Cohort study of relation between donating blood and risk of myocardial infarction in 2682 men in eastern Finland

The healthy donor effect and survey participation, becoming a donor and donor career

BACKGROUND

The healthy donor effect (HDE) is a selection bias caused by the health criteria blood donors must meet. It obscures investigations of beneficial/adverse health effects of blood donation and complicates the generalizability of findings from blood donor cohorts. To further characterize the HDE we investigated how self-reported health and lifestyle are associated with becoming a blood donor, lapsing, and donation intensity. Furthermore, we examined differences in mortality based on donor status.

STUDY DESIGN AND METHODS

The Danish National Health Survey was linked to the Scandinavian Donations and Transfusions (SCANDAT) database and Danish register data. Logistic- and normal regression was used to compare baseline characteristics and participation. Poisson regression was used to investigate future donation choices. Donation intensity was explored by the Anderson-Gill model and Poisson regression. Mortality was investigated using Poisson regression.

RESULTS

Blood donors were more likely to participate in the surveys, OR = 2.45 95% confidence interval (2.40-2.49) than non-donors. Among survey participants, better self-reported health and healthier lifestyle were associated with being or becoming a blood donor, donor retention, and to some extent donation intensity, for example, current smoking conveyed lower likelihood of becoming a donor, OR = 0.70 (0.66-0.75). We observed lower mortality for donors and survey participants, respectively, compared with non-participating non-donors.

CONCLUSION

We provide evidence that blood donation is associated with increased likelihood to participate in health surveys, possibly a manifestation of the HDE. Furthermore, becoming a blood donor, donor retention, and donation intensity was associated with better self-reported health and healthier lifestyles.

A Case-Based Review of Iron Overload With an Emphasis on Porphyria Cutanea Tarda, Hepatitis C, C282Y Heterozygosity, and Coronary Artery Disease

Iron overload can impact disease progression and treatment options for patients with comorbid conditions, such as porphyria cutanea tarda, hepatitis C virus, and coronary artery disease.

Effects of serial phlebotomy on vascular endothelial function: Results of a prospective double-blind randomized study

INTRODUCTION

Blood donation has been proposed as a potential therapy to reduce risk of cardiovascular disease, but the effects of phlebotomy on vascular function in human subjects have not been well characterized.

AIMS

We conducted a prospective randomized double-blind study to determine the effects of serial phlebotomy on vascular endothelial function in the brachial artery. Eighty-four iron-replete, non-anemic subjects were randomly assigned to one of three study treatment groups: (a) four serial phlebotomy procedures each followed by intravenous infusion of placebo normal saline; (b) four serial phlebotomy procedures each followed by intravenous infusion to replete lost iron; and (c) four serial sham phlebotomy procedures each followed by intravenous infusion of placebo normal saline. Assigned phlebotomy procedures were conducted at 56-day intervals. We measured brachial artery reactivity (BAR, %) in response to transient oxidative stress induced by oral methionine with high-resolution duplex ultrasound imaging before and one week after the fourth study phlebotomy.

RESULTS

Before phlebotomy, oral methionine decreased BAR by -2.04% (95% CI -2.58%, -1.50%), P < 0.001) with no significant difference between groups (P = 0.42). After phlebotomy, the BAR response to oral methionine did not significantly change between groups (P = 0.53). Brachial artery nitroglycerin-mediated dilation did not change in response to phlebotomy.

CONCLUSIONS

Four serial phlebotomy procedures over six months with or without intravenous iron supplementation did not alter vascular endothelial function in the brachial artery when compared with sham phlebotomy.

Long-term donors versus non-donor men: Iron metabolism and the atherosclerotic process

BACKGROUND AND AIMS

The increased iron level and the labile iron pool (LIP) in circulating monocytes are connected to a higher frequency of cardiovascular events.

METHODS

The study investigates the relationship between LIP in circulating monocytes and markers of iron metabolism and atherosclerosis (inflammation, oxidative stress, endothelial dysfunction and arterial elasticity) in long-term blood donors and non-donor volunteers.

RESULTS

We found that donors had significantly higher LIP values than the control group (1.89 ± 0.47 μM vs. 1.50 ± 0.41 μM, p = 0.007). Despite the observed tendency for the donor group to have higher blood pressure, cholesterol, glucose and HOMAR-IR (homeostasis model assessment of insulin resistance), the groups did not differ in inflammatory markers, markers of endothelial dysfunction and markers of impaired arterial elasticity. The donor group had significant changes in iron metabolism (higher serum Fe, ceruloplasmin, and TfR/Ft ratio (transferrin receptor/ferritin ratio) and lower hepcidin, ferritin, and CD163), indicating depletion of body iron stores and activation of iron turnover.

CONCLUSIONS

LIP seems to be a good marker of iron turnover activity in these individuals despite the lack of a decrease in the hemoglobin concentration. We did not find a significant correlation between LIP levels and atherosclerosis progression in the two groups. However, further studies are needed to assess long-term donorship as a protective factor against atherosclerosis.

Donating blood on a regular basis appears to reduce blood pressure, but appearances can be deceiving

BACKGROUND

Previous studies have reported a relationship between blood donation and decreased risk for cardiovascular events, and it has been proposed that this may be due to a lowering of blood pressure among hypertensive individuals who donate on a regular basis.

