Insulin sensitivity, vascular function, and iron stores in voluntary blood donors

Factors influencing new-onset hypertension in elderly patients with obstructive sleep apnea: A multicenter cohort study

Investigating the influencing factors of new-onset hypertension in the elderly with obstructive sleep apnea (OSA). 450 Chinese older patients with OSA who were non-hypertensive at baseline were enrolled. All patients had undergone polysomnography monitoring in the multicenter study. The primary endpoint was incident hypertension. Kaplan-Meier survival analysis was performed, and multivariate Cox proportional hazards models were generated to determine the factors influencing new-onset hypertension. A total of 176 (39.1%) patients developed hypertension. The hypertension group had older age, higher hemoglobin (Hb) level and apnea-hypopnea index (AHI) values than the non-hypertension group (all p < 0.05). During the median 33-month follow-up period, multivariate Cox analysis showed age (hazard ratio (HR) = 1.039, 95% confidence interval (95% CI): 1.016-1.062), AHI (HR = 1.015, 95% CI: 1.007-1.023) and Hb level (HR = 1.016, 95% CI: 1.008-1.025) were independent predictors of new-onset hypertension. However, continuous positive airway pressure (CPAP; HR = 0.508, 95% CI: 0.271-0.951) reduced the risk of developing hypertension. Notably, the subgroup analysis demonstrated that the plasma glucose level (HR = 1.168, 95% CI: 1.029-1.326) was a risk factor for male patients. Besides length of time with the pulse oxygen saturation less than 90% (Tsat90; HR = 1.005, 95% CI: 1.003-1.007), body mass index (BMI; HR = 1.170, 95% CI: 1.043-1.311), and dyslipidemia (HR = 2.335, 95% CI: 1.144-4.766) had statistically significant effects on the incidence of hypertension in certain subgroups. Although this study lacked analysis of items such as living habits and medication, it did show age, AHI, Hb and CPAP affected the development of hypertension in elderly OSA patients. These findings suggested that targeted interventions in specific populations may be more effective in preventing hypertension.

Iron Overload in Functional Hyperandrogenism: In a Randomized Trial, Bloodletting Does Not Improve Metabolic Outcomes

CONTEXT

Functional hyperandrogenism may be associated with a mild increase in body iron stores. Iron depletion exerts a beneficial effect on metabolic endpoints in other iron overload states.

OBJECTIVES

(i) To determine the effect of iron depletion on the insulin sensitivity and frequency of abnormal glucose tolerance in patients with functional hyperandrogenism submitted to standard therapy with combined oral contraceptives (COC). ii) To assess the overall safety of this intervention.

DESIGN

Randomized, parallel, open-label, clinical trial.

SETTING

Academic hospital.

PATIENTS

Adult women with polycystic ovary syndrome or idiopathic hyperandrogenism.

INTERVENTION

After a 3-month run-in period of treatment with 35 μg ethinylestradiol plus 2 mg cyproterone acetate, participants were randomized (1:1) to 3 scheduled bloodlettings or observation for another 9 months.

MAIN OUTCOME MEASURES

Changes in insulin sensitivity index and frequency of prediabetes/diabetes, and percentage of women in whom bloodletting resulted in plasma hemoglobin <120 g/L and/or hematocrit <0.36.

RESULTS

From 2015 to 2019, 33 women were included by intention-to-treat. During the follow-up, insulin sensitivity did not change in the whole group of women or between study arms [mean of the differences (MD): 0.0 (95%CI: -1.6 to 1.6)]. Women in the experimental arm showed a similar odds of having prediabetes/diabetes than women submitted to observation [odds ratio: 0.981 (95%CI: 0.712 to 1.351)]. After bloodletting, 4 (21.1%) and 2 women (10.5%) in the experimental arm had hemoglobin (Hb) levels <120 g/L and hematocrit (Hct) values <0.36, respectively, but none showed Hb <110 g/L or Hct <0.34.

CONCLUSIONS

Scheduled bloodletting does not improve insulin sensitivity in women with functional hyperandrogenism on COC.

