Association among serum ferritin, alanine aminotransferase levels, and metabolic syndrome in Korean postmenopausal women

Sex difference in the association between blood alcohol concentration and serum ferritin

Introduction

The sex difference in alcohol use disorder (AUD) is ingrained in distinctive neurobiological responses between men and women, which necessitates further investigation for a more tailored management.

Methods

Minding the findings of iron dysregulation in AUD and the sex difference in iron homeostasis in multiple physiological and pathological settings, we examined the sex difference in the association between serum ferritin and blood alcohol concentration (BAC) in intoxicated males (n = 125) and females (n = 59). We included patients with both serum ferritin tested of any value and a BAC above the level of detection during the same hospital admission period. We investigated sex difference in the relationship between BAC, serum ferritin and liver enzymes in intoxicated critically ill and noncritically ill patients.

Results

We found a negative association between serum ferritin and BAC in critically ill, intoxicated females [R2 = 0.44, F(1,14) = 11.02, p = 0.005], with much attenuated serum ferritin in females compared to their male counterparts (194.5 ± 280.4 vs. 806.3 ± 3405.7 ng/L, p = 0.002). We found a positive association between serum ferritin and liver enzymes [alanine transaminase (ALT) and aspartate transferase (AST)] in critically ill intoxicated females [ALT: R2 = 0.48, F(1,10) = 9.1, p = 0.013; AST: R2 = 0.68, F(1,10) = 21.2, p = 0.001] and in noncritically ill intoxicated males [ALT: R2 = 0.1, F(1,83) = 9.4, p = 0.003; AST: R2 = 0.1, F(1,78) = 10.5, p = 0.002]. The effect of BAC on serum ferritin was not mediated by ALT [indirect effect: (B = 0.13, p = 0.1)]. We also found a significant effect of sex, anemia, intensive care unit (ICU) admission and mortality on serum ferritin.

Discussion

Our results suggest that high BAC in intoxicated female patients is associated with attenuated serum ferritin levels, questioning the role of low serum ferritin in female vulnerability to alcohol.

Association of multiple metals with lipid markers against different exposure profiles: A population-based cross-sectional study in China

We sought to evaluate whether essential and toxic metals are cross-sectionally related to blood lipid levels using data among adults from Shimen (n = 564) and Huayuan (n = 637), two counties with different exposure profiles in Hunan province of China. Traditional and grouped weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) were performed to assess association between exposure to a mixture of 22 metals measured in urine or plasma, and lipid markers. Most of the exposure levels of metals were significantly higher in Shimen area than those in Huayuan area (all P-values < 0.001). Traditional WQS regression analyses revealed that the WQS index were both significantly associated with lipid markers in two areas, except for the HDL-C. Grouped WQS revealed that essential metals group showed significantly positive associations with lipid markers except for HDL-C in Huayuan area, while toxic metals group showed significantly negative associations except for HDL-C and LDL-C in Huayuan area. There were no significant joint effects, but potential non-linear relationships between metals mixture and TC or LDL-C levels were observed in BKMR analyses. Although consistent significantly associations of zinc and titanium with TG levels were found in both areas, the metals closely related to other lipid markers were varied by sites. Additionally, the BKMR analyses revealed an inverse U shaped association of iron with LDL-C levels and interaction effects of zinc and cadmium on LDL-C in Huayuan area. The relationship between metal exposure and blood lipid were not identical against different exposure profiles.

Associations of iron markers with type 2 diabetes mellitus and metabolic syndrome: Results from the prospective SHIP study

AIMS

To assess the role of serum ferritin and transferrin with prevalent and incident type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS) and whether these associations are independent of inflammatory markers and hepatic enzymes.

METHODS

We analyzed data from 3,232 participants aged 20-81 years of the population-based Study of Health in Pomerania (SHIP) from Northeast Germany with a median follow-up time of 10.6 years. Logistic and Cox regression analyses were performed.

RESULTS

Serum ferritin concentrations were associated with a higher prevalence of T2DM (total population OR: 1.16 [95% CI: 1.07, 1.26]; men OR: 1.18 [95% CI: 1.08, 1.30) and MetS (total population OR: 1.27 [95% CI: 1.16, 1.38]; men OR: 1.26 [95% CI: 1.15, 1.38]) in the total population and men independently of inflammatory markers and hepatic enzymes. In longitudinal analyses, baseline ferritin concentrations were associated with a higher risk of incident T2DM in women (HR: 1.38 [95% CI: 1.10, 1.71]), but not in men or in the total population and also with a higher risk of incident MetS (HR: 1.09 [95% CI: 1.01, 1.17]) in the total population. These longitudinal associations attenuated considerably after adjustment for hepatic enzymes but not inflammatory markers. Transferrin was not associated with any of the outcomes.

CONCLUSIONS

Our results suggest a link between ferritin and T2DM and MetS, which might be partially explained by hepatic dysfunction.

Serum lipid profiles of young Japanese women with iron deficiency without anemia

PURPOSE

We aimed to evaluate the association between iron deficiency without anemia (IDNA) and serum lipid profiles in young women of around 20 years of age.

METHODS

This study included non-anemic (hemoglobin ≥ 12 g/dL) female volunteers aged 18 to 22 years who were not taking mineral/vitamin supplements and living in the metropolitan area of Tokyo, Japan. These volunteers were classified into two groups based on their sFer (serum ferritin) levels: normal group (sFer ≥ 20 ng/mL, n = 36) and IDNA group (sFer < 20 ng/mL, n = 29). Venous blood samples were obtained from the antecubital veins of these volunteers after 10-12-h fasting to measure the hematological and biochemical parameters, including lipid levels and iron status. The results of each group were compared using Student's t-test or the Mann-Whitney U test (for inhomogeneous variance).

RESULTS

The serum cholesterol levels varied depending on the iron status in the women. Serum high-density lipoprotein cholesterol (HDL-C) levels in the IDNA group were significantly higher (P = 0.006) than that in the normal group. However, the levels of total cholesterol (T-CHO), triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C) were not significantly different between the groups. Serum LDL-C levels were positively and significantly correlated with sFer levels in the IDNA group (Kendall's rank correlation 0.264, P = 0.044), but not in the normal group. The sFer level was not correlated with serum HDL-C in both groups. The reason for the high serum HDL-C levels in young women with IDNA is not yet clear. Compared to the normal group, the frequency of eating bread containing bran was significantly higher (P = 0.031) and that for yogurt was significantly lower (P = 0.040) in the IDNA group. The proportion of the women who were susceptible to infection, which was measured using the Cornell Medical Index, was significantly higher in the IDNA group than in the normal group. Among those susceptible to infection, the serum HDL-C level of the volunteers in the IDNA group was significantly higher than that of the volunteers in the normal group (P = 0.024).

CONCLUSIONS

Our findings suggest that lipid parameters may be associated with IDNA and susceptibility to infection. Further research is needed to elucidate the mechanisms underlying the changes in the serum cholesterol levels in individuals with IDNA and the clinical significance of these findings.

Association of serum ferritin level and depression with respect to the body mass index in Korean male adults

BACKGROUND/OBJECTIVES

Obesity is globally a major public health issue. Evidence suggests that elevated ferritin levels are associated with obesity, dyslipidemia, insulin resistance, and metabolic syndrome. This study was undertaken to examine the relationship between the serum ferritin level and depression in Korean male adults with respect to classification of the prevailing obesity.

SUBJECTS/METHODS

This was a case-control study; subjects were classified into obese group (≥ 25.0 kg/m², 28 subjects) and normal group (18.5–22.9 kg/m², 27 subjects). A survey was conducted to assess the depression levels as per the guidelines suggested by the Center program for Epidemiological Studies-Depression (CES-D). Blood was collected from each group for assessing biomarkers, and isolated plasma was evaluated for fasting glucose, insulin, quantitative insulin sensitivity check index, and ferritin levels. Data were analyzed, and groups were compared with respect to Body Mass Index (BMI), depression scale and biomarkers.

