Metabolic syndrome, insulin resistance and the inflammation markers C-reactive protein and ferritin

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.

Iron homeostasis: a new job for macrophages in adipose tissue?

Elevated serum ferritin and increased cellular iron concentrations are risk factors for diabetes; however, the etiology of this association is unclear. Metabolic tissues such as pancreas, liver, and adipose tissue (AT), as well as the immune cells resident in these tissues, may be involved. Recent studies demonstrate that the polarization status of macrophages has important relevance to their iron-handling capabilities. Furthermore, a subset of macrophages in AT have elevated iron concentrations and a gene expression profile indicative of iron handling, a capacity diminished in obesity. Because iron overload in adipocytes increases systemic insulin resistance, iron handling by AT macrophages may have relevance not only to adipocyte iron stores but also to local and systemic insulin sensitivity.

The Relationship between Serum Ferritin and Insulin Resistance in Different Glucose Metabolism in Nonobese Han Adults

The exact mechanism through which elevated serum ferritin promotes the development of type 2 diabetes is unknown. This study showed that ferritin concentration in impaired glucose regulation and newly diagnosed diabetes mellitus subjects of nonobesity already significantly increased when compared with normal glucose tolerant subjects of nonobesity. Elevated serum ferritin levels are associated with insulin resistance and may be not associated with the decline of insulin beta cells in different status of glucose tolerance in nonobese Han adults.

Clinical significance of serum ferritin level as an independent predictor of insulin resistance in Korean men

AIMS

Elevated serum ferritin level has been reported to be associated with type 2 diabetes mellitus and metabolic syndrome, which have significant relation with insulin resistance (IR). However, clinical association between serum ferritin level and IR remained unclear. Accordingly, this study was designed to evaluate the longitudinal effects of baseline serum ferritin level on the development of IR.

METHODS

An IR-free 22,057 healthy Korean men (HOMA-IR<2.7), who had participated in a medical health check-up program in 2005, were followed up until 2010. During follow up, the development rate of IR, defined in case of HOMA-IR≥2.7, was monitored according to the quartile groups of serum ferritin levels. Cox proportional hazards models were used to measure the hazard ratios (HRs) of baseline serum ferritin levels on IR.

RESULTS

During 77,471.1 person-years of follow-up, 4494 incident cases of insulin resistance developed between 2006 and 2010 (overall development rate: 20.4%). The development rate of IR increased in proportion to the baseline serum ferritin levels (quartile 1: 16.7%, quartile 2: 18.5%, quartile 3: 19.9%, quartile 4: 25.5%, P<0.001). After adjusting for multiple covariates, the HRs (95% CI) for IR, comparing the second to the fourth quartile of serum ferritin levels with the first quartile, were 1.11 (0.99-1.24), 1.19 (1.07-1.33) and 1.51 (1.35-1.68), respectively (P for trend <0.001).

CONCLUSIONS

Elevated serum ferritin level was independently associated with the future development of IR in Korean men.

Serum ferritin, diabetes, diabetes control, and insulin resistance

AIMS

The present study aims to investigate the association between serum ferritin and diabetes, diabetes control, and insulin resistance (IR) and examine whether gender is a modifier for these associations in a community-based sample.

METHODS

A cross-sectional survey of 8,235 participants was conducted in 2009. Serum ferritin, glucose, hemoglobin A1c (HbA1c), insulin, inflammatory markers, and lipid markers were measured. IR was estimated with a Homeostasis Model Assessment (HOMA-IR) equation. Multiple logistic and linear regression models were applied to evaluate these associations.

RESULTS

The numbers of diabetic patients and non-diabetic participants in the present study were 644 (7.8 %) and 7,591 (92.2 %). After adjusting for multiple confounders, the odds ratios (ORs) and 95 % confidence intervals (CIs) for diabetes were 1.48 (1.31-1.69) in men and 1.43 (1.24-1.65) in women for one-unit increase in log-transformed serum ferritin levels. Likewise, ORs (95 % CIs) for poor diabetes control (HbA1c ≥7.5 %) were 1.58 (1.21-2.05) and 1.37 (1.07-1.77) in men and women, respectively. As for HOMA-IR, the respective betas (P value) for one-unit increase in log-transformed serum ferritin were 0.07 (P < 0.0001) and 0.06 (P < 0.0001) in men and women.

CONCLUSIONS

In conclusion, elevated serum ferritin levels were associated with higher risks of diabetes, higher levels of HbA1c, and HOMA-IR independent of several confounders.

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.

Metabolomics of ApcMin/+ mice genetically susceptible to intestinal cancer

Background

To determine how diets high in saturated fat could increase polyp formation in the mouse model of intestinal neoplasia, Apc^Min/+, we conducted large-scale metabolome analysis and association study of colon and small intestine polyp formation from plasma and liver samples of Apc^Min/+ vs. wild-type littermates, kept on low vs. high-fat diet. Label-free mass spectrometry was used to quantify untargeted plasma and acyl-CoA liver compounds, respectively. Differences in contrasts of interest were analyzed statistically by unsupervised and supervised modeling approaches, namely Principal Component Analysis and Linear Model of analysis of variance. Correlation between plasma metabolite concentrations and polyp numbers was analyzed with a zero-inflated Generalized Linear Model.

Results

Plasma metabolome in parallel to promotion of tumor development comprises a clearly distinct profile in Apc^Min/+ mice vs. wild type littermates, which is further altered by high-fat diet. Further, functional metabolomics pathway and network analyses in Apc^Min/+ mice on high-fat diet revealed associations between polyp formation and plasma metabolic compounds including those involved in amino-acids metabolism as well as nicotinamide and hippuric acid metabolic pathways. Finally, we also show changes in liver acyl-CoA profiles, which may result from a combination of Apc^Min/+-mediated tumor progression and high fat diet. The biological significance of these findings is discussed in the context of intestinal cancer progression.