Iron overload reduces adiponectin receptor expression via a ROS/FOXO1-dependent mechanism leading to adiponectin resistance in skeletal muscle cells

Iron overload (IO) is a common yet underappreciated finding in metabolic syndrome (MetS) patients. With the prevalence of MetS continuing to rise, it is imperative to further elucidate cellular mechanisms leading to metabolic dysfunction. Adiponectin has many beneficial effects and is a therapeutic target for the treatment of MetS and cardiovascular diseases. IO positively correlates with reduced circulating adiponectin levels yet the impact of IO on adiponectin action is unknown. Here, we established a model of IO in L6 skeletal muscle cells and found that IO-induced adiponectin resistance. This was shown via reduced p38 mitogen-activated protein kinase phosphorylation in response to the small molecule adiponectin receptor (AdipoR) agonist, AdipoRon, in presence of IO. This correlated with reduced messenger RNA and protein levels of AdipoR1 and its facilitative signaling binding partner, APPL1. IO caused phosphorylation, nuclear extrusion, and thus inhibition of FOXO1, a known transcription factor regulating AdipoR1 expression. The antioxidant N-acetyl cystine attenuated the production of reactive oxygen species (ROS) by IO, and blunted its effect on FOXO1 phosphorylation and removal from the nucleus, as well as subsequent adiponectin resistance. In conclusion, our study identifies a ROS/FOXO1/AdipoR1 axis as a cause of skeletal muscle adiponectin resistance in response to IO. This new knowledge provides insight into a cellular mechanism with potential relevance to disease pathophysiology in MetS patients with IO.

Initiating guideline-concordant gout treatment improves arterial endothelial function and reduces intercritical inflammation: a prospective observational study

Background

Patients with gout have arterial dysfunction and systemic inflammation, even during intercritical episodes, which may be markers of future adverse cardiovascular outcomes. We conducted a prospective observational study to assess whether initiating guideline-concordant gout therapy with colchicine and a urate-lowering xanthine oxidase inhibitor (XOI) improves arterial function and reduces inflammation.

Methods

Thirty-eight untreated gout patients meeting American College of Rheumatology (ACR)/European League Against Rheumatism classification criteria for gout and ACR guidelines for initiating urate-lowering therapy (ULT) received colchicine (0.6 mg twice daily, or once daily for tolerance) and an XOI (allopurinol or febuxostat) titrated to ACR guideline-defined serum urate (sU) target. Treatment was begun during intercritical periods. The initiation of colchicine and XOI was staggered to permit assessment of a potential independent effect of colchicine. Brachial artery flow-mediated dilation (FMD) and nitrate-mediated dilation (NMD) assessed endothelium-dependent and endothelium-independent (smooth muscle) arterial responsiveness, respectively. High-sensitivity C-reactive protein (hsCRP), IL-1β, IL-6, myeloperoxidase (MPO) concentrations, and erythrocyte sedimentation rate (ESR) assessed systemic inflammation.

Results

Four weeks after achieving target sU concentration on colchicine plus an XOI, FMD was significantly improved (58% increase, p = 0.03). hsCRP, ESR, IL-1β, and IL-6 also all significantly improved (30%, 27%, 19.5%, and 18.8% decrease respectively; all p ≤ 0.03). Prior to addition of XOI, treatment with colchicine alone resulted in smaller numerical improvements in FMD, hsCRP, and ESR (20.7%, 8.9%, 13% reductions, respectively; all non-significant), but not IL-1β or IL-6. MPO and NMD did not change with therapy. We observed a moderate inverse correlation between hsCRP concentration and FMD responsiveness (R = − 0.41, p = 0.01). Subgroup analyses demonstrated improvement in FMD after achieving target sU concentration in patients without but not with established cardiovascular risk factors and comorbidities, particularly hypertension and hyperlipidemia.

Conclusions

Initiating guideline-concordant gout treatment reduces intercritical systemic inflammation and improves endothelial-dependent arterial function, particularly in patients without established cardiovascular comorbidities.

Blood donation and health status based on SF-36: The mediating effect of cognition in blood donation

Objective

The relationship among blood donation, cognition in blood donation and health condition of blood donors remains unclear. Based on our hypothesis, this study aimed to explore the mediating effect of cognition in blood donation on the relationship between blood donation and blood donors’ health status.

Methods

A total of 837 participants who had prior experience in donating whole blood were recruited into a cross-sectional survey. The Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) and the Questionnaire on Cognition in Non-remunerated Blood Donation were used to evaluate the health status and the level of cognition in blood donation, respectively. Blood donation referred to the cumulative times of blood donation. The mediating effect of cognition in blood donation was analyzed by applying a path model.

Results

The results revealed that blood donation was positively related to the physical component summary (PCS) and mental component summary (MCS) of SF-36, and cognition in blood donation was shown to have a partial mediating effect on the relationship between blood donation and both PCS and MCS. The effect size of cognition in blood donation was 24.63% in PCS and 26.72% in MCS.