STUDY DESIGN AND METHODS

With the use of a retrospective longitudinal analysis, predonation blood pressure readings were examined across consecutive whole blood donations for New York Blood Center donors. With blood pressure levels recorded at the first, second, third, and fourth donations, the sample was divided into three subgroups including high (≥140 mmHg), intermediate (>100 and <40 mmHg), and low (≤100 mmHg) systolic blood pressure (SBP). In addition, a computational approach was used to estimate regression to the mean effects for donors with high SBP or high diastolic blood pressure (DBP) at their first, second, or third donation.

RESULTS

Visual examination of SBP and DBP patterns across donations revealed that, on average, donors with extreme values at one donation had relatively normal values at the other donations. Further, comparison of computed expected versus observed blood pressure decreases supported the notion of a subsequent regression to the mean among donors with elevated SBP or DBP at Donation 1, 2, or 3.

CONCLUSION

Among individuals who are hypertensive at initial donation, reductions in blood pressure at subsequent donations appear to result from regression to the mean as opposed to a salutary physiologic process.

Iron and peripheral arterial disease: revisiting the iron hypothesis in a different light

The relationship between iron status and atherosclerosis has long been a topic of debate in the literature. Despite more than 25 years of research, there is no consensus regarding a causal relationship. To date, the vast majority of studies have focused on iron burden with respect to a hypothesized role in the onset and progression of coronary artery disease. However, the effect of iron in the coronary arterial system may differ mechanistically and therefore clinically from its effect in the peripheral arterial system. This review will summarize the biochemical, pathologic, animal, and clinical research data with respect to iron and atherosclerosis. This background will be expanded upon to provide insights into ongoing studies and paths for future investigations into the role of iron and peripheral arterial disease.

Effects of Environmental Pollutants on Cellular Iron Homeostasis and Ultimate Links to Human Disease

Chronic disease has increased in the past several decades, and environmental pollutants have been implicated. The magnitude and variety of diseases may indicate the malfunctioning of some basic mechanisms underlying human health. Environmental pollutants demonstrate a capability to complex iron through electronegative functional groups containing oxygen, nitrogen, or sulfur. Cellular exposure to the chemical or its metabolite may cause a loss of requisite functional iron from intracellular sites. The cell is compelled to acquire further iron critical to its survival by activation of iron-responsive proteins and increasing iron import. Iron homeostasis in the exposed cells is altered due to a new equilibrium being established between iron-requiring cells and the inappropriate chelator (the pollutant or its catabolite). Following exposure to environmental pollutants, the perturbation of functional iron homeostasis may be the mechanism leading to adverse biological effects. Understanding the mechanism may lead to intervention methods for this major public health concern.

Regular blood donation may help in the management of hypertension: an observational study on 292 blood donors

BACKGROUND

Hypertension is one of the leading global risks for cardiovascular events worldwide. There is preliminary evidence that regular blood donation may be beneficial.

STUDY DESIGN AND METHODS

Unselected blood donors were included in this observational study. Blood pressure (BP) was measured before and after blood donation, with participants donating between one and four occasions in a 1-year study period.

RESULTS

In this study, 292 donors were enrolled. At baseline, 146 had elevated BP (> 140/90 mmHg). In hypertensives, after four blood donations, systolic and diastolic blood pressure (SBP and DBP, respectively) decreased from a mean of 155.9 ± 13.0 to 143.7 ± 15.0 mmHg and from 91.4 ± 9.2 to 84.5 ± 9.3 mmHg, respectively (each p < 0.001). There was a clear dose effect with decreasing BP by the increasing number of blood donations. After at least four blood donations, donors with Stage II hypertensive baseline values (≥ 160 mmHg SBP and/or ≥ 100 mmHg DBP) were found to have the most marked reduction in BP, with 17.1 mmHg (95% confidence interval [CI], -23.2 to -11.0; p < 0.0001) and 11.7 mmHg (95% CI, -17.1 to -6.1; p = 0.0006) for SBP and DBP, respectively. The decrease in BP was not significantly associated with changes of blood count or variables of iron metabolism.

CONCLUSIONS

Regular blood donation is associated with pronounced decreases of BP in hypertensives. This beneficial effect of blood donation may open a new door regarding community health care and cost reduction in the treatment of hypertension.

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.

Blood donation and blood donor mortality after adjustment for a healthy donor effect

BACKGROUND

Studies have repeatedly demonstrated that blood donors experience lower mortality than the general population. While this may suggest a beneficial effect of blood donation, it may also reflect the selection of healthy persons into the donor population. To overcome this bias, we investigated the relation between blood donation frequency and mortality within a large cohort of blood donors. In addition, our analyses also took into consideration the effects of presumed health differences linked to donation behavior.

STUDY DESIGN AND METHODS

Using the Scandinavian Donation and Transfusion database (SCANDAT), we assessed the association between annual number of donations in 5-year windows and donor mortality by means of Poisson regression analysis. The analyses included adjustment for demographic characteristics and for an internal healthy donor effect, estimated among elderly donors exempted from continued donation because of age criteria.

RESULTS

Statistical analyses included 1,182,495 donors of whom 15,401 died during 9,526,627 person-years of follow-up. Analyses adjusted only for demographic characteristics showed a 18.6% reduction in mortality per additional annual donation (95% confidence interval [CI], 16.8%-20.4%). After additional adjustment for the internal healthy donor effect, each additional annual donation was associated with a 7.5% decreased mortality risk 7.5% (95% CI, 5.7%-9.4%).

