects, comprising males and females in the age group of 30 - 70 years were recruited for the study. Case group constituted 81 participants who were diagnosed with type 2 diabetes mellitus and control group constituted 42 healthy individuals who attended routine health check-ups in the hospital. Iron profile parameters including Serum Iron, Serum Ferritin, Total Iron binding Capacity and Glycemic profile parameter like fasting blood glucose, serum insulin were estimated. Transferrin saturation and HOMA-IR were calculated.

Result

Ferritin and Transferrin saturation was found to be higher in cases than in controls with significance of p = 0.003 and p = 0.021 respectively and TIBC (total iron-binding capacity) was lesser in cases with p = 0.031. Comparison of Serum Iron values did not yield a significant result. Correlation study between ferritin and insulin resistance parameters yielded a satisfactory result in the cases (p<0.05) and controls (p<0.01) separately.

Conclusion

This study implies that there is a clear link between iron profile status, notably ferritin, and the emergence of insulin resistance, and hence insulin production. This study supports the function of the micronutrient iron in the etiology of type 2 diabetes and its consequences.

Nutritional Aspects of Iron in Health and Disease

Dietary iron assimilation is critical for health and essential to prevent iron-deficient states and related comorbidities, such as anemia. The bioavailability of iron is generally low, while its absorption and metabolism are tightly controlled to satisfy metabolic needs and prevent toxicity of excessive iron accumulation. Iron entry into the bloodstream is limited by hepcidin, the iron regulatory hormone. Hepcidin deficiency due to loss-of-function mutations in upstream gene regulators causes hereditary hemochromatosis, an endocrine disorder of iron overload characterized by chronic hyperabsorption of dietary iron, with deleterious clinical complications if untreated. The impact of high dietary iron intake and elevated body iron stores in the general population is not well understood. Herein, we summarize epidemiological data suggesting that a high intake of heme iron, which is abundant in meat products, poses a risk factor for metabolic syndrome pathologies, cardiovascular diseases, and some cancers. We discuss the clinical relevance and potential limitations of data from cohort studies, as well as the need to establish causality and elucidate molecular mechanisms.

Dysmetabolic Iron Overload Syndrome: Going beyond the Traditional Risk Factors Associated with Metabolic Syndrome

Dysmetabolic iron overload syndrome (DIOS) corresponds to the increase in iron stores associated with components of metabolic syndrome (MtS) and in the absence of an identifiable cause of iron excess. The objective of this work was to review the main aspects of DIOS. PUBMED and EMBASE were consulted, and PRISMA guidelines were followed. DIOS is usually asymptomatic and can be diagnosed by investigating MtS and steatosis. About 50% of the patients present altered hepatic biochemical tests (increased levels of γ-glutamyl transpeptidase itself or associated with increased levels of alanine aminotransferase). The liver may present parenchymal and mesenchymal iron overload, but the excess of iron is commonly mild. Steatosis or steatohepatitis is observed in half of the patients. Fibrosis is observed in about 15% of patients. Hyperferritinemia may damage the myocardium, liver, and several other tissues, increasing morbidity and mortality. Furthermore, DIOS is closely related to oxidative stress, which is closely associated with several pathological conditions such as inflammatory diseases, hypertension, diabetes, heart failure, and cancer. DIOS is becoming a relevant finding in the general population and can be associated with high morbidity/mortality. For these reasons, investigation of this condition could be an additional requirement for the early prevention of cardiovascular diseases.

The Effect of Dietary Protein Intake on the Risk of Gestational Diabetes

Background. The results of epidemiological studies on the association between dietary protein intake and gestational diabetes mellitus (GDM) are controversial. Thus, this systematic review and meta-analysis of cohort studies were established to attain comprehensive findings regarding the association between dietary protein and the risk of GDM. Methods. Bibliographic databases including PubMed, Scopus, Web of Science, and Google Scholar were searched to discover papers related to dietary protein and the risk of GDM. The summary relative risks with 95% confidence intervals (CIs) were estimated through a random effect model for the analysis of the highest versus the lowest categories of dietary proteins. Results. A significantly increased risk of GDM among women who consumed the highest amount of animal protein was observed (summarized risk estimate: 1.52; 95% CI: 1.07, 2.17; I2 = 50.8%). No significant associations were identified regarding vegetable protein (summarized risk estimate:0.99, 95% CI: 0.80 to 1.23, I2 = 63.8%) and total protein (summarized risk estimate: 1.12; 95% CI: 0.88, 1.41; I2 = 35.4%). Conclusion. This review revealed that total protein intake had no relationship with the risk of GDM, while animal protein increases this risk. Further larger prospective cohort studies are required to confirm our results.