Conclusions

Blood donation is positively correlated with SF-36 outcomes (PCS and MCS) of blood donors, and cognition in blood donation plays a partial mediating effect in the relationship between blood donation and PCS and MCS.

Cardiovascular risk in 159 934 frequent blood donors while addressing the healthy donor effect

OBJECTIVE

To investigate whether regular blood donation decreases cardiovascular risk.

METHODS

All 159 934 Dutch whole-blood donors with an active donation career of at least 10 years were categorised into sex-specific donation tertiles based on the number of donations during this 10-year qualification period. Cardiovascular endpoints were based on hospital discharge diagnoses and death certificates from Dutch Hospital Data and Statistics Netherlands and occurring after the 10-year qualification period. Cox regression was used to estimate the age-adjusted and starting year-adjusted hazard rate ratio (HRR).

RESULTS

Female high-frequency blood donors had a reduced cardiovascular morbidity (HRR=0.91, 95% CI 0.85 to 0.98) compared with low-frequency blood donors. No effect was observed in men (HRR=1.00, 95% CI 0.95 to 1.05). To rule out a residual healthy donor effect (HDE), additional sensitivity analyses using a 5-year qualification period were conducted. The results supported the absence of a residual HDE.

CONCLUSIONS

This study showed a protective effect of long-term, high-frequency blood donation against cardiovascular disease. This effect was only observed in women and not in men.

Impaired arterial responsiveness in untreated gout patients compared with healthy non-gout controls: association with serum urate and C-reactive protein

To determine whether arterial responsiveness is impaired among patients with gout, and whether arterial responsiveness inversely correlates with serum urate and inflammatory measures. This is a cross-sectional study of untreated gout subjects (n = 34) and non-gout healthy controls (n = 64). High-resolution dynamic ultrasound-measured flow-mediated dilation (FMD) and nitroglycerin-mediated dilation (NMD) assessed endothelium-dependent and endothelium-independent arterial responsiveness respectively. Serum urate (sUA) and high-sensitivity C-reactive protein (hsCRP) were measured in the gout group, and correlated with FMD and NMD responses. Both FMD (2.20 ± 0.53 vs 3.56 ± 0.31, p = 0.021) and NMD (16.69 ± 1.54 vs 24.51 ± 0.90, p = 0.00002) were impaired in the gout versus control group. Stratification for individual comorbidities suggested that no single risk factor accounted for impaired FMD/NMD in the gout subjects. However, the degree of association between gout and FMD, but not NMD impairment, was dampened after multivariable adjustment (FMD unadjusted beta = - 1.36 (SE 0.58), p = 0.02; adjusted beta = - 1.16 (SE 0.78), p = 0.14 and NMD unadjusted beta = - 7.68 (SE 1.78), p < 0.0001; adjusted beta = - 5.33 (SE 2.46), p = 0.03). Within the gout group, there was an inverse correlation between FMD and sUA (R = - 0.5, p = 0.003), and between FMD and hsCRP (R = - 0.42, p = 0.017), but not between NMD and sUA or hsCRP. Compared with healthy controls, subjects with gout have reduced arterial function. Individual comorbidities are insufficient to account for differences between gout and control groups, but multiple comorbidities may collectively contribute to impairment in endothelium-dependent arterial responsiveness. Endothelial impairment is also related to sUA and hsCRP, markers of gout severity and inflammation respectively. Studies to determine whether gout therapy may improve arterial responsiveness are warranted.

Changes in metabolic indices in response to whole blood donation in male subjects with normal glucose tolerance

OBJECTIVES

Previous studies have investigated the impact of venesection upon different metabolic indices in patients with various conditions (e.g., type 2 diabetes and iron overload). We aimed to investigate the changes on different metabolic indices including glycemic, iron, lipids and inflammatory markers at different time points after blood donation in male subjects with normal glucose tolerance.

DESIGN AND METHODS

42 male subjects were recruited to the study. Glucose tolerance was assessed by oral glucose tolerance test before (visit A) and after the blood donation (1day, visit B; 1week, visit C; 3weeks, visit D; and 3months, visit E). Fasting glucose, HbA1c, insulin, lipids, uric acid, C-reactive protein, iron stores and insulin resistance (HOMA-IR, ISI-gly) indices were measured. A repeated measures ANOVA was used for comparisons of quantitative variables between different visits.