Conclusions

These studies show that high-throughput metabolomics combined with appropriate statistical modeling and large scale functional approaches can be used to monitor and infer changes and interactions in the metabolome and genome of the host under controlled experimental conditions. Further these studies demonstrate the impact of diet on metabolic pathways and its relation to intestinal cancer progression. Based on our results, metabolic signatures and metabolic pathways of polyposis and intestinal carcinoma have been identified, which may serve as useful targets for the development of therapeutic interventions.

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.

Meal replacement based on Human Ration modulates metabolic risk factors during body weight loss: a randomized controlled trial

PURPOSE

A meal replacement may be an effective strategy in the management of obesity to increase antioxidant intake, attenuating oxidative stress and inflammation. In the present study, we investigated the efficacy of a new nutritional supplement to reduce metabolic risk parameters in obese women.

METHODS

In a randomized controlled crossover study (2 × 2), 22 women (percentage body fat 40.52 ± 3.75%; body mass index-BMI 28.72 ± 2.87 kg/m²; 35.04 ± 5.6 years old) were allocated into two treatments: hypocaloric diet and drink containing "Human Ration" (HR) consumption (CRHR), and hypocaloric diet and control drink consumption (CR). The study consisted of 2 periods of 5 weeks with 1 week of washout in two orders (CR → CRHR and CRHR → CR). Caloric restriction was 15%, based on estimated energy requirement. Anthropometric, clinical and metabolic risk parameters were assessed at baseline and at the end of each period.

RESULTS

Some metabolic risk factors were favorably modulated in both interventions: reduction in body weight (CR -0.74 ± 1.27 kg; p = 0.01; CRHR -0.77 ± 1.3 kg; p = 0.02), body mass index (BMI) (CR -0.27 ± 0.51 kg/m²; p = 0.02; CRHR -0.30 ± 0.52 kg/m²; p = 0.01) and HOMA-IR (CR -0.35 ± 0.82; p = 0.02, CRHR -0.41 ± 0.83; p = 0.03). However, CRHR reduced waist circumference (-2.54 ± 2.74 cm; p < 0.01) and gynoid fat (-0.264 ± 0.28 g; p < 0.01), and increased HDL-c levels (0.08 ± 0.15 mmol/l; p = 0.04).

CONCLUSION

Associated with hypocaloric diet, the intake of a nutritional supplement rich in phytochemicals as a breakfast substitute for 5 weeks had no additional effect on weight reduction than caloric restriction alone, but increased central lipolysis and improved the lipoprotein profile.

A comprehensive review on metabolic syndrome

Metabolic syndrome is defined by a constellation of interconnected physiological, biochemical, clinical, and metabolic factors that directly increases the risk of cardiovascular disease, type 2 diabetes mellitus, and all cause mortality. Insulin resistance, visceral adiposity, atherogenic dyslipidemia, endothelial dysfunction, genetic susceptibility, elevated blood pressure, hypercoagulable state, and chronic stress are the several factors which constitute the syndrome. Chronic inflammation is known to be associated with visceral obesity and insulin resistance which is characterized by production of abnormal adipocytokines such as tumor necrosis factor α , interleukin-1 (IL-1), IL-6, leptin, and adiponectin. The interaction between components of the clinical phenotype of the syndrome with its biological phenotype (insulin resistance, dyslipidemia, etc.) contributes to the development of a proinflammatory state and further a chronic, subclinical vascular inflammation which modulates and results in atherosclerotic processes. Lifestyle modification remains the initial intervention of choice for such population. Modern lifestyle modification therapy combines specific recommendations on diet and exercise with behavioural strategies. Pharmacological treatment should be considered for those whose risk factors are not adequately reduced with lifestyle changes. This review provides summary of literature related to the syndrome's definition, epidemiology, underlying pathogenesis, and treatment approaches of each of the risk factors comprising metabolic syndrome.

Association between serum ferritin levels and the incidence of obesity in Korean men: a prospective cohort study

Elevated serum ferritin levels are associated with insulin resistance, type 2 diabetes, cardiovascular disease, and metabolic syndrome. To date, however, no cohort studies have examined whether serum ferritin levels are an independent risk factor for the obesity. Therefore, we conducted a prospective cohort study to evaluate the temporal relationship between serum ferritin levels and obesity development in Korean men. Total 17,812 healthy Korean men who participated in a medical health check-up program in 2005 were followed-up until 2010. Obesity was defined as a body mass index ≥25 kg/m(2). Cox proportional hazards model was used to measure the hazard ratio of the quartile groups of serum ferritin levels. During 64,446.5 person-years of follow-up carried out, 2,627 patients became obese. After adjusting for multiple covariates, we found that the hazard ratios (95% confidence interval) for incident obesity when we compared the second, third and fourth quartiles of serum ferritin levels with the first quartile were 1.08 (0.95-1.23), 1.14 (1.00-1.30), and 1.24 (1.09-1.41), respectively (p for trend = 0.003). Both severe obesity (body mass index ≥ 30 kg/m(2)) and abdominal obesity based on waist circumference (>90 cm) showed consistent longitudinal associations (p for trend <0.001). Elevated serum ferritin levels may have been a predictive factor for obesity during the 5-year follow-up in 17,812 Korean men.

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.

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.

Obesity and inflammation: epidemiology, risk factors, and markers of inflammation

Obesity is a public health problem that has reached epidemic proportions with an increasing worldwide prevalence. The global emergence of obesity increases the risk of developing chronic metabolic disorders. Thus, it is an economic issue that increased the costs of the comorbidities associated. Moreover, in recent years, it has been demonstrated that obesity is associated with chronic systemic inflammation, this status is conditioned by the innate immune system activation in adipose tissue that promotes an increase in the production and release of pro-inflammatory cytokines that contribute to the triggering of the systemic acute-phase response which is characterized by elevation of acute-phase protein levels. On this regard, low-grade chronic inflammation is a characteristic of various chronic diseases such as metabolic syndrome, cardiovascular disease, diabetes, hypertension, non-alcoholic fatty liver disease, and some cancers, among others, which are also characterized by obesity condition. Thus, a growing body of evidence supports the important role that is played by the inflammatory response in obesity condition and the pathogenesis of chronic diseases related.