CONCLUSION

We observed an inverse relationship between donation frequency and mortality. The magnitude of the association was reduced after adjustment for an estimate of self-selection in the donor population. Our observations indicate that repeated blood donation is not associated with premature death, but cannot be interpreted as conclusive evidence of a beneficial health effect.

Soluble urokinase plasminogen activator receptor as a marker for use of antidepressants

Objectives

Inflammation is involved in the pathogenesis of depression. A few cross-sectional population-based studies have found that depression is associated with increased levels of inflammatory markers. Soluble urokinase plasminogen activation receptor (suPAR) is known to be a stable marker for inflammation. We investigated the bidirectional association between suPAR levels and use of antidepressants.

Methods

suPAR level was measured in 9305 blood donors and analysed in relation to 5-years follow-up data on purchase of antidepressants and hospital diagnoses of depression from a nationwide Danish register.

Results

For men and women without prior use of antidepressants we found a significantly higher risk for incident use of antidepressants with higher suPAR values. For men, the risk of first use of antidepressants increased by 72% from the 1^st to the 4^th quartile (HR = 1.72, 95% CI: 1.11–2.69). For women, it increased by 108% from the 1^st to the 4^th quartile (HR = 2.08, 95% CI: 1.45–2.98). Previous use of antidepressants was also significantly associated with higher suPAR levels (p = 0.002).

Conclusions

High suPAR levels are associated with an increased risk for both previous and future use of antidepressants in healthy men and women. High suPAR are also associated with increased risk for a hospital diagnosis of depression.

Risk of illness, hospitalization and death in a cohort of blood donors in Italy

OBJECTIVE

The aim of this study was to determine whether blood donors (BDs), compared with non blood donors (nBDs), present significant differences in risk of illness, hospitalization and death.

METHODS

All subjects included in the database of the Association of Voluntary Italian Blood Donors of Ferrara entered the study. The analysis only included residents who donated at least once. For each BD, four age- and sex-matched non-donor controls were selected from the master archive of the Province of Ferrara. Then, all hospitalizations of BDs and controls from January 2005 to December 2010 were extracted from the hospital admission and discharge database of the region.

RESULTS

During the considered period, 26,140 hospital admissions in BDs and 98,685 in controls were recorded; 11,862 individual BDs and 43,138 nBDs. Compared with controls, BDs were characterized by older age, lower average number of admissions and diagnoses, Charlson comorbidity index score, shorter hospital length-of-stay (LOS), lower mortality rates and higher age at death. Age at death was significantly higher for BDs with longer duration and higher number of donations. In particular, blood donation was not related to an increased risk of malignancies. The main limitation of this study is potential selection bias (i.e. a healthy donor effect). Matching with the control population also has its limitations.

CONCLUSIONS

This study confirms that BDs have a lower risk of hospitalization, and, more specifically, do not have an increased risk of malignancies, leukemias, lymphomas and myeloma.

Atherogenesis and iron: from epidemiology to cellular level

Iron accumulates in human atherosclerotic lesions but whether it is a cause or simply a downstream consequence of the atheroma formation has been an open question for decades. According to the so called "iron hypothesis," iron is believed to be detrimental for the cardiovascular system, thus promoting atherosclerosis development and progression. Iron, in its catalytically active form, can participate in the generation of reactive oxygen species and induce lipid-peroxidation, triggering endothelial activation, smooth muscle cell proliferation and macrophage activation; all of these processes are considered to be proatherogenic. On the other hand, the observation that hemochromatotic patients, affected by life-long iron overload, do not show any increased incidence of atherosclerosis is perceived as the most convincing evidence against the "iron hypothesis." Epidemiological studies and data from animal models provided conflicting evidences about the role of iron in atherogenesis. Therefore, more careful studies are needed in which issues like the source and the compartmentalization of iron will be addressed. This review article summarizes what we have learnt about iron and atherosclerosis from epidemiological studies, animal models and cellular systems and highlights the rather contributory than innocent role of iron in atherogenesis.

Iron deficiency anemia in heart failure

Anemia and iron deficiency are quite prevalent in patients with heart failure (HF) and may overlap. Both anemia and iron deficiency are associated with worse symptoms and adverse clinical outcomes. In the past few years, there has been an enormous interest in the subject of iron deficiency and its management in patients with HF. In this review, the etiology and relevance of iron deficiency, iron metabolism in the setting of HF, studies on iron supplementation in patients with HF and potential cardiovascular effects of subclinical iron overload are discussed.

Iron, human growth, and the global epidemic of obesity

Iron is an essential nutrient utilized in almost every aspect of cell function and its availability has previously limited life. Those same properties which allow iron to function as a catalyst in the reactions of life also present a threat via generation of oxygen-based free radicals. Accordingly; life exists at the interface of iron-deficiency and iron-sufficiency. We propose that: (1) human life is no longer positioned at the limits of iron availability following several decades of fortification and supplementation and there is now an overabundance of the metal among individuals of many societies; (2) this increased iron availability exerts a positive effect on growth by targeting molecules critical in regulating the progression of the cell cycle; there is increased growth in humans provided greater amounts of this metal; and indices of obesity can positively correlate with body stores of iron; and (3) diseases of obesity reflect this over-abundance of iron. Testing potential associations between iron availability and both obesity and obesity-related diseases in populations will be difficult since fortification and supplementation is so extensively practiced.

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.

Relation between Body Iron Status and Cardiovascular Risk Factors in Patients with Cardiovascular Disease

BACKGROUND

There is conflicting evidence regarding the relationship between iron stores and cardiovascular disease (CVD). The present study aimed to investigate the association between body iron indices and some cardiovascular risk factors.