RESULTS

The average depression score of the obesity group was 16.86, which was higher than the normal group (12.56). Subjects scoring more than 16 points comprised 53.6% of the population in the obese group, which was more than double that in the normal group, as assessed by the CES-D program. Furthermore, the serum ferritin level of the obesity group was 207.12 ng/mL, which was higher than that of the normal group (132.66 ng/mL). Lastly, the BMI appeared to be significantly correlated with both depression (r = 0.320, P = 0.017) and elevated ferritin levels (r = 0.352, P = 0.008).

CONCLUSION

This study provides evidence of existing correlation between ferritin and depression with obesity.

Association between Serum Liver Enzymes and Metabolic Syndrome in Korean Adults

The purpose of this study was to evaluate the association between alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and metabolic syndrome (MS) in the Korean population. A total of 11,587 adults ≥30 years of age and with complete data were selected from Korea National Health and Nutrition Examination Survey VI conducted from 2013 to 2015. Normal ALT and AST levels were divided into quartiles, and their associations with MS were assessed by logistic regression analysis. Elevated levels of ALT [adjusted odds ratio (aOR) = 7.90, 95% confidence interval (CI) = 6.50–9.60] and AST (aOR = 3.81, 95% CI = 3.10–4.74) were both significantly associated with a higher prevalence of MS. The quartile group containing the highest levels of ALT and AST within the normal range also showed an increased risk of MS and its components. Elevated levels of ALT and AST, even within the normal range, were associated with prevalence of MS.

The relationship between serum ferritin levels and serum lipids and HDL function with respect to age and gender

Elevated serum ferritin (SFer) levels have been associated with chronic diseases such as coronary heart disease and diabetes mellitus type 2. The aim of this study was to examine the relationship between SFer levels and serum lipid parameters, and how this relation changes in terms of age and gender. Additionally, we investigated a possible relationship between SFer levels and high-density lipoprotein (HDL) function. SFer levels and lipid panel (total cholesterol (TC), triglyceride (TG), low-density lipoprotein-cholesterol (LDL-C) and HDL-C) of 4205 people (3139 women, 1066 men) were examined retrospectively. Study population was classified according to age and gender. Separately, 100 subjects (52 women, 48 men) were randomly recruited to investigate the relation between SFer levels, and HDL dependent paraoxonase-1 (PON1) and arylesterase (ARE) activities. In all age groups, women’s SFer levels were found to be significantly lower and HDL-C levels significantly higher compared to men. In the 50-70 ages range, TC and LDL-C levels of women were found to be significantly higher than those of men (P < 0.01). SFer levels tended to increase with age in women. Correlation analyses revealed a negative correlation between levels of SFer and HDL-C, while positive correlations existed between levels of SFer, and TC, TG and LDL-C. There was no significant correlation between SFer levels and PON1 or ARE activities. The finding that increased SFer levels are accompanied by increased serum TC, TG and LDL-C levels may help us to explain the increased risk of metabolic disorders and cardiovascular disease in postmenopausal women.

Iron Status and Metabolic Syndrome in Patients with Non-Alcoholic Fatty Liver Disease

BACKGROUND

A hypothesis has been presented about the role of serum iron, ferritin and transferrin saturation among patients with non-alcoholic fatty liver disease (NAFLD) and resistance to insulin (metabolic syndrome [MetS]), but there is much controversy. This study aimed at investigating the level of serum iron and demographic characteristics in patients with NAFLD with or without MetS.

METHODS

A case-control study was conducted on patients with elevated liver enzymes referring to Baqiyatallah clinic, Tehran, Iran during 2010-2011. After ruling out other causes of increased aminotransferases and approving the diagnosis of NAFLD, the patients were divided into two groups of with or without MetS. Then, the individuals’ demographic, sonographic, and laboratory characteristics were recorded.

RESULTS

This research included 299 patients suffering from NAFLD who were divided into MetS (n=143; 47.8%) and non-MetS (n=156; 52.2%) groups. The age, systolic and diastolic blood pressure, body mass index, waist/hip ratio, glucose tolerance test, serum insulin, C. peptide, triglyceride, and HB A1c were different between MetS and non-MetS groups (p<0.05). There was no significant difference in serum iron and ferritin levels between the two groups, however, a significant correlation was found between serum ferritin and alanine transaminase (p=0.005) and also aspartate aminotransferase (p=0.032).

CONCLUSION

Our findings did not show a significant relationship between iron, in free or storage form, and the presence of MetS among patients with NAFLD, but serum ferritin can correlate with hepatocytes injuries indicated by raised aminotransferases. Nevertheless, to clarify this relationship further molecular, genomic, and histopathological studies are required.

Metabolic Syndrome and Serum Liver Enzymes in the General Chinese Population

Background: The aim of this study was to evaluate the associations between alanine aminotransferase (ALT) and aspartate aminotransferase (AST) with metabolic syndrome (MetS) in the general Chinese population. Methods: This study was a multicenter, cross-sectional study which was conducted in rural areas of China from the 2012 to 2013 Northeast China Rural Cardiovascular Health Study (NCRCHS), and 11,573 adults with complete data were included in our final analysis. Elevated ALT and AST levels were defined as >40 U/L. Serum ALT and AST levels within the reference range were divided into quartiles, and their associations with MetS were evaluated by logistic regressions. Results: A total of 7.4% and 3.5% participants had elevated serum ALT and AST levels, respectively. The prevalence of MetS was 37.3% in males and 45.8% in females. After adjusting for potential confounders, we found ALT level elevation, even within the reference range, was independently associated with MetS. The odds ratio (OR) values of MetS in the ALT quartiles 2–4 groups within the reference range were 1.113 (95% CI: 1.019–1.280), 1.375 (95% CI: 1.212–1.560), 1.878 (95% CI: 1.650–2.138) compared with the ALT quartile 1 group, and OR in the elevated ALT group was 3.020 (95% CI: 2.496–3.653). Positive relationship for MetS was also observed in elevated AST group (OR: 1.689, 95% CI: 1.314–2.171), but within the reference range, the AST level was not associated with MetS. Conclusions: Serum ALT level, even within the reference range, was significantly associated with MetS. However, only elevated AST levels above 40 U/L was positively associated with MetS. Within the reference range, we did not find a relationship between AST levels and MetS.

Biomarkers of Metabolic Syndrome: Biochemical Background and Clinical Significance

Biomarkers of the metabolic syndrome are divided into four subgroups. Although dividing them in groups has some limitations, it can be used to draw some conclusions. In a first part, the dyslipidemias and markers of oxidative stress are discussed, while inflammatory markers and cardiometabolic biomarkers are reviewed in a second part. For most of them, the biochemical background and clinical significance are discussed, although here also a well-cut separation cannot always be made. Altered levels cannot always be claimed as the cause, risk, or consequence of the syndrome. Several factors are interrelated to each other and act in a concerted, antagonistic, synergistic, or modulating way. Most important conclusions are summarized at the end of every reviewed subgroup. Genetic biomarkers or influences of various food components on concentration levels are not included in this review article.

Association of insulin resistance with serum ferritin and aminotransferases-iron hypothesis

AIM: To investigate the relationship of iron indices with diabetes mellitus (DM) in those without hemochromatosis.

METHODS: This cross-sectional study examined data collected during the Third National Health and Nutrition Examination Survey (NHANES III). Only those who fasted properly and were not anemic with transferrin saturation < 45% were included (n = 6849). Insulin sensitivity and beta cell function were calculated from fasting glucose and insulin concentrations. Indices of iron metabolism were examined in the presence or absence of DM. We examined the relationship of insulin sensitivity and beta cell function with serum ferritin concentration. The influence of C-reactive protein and liver enzymes was also investigated.