Inflammation in high blood pressure: a clinician perspective

Hypertension is one of the most important contributors to atherosclerosis. A possible link between inflammation and elevated blood pressure has been suggested by several cross-sectional and longitudinal studies. Possible mechanisms include an imbalance between vasoconstrictors and vasodilators, amplified thrombogenesis and platelet activation, and perhaps a direct effect of inflammatory mediators. C-reactive protein (CRP), an inflammatory cytokine, may play an essential role in vascular inflammation and can directly decrease the production of nitric oxide, a vasocodilator. Angiotensin II (Ang II) up-regulates several inflammatory cytokines, leukocyte adhesion molecules, and chemokines through the activation of the nuclear factor-kappa B leading to a decrease in the bioavailability of vasodilators. The increase in oxidative stress and endothelin-1 production through Ang II may further contribute to vasoconstriction. Adipose tissue can add to the production of CRP and creates a prothrombotic state. The presence of low-grade inflammation, especially elevations of CRP, can help predict the risk of future cardiovascular events and is associated with target organ damage in hypertensive individuals. Angiotensin converting enzyme inhibitors, angiotensin receptor blockers, beta-adrenoreceptor antagonists, and, to a lesser degree calcium channel antagonists, have shown efficacy in reducing CRP. Lifestyle changes such as exercise, weight loss, and tobacco cessation have also shown a similar efficacy. Whether targeting inflammation in the treatment of uncomplicated hypertension can alter the natural history of the disease or lead to improved outcome has yet to be determined.

Postmenopausal vegetarians' low serum ferritin level may reduce the risk for metabolic syndrome

The present study was conducted to compare the serum ferritin status between the postmenopausal vegetarians and non-vegetarians and to identify the relation of serum ferritin with metabolic syndrome (MetS) risk factors in postmenopausal women. The two study groups consisted of postmenopausal vegetarians (n=59) who maintained a vegetarian diet for over 20 years and age-matched non-vegetarian controls (n=48). Anthropometric measurements, dietary intakes, serum metabolic syndrome-related parameters, and serum ferritin level between the two groups were compared. The vegetarians exhibited significantly lower weight (p<0.01), body mass index (BMI) (p<0.001), percentage of body fat (p<0.001), waist circumference (p<0.01), SBP (p<0.001), DBP (p<0.001), and fasting glucose (p<0.05). According to the National Cholesterol Education Program (NCEP)-Adult Treatment Panel III criteria for MetS applying Korean guidelines for waist circumference, the prevalence of MetS was lower in vegetarians (33.9 %) than in non-vegetarians (47.9 %). Vegetarians had significantly lower serum level of ferritin (p<0.01) than non-vegetarians. In the correlation analysis, serum ferritin was positively related to fasting glucose (r=0.264, p<0.01), triglycerides (r=0.232, p<0.05), and the NCEP score (r=0.214, p<0.05) and negatively related to high-density lipoprotein-cholesterol (r=-0.225, p<0.05) after adjusting for BMI, lifestyle, and dietary factors (animal protein, animal fat, and dietary fiber intake). In conclusion, postmenopausal vegetarians had lower MetS presence and a lower serum ferritin level compared to non-vegetarians. Furthermore, vegetarians' low serum ferritin level may reduce the risk of MetS in postmenopausal women.

C-reactive protein, waist circumference, and family history of heart attack are independent predictors of body iron stores in apparently healthy premenopausal women

Ferritin levels have been associated with metabolic syndrome and insulin resistance. The aim of the present study was to evaluate the prediction of ferritin levels by variables related to cardiometabolic disease risk in a multivariate analysis. For this aim, 123 healthy women (72 premenopausal and 51 posmenopausal) were recruited. Data were collected through procedures of anthropometric measurements, questionnaires for personal/familial antecedents, and dietary intake (24-h recall), and biochemical determinations (ferritin, C reactive protein (CRP), glucose, insulin, and lipid profile) in blood serum samples obtained. Multiple linear regression analysis was used and variables with no normal distribution were log-transformed for this analysis. In premenopausal women, a model to explain log-ferritin levels was found with log-CRP levels, heart attack familial history, and waist circumference as independent predictors. Ferritin behaves as other cardiovascular markers in terms of prediction of its levels by documented predictors of cardiometabolic disease and related disorders. This is the first report of a relationship between heart attack familial history and ferritin levels. Further research is required to evaluate the mechanism to explain the relationship of central body fat and heart attack familial history with body iron stores values.

High-sensitivity C-reactive protein to detect metabolic syndrome in a centrally obese population: a cross-sectional analysis

Background

People with central obesity have an increased risk for developing the metabolic syndrome, type 2 diabetes and cardiovascular disease. However, a substantial part of obese individuals have no other cardiovascular risk factors, besides their obesity. High sensitivity C-reactive protein (hs-CRP), a marker of systemic inflammation and a predictor of type 2 diabetes and cardiovascular disease, is associated with the metabolic syndrome and its separate components. We evaluated the use of hs-CRP to discriminate between centrally obese people with and without the metabolic syndrome.

Methods

1165 people with central obesity but without any previous diagnosis of hypertension, dyslipidemia, diabetes or cardiovascular disease, aged 20-70 years, underwent a physical examination and laboratory assays to determine the presence of the metabolic syndrome (NCEP ATP III criteria). Multivariable linear regression analyses were performed to assess which metabolic syndrome components were independently associated with hs-CRP. A ROC curve was drawn and the area under the curve was calculated to evaluate whether hs-CRP was capable to predict the presence of the metabolic syndrome.

Results

Median hs-CRP levels were significantly higher in individuals with central obesity with the metabolic syndrome (n = 417; 35.8%) compared to individuals with central obesity without the metabolic syndrome (2.2 mg/L (IQR 1.2-4.0) versus 1.7 mg/L (IQR 1.0-3.4); p < 0.001). Median hs-CRP levels increased with an increasing number of metabolic syndrome components present. In multivariable linear regression analyses, waist circumference and triglycerides were the only components that were independently associated with hs-CRP after adjusting for smoking, gender, alcohol consumption and the other metabolic syndrome components. The area under the ROC curve was 0.57 (95%-CI 0.53-0.60).

