Increased serum ferritin predicts the development of hypertension among middle-aged men

Associations Between Genetically Predicted Iron Status and Cardiovascular Disease Risk: A Mendelian Randomization Study

BACKGROUND

Mendelian randomization (MR) studies suggest a causal effect of iron status on cardiovascular disease (CVD) risk, but it is unknown if these associations are confounded by pleiotropic effects of the instrumental variables on CVD risk factors. We aimed to investigate the effect of iron status on CVD risk controlling for CVD risk factors.

METHODS AND RESULTS

Iron biomarker instrumental variables (total iron-binding capacity [n=208 422], transferrin saturation [n=198 516], serum iron [n=236 612], ferritin [n=257 953]) were selected from a European genome-wide association study meta-analysis. We performed 2-sample univariate MR of each iron trait on CVD outcomes (all-cause ischemic stroke, cardioembolic ischemic stroke, large-artery ischemic stroke, small-vessel ischemic stroke, and coronary heart disease) from MEGASTROKE (n=440 328) and CARDIoGRAMplusC4D (Coronary Artery Disease Genome Wide Replication and Meta-Analysis Plus the Coronary Artery Disease Genetics) (n=183 305). We then implemented multivariate MR conditioning on 7 CVD risk factors from independent European samples to evaluate their potential confounding or mediating effects on the observed iron-CVD associations. With univariate MR analyses, we found higher genetically predicted iron status to be associated with a greater risk of cardioembolic ischemic stroke (transferrin saturation: odds ratio, 1.17 [95% CI, 1.03-1.33]; serum iron: odds ratio, 1.21 [95% CI, 1.02-1.44]; total iron-binding capacity: odds ratio, 0.81 [95% CI, 0.69-0.94]). The detrimental effects of iron status on cardioembolic ischemic stroke risk remained unaffected when adjusting for CVD risk factors (all P<0.05). Additionally, we found diastolic blood pressure to mediate between 7.1 and 8.8% of the total effect of iron status on cardioembolic ischemic stroke incidence. Univariate MR initially suggested a protective effect of iron status on large-artery stroke and coronary heart disease, but controlling for CVD factors using multivariate MR substantially diminished these associations (all P>0.05).

CONCLUSIONS

Higher iron status was associated with a greater risk of cardioembolic ischemic stroke independent of CVD risk factors, and this effect was partly mediated by diastolic blood pressure. These findings support a role of iron status as a modifiable risk factor for cardioembolic ischemic stroke.

A cross-sectional analysis of the PURE study on minerals intake among Malaysian adult population with hypertension

Hypertension (HPT) is the leading modifiable risk factor for cardiovascular diseases and premature death worldwide. Currently, attention is given to various dietary approaches with a special focus on the role of micronutrient intake in the regulation of blood pressure. This study aims to measure the dietary intake of selected minerals among Malaysian adults and its association with HPT. This cross-sectional study involved 10,031 participants from the Prospective Urban and Rural Epidemiological study conducted in Malaysia. Participants were grouped into HPT if they reported having been diagnosed with high blood pressure [average systolic blood pressure (SBP)/average diastolic blood pressure (DBP) ≥ 140/90 mm Hg]. A validated food frequency questionnaire (FFQ) was used to measure participants' habitual dietary intake. The dietary mineral intake of calcium, copper, iron, magnesium, manganese, phosphorus, potassium, sodium, and zinc was measured. The chi-square test was used to assess differences in socio-demographic factors between HPT and non-HPT groups, while the Mann-Whitney U test was used to assess differences in dietary mineral intake between the groups. The participants' average dietary intake of calcium, copper, iron, magnesium, manganese, phosphorus, potassium, selenium, sodium, and zinc was 591.0 mg/day, 3.8 mg/day, 27.1 mg/day, 32.4 mg/day, 0.4 mg/day, 1431.1 mg/day, 2.3 g/day, 27.1 µg/day, 4526.7 mg/day and 1.5 mg/day, respectively. The intake was significantly lower among those with HPT than those without HPT except for calcium and manganese. Continuous education and intervention should be focused on decreasing sodium intake and increasing potassium, magnesium, manganese, zinc, and calcium intake for the general Malaysian population, particularly for the HPT patients.