RESULTS: Serum ferritin concentration was significantly higher in diabetic subjects (P = 0.0001 to < 0.000001). The difference remained significant after adjustment for age, body mass index, alcohol consumption, and mineral/iron supplement (P = 0.03 to < 0.000001). In those who did not take insulin, serum ferritin concentration was negatively associated with insulin sensitivity (P = 0.05 to 0.00001), but not with beta cell function. The alanine aminotransferase was correlated with serum ferritin concentration (P = 0.02 to < 0.000001) but not with insulin sensitivity, suggesting the role of the liver in iron-associated insulin resistance.

CONCLUSION: As most of diabetes is type 2 diabetes and insulin resistance is a cardinal feature of type 2 diabetes, disordered iron metabolism could play a role in the pathogenesis of insulin resistance and type 2 diabetes through its effect on liver function.

Association of Serum Ferritin Levels with Metabolic Syndrome and Insulin Resistance

INTRODUCTION

The impact of CVDs and Type II DM is increasing over the last decade. It has been estimated that by 2025 their incidence will double. Ferritin is one of the key proteins regulating iron homeostasis and is a widely available clinical biomarker of iron status. Some studies suggest that prevalence of atherosclerosis and insulin resistance increases significantly with increasing serum ferritin. Metabolic syndrome is known to be associated with increased risk of atherosclerosis as well as insulin resistance.

AIM

The present study was designed to explore the association of serum ferritin levels with metabolic syndrome and insulin resistance.

MATERIALS AND METHODS

The present study was prospective, cross sectional. The study protocol was approved by IEC. The study group consisted of 90 participants (50 cases of metabolic syndrome and 40 age and sex matched controls). Diagnosis of metabolic syndrome was done as per NCEP ATP III criteria. Estimation of serum Ferritin and Insulin was done by Chemiluminescence Immunoassay (CLIA) while Glucose by Glucose Oxidase and Peroxidase (GOD-POD) method. Insulin Resistance was calculated by HOMA IR score.

STATISTICAL ANALYSIS

Data obtained was statistically analysed by using student t-test.

RESULTS

We found statistically significant rise in the levels of serum ferritin (p=<0.001), glucose (p=<0.001), insulin (p=<0.001) and HOMA IR score (p=<0.0001) in cases of metabolic syndrome as compared with controls.

CONCLUSION

High serum ferritin levels though within normal range are significantly associated with both metabolic syndrome and insulin resistance.

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.

Increased Dietary Intake of Saturated Fatty Acid Heptadecanoic Acid (C17:0) Associated with Decreasing Ferritin and Alleviated Metabolic Syndrome in Dolphins

Similar to humans, bottlenose dolphins (Tursiops truncatus) can develop metabolic syndrome and associated high ferritin. While fish and fish-based fatty acids may protect against metabolic syndrome in humans, findings have been inconsistent. To assess potential protective factors against metabolic syndrome related to fish diets, fatty acids were compared between two dolphin populations with higher (n = 30, Group A) and lower (n = 19, Group B) mean insulin (11 ± 12 and 2 ± 5 μIU/ml, respectively; P < 0.0001) and their dietary fish. In addition to higher insulin, triglycerides, and ferritin, Group A had lower percent serum heptadecanoic acid (C17:0) compared to Group B (0.3 ± 0.1 and 1.3 ± 0.4%, respectively; P < 0.0001). Using multivariate stepwise regression, higher percent serum C17:0, a saturated fat found in dairy fat, rye, and some fish, was an independent predictor of lower insulin in dolphins. Capelin, a common dietary fish for Group A, had no detectable C17:0, while pinfish and mullet, common in Group B's diet, had C17:0 (41 and 67 mg/100g, respectively). When a modified diet adding 25% pinfish and/or mullet was fed to six Group A dolphins over 24 weeks (increasing the average daily dietary C17:0 intake from 400 to 1700 mg), C17:0 serum levels increased, high ferritin decreased, and blood-based metabolic syndrome indices normalized toward reference levels. These effects were not found in four reference dolphins. Further, higher total serum C17:0 was an independent and linear predictor of lower ferritin in dolphins in Group B dolphins. Among off the shelf dairy products tested, butter had the highest C17:0 (423mg/100g); nonfat dairy products had no detectable C17:0. We hypothesize that humans' movement away from diets with potentially beneficial saturated fatty acid C17:0, including whole fat dairy products, could be a contributor to widespread low C17:0 levels, higher ferritin, and metabolic syndrome.

Relationship between the concentrations of heavy metals and bioelements in aging men with metabolic syndrome

Heavy metals may exacerbate metabolic syndrome (MS) but abnormal serum concentrations of bioelements may also co-exist with MS. The primary aim of the study was to assess the relationship of blood heavy metal and bioelement concentrations and MS, in men aged 50-75 years. Heavy metals-lead (Pb), cadmium (Cd), mercury (Hg), arsenic (As), tungsten (W), Macroelements-magnesium (Mg) and calcium (Ca), and microelements-iron (Fe), zinc (Zn) copper (Cu), chromium (Cr), molybdenum (Mo), selenium (Se) and manganese (Mn), body mass index (BMI), waist to hip ratio (WHR), abdominal circumference (AC) and blood pressure (BP), total cholesterol (TCh), high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglyceride (TG), fasting plasma glucose (FPG), insulin, and Homeostasis Model Assessment-Insulin resistance (HOMA-IR). The men with MS showed statistically significant higher Zn and lower Mg concentrations. Those with diabetes had higher Ca concentration and lower Mg concentration. Cr and Mn concentrations were significantly higher in obese men. The participants with hypertension had lower Mg concentration. We found statistically significant positive correlations (W-TCh, W-LDL, Mg-TCh, Mg-LDL, Ca-TCh, Ca-LDL, Ca-insulin, Ca-HOMAR-IR, Zn-TG, Zn-insulin, Zn-HOMA-IR, Cu-BP systolic, Mn-BMI, Mn-AC, Mn-WHR, Mn-insulin, Mn-HOMA-IR, Se-TCh, Se-LDL, Se-TG, Se-insulin, Se-HOMA-IR, Cr-TCh, Cr-HDL, Cr-LDL, Cr-TG) and negative correlations (Cd-insulin, Hg-WHR, W-insulin, W-HOMA-IR, Mg-BMI, Mg-AC, Mg-WHR, Mg-BP systolic, Mo-insulin, Mn-HDL). Tungsten may contribute to lipid disorders. Magnesium appears to play the protective role in the occurrence of metabolic disorders. Microelements Mn, Cr and Se may intensify MS.

Serum ferritin is an important inflammatory disease marker, as it is mainly a leakage product from damaged cells

"Serum ferritin" presents a paradox, as the iron storage protein ferritin is not synthesised in serum yet is to be found there. Serum ferritin is also a well known inflammatory marker, but it is unclear whether serum ferritin reflects or causes inflammation, or whether it is involved in an inflammatory cycle. We argue here that serum ferritin arises from damaged cells, and is thus a marker of cellular damage. The protein in serum ferritin is considered benign, but it has lost (i.e. dumped) most of its normal complement of iron which when unliganded is highly toxic. The facts that serum ferritin levels can correlate with both disease and with body iron stores are thus expected on simple chemical kinetic grounds. Serum ferritin levels also correlate with other phenotypic readouts such as erythrocyte morphology. Overall, this systems approach serves to explain a number of apparent paradoxes of serum ferritin, including (i) why it correlates with biomarkers of cell damage, (ii) why it correlates with biomarkers of hydroxyl radical formation (and oxidative stress) and (iii) therefore why it correlates with the presence and/or severity of numerous diseases. This leads to suggestions for how one might exploit the corollaries of the recognition that serum ferritin levels mainly represent a consequence of cell stress and damage.