Association between iron status and incident coronary artery disease: a population based-cohort study

Disorders of iron metabolism has been implicated in cardiovascular disease. However, the association of serum iron stores and coronary artery disease (CAD) remains inconsistent. Here, we investigated the associations of serum iron metabolism with the incidence of CAD, the severity of coronary artery stenosis, metabolic biomarkers, and the risk of major adverse cardiovascular event (MACE). A total of 643 CAD patients and 643 healthy controls were enrolled to assess the associations of serum iron status with the presence of CAD, the severity of CAD, and the risk of MACE. Serum iron metabolism and other metabolic markers were measured in all subjects. All statistical analyses were analyzed using SPSS22.0 software and STATA statistical package. Serum level of iron metabolism markers, including serum iron, unsaturated transferrin iron binding capacity (UIBC), Total iron binding capacity (TIBC) levels, in CAD groups was significantly lower than the control group (P < 0.001). UIBC and TIBC were negatively correlated with ferritin in both sexes. Each unit increase of serum iron and TIBC were found to have a protective role for CAD in women (iron: OR 0.794, 95% CI (0.647-0.973), TIBC: OR 0.891, 95% CI (0.795-0.999), P < 0.05). However, high ferritin level was significant associated the CAD incident in both sexes (OR 1.029, 95% CI (1.002-1.058) in men, OR 1.013, 95% CI (1.0-1.025) in women, P < 0.05). Serum iron metabolism markers exhibited no significant association with the severity of CAD. Increased serum level of iron and TIBC levels were found to have a protective role for CAD in women, but not in men. Elevated serum ferritin is independently and positively associated with CAD in men and women.

MALDI-TOF MS Characterisation of the Serum Proteomic Profile in Insulin-Resistant Normal-Weight Individuals

Insulin resistance (IR) is one of the most common metabolic disorders worldwide and is involved in the development of diseases, such as diabetes and cardiovascular diseases, affecting civilisations. The possibility of understanding the molecular mechanism and searching for new biomarkers useful in assessing IR can be achieved through modern research techniques such as proteomics. This study assessed the protein–peptide profile among normal-weight patients with IR to understand the mechanisms and to define new risk biomarkers. The research involved 21 IR and 43 healthy, normal-weight individuals, aged 19–65. Serum proteomic patterns were obtained using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. The proposed methodology identified six proteins differentiating normal weight IR and insulin sensitive individuals. They were fibrinogen alpha chain, serum albumin, kininogen-1, complement C3, serotransferrin, and Ig gamma-1 chain, which could potentially be related to inflammation. However, further investigation is required to confirm their correlation with IR.

Diabesity negatively affects transferrin saturation and iron status. The DICARIVA study

AIMS

The relationship between iron status, obesity and type 2 diabetes mellitus (T2DM) has scarcely been tested. This study hypothesizes that patients with obesity and T2DM have altered iron metabolism.

METHODS

537 T2DM patients were selected from the cross-sectional DICARIVA study excluding patients with high-sensitivity-C-reactive-protein (hs-CRP) ≥  10 mg/L. Three groups according to body mass index (BMI) and waist perimeter (WP) were analysed: a) BMI < 30 kg/m², non-high WP (n = 105); b) BMI < 30 kg/m², high WP (n = 202); and c) diabesity, BMI ≥  30 kg/m², high WP (n = 230). Group differences on cardiometabolic and iron status markers were tested.

RESULTS

Women had significantly lower iron, ferritin, and transferrin saturation (TSAT) but higher transferrin and total iron binding capacity than men. Triglycerides/HDL-c ratio, as insulin-resistance (IR) marker, was higher in men while hs-CRP in women. TSAT was inversely related to BMI and hs-CRP. The diabesity group showed the highest hs-CRP (p < 0.001) and IR (p < 0.001) with the lowest TSAT (p = 0.003).

CONCLUSIONS

Low TSAT was highly prevalent in diabesity, mainly in women, suggesting that IR, inflammation, and abdominal adiposity alter iron transport and accumulation. The convenience of iron supplementation in diabesity patients with low TSAT should be urgently assessed, due the pro-oxidant effects of excess iron.