Environmentally sustainable synthesis of whey-based carbon dots for ferric ion detection in human serum and water samples: evaluating the greenness of the method

Carbon dots (CDs) are valued for their biocompatibility, easy fabrication, and distinct optical characteristics. The current study examines using whey to fabricate CDs using the hydrothermal method. When stimulated at 350 nm, the synthetic CDs emitted blue light at 423 nm and revealed a selective response to ferric ion (Fe3+) in actual samples with great sensitivity, making them a suitable probe for assessing Fe3+ ions. The produced carbon dots demonstrated great photostability, high sensitivity, and outstanding biocompatibility. The findings showed that Fe3+ ions could be quickly, sensitively, and extremely selectively detected in an aqueous solution of carbon dots, with a revealing limit of 0.409 μM in the linear range of 0-180 μM. Interestingly, this recognition boundary is far inferior to the WHO-recommended threshold of 0.77 μM. Two metric tools which were AGREE and the ComplexGAPI were also used to evaluate the method's greenness. The evaluation confirmed its superior environmental friendliness.

Associations between genetically predicted iron status and cardiovascular disease risk: A Mendelian randomization study

Background

Mendelian randomization (MR) studies suggest a causal effect of iron (Fe) status on cardiovascular disease (CVD) risk, but it is unknown if these associations are confounded by pleiotropic effects of the instrumental variables (IV) on CVD risk factors. We aimed to investigate the effect of Fe status on CVD risk controlling for CVD risk factors.

Methods

Fe biomarker IVs (total Fe binding capacity (TIBC, n=208,422), transferrin saturation (TSAT, n=198,516), serum Fe (SI, n=236,612), ferritin (n=257,953)) were selected from a European GWAS meta-analysis. We performed two-sample univariate (UV) MR of each Fe trait on CVD outcomes (all-cause ischemic stroke (IS), cardioembolic IS (CES), large artery IS (LAS), small vessel IS (SVS), and coronary heart disease (CHD)) from MEGASTROKE (n=440,328) and CARDIoGRAMplusC4D (n=183,305). We then implemented multivariate (MV) MR conditioning on six CVD risk factors from independent European samples to evaluate their potential confounding and/or mediating effects on the observed Fe-CVD associations.

Results

With UVMR analyses, we found higher genetically predicted Fe status to be associated with a greater risk of CES (TSAT: OR 1.17 [95%CI 1.03, 1.33], SI: OR 1.21 [ 95%CI 1.02, 1.44]; TIBC: OR 0.81 [95%CI 0.69, 0.94]). The detrimental effects of Fe status on CES risk remained unaffected when adjusting for CVD risk factors (all P<0.05). Additionally, we found diastolic blood pressure (DBP) to mediate between 7.1-8.8% of the total effect of Fe status on CES incidence. While UVMR initially suggested a protective effect of Fe status on LAS and CHD, MVMR analyses factoring CVD risk factors revealed a complete annulment of this perceived protective effect (all P>0.05).

Discussion

Higher Fe status was associated with a greater risk of CES independent of CVD risk factors, and this effect was partly mediated by DBP. These findings support a role of Fe status as a modifiable risk factor for CES.

Study of the Relationship Between Insulin Resistance, Iron Status Markers, and Body Weight in a Sample of Egyptian Population

BACKGROUND

Iron plays a key role in the regulation of body iron homeostasis and is used as a clinical marker for iron deficiency (ID) and hemochromatosis. The idea that iron dysregulation may contribute to various metabolic diseases, such as obesity, insulin resistance, MetS, and T2DM, is a hot topic of discussion.

AIM

The aim of this study is to investigate the relationship insulin resistance, iron status markers, and body weight in a sample of Egyptian population.

METHODS

A case control study was conducted on 90 subjects with age ranging from 18 to 70 years old from a diabetes outpatient clinic, and they were divided to three groups: Group I, non-obese- non-diabetic as the control group; Group II, obese-non-diabetic; and Group III, obese-diabetic.