Ferritin levels and risk of metabolic syndrome: meta-analysis of observational studies

Background

Elevated ferritin levels have been associated with single cardiovascular risk factors but the relationship to the presence of metabolic syndrome is inconclusive.

The aim of this systematic review and meta-analysis of published observational studies was to estimate the association between serum ferritin levels and metabolic syndrome in adults.

Methods

The Pubmed, SCOPUS and the Cochrane Library databases were searched for epidemiological studies that assessed the association between ferritin levels and metabolic syndrome and were published before September 2013. There were no language restrictions. Two investigators independently selected eligible studies. Measures of association were pooled by using an inverse-variance weighted random-effects model. The heterogeneity among studies was examined using the I² index. Publication bias was evaluated using the funnel plot.

Results

Twelve cross-sectional, one case–control and two prospective studies met our inclusion criteria including data from a total of 56,053 participants. The pooled odds ratio (OR) for the metabolic syndrome comparing the highest and lowest category of ferritin levels was 1.73 (95% CI: 1.54, 1.95; I² = 75,4%). Subgroup analyses indicate that pooled OR was 1.92 (95% CI: 1.61, 2.30; I² = 78%) for studies adjusting for C-reactive protein (CRP), and 1.52 (95% CI:1. 36, 1.69; I² = 41%) for studies that did not adjust for CRP (P = 0.044). This finding was remarkably robust in the sensitivity analysis. We did not find publication bias.

Conclusions

The meta-analysis suggests that increased ferritin levels are independently and positively associated with the presence of the metabolic syndrome with an odds ratio higher than 1.73.

Epidemiological associations between iron and cardiovascular disease and diabetes

Disruptions in iron homeostasis are linked to a broad spectrum of chronic conditions including cardiovascular, malignant, metabolic, and neurodegenerative disease. Evidence supporting this contention derives from a variety of analytical approaches, ranging from molecular to population-based studies. This review focuses on key epidemiological studies that assess the relationship between body iron status and chronic diseases, with particular emphasis on atherosclerosis ,metabolic syndrome and diabetes. Multiple surrogates have been used to measure body iron status, including serum ferritin, transferrin saturation, serum iron, and dietary iron intake. The lack of a uniform and standardized means of assessing body iron status has limited the precision of epidemiological associations. Intervention studies using depletion of iron to alter risk have been conducted. Genetic and molecular techniques have helped to explicate the biochemistry of iron metabolism at the molecular level. Plausible explanations for how iron contributes to the pathogenesis of these chronic diseases are beginning to be elucidated. Most evidence supports the hypothesis that excess iron contributes to chronic disease by fostering excess production of free radicals. Overall, epidemiological studies, reinforced by basic science experiments, provide a strong line of evidence supporting the association between iron and elevated risk of cardiovascular disease and diabetes. In this narrative review we attempt to condense the information from existing literature on this topic.

Serum ferritin concentration predicts mortality in patients with hepatitis B virus-related acute on chronic liver failure

BACKGROUND AND AIMS

This study was designed to investigate the association between serum ferritin concentration (SF) and hepatitis B virus infected patients with acute-on-chronic liver failure (AoCLF). In addition, we analyzed whether SF levels are associated with mortality in AoCLF patients.

METHODS

One hundred and seventeen patients, including 46 patients with chronic hepatitis B (CHB), 71 with AoCLF, and 55 healthy controls (HCs) were enrolled in this study. All patients were followed for 4 months. In all subjects, a blood sample was collected at admission to examine liver function, renal function, international normalized ratio, and SF levels. A total of six clinical chemistry and biochemical variables (e.g., model for end-stage liver disease [MELD] score, age, levels of SF, total protein, albumin, and alanine aminotransferase) were measured and analyzed for their association with outcomes by using Cox proportional hazards and multiple regression models.

RESULTS

AoCLF patients had significantly higher SF levels at admission compared to HCs and CHB (all p = 0.001). Elevated SF levels were associated with increased severity of liver disease and 3-month mortality rate. Multivariate analysis demonstrated that SF levels and MELD score were independent predictors for mortality (both p <0.001).

CONCLUSION

The SF measured at admission may serve as an independent predictor for 3-month mortality rate in AoCLF patients.

Association between serum ferritin levels and risk of the metabolic syndrome in Chinese adults: a population study

Ferritin is a ubiquitous intracellular protein that can store and release iron and act as a buffer against iron deficiency and iron overload. Ferritin is widely used as a clinical biomarker to evaluate iron status. Increased serum ferritin concentrations have been reported to be associated with metabolic syndrome (MetS) features. However, serum ferritin concentrations differ significantly according to sex and ethnicity, and the data concerning the relationship between serum ferritin concentrations and MetS in Asian men and women are conflicting. This study aimed to explore the relationship between serum ferritin and MetS in Chinese population. Fasting blood samples and anthropometric data collected on 8,441 adults aged 18 and older in 2009 as part of the China Health and Nutrition Survey, a large-scale longitudinal, household-based survey in China. Data was collected by trained physicians and biomarkers were measured with Hitachi Clinical Autoanalyzer 7600 D model and P model. Median levels of serum ferritin were significantly higher in men compared with women (121.9 vs. 51.0 ng/ml, P < 0.001), and significantly lower in non metabolic syndrome population with MetS population (73.2 vs. 106.0 ng/ml, P < 0.001). The difference remained significant after further adjusted for age, nationality, Body mass index (BMI), smoking status, and alcohol consumption. For both men and women, the highest prevalence of MetS occurred in the highest quartile of serum ferritin. The odds ratios increased progressively across the ferritin quartiles (P<0.001 for trend). Increased serum ferritin concentrations are associated with the metabolic syndrome among men and women in China.

Serum ferritin level is higher in male adolescents with obesity: results from the Korean National Health and Nutrition Examination Survey 2010

PURPOSE

Previous reports show an association between high serum ferritin levels and metabolic syndrome (MS) in adults. In adolescents, little information is available with obesity and serum ferritin levels.

METHODS

This is a cross-sectional study. Data were obtained from the 5th Korean National Health and Nutrition Examination Survey (K-NHANES) conducted during 2010 by the Korean Ministry of Health and Welfare. A total of 849 subjects aged 10-18 years participated in the 2010 survey. A body mass index (BMI) ≥95th percentile for age and sex or a BMI ≥25 was used to diagnose as obesity.

RESULTS

The weighted prevalence of obesity was 13.4% (62/462) in male and 8.5% (33/387) in female. We observed significantly higher serum ferritin in male than in female (mean±standard error [SE], 50.5±2.3 µU/L vs. 30.6±1.3 µU/L; P<0.0001). In male, serum ferritin is positively correlated with age (P<0.0001). White blood cell (WBC) count, serum fasting blood sugar, triglyceride (TG), total cholesterol, low-density lipoprotein, insulin, homeostasis model assessment-insulin resistance (HOMA-IR), systolic and diastolic blood pressure, and ferritin levels were higher and high-density lipoprotein (HDL) were lower in the obesity than in the normal group. In female adolescents, WBC count, TG, insulin, and HOMA-IR were higher and HDL were lower in the obesity than in the normal group. In male, serum ferritin levels showed positive association with obesity (β=21.196, P=0.016).

CONCLUSION

Serum ferritin levels appear to be associated with obesity in Korean male adolescents.