METHODS

In a case-control study conducted in the south of Shiraz, Iran, we determined ferritin, iron, total iron binding capacity (TIBC), metabolic risk factors, C-reactive protein (CRP), and anthropometric measurements in 100 men aged 45 years and higher with newly diagnosed CVD and 100 adjusted controls without evidence for CVD.

RESULTS

The mean of low density lipoprotein (LDL-c), CRP, and ferritin concentrations were significantly higher in cases than controls, and high density lipoprotein (HDL-c) was significantly lower in cases than controls. Pearson correlation coefficient between CRP and the other risk factors in case group showed that only ferritin, serum iron, waist circumference, and LDL-c significantly correlated with CRP (r = 0.32 with P < 0.001, r = 0.29 with P < 0.05, r = 0.41 with P < 0.01, and r = 0.36 with P < 0.001, respectively).

CONCLUSIONS

This study indicated an association between a positive balance of body iron and CVD. Hence, caution should be exercised in administration of iron supplements to patients with CVD and in consumption of food rich in iron by them.

Iron and cardiac ischemia: a natural, quasi-random experiment comparing eligible with disqualified blood donors

BACKGROUND

The theory that elevated iron stores can induce vascular injury and ischemia remains controversial. We conducted a cohort study of the effect of blood donation on the risk of coronary heart disease (CHD) by taking advantage of the quasi-random exclusion of donors who obtained a falsely reactive test for a transmissible disease (TD) marker.

STUDY DESIGN AND METHODS

Whole blood donors who were permanently disqualified because of a false-reactive test between 1990 and 2007 in the province of Quebec were compared to donors who remained eligible, matched for baseline characteristics. The incidence of CHD after entry into the study was determined through hospitalization and death records. We compared eligible and disqualified donors using an "intention-to-treat" framework.

RESULTS

Overall, 12,357 donors who were permanently disqualified were followed for 124,123 person-years of observation, plus 50,889 donors who remained eligible (516,823 person-years). On average, donors who remained eligible made 0.36 donation/year during follow-up and had an incidence of hospitalizations or deaths attributable to CHD of 3.60/1000 person-years, compared to 3.52 among permanently disqualified donors (rate ratio, 1.02; 95% confidence interval, 0.92-1.13).

CONCLUSION

Donors who remained eligible did not have a lower risk of CHD, compared to donors who were permanently disqualified due to a false-reactive TD marker. Because of the quasi-random nature of false-reactive screening tests, this natural experiment has a level of validity approaching that of a randomized trial evaluating the effect of regular blood donation on CHD risk. These results do not support the iron hypothesis.

The evaluation of carotid intima-media thickness in children with beta-thalassaemia major

BACKGROUND

Cardiovascular complications and vascular changes are common in patients with beta-thalassaemia major. The aim of this study is to investigate the common carotid artery intima-media thickness in children.

METHODS

The study population was consisted of 33 thalassaemic children (22 boys and 11 girls, with a median age of 8 years) and 30 healthy children for control (12 girls and 18 boys, with a median age of 8 years) who were matched for age and gender. Common carotid artery intima-media thickness of the children was measured.

RESULTS

The patients' age at diagnosis ranged from 0.25 to 2 years, with a median of 0.6 months. Their disease duration ranged from 4 to 13.75 years, with a median of 6.5 years. The patients' median common carotid artery intima-media thickness was significantly higher than controls - that is, 0.87 versus 0.74, with a p-value less than 0.005. The mean common carotid artery intima-media thickness value was positively correlated with disease duration (r = 0.535), with a p-value less than 0.01 and ferritin level (r = 0.501), with a p-value less than 0.01.

CONCLUSION

Owing to the nature of the disease, patients with beta-thalassaemia major should be considered to have an increased risk of early vascular alteration and atherosclerosis. For this reason, common carotid artery intima-media thickness measurement can be recommended as a non-invasive and early diagnostic method.

Left ventricular morphology and function in diabetic and nondiabetic hemodialyzed patients

Morbidity in end-stage renal disease (ESRD) diabetic patients is worse than in patients without diabetes mellitus (DM). This study aims to compare clinical, laboratory, and echocardiographic features between the ESRD patients with and without DM. Fifty-eight ESRD patients on dialysis were prospectively divided into two groups according to the presence of DM. Demographic, clinical, laboratory, and echocardiographic features (ejection fraction and wall motion score index) were compared between the two groups. Overall, 20 out of 58 patients (37.8%) with ESRD had DM. There were no significant differences between the patients with DM and those without DM when it comes to age (60.6 ± 10.6 vs. 59.0 ± 10.6 years, P = 0.665), ejection fraction (52.6% ± 12.8% vs. 54.2% ± 12.8%, P = 0.59), and wall motion score index (1.21 ± 0.3 vs.1.15 ± 0.3, P = 0.37). In multivariant analysis of the interventricular septum, posterior wall thickness and left atrium size correlated positively with DM. There was also no statistical difference in myocardial perfusion disturbances on real-time contrast echocardiography between the groups with and without DM (12 (60%) patients vs. 14 patients (36.8%), P = 0.079). Among diabetics 77.8% had significant atherosclerotic changes, while in the group without DM, only 38.1%, P = 0.01. From the laboratory parameters ferritin and high-sensitivity C-reactive protein levels were significantly higher in the group with DM, P = 0.014 and P = 0.026, respectively. Patients with ESRD and DM have significantly bigger left atrial size, thicker left ventricular walls, and higher serum ferritin and high-sensitivity C-reactive protein levels than the patients without DM. The aforementioned features may be possible risk factors for the development of adverse cardiac events in patients on hemodialysis.