Conclusions

Hs-CRP has limited capacity to predict the presence of the metabolic syndrome in a population with central obesity.

Body iron stores as predictors of insulin resistance in apparently healthy urban Colombian men

The aim of this study was to evaluate body iron stores as predictors of insulin resistance. We developed a cross-sectional study among 123 men, 25-64 years of age and determined fasting plasma glucose, insulin, serum ferritin, and C-reactive protein levels. A survey was performed to record personal antecedents and family history of non-transmissible chronic diseases. Log-transformed ferritin levels was an independent predictor for log-transformed insulin resistance index assessed by homeostatic model assessment when body mass index or waist circumference were not included in multiple linear regression models. Sedentarism, heart attack family history, and log-C reactive protein levels were also significant predictors for insulin resistance. In conclusion, documented anthropometric predictors affect the significance of ferritin as a potential prediction variable for insulin resistance. Mechanisms of how body fat could influence ferritin levels should be evaluated. To our knowledge, this is the first evaluation of the relationship between body iron stores and insulin resistance in a Latin American population.

Dietary strawberry powder reduces blood glucose concentrations in obese and lean C57BL/6 mice, and selectively lowers plasma C-reactive protein in lean mice

The purpose of the present study was to test the anti-inflammatory and blood glucose (BG)-regulating capacity of strawberries in a mouse model of diet-induced obesity. A total of thirty-six male C57BL/6J mice were randomly divided into four groups (nine mice per group). Mice were fed a low-fat diet (LF, 13 % fat), the LF supplemented with 2·6 % freeze-dried strawberry powder (LFSB), a high-fat diet (HF, 44 % fat) or the HF supplemented with 2·6 % strawberry powder (HFSB). Blood samples were collected to measure BG, inflammation and systemic markers for endocrine function of pancreas and adipose tissue. Splenocytes were harvested at the end of the study and activated with either anti-cluster of differentiation (CD) 3/anti-CD28 antibodies or lipopolysaccharide to test immune responsiveness. The HF increased non-fasted BG, insulin, soluble intracellular adhesion molecule-1, E-selectin, leptin, resistin and plasminogen activator protein-1 (P < 0·05). High dietary fat decreased IL-4 production from activated splenocytes (P < 0·05). BG concentrations were lower in the mice supplemented with SB (10·64 mmol/l) compared to the non-supplemented mice (11·37 mmol/l; P = 0·0022). BG values were approximately 6·5 % lower in the supplemented mice. Additionally, SB lowered plasma C-reactive protein in the LFSB group compared to the other three groups (P < 0·05). The dietary intake of SB approximated one human serving of strawberries. These results, although modest, support a promising role for dietary strawberries in reducing the risks associated with obesity and diabetes, and regulating the levels of inflammatory markers in non-obese individuals.

CD14 deficiency impacts glucose homeostasis in mice through altered adrenal tone

The toll-like receptors comprise one of the most conserved components of the innate immune system, signaling the presence of molecules of microbial origin. It has been proposed that signaling through TLR4, which requires CD14 to recognize bacterial lipopolysaccharide (LPS), may generate low-grade inflammation and thereby affect insulin sensitivity and glucose metabolism. To examine the long-term influence of partial innate immune signaling disruption on glucose homeostasis, we analyzed knockout mice deficient in CD14 backcrossed into the diabetes-prone C57BL6 background at 6 or 12 months of age. CD14-ko mice, fed either normal or high-fat diets, displayed significant glucose intolerance compared to wild type controls. They also displayed elevated norepinephrine urinary excretion and increased adrenal medullary volume, as well as an enhanced norepinephrine secretory response to insulin-induced hypoglycemia. These results point out a previously unappreciated crosstalk between innate immune- and sympathoadrenal- systems, which exerts a major long-term effect on glucose homeostasis.

Serum ferritin level is associated with the prevalence of metabolic syndrome in Korean adults: the 2007-2008 Korean National Health and Nutrition Examination Survey

BACKGROUND

Increased ferritin concentrations, which reflect body iron stores, contribute to insulin dysfunction and metabolic syndrome (MetS).

METHODS

This cross-sectional study included 7346 subjects (3229 men and 4117 women) who participated in the 2007-2008 Korean National Health and Nutrition Examination Survey (KNHANES). We adopted the modified Asian criteria for MetS from the American Heart Association/National Heart, Lung, and Blood Institute.

RESULTS

In comparison with participants in the first serum ferritin quartile, the odds ratio (95% confidence interval) for MetS for participants in the fourth serum ferritin quartile was 1.67 (1.24-2.23) in men and 1.41 (1.06-1.88) in women after adjusting for multiple covariates (including menopausal status in women) except insulin resistance. This association was attenuated, however, after additionally adjusting for insulin resistance [1.46 (1.08-1.98) in men and 1.22 (0.91-1.65) in women]. In particular, higher serum ferritin concentrations were associated with increased triglyceride concentrations in men and glucose intolerance in women.

CONCLUSIONS

Increased serum ferritin level was positively associated with the prevalence of MetS and with some diagnostic components of MetS, i.e., we found that increased serum ferritin concentrations were associated with high triglyceride and glucose concentrations in men and women, respectively.