RESULTS

All subjects had normal glucose tolerance according to WHO criteria. Fasting glucose, insulin and HOMA-IR were significantly higher (~2%, p<0.05; ~21%, p<0.01; and ~11%, p<0.05 respectively) at visit B following donation. At visit D, the mean±SE for HbA1c (5.28±0.06%) was significantly lower with a difference in percentage of ~-3% and p<0.05 compared to visit A (5.44±0.06%). Ferritin decreased significantly at visits B, C, D and E (~-8%, p<0.01, ~-24%, p<0.001, ~-39%, p<0.001 and ~-29%, p<0.01 respectively), when compared to visit A.

CONCLUSIONS

At different time points after blood donation, glycemic status and iron stores are affected significantly in male blood donors with normal glucose tolerance. The changes were particularly evident three weeks after donation. Hence, the interpretation of these parameters in male blood donors needs to take this into account, and the mechanisms resulting in these effects need to be clarified.

A review of potential metabolic etiologies of the observed association between red meat consumption and development of type 2 diabetes mellitus

Epidemiological studies suggest that red and processed meat consumption is related to an increased risk of type 2 diabetes. However, it is not clearly understood which components of red and processed meat contribute to this increased risk. This review examines potential mechanisms addressing the role of saturated fatty acid, sodium, advanced glycation end products (AGEs), nitrates/nitrites, heme iron, trimethylamine N-oxide (TMAO), branched amino acids (BCAAs) and endocrine disruptor chemicals (EDCs) in the development of type 2 diabetes based on data from published clinical trials and animal models. TMAO which is derived from dietary carnitine and choline by the action of bacterial enzymes followed by oxidation in the liver may be a strong candidate molecule mediating the risk of type 2 diabetes. BCAAs may induce insulin resistance via the mammalian target of rapamycin complex 1 (mTORC1) and ribosomal protein S6 kinase β 1 (S6k1)-associated pathways. The increased risk associated with processed meat compared with red meat suggests that there are interactions between the saturated fat, salt, and nitrates in processed meat and iron, AGEs and TMAO. Intervention studies are required to clarify potential mechanisms and explore interactions among components, in order to make firm recommendations on red and processed meat consumption.

Cardiovascular benefits of phlebotomy: relationship to changes in hemorheological variables

Renewed interest in the age-old concept of “bloodletting”, a therapeutic approach practiced until as recently as the 19th century, has been stimulated by the knowledge that blood loss, such as following regular donation, is associated with significant reductions in key hemorheological variables, including whole blood viscosity (WBV), plasma viscosity, hematocrit and fibrinogen. An elevated WBV appears to be both a strong predictor of cardiovascular disease and an important factor in the development of atherosclerosis. Elevated WBV through wall shear stress is the most direct physiological parameter that influences the rupture and erosion of vulnerable plaques. In addition to WBV reduction, phlebotomy may reduce an individual’s cardiovascular risk through reductions in excessive iron, oxidative stress and inflammation. Reflecting these findings, blood donation in males has shown significant drops in the incidence of cardiovascular events, as well as in procedures such as percutaneous transluminal coronary angioplasty and coronary artery bypass grafting. Collectively, the available data on the benefits of therapeutic phlebotomy point to the importance of monitoring WBV as part of a cardiovascular risk factor, along with other risk-modifying measures, whenever an increased cardiovascular risk is detected. The development of a scanning capillary tube viscometer allows the measurement of WBV in a clinical setting, which can prove to be valuable in providing an early warning sign of an increased risk of cardiovascular disease.

Red meat, dietary heme iron, and risk of type 2 diabetes: the involvement of advanced lipoxidation endproducts

There is growing evidence of disordered iron homeostasis in the diabetic condition, with links proposed between dietary iron intakes and both the risk of disease and the risk of complications of advanced disease. In the United States, Britain, and Canada, the largest dietary contributors of iron are cereals and cereal products and meat and meat products. This review discusses the findings of cohort studies and meta-analyses of heme iron and red meat intakes and the risk of type 2 diabetes. These suggest that processed red meat is associated with increased risk, with high intakes of red meat possibly also associated with a small increased risk. Historically, humans have relied on large quantities of heme iron and red meat in their diets, and therefore it is paradoxical that iron from meat sources should be associated with the risk of type 2 diabetes. A reason for this association may be drawn from studies of dietary advanced glycation and lipoxidation endproducts present in processed food and the mechanisms by which insulin output by pancreatic islet cells might be influenced by the protein modifications present in processed red meat.