Iron in child obesity. Relationships with inflammation and metabolic risk factors

Iron (Fe) sequestration is described in overweight and in its associated metabolic complications, i.e., metabolic syndrome (MetS) and non-alcoholic liver fatty disease (NAFLD); however, the interactions between Fe, obesity and inflammation make it difficult to recognize the specific role of each of them in the risk of obesity-induced metabolic diseases. Even the usual surrogate marker of Fe stores, ferritin, is influenced by inflammation; therefore, in obese subjects inflammation parameters must be measured together with those of Fe metabolism. This cross-sectional study in obese youth (502 patients; 57% girls): 11.4 ± 3.0 years old (x ± SD); BMI z score 5.5 ± 2.3), multivariate regression analysis showed associations between Fe storage assessed by serum ferritin with risk factors for MetS and NAFLD, assessed by transaminase levels, which were independent of overweight and the acute phase protein fibrinogen. Further studies incorporating the measurement of complementary parameters of Fe metabolism could improve the comprehension of mechanisms involved.

Insulin resistance: an emerging link in Alzheimer's disease

Relentless progression of Alzheimer's disease (AD) poses a grave situation for the biomedical community to tackle. Agents starting as hot favorites in clinical trials have failed in later stages and it is time we reconsidered our approaches to intervene the disease. Quite some interesting work in the last decade has introduced a new school of thought which factors in neuronal glycemic imbalance as a major component for the development of AD. Insulin resistance in the brain has brought forward subsequent sequelae which might work towards amyloid accretion and/or tau hyperphosphorylation. It is also pointed out that insulin works by distributing iron to neuronal tissue and an insulin resistant state throws it off gear leading to iron overloading of neurons which is ultimately detrimental. A relatively recent investigation finds the role of c-Jun-N-terminal kinase (JNK3) in AD which also seems to bear a link with insulin resistance.

Relationship between iron metabolism, oxidative stress, and insulin resistance in patients with systemic lupus erythematosus

OBJECTIVE

The aim of the present study was to assess oxidative stress and iron metabolism in systemic lupus erythematosus (SLE) patients with and without insulin resistance (IR).

METHOD

This study included 236 subjects (125 controls and 111 SLE patients). Patients with SLE were divided in two groups: with (n = 72) or without (n = 39) IR.

RESULTS

SLE patients with IR showed higher advanced oxidation protein product (AOPP) levels (p = 0.030) and gamma-glutamyltransferase (GGT) levels (p = 0.001) and lower sulfhydryl groups of proteins (p = 0.0002) and total radical-trapping antioxidant parameter (TRAP) corrected by uric acid (UA) levels (p = 0.04) when compared to SLE patients without IR. However, SLE patients with IR presented lower serum 8-isoprostane (p = 0.05) and carbonyl protein levels (p = 0.04) when compared to SLE patients without IR. Serum ferritin levels were significantly higher in SLE patients (p = 0.0006) than in controls, and SLE patients with IR presented higher serum ferritin levels (p = 0.01) than SLE patients without IR. Patients with SLE showed that IR was inversely correlated to TRAP/UA (r = -0.2724, p = 0.0008) and serum ferritin was positively correlated to AOPP (r = 0.2870, p = 0.004).

CONCLUSIONS

This study found that oxidative stress was higher in the group of SLE patients with IR, and increased ferritin, whether caused by the inflammatory process per se or hyperinsulinaemia, can favour the redox process. In addition, the preset data reinforce the need to measure oxidative stress with several methodologies with different assumptions.

Heme Iron Intake and Risk of Stroke

Background and Purpose—

Intake of iron, especially heme iron, has been associated with several diseases. However, epidemiological studies of heme iron and nonheme iron intake in relation to risk of stroke are lacking. The aim of this study was to examine the associations between heme iron and nonheme iron intake and stroke incidence in men.

Methods—

The population-based prospective Cohort of Swedish Men included 38 859 men, aged 45 to 79 years, who had no history of stroke, coronary heart disease, or cancer at baseline. Hazard ratios and 95% confidence intervals (95% CIs) were calculated using Cox proportional hazards regression models.

Results—

During an 11.7 years follow-up, 3097 incident cases of stroke, including 2482 cerebral infarctions and 450 intracerebral hemorrhages, were registered. The hazard ratios of total stroke and cerebral infarction for the highest compared with the lowest quintiles of heme iron intake were 1.16 (95% CI, 1.03–1.31; P trend=0.037) and 1.15 (95% CI, 1.00–1.31; P trend=0.089), respectively. The incidence rates of total stroke per 10 000 person-years were 72.6 in the lowest quintile and 84.4 in the highest. The association was confined to men with body mass index <25 kg/m 2 , the hazard ratios were 1.40 (95% CI, 1.17–1.68; P trend<0.001) for total stroke and 1.38 (95% CI, 1.13–1.70; P trend=0.001) for cerebral infarction; no association was observed among overweight and obese men. There was no association between nonheme iron intake and risk of total stroke and stroke types.

Conclusions—

Findings from this prospective study indicate that a high heme iron intake, particularly in normal weight individuals, may increase the risk of stroke.

Body iron stores and risk of type 2 diabetes: results from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam study

AIMS/HYPOTHESIS

The aim of this study was to prospectively examine the association between body iron stores and risk of type 2 diabetes.

METHODS

We designed a case-cohort study among 27,548 individuals within the population-based European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam study. During 7 years of follow-up, 849 incident cases of type 2 diabetes were identified. Of these, 607 remained for analyses after exclusion of participants with missing data or abnormal glucose levels at baseline. A sub-cohort of 2,500 individuals was randomly selected from the full cohort, comprising 1,969 individuals after applying the same exclusion criteria.

RESULTS

After adjustment for age, sex, BMI, waist circumference, sports activity, bicycling, education, occupational activity, smoking habit, alcohol consumption and circulating levels of γ-glutamyltransferase, alanine aminotransferase, fetuin-A, high-sensitivity C-reactive protein, adiponectin, HDL-cholesterol and triacylglycerol, higher serum ferritin concentrations were associated with a higher risk of type 2 diabetes (RR in the highest vs lowest quintile, 1.73; 95% CI 1.15, 2.61; p(trend) = 0.002). No significant association was observed for soluble transferrin receptor (RR 1.33; 95% CI 0.85, 2.09; p(trend) = 0.50). The soluble transferrin receptor-to-ferritin ratio was significantly inversely related to risk (RR 0.61; 95% CI 0.41, 0.91; p(trend) = 0.02).

CONCLUSIONS/INTERPRETATION

High ferritin levels are associated with higher risk of type 2 diabetes independently of established diabetes risk factors and a range of diabetes biomarkers whereas soluble transferrin receptor concentrations are not related to risk. These results support the hypothesis that higher iron stores below the level of haemochromatosis are associated with risk of type 2 diabetes.

Changes in iron measures over menopause and associations with insulin resistance

OBJECTIVES

No longitudinal studies have examined how iron measures change over menopause. Our objectives were to examine iron measures in individual women at premenopause and at postmenopause and, secondarily, to determine if any changes contributed to insulin resistance.

METHODS

In a subset of participants (n=70) in a longitudinal study of menopause, we measured ferritin, transferrin, and soluble transferrin receptor (sTfR) once in the premenopause and once in the postmenopause. We also examined associations between menopausal status and change in iron markers after adjustment for age at menopause, race/ethnicity, and waist circumference. In linear regression models, we examined associations between premenopause iron measures and changes in iron markers over menopause with homeostasis model assessment of insulin resistance (HOMA-IR) changes over menopause, before and after adjustment for age at menopause, race/ethnicity, changes in waist circumference, C-reactive protein (CRP), and sex hormone-binding globulin (SHBG) levels.

RESULTS

Women had lower ferritin (p<0.01), higher sTfR:ferritin levels (p<0.01), lower HOMA-IR (p=0.022), and lower glucose (p=0.05) in premenopause compared to postmenopause. After adjustment, lower premenopausal iron levels (sTfR:ferritin levels β=11.0, 95% confidence interval [CI] 0.017-22.0) and larger increases in iron over menopause (changes in sTfR:ferritin β=13.6, 95% CI 0.93-26.3) were associated with larger increases in HOMA-IR.