Association of serum ferritin with metabolic syndrome and diabetes mellitus in the South Korean general population according to the Korean National Health and Nutrition Examination Survey 2008

We examined the association of serum ferritin levels with metabolic syndrome (MS) and diabetes mellitus in a representative sample of the adult South Korean population using data from the 2008 Korean National Health and Nutrition Examination Survey. We conducted a cross-sectional study of 6311 adults older than 20 years who participated in the 2008 Korean National Health and Nutrition Examination Survey. Metabolic syndrome was defined as the presence of at least 3 of the following: elevated blood pressure, low high-density lipoprotein cholesterol, elevated serum triglycerides, elevated plasma glucose, and abdominal obesity. Diabetes mellitus was defined as fasting glucose of at least 126 mg/dL. Insulin resistance was determined using the homeostasis model assessment estimate of insulin resistance. In a representative sample of the adult Korean population, MS was more prevalent in the highest quartile compared with the lowest quartile of serum ferritin concentrations in women following adjustments for age, education, smoking, alcohol intake, body mass index, aspartate aminotransferase, and alanine aminotransferase. Diabetes mellitus was more prevalent in the highest quartile compared with the lowest quartile of serum ferritin concentrations in premenopausal women and men. The geometric means of fasting insulin and insulin resistance determined using the homeostasis model assessment of insulin resistance in the fourth serum ferritin quartiles of postmenopausal women and men were significantly higher compared with those in the first quartile of the respective groups. The present study demonstrates that elevated serum ferritin concentrations are associated with an increased risk of MS and diabetes mellitus in a representative sample of the adult South Korean population.

Waist circumference is positively correlated with markers of inflammation and negatively with adiponectin in women with metabolic syndrome

The purpose of this study was to correlate biomarkers of metabolic syndrome (MetS), with markers of inflammation and macronutrient intake in 89 women (25-72 years) with MetS. We hypothesized that waist circumference (WC) would have the stronger correlations with inflammatory parameters and would correlate with carbohydrate intake. Values for WC (108.7 ± 11.1 cm) and plasma triglycerides (202.7 ± 52.1 mg/dL) were elevated, whereas plasma glucose levels varied from 66 to 179 mg/dL, with 42% of women having insulin resistance. Plasma levels of interleukin 6 (0.2-15.9 mg/L), tumor necrosis factor α (1.47-12.3 mg/L), and high-sensitivity C-reactive protein (0.06-3.08 mg/dL) varied widely, with most women being above values considered normal. Subjects had high intake of total sugar (92.3 ± 56.4 g/d), high glycemic index (59.8 ± 6.5), and glycemic load (127.2 ± 56.1), whereas dietary fiber (17.1 ± 9.1 g/d) was below recommended intake. Waist circumference was positively correlated with insulin (r = 0.275, P < .01) and with the inflammatory markers interleukin 6 (r = 0.307, P < .01) and tumor necrosis factor α (r = 0.228, P < .05) and negatively correlated with plasma adiponectin (r = -0.309, P < .0001). In addition, WC was positively correlated with total carbohydrate, added sugar, and glycemic load (P < .05) but not with fat or protein. These results are consistent with central obesity being a key marker of the inflammatory state, and they also suggest that carbohydrates, particularly those that are digested rapidly, contribute to increased risk of central obesity and development of MetS.

Elevated interferon gamma signaling contributes to impaired regeneration in the aged liver

Our previous study on immune-related changes in the aged liver described immune cell infiltration and elevation of inflammation with age. Levels of interferon (IFN)-γ, a known cell cycle inhibitor, were elevated in the aging liver. Here, we determine the role played by IFN-γ in the delayed regenerative response observed in the aged livers. We observed elevated IFN signaling in both aged hepatocytes and regenerating livers post-partial hepatectomy. In vivo deletion of the major IFN-γ producers-the macrophages and the natural killer cells, leads to a reduction in the IFN-γ levels accompanied with the restoration of the DNA synthesis kinetics in the aged livers. Eighteen-month-old IFN-γ-/- mice livers, upon resection, exhibited an earlier entry into the cell cycle compared with age-matched controls. Thus, our study strongly suggests that an age-related elevation in inflammatory conditions in the liver often dubbed as "inflammaging" has a detrimental effect on the regenerative response.

Central obesity and smoking are key modifiable risk factors for elevated C-reactive protein in Asian individuals who are not eligible for statin therapy

Objective:

Statin therapy reduces coronary heart disease (CHD) and mortality in individuals with elevated C-reactive protein (CRP) but low-density lipoprotein cholesterol below the threshold at which statin therapy is recommended. We determined the proportion of individuals with elevated CRP in whom statin therapy was not indicated, and examined predictors for elevated CRP in a multi-ethnic Asian population.

Design:

We studied 3404 participants (Chinese, Malays and Asian-Indians) without a history of hypercholesterolemia living in Singapore (mean age±s.d.: 48.9±11.2 years). Eligibility for statin therapy was determined based on the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III (ATPIII)) guideline. CRP was measured by high-sensitivity enzyme-linked immunosorbent assay method. CRP level greater than 2 mg l⁻¹ was considered as elevated.

Results:

Elevated CRP was found in 29.3% participants who were not eligible for statin therapy (n=2974). Elevated CRP was more common in females and amongst those of Malay or Asian-Indian ethnicity. Compared with participants with low CRP, those with elevated CRP were shown to have higher levels of obesity, blood pressure, triglyceride and insulin resistance (IR), but lower high-density lipoprotein cholesterol levels (all Ps<0.001). After multivariate analysis, gender (odds ratio (OR) 3.34 for females), ethnicity (Malay OR 1.57, 95% confidence interval (CI) 1.25–1.96; Asian-Indian OR 1.97, 95% CI 1.55–2.50), waist circumference (OR 1.06, 95% CI 1.05–1.07), smoking (OR 1.49, 95% CI 1.08–2.05) and IR (OR 1.14, 95% CI 1.07–1.22) were significant predictors of CRP (all Ps--values<0.05).

Conclusion:

Routine measurement of CRP identifies a substantial number of Asian individuals at risk of CHD in whom statin therapy is not currently indicated, particularly in women and certain ethnic groups (Malays and Asian Indians). Weight loss and smoking cessation are important measures to reduce the proportion of individuals with elevated CRP.

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.

Iron stores in relation to dietary patterns in a multiethnic population: the SAMINOR study

OBJECTIVE

We evaluated the association between serum ferritin (s-ferritin), transferrin saturation and dietary patterns, in connection with ethnicity, geographical settlement and lifestyle factors.