Relationship between blood donors' iron status and their age, body mass index and donation frequency

CONTEXT AND OBJECTIVE

Regular blood donation may decrease body iron storage and lead to anemia. The aim here was to evaluate the iron status of Iranian male blood donors and the impact of age, body mass index (BMI) and donation frequency over one year, on iron status indices.

DESIGN AND SETTING

Cross-sectional, descriptive and analytical study at Tehran Blood Transfusion Center, Tehran, Iran.

METHODS

Between July and September 2011, 117 male blood donors were selected and divided into four groups according to their frequency of blood donation. Thirty male non-donors were also recruited as controls after adjusting for age, weight, height, smoking habits and monthly income. Iron status indices and some criteria such as general health and dietary measurements were determined among all subjects.

RESULTS

The values of the iron-related parameters were significantly lower among donors than among non-donors. Only total iron binding capacity (TIBC) was found to be significantly higher among different donor groups than in the controls. A significant positive correlation was observed between age and serum ferritin (SF) only among the donors who had donated once within the preceding year. The iron status indices did not show any significant relationship with BMI among donors or non-donors.

CONCLUSION

A donation frequency of more than twice a year had a significant influence on iron-related parameters. Therefore, without annual measurement of these parameters, further phlebotomies may lead to iron deficiency and donor rejection in the future.

Back to past leeches: repeated phlebotomies and cardiovascular risk

In patients with metabolic syndrome, body iron overload exacerbates insulin resistance, impairment of glucose metabolism, endothelium dysfunction and coronary artery responses. Conversely, iron depletion is effective to ameliorate glucose metabolism and dysfunctional endothelium. Most of its effectiveness seems to occur through the amelioration of systemic and hepatic insulin resistance. In a study published by BMC Medicine, Michalsen et al. demonstrated a dramatic improvement of blood pressure, serum glucose and lipids after removing 550 to 800 ml of blood in subjects with metabolic syndrome. This effect was apparently independent of changes in insulin resistance, in contrast to previous cross-sectional and cohort studies investigating the association between iron overload, insulin resistance and cardiovascular disease. Despite drawbacks in the study design, its findings may lead the way to investigations aimed at exploring iron-dependent regulatory mechanisms of vascular tone in healthy individuals and patients with metabolic disease, thus providing a rationale for novel preventive and therapeutic strategies to counteract hypertension. Please see related article: http://www.biomedcentral.com/1741-7015/10/54.

Dietary intake and serum and hair concentrations of minerals and their relationship with serum lipids and glucose levels in hypertensive and obese patients with insulin resistance

Inadequate minerals intake, as well as disruption of some metabolic processes in which microelements are cofactors, are suggested to lead to the development of hypertension. The role of minerals in the pathogenesis of hypertension still remains to be explained. In the present study, we sought to determine associations between serum and hair mineral concentrations and serum lipids and glucose levels. Forty obese hypertensive subjects with insulin resistance and 40 healthy volunteers were recruited in the study. Blood pressure, BMI, and insulin resistance were recorded in all subjects. Levels of lipids, glucose, sodium and potassium, iron, copper, zinc, magnesium, and calcium were assessed in serum. Iron, copper, zinc, magnesium, and calcium were assessed in hair. Dietary intake of the analyzed minerals was estimated. We found distinctly higher concentrations of serum iron and serum and hair calcium as well as markedly lower levels of hair zinc in the hypertensive subjects. The study group manifested also significantly lower daily intake of calcium, magnesium, and iron. We observed a relationship between the concentrations of iron, zinc, and copper in serum and hair and high and low range of cholesterol, triglycerides, and glucose serum levels in the studied patients. Moreover, this study demonstrated significant correlation between serum and hair concentrations of selected minerals and their dietary intake and levels of serum lipids and glucose and blood pressure in the study and the control groups. The obtained results seem to indicate the association between lipid and glucose metabolism and iron, copper, zinc, and calcium concentrations in blood and hair of hypertensive and obese patients with insulin resistance.

Do high ferritin levels confer lower cardiovascular risk in men with Type 2 diabetes?

AIMS

High ferritin levels are associated with insulin resistance and liver steatosis, both thought of as emerging cardiovascular risk factors. The association between ferritin and cardiovascular disease is poorly documented in cardiometabolic states with higher cardiovascular risk, such as diabetes and metabolic syndrome. We therefore characterized a cohort of males with Type 2 diabetes mellitus (T2DM) according to ferritin levels and prevalent macroangiopathy.