Iron deficiency in community-dwelling US adults with self-reported heart failure in the National Health and Nutrition Examination Survey III: prevalence and associations with anemia and inflammation

BACKGROUND

Iron deficiency has been proposed as a potential therapeutic target in heart failure, but its prevalence and association with anemia and clinical outcomes in community-dwelling adults with heart failure have not been well characterized.

METHODS AND RESULTS

Using data from the Third National Health and Nutrition Examination Survey, we evaluated the associations between iron deficiency, hemoglobin, C-reactive protein (CRP), and all-cause and cardiovascular mortality in 574 adults with self-reported heart failure. Iron deficiency was defined in both absolute and functional terms as a ferritin level <100 μg/L or between 100 and 299 μg/L if the transferrin saturation was <20%. Iron deficiency was present in 61.3% of participants and was associated with reduced mean hemoglobin (13.6 versus 14.2 g/dL, P=0.007) and increased mean CRP (0.95 versus 0.63 mg/dL, P=0.04). Over a median of 6.7 years of follow-up, there were 300 all-cause deaths, 193 of which were from cardiovascular causes. In age- and sex-adjusted Cox proportional hazards models, hemoglobin, CRP, and transferrin saturation but not iron deficiency were significantly associated with all-cause and cardiovascular mortality. In multivariate models, hemoglobin remained an independent predictor of cardiovascular mortality, whereas CRP remained an independent predictor of both all-cause and cardiovascular mortality.

CONCLUSIONS

Iron deficiency is common in heart failure and is associated with decreased hemoglobin and increased CRP. In multivariate analysis, hemoglobin was associated with cardiovascular mortality while CRP was associated with both all-cause and cardiovascular mortality. Iron deficiency was not associated with all-cause or cardiovascular mortality in this cohort.

Iron stores are associated with asymptomatic atherosclerosis in healthy men of primary prevention

BACKGROUND

The aim of our study was to assess the impact of increased iron stores on the presence of asymptomatic atherosclerosis in a cohort of healthy men. We anticipated that higher iron stores would be associated with higher soluble cluster of differentiation 163 (sCD163) concentrations, elevated markers of oxidative stress, inflammation and higher common carotid intima-media thickness, independently of traditional risk factors of atherosclerosis.

METHODS

In this cross-sectional study that included 72 healthy men, we measured the ultrasonography of common carotid intima-media thickness (IACC), the ratio of plasma-circulating transferrin receptors concentration to plasma ferritin concentration, certain inflammatory and oxidative stress markers, insulin sensitivity, plasma lipids and markers of endothelial dysfunction.

RESULTS

The plasma-circulating transferrin receptor concentration to plasma ferritin concentration ratio (TfR/F) showed significant association with IACC (r=-0·310, P=0·008 vs. r=0·295, P=0·012). Multivariate analysis confirmed that the correlation of TfR/F with IACC is independent of traditional risk factors of atherosclerosis. The TfR/F ratio correlated with other indicators of atherosclerotic process fibrinogen (r=-0·292, P=0·013), von Willebrand factor (vWf; r=0·284, P=0·017), sCD163 (r=0·239, P=0·043) and IL-8 (r=0·233, P=0·049). In multivariate analysis, TfR/F independently correlated with haemoglobin (β=-0·220, P=0·047), fibrinogen (β=-0·290, P=0·009), IL-8 (β=0·227, P=0·039) and sCD163 (β=0·244, P=0·025); however, when vWf was added, significant independent correlation was seen only with fibrinogen (β=-0·301, P=0·007) and IL-8 (β=0·219, P=0·047). In addition, we demonstrated the independent correlation of sCD163 with vWf (β=0·240, P=0·040).

CONCLUSIONS

Our study showed a clear association of body iron stores expressed by the TfR/F ratio with asymptomatic carotid atherosclerosis. TfR/F further exhibited an independent positive correlation with fibrinogen and a negative correlation with sCD163 and IL-8.

Treatment of anemia in heart failure: potential risks and benefits of intravenous iron therapy in cardiovascular disease

Iron-deficiency anemia is common in patients with heart failure (HF), but the optimum diagnostic tests to detect iron deficiency and the treatment options to replete iron have not been fully characterized. Recent studies in patients with HF indicate that intravenous iron can rapidly replenish iron stores in patients having iron-deficiency anemia, with resultant increased hemoglobin levels and improved functional capacity. Preliminary data from a subgroup analysis also suggest that supplemental intravenous iron therapy can improve functional capacity even in those subjects without anemia. The mechanisms responsible for this observation are not fully characterized, but may be related to beneficial effects of iron supplementation on mitochondrial respiration in skeletal muscle. The long-term safety of using intravenous iron supplementation in HF populations is not known. Iron is a known pro-oxidant factor that can inhibit nitric oxide signaling and irreversibly injury cells. Increased iron stores are associated with vascular endothelial dysfunction and increased risk of coronary heart disease events. Additional clinical trials are needed to more fully characterize the therapeutic potential and safety of intravenous iron in HF patients.