DESIGN

In 2003-2004, a cross-sectional study of health and living conditions was carried out in northern Norway.

SETTING

A questionnaire explored, among other factors, ethnicity and food consumption habits. Principal component analysis was used to assess the association between variables. Seven principal components were then used as input to a cluster analysis. To characterise food consumptions, five dietary patterns were identified and used to assess the effect of food consumption habits on Fe stores.

SUBJECTS

A total of 16 323 men and women between the ages of 36 and 79 years participated.

RESULTS

Participants who frequently consumed reindeer meat had higher levels of s-ferritin (P < 0.0001) than did individuals with other dietary patterns. This pattern was highly represented by subjects with three generations of Sami language (Sami I). Further, mean transferrin saturation in the reindeer group was higher compared with the other dietary clusters for men (P < 0.04) and women (P < 0.02). However, the reindeer pattern individuals also had the highest proportion of subjects with overweight and obesity. Obesity was positively associated with s-ferritin in both men and women (P < 0.0001).

CONCLUSIONS

The differences in Fe status described earlier between inland Sami and non-Sami can be explained by several factors such as food habits, age and obesity. High level of s-ferritin may reflect high intake of reindeer meat. Being overweight and obese is also associated with s-ferritin levels.

Detection of homocysteine and C-reactive protein in the saliva of healthy adults: comparison with blood levels

Inflammation and cardiovascular disease are associated with elevated serum levels of C-Reactive Protein (CRP) and homocysteine. The presence of both molecules in saliva provides an opportunity for development of non-invasive assessments of disease risk. However, salivary CRP and homocysteine reference ranges and their correlation with serum levels are unknown. This study investigated if CRP and homocysteine could be routinely detected in the saliva of healthy adults and the relationship between salivary and blood levels. CRP and homocysteine concentrations were determined using ELISA and enzymatic assays respectively. Homocysteine was detected in only two saliva samples (n = 55). CRP was measurable in all saliva samples (range: 0.05 to 64.3 μg/L; median = 1.2 μg/L) and plasma samples (range: 0.14 to 31.1 mg/L; median = 2.0 mg/L). Regression analysis demonstrated no relationship between CRP concentration in saliva and plasma (R² = 0.001). Generalized linear models including variables such as saliva flow rate and time since eating or drinking also did not pass lack of fit testing. Therefore, a relationship between CRP concentration in saliva and blood could not be established in this group of subjects. More sensitive detection methods are needed to determine if a correlation between salivary and serum homocysteine levels exists.

Consumption of a legume-enriched, low-glycemic index diet is associated with biomarkers of insulin resistance and inflammation among men at risk for colorectal cancer

The Legume Inflammation Feeding Experiment is, to our knowledge, the first randomized crossover feeding trial testing the effects of a legume-enriched, low-glycemic index (GI) diet among men characterized for colorectal adenomas and insulin resistance (IR) status. This study was designed to test the effects of a legume-enriched diet compared with a healthy American (HA) diet under weight-stable conditions. The primary objective was to assess effects on C-reactive protein (CRP) and C-peptide levels. The secondary objective was to assess changes by IR status or history of adenomas. A total of 64 men who completed a colonoscopy within the previous 2 y consumed 2 diets in random order each for 4 wk separated by a washout period. The diets were a legume-enriched (250 g/d), low-GI (GI 38) diet and a high-GI (GI 69) HA diet. We measured fasting glucose, insulin, C-peptide, CRP, and soluble tumor necrosis factor-alpha receptors I and II (sTNFRI/II) at the beginning and end of the diet periods. Participants who consumed both the legume and HA diets had favorably improved CRP (-20.2 and -18.3%) and sTNFRI (-3.7 and -4.4%) concentrations, respectively. The sTNFRII concentrations declined marginally during the legume diet period (-3.8%; P = 0.060) and significantly during the HA diet period (-5.1%; P < 0.001). Fasting glucose increased significantly during both the legume (+1.8%) and HA (-2.2%) diet periods. Only the changes in glucose differed between the diet periods. Serum C-peptide and plasma insulin levels did not change in participants consuming either diet. Healthful dietary changes can improve biomarkers of IR and inflammation.

Cytokine biomarkers, endothelial inflammation, and atherosclerosis in the metabolic syndrome: emerging concepts

In recent years, an explosion of research related to the cellular and vascular accompaniments of the metabolic syndrome has generated intense interest and controversy. Attention has focused on the vascular endothelium, where heightened, low-grade inflammatory processes lead to a continuum of vascular insults ranging from early endothelial derangements to advanced atherosclerosis. Inflammatory biocytokines, such as C-reactive protein, have been speculated to be both markers and mediators of oxidative stress and endovascular toxicity. Adipocytokines originating from fatty tissue have reinforced the concept that fat is a metabolically active organ rather than inert tissue. To fully elucidate its complex pathogenetic mechanisms, further inquiry into the inflammatory components of the metabolic syndrome is warranted. Unraveling the role of emerging proinflammatory markers has the promising potential to shed light into the underlying pathophysiology of the epidemic of obesity and the metabolic syndrome and thus help devise effective therapies.

Components of the Metabolic Syndrome among a Sample of Overweight and Obese Costa Rican Schoolchildren

Background

The term “pediatric metabolic syndrome” includes a cluster of cardiovascular risk factors such as insulin resistance, dyslipidemia (including increased triglycerides and decreased HDL cholesterol), hypertension, and obesity in children. No studies have been performed on this syndrome in a pediatric population in Costa Rica.

Objective

To establish the prevalence of metabolic syndrome and its components in 8- to 10-year old prepuberal overweight and obese schoolchildren.

Methods

This cross-sectional survey was conducted in 214 overweight and obese boys and girls, aged 8 to 10 years, who were selected from six urban schools from San José, Costa Rica. Anthropometric measurements and determinations of blood glucose, insulin, triglycerides, total cholesterol, HDL cholesterol, and high-sensitivity C-reactive protein (hs-CRP) were performed. The home-ostasis model assessment of insulin resistance (HOMA-IR) index and the Castelli index were calculated to assess insulin resistance and cardiovascular risk, respectively. Social and lifestyle variables were obtained through validated questionnaires.