CONCLUSIONS

From premenopause to postmenopause, women on average have increases in measures of iron stores. Women who had the greatest changes in iron over menopause (lower measures of premenopausal iron and greater increases in iron measures over the menopause) had the strongest associations between changes in iron and changes in insulin resistance.

Serum ferritin levels are associated with metabolic syndrome in postmenopausal women but not in premenopausal women

OBJECTIVE

Ferritin, a marker of total body iron stores, is known to be associated with the risk of having metabolic syndrome and has been demonstrated to increase after the onset of menopause. Postmenopause status is an important determinant of metabolic syndrome. The aim of this study was to perform a menopause status-specific analysis of the association between ferritin levels and metabolic syndrome.

METHODS

We conducted a cross-sectional study of 3,082 participants (1,691 premenopausal women and 1,391 postmenopausal women), all of whom were enrolled in the Korean National Health and Nutrition Examination Survey 2007.

RESULTS

Premenopausal and postmenopausal women with metabolic syndrome had higher ferritin levels than did those without metabolic syndrome. After adjustments for age; body mass index; alcohol intake; smoking history; exercise; hormone therapy use; hemoglobin, aspartate aminotransferase, and alanine aminotransferase levels; and intake of energy and iron, multivariate logistic regression analysis revealed that postmenopausal women with ferritin levels in the third tertile had an increased risk of having metabolic syndrome (odds ratio, 1.62; 95% CI, 1.04-2.81) compared with postmenopausal women with levels in the first quartile. No such association was detected in premenopausal women.

CONCLUSIONS

Increased ferritin levels may be a determinant for metabolic syndrome in postmenopausal women but not in premenopausal women.

Red meat consumption and risk of stroke in Swedish men

BACKGROUND

Red and processed meat consumption has been implicated in several diseases. However, data on meat consumption in relation to stroke incidence are sparse.

OBJECTIVE

Our objective was to examine the associations of red meat and processed meat consumption with stroke incidence in men.

DESIGN

We prospectively followed 40,291 men aged 45-79 y who had no history of cardiovascular disease or cancer at baseline. Meat consumption was assessed with a self-administered questionnaire in 1997.

RESULTS

During a mean follow-up of 10.1 y, 2409 incident casesof stroke (1849 cerebral infarctions, 350 hemorrhagic strokes, and 210 unspecified strokes) were identified from the Swedish Hospital Discharge Registry. Consumption of processed meat, but not of fresh red meat, was positively associated with risk of stroke. The multivariable relative risks (RRs) of total stroke for the highest compared with the lowest quintiles of consumption were 1.23 (95% CI: 1.07, 1.40; P for trend = 0.004) for processed meat and 1.07 (95% CI: 0.93, 1.24; P for trend = 0.77) for fresh red meat. Processed meat consumption was also positively associated with risk of cerebral infarction in a comparison of the highest with the lowest quintile (RR: 1.18; 95% CI: 1.01, 1.38; P for trend = 0.03).

CONCLUSION

The findings from this prospective cohort of men indicate that processed meat consumption is positively associated with risk of stroke. The Cohort of Swedish Men is registered at clinicaltrials.gov as NCT01127711.

Association of elevated serum ferritin concentration with insulin resistance and impaired glucose metabolism in Korean men and women

Increased serum ferritin concentrations in nonpathologic conditions, reflecting subclinical iron overload, have been reported to be associated with insulin resistance and an increased risk of type 2 diabetes mellitus (DM). However, serum ferritin concentrations differ significantly according to sex and ethnicity; and data concerning the relationship between serum ferritin concentrations and glucose metabolism abnormalities in Asian men and women are conflicting. This cross-sectional study investigated the association of serum ferritin concentrations with insulin resistance and impaired glucose metabolism in a large number of subjects with normal fasting glucose (NFG) level, impaired fasting glucose (IFG) level, or type 2 DM. We analyzed clinical and laboratory data from 12 090 subjects (6378 men and 5712 women; age, 20-89 years) who underwent general medical checkups. The study population included 1054 subjects with type 2 DM, 3783 subjects with IFG level, and 7253 subjects with NFG level. Serum ferritin, hemoglobin A(1c), fasting glucose, lipid, and insulin levels were measured. Insulin resistance and β-cell function indices were derived from a homeostasis model assessment. Serum ferritin concentrations were highest in the DM group, followed by the IFG group and the NFG group, in both men and women (186 ± 127, 176 ± 108, and 156 ± 92 ng/mL, respectively, in men; 85 ± 62, 75 ± 55, and 59 ± 47 ng/mL, respectively, in women). After adjustment for other variables using multiple regression analysis, homeostasis model assessment of insulin resistance was independently associated with serum ferritin concentration in men, but not in women. When the fourth quartile of ferritin was compared with the first quartile, the age-adjusted odds ratio (OR) for type 2 DM was 1.71 (95% confidence interval, 1.38-2.12) in men and 1.50 (1.05-2.13) in women. The OR in men was attenuated to 1.27 (1.01-1.60) but remained significant after adjustment for body mass index (BMI), waist circumference, blood pressure, serum lipids, liver enzymes, and high-sensitivity C-reactive protein (hsCRP). In nondiabetic subjects, the age-adjusted OR for IFG in the fourth quartile of ferritin was 1.82 (1.56-2.13) in men and 1.68 (1.40-2.02) in women. The OR was attenuated to 1.31 (1.11-1.55) in men and 1.45 (1.19-1.78) in women after adjustment for BMI, waist circumference, blood pressure, serum lipids, liver enzymes, and hsCRP. In NFG subjects, the age-adjusted OR for metabolic syndrome in the fourth quartile of ferritin concentration was 2.85 (1.99-4.07) in men and 1.21 (0.82-1.79) in women. In men, the OR was attenuated to 1.58 (1.06-2.37) after adjustment for BMI, liver enzymes, and hsCRP. Increased serum concentrations of ferritin are associated with insulin resistance, type 2 DM, IFG, and metabolic syndrome in men, but only with IFG in women. These results suggest that iron overload is associated with insulin resistance in men, but not in women.

Red meat consumption and risk of stroke in Swedish women

BACKGROUND AND PURPOSE

High red meat consumption has been associated with increased risk of some cancers and may also be a risk factor for cardiovascular diseases. However, epidemiological studies of red meat consumption in relation to risk of stroke are very limited. Our objective was to examine the association between red meat consumption and stroke incidence in the Swedish Mammography Cohort.

METHODS

We prospectively followed 34 670 women without cardiovascular disease and cancer at baseline. Participants completed a self-administered questionnaire on diet and other risk factors for cardiovascular diseases in 1997. Cox proportional hazards models were used to estimate multivariable-adjusted relative risks (RR) and 95% CI.

RESULTS

During a mean follow-up of 10.4 years, we ascertained 1680 incident cases of stroke, comprising 1310 cerebral infarction, 154 intracerebral hemorrhage, 79 subarachnoid hemorrhage, and 137 unspecified stroke. Total red meat and processed meat consumption was associated with a statistically significant increased risk of cerebral infarction, but not of total stroke, intracerebral hemorrhage, or subarachnoid hemorrhage. The multivariable RR of cerebral infarction for the highest versus the lowest quintile of consumption were 1.22 (95% CI, 1.01-1.46) for red meat and 1.24 (95% CI, 1.04-1.49) for processed meat. Fresh (unprocessed) meat consumption was not associated with total stroke or with any stroke subtype.

CONCLUSIONS

Findings from this study suggest that red and processed meat consumption may increase the risk of cerebral infarction in women.