METHODS

The presence of overall macroangiopathy, peripheral and/or coronary artery disease was documented in 424 consecutive T2DM males, who were divided according to ferritin quartiles (Q) as follows: QI-III, normal ferritin (NF; n=318), mean+/-1 sd ferritin 133+/-72 ng/ml; and QIV patients, high ferritin (HF; n=106), ferritin 480+/-228 ng/ml.

RESULTS

Age, age at diabetes diagnosis, smoking, ethanol intake, body mass index, waist circumference, blood pressure and presence of metabolic syndrome did not differ between groups. However, the prevalence of macroangiopathy was unexpectedly much lower in patients with high ferritin, as follows: 25% vs. 43% for overall macroangiopathy; 7% vs. 16% for peripheral artery disease; and 16% vs. 31% for coronary artery disease (P=0.0009, P=0.0140 and P=0.0035, respectively, vs. NF patients). Insulin resistance index and prevalence of liver steatosis were higher in HF compared with NF patients as follows: 2.17% vs. 1.89% and 78% vs. 64% (P=0.0345 and P=0.0059, respectively). Liver enzymes (aspartate aminotransferase, alanine aminotransferase and gamma-glutamyl transferase) were significantly higher in HF, by 33%, 42% and 72%, respectively (all P<0.0002), suggesting a higher prevalence of steatohepatitis. Glycated haemoglobin, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, triglycerides, urate, high-sensitivity C-reactive protein and albuminuria were not different between groups.

CONCLUSIONS

Our results demonstrate that T2DM males with high ferritin levels exhibit a markedly decreased prevalence of macroangiopathy, despite more severe insulin resistance and higher markers of steatohepatitis. High ferritin levels and/or steatosis may thus paradoxically confer a lowered cardiovascular risk in diabetic males.

Glucose abnormalities in non-alcoholic fatty liver disease and chronic hepatitis C virus infection: the role of iron overload

Non-alcoholic fatty liver disease (NAFLD) and chronic hepatitis C virus (HCV) infection are major causes of liver disease frequently described in outpatient patients with glucose abnormalities. Hyperferritinemia, which suggests that iron overload plays a decisive role in the pathophysiology of insulin resistance and hyperglycemia, is a common finding in both disorders. However, the role of the hepatic iron deposition differs from one to the other. In NAFLD, a moderate liver iron accumulation has been observed and molecular mechanisms, including the downregulation of the liver iron exporter ferroportin-1, have been described. Iron overload will enhance intrahepatic oxidative stress that promotes hepatic fibrosis, interfere with insulin signalling at various levels and may hamper hepatic insulin extraction. Therefore, liver fibrosis, hyperglycemia and hyperinsulinemia will lead to increased levels of insulin resistance and the development of glucose abnormalities. Furthermore, iron depletion by phlebotomy removes liver iron content and reduces serum glucose and insulin resistance in NAFLD patients. Therefore, it seems that iron overload participates in those glucose abnormalities associated with NAFLD. Concerning chronic HCV infection, it has been classically assumed that iron overload contributes to insulin resistance associated with virus infection. However, recent evidence argues against the presence of iron overload in these patients and points to inflammation associated with diabetes as the main contributor to the elevated ferritin levels. Therefore, glucose abnormalities, and specially type 2 diabetes, should be taken into account when evaluating serum ferritin levels in patients with HCV infection.

The role of iron in type 2 diabetes in humans

The role of micronutrients in the etiology of type 2 diabetes is not well established. Several lines of evidence suggest that iron play may a role in the pathogenesis of type 2 diabetes. Iron is a strong pro-oxidant and high body iron levels are associated with increased level of oxidative stress that may elevate the risk of type 2 diabetes. Several epidemiological studies have reported a positive association between high body iron stores, as measured by circulating ferritin level, and the risk of type 2 diabetes and of other insulin resistant states such as the metabolic syndrome, gestational diabetes and polycystic ovarian syndrome. In addition, increased dietary intake of iron, especially that of heme iron, is associated with risk of type 2 diabetes in apparently healthy populations. Results from studies that have evaluated the association between genetic mutations related to iron metabolism have been inconsistent. Further, several clinical trials have suggested that phlebotomy induced reduction in body iron levels may improve insulin sensitivity in humans. However, no interventional studies have yet directly evaluated the effect of reducing iron intake or body iron levels on the risk of developing type 2 diabetes. Such studies are required to prove the causal relationship between moderate iron overload and diabetes risk.