Serum ferritin is linked with aortic stiffness in apparently healthy Korean women

BACKGROUND

There has been strong recent interest in the association between serum ferritin concentrations and increased risk of cardiovascular events. Surplus nutrition and convenience-seeking behavior has contributed to emergence of an increasingly obese population, with a concurrent increase in the prevalence of cardiovascular diseases. To date, few studies have specifically examined the association between serum ferritin and aortic stiffness in healthy populations, thus we investigated the association between serum ferritin and aortic stiffness according to sex and obesity in healthy subjects.

METHODS AND RESULTS

From a register of 196 healthy subjects (146 males, 50 females) 23 to 76 years of age, we measured BMI, serum ferritin, blood pressures, metabolic variables, and brachial ankle pulse wave velocity (baPWV). The average baPWV, serum ferritin and the sociodemographic prevalence (smoking, alcohol, and exercise) were higher in men than women. There was a positive association between serum ferritin and baPWV (R = 0.02) in total subjects after adjusting for age, sex, and blood pressures. The association between serum ferritin and baPWV (R = 0.099) in women was positive, yet negative in men (R = -0.007). The average baPWV and serum ferritin were highest in obese men, on the other hand lowest in nonobese women among 4 groups according to sex and obesity.

CONCLUSIONS

In conclusion, there was a stronger association between serum ferritin and PWV in healthy Korean women than men. Our finding suggests that cardiovascular risk factor monitoring through baPWV should be considered for even apparently healthy Korean women.

Insights into the ethnic differences in serum ferritin between black and white US adult men

Although higher serum ferritin (SF) concentrations have been consistently observed among blacks, despite their lower hemoglobin (Hb) concentrations compared with whites, few studies attempted to explain this SF difference. To determine the possible factors contributing to the observed SF difference between blacks and whites, 1,938 non-Hispanic white (NHW) and 1,616 non-Hispanic black (NHB) male subjects, aged 20-65 years were selected from the third National Health and Nutrition Examination Survey (NHANES III). Multiple regression analysis was used to examine the contribution of dietary, biochemical, and socioeconomic variables to the observed SF difference between the two groups. NHB subjects showed a continuing, significantly higher SF concentration compared with NHW subjects at each age group. Age, serum total protein, mean cell volume (MCV), and gamma glutamyl transferase (GGT) were positively associated with SF, whereas percent energy from carbohydrate and fat, calcium intake, serum alpha-carotene, and iron binding capacity (TIBC) were inversely associated with SF (P < 0.01). After excluding subjects with abnormal serum total protein, TIBC and GGT levels from the analysis (the final regression model), the SF difference dropped to 3.95 microg/l (initial difference = 37.1 microg/l) between NHWs and NHBs. The results suggest that the oft-noted black-white SF difference is a result of factors including overall nutrition and health, iron status, and hepatic well-being. Higher SF, low Hb, and reduced TIBC level observed in blacks are consistent with the definition of anemia of chronic disease (ACD). Future investigations are needed to confirm the role of ACD in the black-white SF difference.

Iron homeostasis and eye disease

BACKGROUND

Iron is necessary for life, but excess iron can be toxic to tissues. Iron is thought to damage tissues primarily by generating oxygen free radicals through the Fenton reaction.

METHODS

We present an overview of the evidence supporting iron's potential contribution to a broad range of eye disease using an anatomical approach.

RESULTS

Iron can be visualized in the cornea as iron lines in the normal aging cornea as well as in diseases like keratoconus and pterygium. In the lens, we present the evidence for the role of oxidative damage in cataractogenesis. Also, we review the evidence that iron may play a role in the pathogenesis of the retinal disease age-related macular degeneration. Although currently there is no direct link between excess iron and development of optic neuropathies, ferrous iron's ability to form highly reactive oxygen species may play a role in optic nerve pathology. Lastly, we discuss recent advances in prevention and therapeutics for eye disease with antioxidants and iron chelators.

GENERAL SIGNIFICANCE

Iron homeostasis is important for ocular health.

Ferritin for the clinician

Ferritin, a major iron storage protein, is essential to iron homeostasis and is involved in a wide range of physiologic and pathologic processes. In clinical medicine, ferritin is predominantly utilized as a serum marker of total body iron stores. In cases of iron deficiency and overload, serum ferritin serves a critical role in both diagnosis and management. Elevated serum and tissue ferritin are linked to coronary artery disease, malignancy, and poor outcomes following stem cell transplantation. Ferritin is directly implicated in less common but potentially devastating human diseases including sideroblastic anemias, neurodegenerative disorders, and hemophagocytic syndrome. Additionally, recent research describes novel functions of ferritin independent of iron storage.

Evidence-based criteria for the care and selection of blood donors, with some comments on the relationship to blood supply, and emphasis on the management of donation-induced iron depletion

Blood Services, which, in the UK, spend over 0.5% of the NHS budget, are generally subject to quality, regulatory, economic and political authority. As only persons in good health should give blood, Services have refined donor selection criteria and aim to base them on evidence; but they also have to balance the number of donations collected with product demand. Applying selection criteria inevitably leads to deferrals, which donors experience very negatively. Compared with successful donors, even temporary deferrals reduce return rates significantly, especially of first attenders. In order to encourage donor return and sustain supplies, selection criteria should be optimal. However, a major tool for managing patients--evidence from randomized controlled trials (RCTs)--cannot apply to donor selection, so criteria have to be defined by alternatives, such as clinical studies, epidemiology and even what experts deem to be pathophysiologically feasible. The recommended volume of blood taken from each donor at each attendance (450 mL, which was based on old studies) was increased because of greater processing losses (buffy-coat derived platelets, leucofiltration etc.). Although faint rates and donation-induced iron depletion are reduced by lowering bleeding volume and bleeding less frequently, other optimizing strategies including iron supplementation have been trialled and could be enhanced by more RCTs. Better but more complex indicators of donor iron status than one-off Hb thresholds are possible. Regulators and decision-makers must encourage more studies. This review does not consider aphaeresis donors of blood components other than red cells in detail, or the prevention of transfusion-transmitted infections.