Results

A total of 110 boys and 104 girls participated in this study; 37.9% of them were overweight and 62.1% were obese. Compared with boys, girls were more sedentary and had higher insulin levels (16.05 ± 10.45 μIU/mL vs. 12.72 ± 7.63 μIU/mL, p = .008), body fat (36.5% vs. 30.9%, p < .001), and HOMA-IR indexes (3.5 ± 2.4 vs. 2.8 ± 1.7, p = .014) but lower HDL cholesterol (0.99 ± 0.23 mmol/L vs. 1.08 ± 0.27 mmol/L, p = .009). Obese children had significantly higher mean serum concentrations of insulin, hs-CRP, and triglycerides and higher insulin resistance (estimated by HOMA-IR) than overweight children, but lower mean serum levels of HDL cholesterol. The prevalence of metabolic syndrome in the study population was 5.6%. Other risk factors for developing cardiovascular disease and type 2 diabetes had high prevalence rates among the children: sedentarism (40.6%), family history of type 2 diabetes (73.3%), high LDL cholesterol levels (≥ 2.84 mmol/L) (57.0%), hyperinsulinemia (> 10.5 μIU/mL) (59.8%), insulin resistance (estimated by HOMA-IR ≥ 2.4) (55.1%), and total cholesterol (> 4.39 mmol/L) (60.7%). Children with metabolic syndrome had significantly higher body mass indexes, glucose levels, and triglyceride levels and lower HDL cholesterol levels than children without metabolic syndrome. Insulin had a very strong positive correlation with HOMA-IR values ( r = 0.982), and hs-CRP had a mild positive correlation with body mass index ( r = 0.296) and body fat ( r = 0.320).

Conclusions

This study reported a prevalence of 5.6% of metabolic syndrome among a sample of Costa Rican overweight and obese prepuberal children. Lifestyle interventions focusing on weight reduction and increasing physical activities should be promoted by education and health authorities in order to avoid the early development and onset of type 2 diabetes and atherosclerosis in childhood.

Low-grade inflammation can partly explain the association between the metabolic syndrome and either coronary artery disease or severity of peripheral arterial disease: the CODAM study

BACKGROUND

Low-grade inflammation has been hypothesized to underlie the coronary artery disease (CAD) risk associated with the metabolic syndrome, but the evidence is not conclusive. For peripheral arterial disease (PAD; as measured by the ankle-arm index), this association has not been studied before. The aim was to study whether the association between the metabolic syndrome and CAD or the severity of PAD can be explained by low-grade inflammation.

METHODS

The Cohort study Diabetes and Atherosclerosis Maastricht population includes 574 subjects, with an increased risk of type 2 diabetes, of whom 560 were included in the analyses (343 males; age: 59.5 +/- 7.0 years). The inflammation markers that were measured were C-reactive protein, interleukin 6, soluble vascular cell adhesion molecule-1, soluble intercellular adhesion molecule-1 and serum amyloid A. All analyses were adjusted for age, sex and smoking.

RESULTS

Logistic regression showed that the metabolic syndrome was significantly associated with CAD [odds ratio (OR) = 1.86, 95% CI: 1.21; 2.84, P = 0.004]. Further adjustment for inflammatory status, as captured in a combination of the inflammation markers (using an averaged Z-score), resulted in significant associations of both the metabolic syndrome and inflammatory status with CAD [OR(metabolic syndrome) (95% CI) = 1.58 (1.01; 2.46), P = 0.044; OR(inflammation) (95% CI) = 1.59 (1.14; 2.21), P = 0.007]. Linear regression analysis showed similar results for the ankle-arm index.

CONCLUSIONS

The association between the metabolic syndrome, on the one hand, and prevalence of CAD or the severity of PAD, on the other, can be partly but not completely, 26% and 29% respectively, explained by low-grade inflammation.

Association of oxidative stress, iron, and centralized fat mass in healthy postmenopausal women

OBJECTIVE

Centralized adiposity, insulin resistance, excess iron, and elevated oxidative stress place postmenopausal women at risk for atherosclerotic cardiovascular disease (CVD). The objective of this study was to determine the relationship among excess iron, oxidative stress, and centralized fat mass in healthy postmenopausal women.

METHODS

The parent project recruited healthy women for a randomized, double-blind, clinical trial designed to examine the effect of soy isoflavones on bone. At baseline (n = 122), we measured three antioxidant enzymes, iron status indices (serum ferritin among others), oxidative stress indices (oxidized low-density lipoprotein [oxLDL], urinary isoprostanes [PGF(2alpha)], protein carbonyls, DNA damage), and waist, hip, and thigh fat mass using dual-energy x-ray absorptiometry (DXA). We calculated insulin resistance using the homeostasis model assessment (HOMA). Multiple regression analysis was used to determine the CVD risk factors that contributed to oxidative stress and centralized fat mass (waist + hip/thigh = AndGynFM ratio).

RESULTS

Almost 14% (p < 0.0005) of the variability in oxLDL was accounted for by AndGynFM ratio (6.1%, p < 0.0005), age (4.0%, p = 0.012), and serum iron (2.8%, p = 0.053). Similarly, 16% (p < 0.0001) of the variability in PGF(2alpha) was accounted for by the AndGynFM ratio (4.8%, p = 0.011), HOMA (3.9%, p = 0.021), and serum iron (2.7%, p = 0.054). We accounted for 33% (p

CONCLUSIONS

Our study suggests that reducing centralized fat mass and maintaining a favorable lipid profile, antioxidant status, and iron status all may be important in protecting postmenopausal women from atherosclerotic CVD.