Towards a unifying, systems biology understanding of large-scale cellular death and destruction caused by poorly liganded iron: Parkinson's, Huntington's, Alzheimer's, prions, bactericides, chemical toxicology and others as examples

Exposure to a variety of toxins and/or infectious agents leads to disease, degeneration and death, often characterised by circumstances in which cells or tissues do not merely die and cease to function but may be more or less entirely obliterated. It is then legitimate to ask the question as to whether, despite the many kinds of agent involved, there may be at least some unifying mechanisms of such cell death and destruction. I summarise the evidence that in a great many cases, one underlying mechanism, providing major stresses of this type, entails continuing and autocatalytic production (based on positive feedback mechanisms) of hydroxyl radicals via Fenton chemistry involving poorly liganded iron, leading to cell death via apoptosis (probably including via pathways induced by changes in the NF-κB system). While every pathway is in some sense connected to every other one, I highlight the literature evidence suggesting that the degenerative effects of many diseases and toxicological insults converge on iron dysregulation. This highlights specifically the role of iron metabolism, and the detailed speciation of iron, in chemical and other toxicology, and has significant implications for the use of iron chelating substances (probably in partnership with appropriate anti-oxidants) as nutritional or therapeutic agents in inhibiting both the progression of these mainly degenerative diseases and the sequelae of both chronic and acute toxin exposure. The complexity of biochemical networks, especially those involving autocatalytic behaviour and positive feedbacks, means that multiple interventions (e.g. of iron chelators plus antioxidants) are likely to prove most effective. A variety of systems biology approaches, that I summarise, can predict both the mechanisms involved in these cell death pathways and the optimal sites of action for nutritional or pharmacological interventions.

The link between iron, metabolic syndrome, and Alzheimer's disease

Both Alzheimer's disease (AD), the most common form of dementia, and type-2 diabetes mellitus (T2DM), a disease associated with metabolic syndrome (MetS), affect a great number of the world population and both have increased prevalence with age. Recently, many studies demonstrated that pre-diabetes, MetS, and T2DM are risk factors in the development of AD and have many common mechanisms. The main focus of studies is the insulin resistance outcome found both in MetS as well as in brains of AD subjects. However, oxidative stress (OS)-related mechanisms, which are well known to be involved in AD, including mitochondrial dysfunction, elevated iron concentration, reactive oxygen species (ROS), and stress-related enzyme or proteins (e.g. heme oxygenase-1, transferrin, etc.), have not been elucidated in MetS or T2DM brains although OS and iron are involved in the degeneration of the pancreatic islet β cells. Therefore, this review sets to cover the current literature regarding OS and iron in MetS and T2DM and the similarities to mechanisms in AD both in human subjects as well as in animal models.

The association between normal alanine aminotransferase levels and the metabolic syndrome: 2005 Korean National Health and Nutrition Examination Survey

The metabolic syndrome is known to sometimes exist in the presence of normal aminotransferase levels. The purpose of this study was to determine the lowest sex-specific level of alanine aminotransferase associated with the metabolic syndrome in a nationwide, representative Korean population. We analyzed data from adults 20 years and older (n = 3405) assessed in the Third Korean National Health and Nutrition Examination Survey (2005). Participants were divided into 4 groups according to the quartiles of alanine aminotransferase levels for each sex. Logistic regression modeling was performed after adjustment for age, body mass index, waist circumference, smoking, ingested alcohol amount, and physical activity. Alanine aminotransferase level groups 3 and 4 in women (> or =15 IU/L) and group 4 in men (> or =27 IU/L) were significantly associated with the metabolic syndrome compared with the lowest alanine aminotransferase groups (<16 IU/L in men, <11 IU/L in women). In men, the odds ratio (95% confidence interval) of the metabolic syndrome was 2.71 (1.31-5.63) for alanine aminotransferase group 4 (> or =27 IU/L). In women, odds ratios were 1.69 (1.02-2.80) and 2.06 (1.23-3.43) for alanine aminotransferase groups 3 (15 < or = alanine aminotransferase < 19 IU/L) and 4 (> or =19 IU/L), respectively. High-normal alanine aminotransferase levels (> or =27 IU/L in men, > or =15 IU/L in women) were strongly associated with the metabolic syndrome in Korean adults.

The effect of fenugreek 4-hydroxyisoleucine on liver function biomarkers and glucose in diabetic and fructose-fed rats

Fenugreek (Trigonella foenum graecum L) is a plant traditionally used for the treatment of diabetes. It contains an unusual amino acid, 4-hydroxyisoleucine, demonstrated to have insulinotropic and antidiabetic properties in animal models. Here we examine the effect of 4-hydroxyisoleucine on liver function and blood glucose in two rat models of insulin resistance, fructose-fed rats and streptozotocin-induced diabetes type 2. In fructose-fed rats, levels of glucose and liver damage marker aspartate transaminase were markedly (84% and 93%, respectively) and significantly elevated compared with controls (p < 0.001 for both). Alanine transaminase was elevated slightly (18%), and all markers were restored to near control values after treatment with 4-hydroxyisoleucine at 50 mg/kg per day for 8 weeks, the effect being significant (p < 0.01) for all markers. This prolonged exposure to 4-hydroxyisoleucine was well tolerated in control animals and did not alter levels of glucose or liver damage markers significantly. In diabetic rats, treatment with 4-hydroxyisoleucine did not affect glucose or liver damage markers, but did improve HDL-cholesterol levels (31% increase, p < 0.05). These findings indicate 4-hydroxyisoleucine as a useful and well-tolerated treatment for insulin resistance, both directly as a hypoglycaemic and also as a protective agent for the liver.

Iron behaving badly: inappropriate iron chelation as a major contributor to the aetiology of vascular and other progressive inflammatory and degenerative diseases

BACKGROUND

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular 'reactive oxygen species' (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation.

REVIEW

We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation).The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible.This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, since in some circumstances (especially the presence of poorly liganded iron) molecules that are nominally antioxidants can actually act as pro-oxidants. The reduction of redox stress thus requires suitable levels of both antioxidants and effective iron chelators. Some polyphenolic antioxidants may serve both roles.Understanding the exact speciation and liganding of iron in all its states is thus crucial to separating its various pro- and anti-inflammatory activities. Redox stress, innate immunity and pro- (and some anti-)inflammatory cytokines are linked in particular via signalling pathways involving NF-kappaB and p38, with the oxidative roles of iron here seemingly involved upstream of the IkappaB kinase (IKK) reaction. In a number of cases it is possible to identify mechanisms by which ROSs and poorly liganded iron act synergistically and autocatalytically, leading to 'runaway' reactions that are hard to control unless one tackles multiple sites of action simultaneously. Some molecules such as statins and erythropoietin, not traditionally associated with anti-inflammatory activity, do indeed have 'pleiotropic' anti-inflammatory effects that may be of benefit here.

CONCLUSION

Overall we argue, by synthesising a widely dispersed literature, that the role of poorly liganded iron has been rather underappreciated in the past, and that in combination with peroxide and superoxide its activity underpins the behaviour of a great many physiological processes that degrade over time. Understanding these requires an integrative, systems-level approach that may lead to novel therapeutic targets.

[Serum ferritin and risk of the metabolic syndrome in some Korean rural residents]

OBJECTIVES

The purpose of this study was to examine the relationship between serum ferritin and the metabolic syndrome (MS).

METHODS

We conducted a cross-sectional study of 1,444 adults over age 40 and under age 70 that lived in a rural area and participated in a survey conducted as part of the Korean Rural Genomic Cohort Study (KRGCS). The MS was defined as the presence of at least three of the followings: elevated blood pressure, low high density lipoprotein cholesterol, elevated serum triglycerides, elevated plasma glucose, or abdominal obesity. After adjustment for age, alcohol intake, menopausal status, body mass index (BMI), high sensitivity C-reactive protein (hs-CRP), and alanine aminotransferase (ALT), odds ratios (ORs) for the prevalence of the MS by sex were calculated for quartiles of serum ferritin using logistic regression analysis.