Blood donation, body iron status and carotid intima-media thickness

Iron could promote free radical formation, which may lead to injury of the arterial wall and atherosclerosis. Blood donation may reduce cardiovascular risk by lowering body iron status. We collected data on blood donation history and intima-media thickness of the common carotid artery (CIMT) in 819 subjects (50-70 years), who were recruited from municipal and blood bank registries in The Netherlands. Serum iron parameters were assessed, including non-transferrin bound iron (NTBI) that has recently been found in conditions of iron overload. Serum ferritin was lower in current donors (n=443; 44 microg/L) than in ex-donors (n=120; 114 microg/L) and never-donors (n=256; 124 microg/L, P for trend <0.001). For NTBI, values were 2.33, 2.54, and 2.51 micromol/L, respectively (P<0.05). CIMT was slightly reduced in frequent donors (i.e., > or =49 times during life or > or =2 times per year), although not statistically significant. CIMT was not significantly related to NTBI. Frequent blood donation, resulting in lowered body iron, might give some protection against accelerated atherosclerosis.

Improving health profile of blood donors as a consequence of transfusion safety efforts

BACKGROUND

Transfusion safety rests heavily on the health of blood donors. Although they are perceived as being healthier than average, little is known about their long-term disease patterns and to which extent the blood banks' continuous efforts to optimize donor selection has resulted in improvements. Mortality and cancer incidence among blood donors in Sweden and Denmark was investigated.

STUDY DESIGN AND METHODS

All computerized blood bank databases were compiled into one database, which was linked to national population and health data registers. With a retrospective cohort study design, 1,110,329 blood donors were followed for up to 35 years from first computer-registered blood donation to death, emigration, or December 31, 2002. Standardized mortality and incidence ratios expressed relative risk of death and cancer comparing blood donors to the general population.

RESULTS

Blood donors had an overall mortality 30 percent lower (99% confidence interval [CI] 29%-31%) and cancer incidence 4 percent lower (99% CI 2%-5%) than the background population. Mortality rates and cancer incidence were lowest for outcomes that are recognized as being related to lifestyle factors such as smoking or to the selection criteria for blood donation. Blood donors recruited in more recent years exhibited a lower relative mortality than those who started earlier.

CONCLUSION

Blood donors enjoy better than average health. Explicit and informal requirements for blood donation in Scandinavia, although mostly of a simple nature, have successfully refined the selection of a particularly healthy subpopulation.

Iron and thrombosis

Although essential for cell physiology, an increase or depletion of body iron has harmful effects on health. Apart from iron deficiency anemia and iron overload-related organ tissue damage, there are increasing evidences that body iron status is implicated in atherosclerotic cardiovascular diseases. The hypothesis formulated in 1981 that iron depletion may protect against cardiovascular events is intriguing and has generated a significant debate in the last two decades. Indeed, to study this phenomenon, several investigators have tried to design appropriate experimental and clinical studies and to identify useful biochemical and genetic markers of iron status. The results of the literature on the effect of iron deficiency and overload on vascular health are critically reviewed in this study from a pathogenic and clinical point of view.

[Cardiac involvement in hemochromatosis]

Cardiac involvement in hemochromatosis affects mainly the myocardium: iron overload of the myocytes reduces left ventricular distensibility. Heart failure is the most frequent manifestation of cardiac involvement. Diagnosis of cardiac involvement depends essentially on Doppler echocardiography showing abnormal left ventricular filling and, later, ventricular dilatation with left ventricular systolic dysfunction. Magnetic resonance imaging can quantify intrahepatic and intramyocardial iron levels. Age at onset of symptoms and specific organ involvement in hemochromatosis depend on the type of mutation. The two principal means of treatment by iron depletion are phlebotomy in primary hemochromatosis and excretion of iron by chemical chelation in secondary hemochromatosis. Early diagnosis and iron depletion improve survival by reducing organ iron overload, especially in the liver and the myocardium. Recent guidelines issued by Anaes (national agency for health evaluation) make it possible to identify risk factors for complications early, to determine disease stage, and to provide appropriate management as a function of disease severity.

Effect on hematologic risk factors for coronary heart disease of a cholesterol reducing diet

BACKGROUND

A dietary portfolio of cholesterol-lowering ingredients has proved effective in reducing serum cholesterol. However, it is not known whether this dietary combination will also affect hematologic risk factors for coronary heart disease (CHD). Reductions in hematocrit and polymorphonuclear leukocytes have been reported to improve cardiovascular risk. We, therefore, report changes in hematological indices, which have been linked to cardiovascular health, in a 1-year assessment of subjects taking an effective dietary combination (portfolio) of cholesterol-lowering foods.

METHODS

For 12 months, 66 hyperlipidemic subjects were prescribed diets high in plant sterols (1.0 g/1000 kcal), soy protein (22.5 g/1000 kcal), viscous fibers (10 g/1000 kcal) and almonds (23 g/1000 kcal). Fifty-five subjects completed the study.