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Key Words Collapse

MESH Headings

• Aged
• Biomarkers/blood
• Body Fat Distribution/adverse effects
• Body Mass Index
• Bone Density/drug effects
• Bone and Bones/drug effects
• Coronary Artery Disease/blood
• Coronary Artery Disease/etiology
• Coronary Artery Disease/prevention & control
• Double-Blind Method
• Female
• Ferritins/blood
• Folic Acid/blood
• Humans
• Iron/metabolism
• Middle Aged
• Oxidative Stress/drug effects
• Postmenopause/blood
• Reference Values
• Soybean Proteins/administration & dosage
• Soybean Proteins/pharmacology
• Waist-Hip Ratio

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Grants

• R01 AR046922 NIAMS NIH HHS
• R01 AR046922 A2 NIAMS NIH HHS
• P01 ES012020 NIEHS NIH HHS
• 95P50AT004155 NCCIH NIH HHS

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Affiliation(s)

Betsy L. Crist Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa
D. Lee Alekel Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa Nutrition and Wellness Research Center, Iowa State University, Ames, Iowa
Laura M. Ritland Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa
Laura N. Hanson Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa
Ulrike Genschel Department of Statistics, Iowa State University, Ames, Iowa
Manju B. Reddy Department of Food Science and Human Nutrition, Iowa State University, Ames, Iowa

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Collaborators Collapse

The metabolic syndrome

The "metabolic syndrome" (MetS) is a clustering of components that reflect overnutrition, sedentary lifestyles, and resultant excess adiposity. The MetS includes the clustering of abdominal obesity, insulin resistance, dyslipidemia, and elevated blood pressure and is associated with other comorbidities including the prothrombotic state, proinflammatory state, nonalcoholic fatty liver disease, and reproductive disorders. Because the MetS is a cluster of different conditions, and not a single disease, the development of multiple concurrent definitions has resulted. The prevalence of the MetS is increasing to epidemic proportions not only in the United States and the remainder of the urbanized world but also in developing nations. Most studies show that the MetS is associated with an approximate doubling of cardiovascular disease risk and a 5-fold increased risk for incident type 2 diabetes mellitus. Although it is unclear whether there is a unifying pathophysiological mechanism resulting in the MetS, abdominal adiposity and insulin resistance appear to be central to the MetS and its individual components. Lifestyle modification and weight loss should, therefore, be at the core of treating or preventing the MetS and its components. In addition, there is a general consensus that other cardiac risk factors should be aggressively managed in individuals with the MetS. Finally, in 2008 the MetS is an evolving concept that continues to be data driven and evidence based with revisions forthcoming.

Recent advances in metabolic syndrome and cardiovascular disease

Metabolic syndrome is defined as an association of central obesity and several other cardiometabolic risk factors. Dysfunctional visceral adipose tissue and inflammatory status appear to be involved in its genesis. New definitions have decreased the threshold for glycaemia and one has lowered the threshold for waist circumference, leading to an increase in the prevalence of metabolic syndrome. However, the impact on mortality with these new definitions is lower than with the National Cholesterol Education Program-Adult Treatment Panel III 2001 definition. An increase in waist circumference, along with increased glycaemia, triglycerides and/or blood pressure is more highly associated with an increased risk of mortality than are other associations, while a decrease in high density lipoprotein cholesterol increases risk of coronary heart disease. The risk of sudden death and stroke is particularly notable with metabolic syndrome. Metabolic syndrome is associated with an increase in heart rate, pulse pressure, arterial stiffness and left ventricular hypertrophy, impairment of diastolic function, enlargement of the left atrium and atrial fibrillation. In the 2007 European recommendations for the management of high blood pressure, metabolic syndrome is now taken into consideration for both risk stratification and in selecting the optimal therapeutic strategy for arterial hypertension.

The metabolic syndrome: similar deleterious impact on all-cause mortality in hypertensive and normotensive subjects

OBJECTIVES

Few data are available on the impact of the metabolic syndrome on all-cause mortality risk according to the presence of hypertension. Our aim was to evaluate the 5-year impact of the metabolic syndrome, according to blood pressure status, on all-cause mortality risk in a large French population.

METHODS

The study population included 39 998 men and 20 756 women with no personal history of cardiovascular disease, who had a health check-up at the IPC Center (Paris, France) between 1999 and 2002, and who were followed up for 4.7 +/- 1.2 years. The metabolic syndrome was defined according to the National Cholesterol Educational Program classification (2001). Cox regression models were used to evaluate risk of all-cause mortality after adjustment for age, sex, classical risk factors and socioeconomic categories. Subjects were classified according to blood pressure status: hypertensive subject (systolic blood pressure > or =140 mmHg and/or diastolic blood pressure > or =90 mmHg or treatment) and normotensive subject.

RESULTS

The risk of all-cause mortality associated with the metabolic syndrome was 1.50 (1.24-1.82) [hazard ratio (HR) (95% confidence interval)]. The risk of all-cause mortality associated with the presence of hypertension was 1.60 (1.38-1.85). During the 4.7 years of follow-up, the impact of the metabolic syndrome was similar among normotensive and hypertensive subjects [HR: 1.09 (0.68-1.75) and 1.40 (1.13-1.74), respectively, P for interaction = 0.35].

CONCLUSION

The findings from this study show that, in a large middle-aged French population, the metabolic syndrome has the same deleterious impact on all-cause mortality in hypertensive subjects and normotensive subjects.

[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.

Prevalence of Metabolic Syndrome in Patients With Clinically Advanced Peripheral Vascular Disease

The aim of this cross-sectional study was to determine the prevalence of metabolic syndrome (MetS) and its components among 100 patients with progressive peripheral arterial disease (PAD) referred for diagnostic angiography in preparation for a revascularization procedure. The prevalence of MetS was more than 95%. Diabetes mellitus was the most prevalent component followed by hypertension and low high-density lipoprotein. Almost half the patients aggregated in the highest metabolic score category. A direct relationship was identified between the number of MetS components and serum uric acid ( P = .001) and C-reactive protein ( P = .826), whereas an inverse relationship was seen between the clustering of components and androgen levels in men ( P < .001). For PAD, which could have a benign clinical course, early screening for MetS might identify those at greater risk of failing conservative therapy and progressing to a more aggressive atherosclerotic disease typically associated with high morbidity and mortality.