RESULTS

The MS was more common in those persons with the highest levels of serum ferritin, compared to persons with the lowest levels, in men (37.1% vs. 22.4%, p=0.006) and women (58.8% vs. 34.8, p<0.001). In both sexes, the greater the number of MS components presents, the greater the serum ferritin levels. After adjustment for age, alcohol intake, and menopausal status, the OR for metabolic syndrome, comparing the fourth quartile of ferritin with the first quartile, was 2.21 (95% confidence interval; CI=1.26-3.87; p-trend=0.024) in men and 2.10 (95% CI=1.40-3.17; p-trend=0.001) in women. However, after further adjustment for BMI, hs-CRP, and ALT, the ORs were statistically attenuated in both sexes.

CONCLUSIONS

Moderately elevated serum ferritin levels were not independently associated with the prevalence of the MS after adjusting for other risk factors. Further studies are needed to obtain evidence concerning the association between serum ferritin levels and the MS.

Association of general and abdominal obesities and metabolic syndrome with subclinical atherosclerosis in asymptomatic Chinese postmenopausal women

OBJECTIVE

This study aimed to investigate the relationships between obesity, especially abdominal obesity, andmetabolic syndrome (MS) with carotid intima-media thickness (IMT) and plaque, markers of subclinical atherosclerosis, in asymptomatic Chinese postmenopausal women in Hong Kong.

DESIGN

A total of 518 postmenopausal women aged 50 to 64 years were recruited through random telephone dialing. Body mass index (BMI), waist circumference, waist-to-hip ratio, sociodemographic characteristics, blood pressures, medical, biochemical and lifestyle factors were obtained. MS was defined on the basis of the National Cholesterol and Education Program, Adult Treatment Panel III criteria. Subclinical atherosclerosis was determined by measuring IMT and plaque using high-resolution B-mode ultrasonography.

RESULTS

Women with a BMI of 25 kg/mor greater, a waist circumference of 80 cm or greater, a waist-to-hip ratio of 0.85 or greater, or MS were observed to have higher IMT values and prevalence of plaque. Multivariate analyses revealed that waist circumference was significantly associated with IMT independent of age, hormone therapy, lifestyle and sociodemographic factors, and BMI (P < 0.05), whereas a waist-to-hip ratio of 0.85 or greater was significantly associated with plaque (odds ratio = 1.7; 95% CI: 1.0-2.8) after controlling for age, hormone therapy, lifestyle and sociodemographic factors, BMI, and the traditional cardiovascular risk factors. MS was also associated with IMT after adjustment for age, hormone therapy, lifestyle and sociodemographic factors, and BMI (P < 0.05), whereas its association with plaque was also significant (odds ratio = 1.7; 95% CI: 1.0-2.6) after controlling for age.

CONCLUSIONS

Abdominal obesity and MS are independent of general obesity markers of subclinical atherosclerosis in Chinese postmenopausal women.

Elevated serum ferritin levels predict new-onset type 2 diabetes: results from the EPIC-Norfolk prospective study

AIMS/HYPOTHESIS

The aim of this study was to examine the association between baseline body iron stores and new-onset diabetes.

SUBJECTS AND METHODS

We studied the association between baseline serum ferritin concentration and type 2 diabetes in 360 clinically incident diabetes cases and 758 controls nested within the EPIC (European Prospective Investigation of Cancer)-Norfolk Cohort Study. Serum ferritin levels were categorised into five groups: sex-specific quartiles of the normal range of ferritin and a group with clinically raised ferritin below levels indicative of haemochromatosis.

RESULTS

Baseline serum ferritin was higher among cases than control participants (geometric mean: men 96.6 vs 67.8 ng/ml, respectively, p < 0.001; women 45.9 vs 34.8 ng/ml, respectively, p = 0.005). In analyses adjusted for known risk factors (age, BMI, sex, family history, physical activity, smoking habit) and dietary factors measured by 7-day food diary, the risk of diabetes was markedly elevated in participants with clinically raised ferritin compared with the lowest quartile (odds ratio [OR] 7.4, 95% CI 3.5-15.4). Further adjustment for potential confounding by inflammation (C-reactive protein, IL-6 and fibrinogen) had no material impact on the observed association, while adjustment for hepatic enzymes (alanine aminotransferase and gamma glutamyl transferase) and adiponectin attenuated the magnitude of association, but it remained statistically significant (OR 3.2 [1.3-7.6]).

CONCLUSIONS/INTERPRETATION

Serum ferritin is an important and independent predictor of the development of diabetes. This finding may have important implications for understanding the aetiology of diabetes.

NAFLD and hyperinsulinemia are major determinants of serum ferritin levels

BACKGROUND/AIMS

There is an increasing body of evidence that serum ferritin is associated with the metabolic syndrome. However, no study has tested for NAFLD. The aim was to test the assumption that the association between serum ferritin and the metabolic syndrome is mediated by NAFLD.

METHODS

A cross-sectional study of a sub-sample of the first Israeli national health survey. Exclusion criteria were any known etiology for secondary NAFLD. Participants underwent an abdominal ultrasound (US), biochemical tests, and dietary and anthropometric evaluations.

RESULTS

Three hundred and forty-nine subjects were included in the analysis. Serum ferritin was higher in the NAFLD group (92.4+/-63.1 vs. 65.1+/-58.0, P<0.001). After adjusting for age and gender, the following variables were significantly associated with increased ferritin levels: abdominal obesity, hyperglycemia, hyperinsulinemia, HOMA, hypertriglyceridemia and the metabolic syndrome itself. After further adjusting for NAFLD, only abdominal obesity [2.1 (1.1-3.9)] and hyperinsulinemia [2.3 (1.3-4.2)] were still significantly associated with ferritin. In a multivariate analysis the interaction between NAFLD and hyperinsulinemia was the second strongest predictor of serum ferritin (P=0.005).

CONCLUSIONS

The association between serum ferritin and the metabolic syndrome is mediated by undiagnosed NAFLD. The interaction between NAFLD and hyperinsulinemia is a major determinant of serum ferritin levels at the population level.

Normal serum aminotransferase levels and the metabolic syndrome: Korean National Health and Nutrition Examination Surveys

Increasing evidence suggests an association between elevated serum aminotransferase level and the metabolic syndrome. However, the significance of relatively low levels of aminotransferase in relation to the metabolic syndrome has not been fully investigated in the general population. We investigated the association between serum amiontransferase level and the metabolic syndrome using data from a nationwide survey in Korea. We measured serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and metabolic conditions among 9771 participants aged 20 or more in the 1998 and 2001 Korean National Health and Nutrition Examination Surveys. Metabolic syndrome was defined according to NCEP-ATP III criteria with a modified waist circumference cutoff (men > 90 cm; women > 80 cm). Serum aminotransferase level, even within normal range, was associated with the metabolic syndrome independent of age, body mass index, waist circumference, smoking, and alcohol intake. Compared with the lowest level (< 20 IU/L), the adjusted odds ratios (95% CI) for an AST level of 20-29, 30-39, 40-49 and > or = 50 IU/L were 1.10 (0.85-1.42), 1.37 (1.02-1.83), 1.62 (1.08-2.43), and 2.25 (1.47-3.44) in men, and 1.18 (0.99-1.41), 1.43 (1.29-1.83), 1.71 (1.09-2.68), and 2.14 (1.20-3.80) in women, respectively. Corresponding odds ratios for ALT levels were 1.27 (0.99-1.63), 1.69 (1.28-2.23), 2.17 (1.58-2.99), and 2.65 (1.96-3.58) in men, and 1.44 (1.22-1.70), 1.65 (1.26-2.15), 2.94 (1.93-4.47), and 2.25 (1.54-3.30) in women, respectively. In conclusion, elevated serum aminotransferase levels, even in the normal to near normal range, are associated with features of the metabolic syndrome.