RESULTS

Over the 1 year, data on completers indicated small but significant reductions in hemoglobin (-1.5+/-0.6 g/l, P=0.013), hematocrit (-0.007+/-0.002 l/l, P<0.001), red cell number (-0.07+/-0.02 10(9)/l, P<0.001) and neutrophils (-0.34+/-0.13 10(9)/l, P=0.014). Mean platelet volume was also increased (0.16+/-0.07 fl, P=0.033). The increase in red cell osmotic fragility (0.05+/-0.03 g/l, P=0.107) did not reach significance.

CONCLUSIONS

These small changes in hematological indices after a cholesterol-lowering diet are in the direction, which would be predicted to reduce CHD risk. Further research is needed to clarify whether the changes observed will contribute directly or indirectly to cardiovascular benefits beyond those expected from reductions previously seen in serum lipids and blood pressure.

Iron stores and vascular function in voluntary blood donors

BACKGROUND

Iron is a pro-oxidant cofactor that may be linked to atherosclerosis progression. Reduction of body iron stores secondary to blood donation has been hypothesized to reduce coronary risk, but retrospective studies have yielded inconsistent findings. We sought to assess the effects of blood donation frequency on body iron stores and physiological and biochemical biomarkers of vascular function associated with atherosclerosis progression.

METHODS AND RESULTS

Forty high-frequency voluntary blood donors (> or =8 donations in past 2 years) and 42 low-frequency blood donors (1 to 2 donations in past 2 years) aged 50 to 75 years were randomly selected from American Red Cross of Connecticut blood donor records. Flow-mediated dilation in the brachial artery, serum markers of iron stores, vascular inflammation and oxidative stress, and cardiac risk factors were assessed in all subjects. Serum ferritin was significantly decreased in high-frequency blood donors when compared with low-frequency blood donors (median values 17 versus 52 ng/mL; P<0.001), but hematocrit did not differ between groups. Flow-mediated dilation in the brachial artery was significantly greater in high-frequency donors when compared with low-frequency donors in univariate analysis (5.5+/-2.6% versus 3.8+/-1.6%; P=0.0003) and in multivariate analysis adjusting for cardiac risk factors and other potential confounders. Serum biomarkers of vascular inflammation did not differ between groups but 3-nitrotyrosine, a marker of oxidative stress, was decreased in high-frequency donors when compared with low-frequency donors.

CONCLUSIONS

High-frequency blood donors had evidence of decreased body iron stores, decreased oxidative stress, and enhanced vascular function when compared with low-frequency donors. These findings support a potential link between blood donation and reduced cardiovascular risk that warrants further investigation in prospective outcome studies.

Ferritin in atherosclerosis

Iron, an essential element for many important cellular functions in all living organisms, can catalyze the formation of potentially toxic free radicals. Excessive iron is sequestered by ferritin in a nontoxic and readily available form in a cell. Ferritin is composed of 24 subunits of different proportions of two functionally distinct subunits: ferritin H and L. The former is involved in ferroxidase activity necessary for iron uptake and oxidation of ferrous iron, while the latter is involved in nucleation of the iron core. The expression of ferritin is under delicate control and is regulated at both the transcriptional and posttranscriptional levels by iron, cytokines and oxidative stress. Elevated ferritin levels are associated with an increased risk of atherosclerotic coronary artery disease (CAD), the leading cause of death and illness in developed countries. Serum ferritin levels are a good indicator of iron stores in the body. In fact, epidemiological studies have suggested that elevated serum ferritin levels are associated with an increased risk of CAD and myocardial infarction (MI), though inconsistent results were obtained in some other studies. Moreover, recent proteomics and molecular biology studies have shown that ferritin levels in arteries are increased in diseased tissues, which further supports the link of ferritin to CAD/MI. Future studies will determine whether increased ferritin levels can serve as a distinct biomarker for the incidence of CAD/MI and distinguish whether increased ferritin levels are a cause of CAD or a consequence of the disease process.

Intracellular Labile Iron Modulates Adhesion of Human Monocytes to Human Endothelial Cells

OBJECTIVE

Elevated iron stores and high plasma iron concentration have been linked to an increased risk of atherosclerosis. Iron may thereby affect the interaction of monocytes to endothelium, an initial event in the formation of atherosclerotic plaques.

METHODS AND RESULTS

Addition of 10 mumol/L non-transferrin-bound iron to the incubation medium caused a 2-fold increase in monocyte adhesion to human umbilical vein endothelial cells (HUVECs). A concordant increase in the expression of the following adhesion molecules was observed: vascular cell adhesion molecule-1, intercellular adhesion molecule-1, and endothelial selectin on HUVECs as well as very late antigen-4, and lymphocyte function-associated antigen-1 on monocytes. The inclusion of either deferiprone or salicylaldehyde isonicotinoylhydrazone counteracted these effects. Intracellular iron chelation by deferoxamine was completed only after 10 hours of incubation, shown by reversal of iron-quenched intracellular calcein signal, and concurrently the effects of iron were blunted. The membrane-impermeable chelator, diethylenetriamine pentaaceticacid, failed to negate iron effects, even after 48 hours of treatment. Furthermore, only membrane-permeable superoxide or hydroxyl radical scavengers were capable of preventing HUVEC activation by iron.

CONCLUSIONS

Non-transferrin-bound iron increases the level of intracellular labile iron, which promotes monocyte recruitment to endothelium and may thereby contribute to the pathogenesis of atherosclerosis. Iron-induced adhesion molecule expression was observed, and this event may involve the production of oxygen radicals.