RESULTS

In our study, there was no statistically significant difference between the three studied groups regarding the different iron parameters. Similarly, we found that neither HOMA-IR nor body weight had a significant correlation with iron status markers. On the contrary, we detected significant positive correlations between the TIBC and the fasting blood glucose, between the serum iron and the LDL, between the TSAT and the systolic blood pressure, and between the HOMA-IR and hematocrit.

CONCLUSION

Our study demonstrated no direct statistical significant relationship between the different iron parameters, obesity, and insulin resistance, either in the diabetic or non-diabetic subjects. This may be due to the complex metabolic dysregulation and the small number of the sample for future investigations.

Development of a convenient and effective hypertension risk prediction model and exploration of the relationship between Serum Ferritin and Hypertension Risk: a study based on NHANES 2017-March 2020

Background

Hypertension is a major public health problem, and its resulting other cardiovascular diseases are the leading cause of death worldwide. In this study, we constructed a convenient and high-performance hypertension risk prediction model to assist in clinical diagnosis and explore other important influencing factors.

Methods

We included 8,073 people from NHANES (2017-March 2020), using their 120 features to form the original dataset. After data pre-processing, we removed several redundant features through LASSO regression and correlation analysis. Thirteen commonly used machine learning methods were used to construct prediction models, and then, the methods with better performance were coupled with recursive feature elimination to determine the optimal feature subset. After data balancing through SMOTE, we integrated these better-performing learners to construct a fusion model based for predicting hypertension risk on stacking strategy. In addition, to explore the relationship between serum ferritin and the risk of hypertension, we performed a univariate analysis and divided it into four level groups (Q1 to Q4) by quartiles, with the lowest level group (Q1) as the reference, and performed multiple logistic regression analysis and trend analysis.

Results

The optimal feature subsets were: age, BMI, waist, SBP, DBP, Cre, UACR, serum ferritin, HbA1C, and doctors recommend reducing salt intake. Compared to other machine learning models, the constructed fusion model showed better predictive performance with precision, accuracy, recall, F1 value and AUC of 0.871, 0.873, 0.871, 0.869 and 0.966, respectively. For the analysis of the relationship between serum ferritin and hypertension, after controlling for all co-variates, OR and 95% CI from Q2 to Q4, compared to Q1, were 1.396 (1.176-1.658), 1.499 (1.254-1.791), and 1.645 (1.360-1.989), respectively, with P < 0.01 and P for trend <0.001.

Conclusion

The hypertension risk prediction model developed in this study is efficient in predicting hypertension with only 10 low-cost and easily accessible features, which is cost-effective in assisting clinical diagnosis. We also found a trend correlation between serum ferritin levels and the risk of hypertension.

Serum Ferritin in Obese Dogs: Changes and Comparison with Other Analytes

Canine obesity is the most common nutritional disorder and is associated with decreased quality of life and longevity as well as comorbidities including cardiorespiratory, endocrine, oncologic, or orthopaedic disorders. Ferritin is a major acute-phase protein in dogs, increasing during inflammation; however, it could also be affected by other conditions, including trauma, iron metabolism dysregulations, neoplasia, or hypoxia. Higher ferritin levels have been reported in obese humans, but ferritin has not been explored in canine obesity. To evaluate the possible changes in serum ferritin in canine obesity, ferritin levels from lean/normal weight (CG, n = 55) and overweight/obese dogs (OG, n = 37) were measured, together with complete hemogram and biochemical analyses. Statistically significant higher ferritin levels (1.2-fold) were found in OG (median, (interquartile range), 204 (166-227.5) µg/L) in comparison to CG animals (172 (137-210) µg/L)), with median levels of ferritin in OG dogs above the reference range for healthy animals in our laboratory (60-190 µg/L). In addition, statistically significant higher mean corpuscular volume (MCV), mean cell haemoglobin concentration (MCHC), total proteins, globulins, haptoglobin, total ferric fixation capacity (TIBC), alkaline phosphatase (ALP), butyrylcholinesterase (BChE), triglycerides, and calcium were observed in OG in comparison to CG. The higher levels in ferritin, together with higher TBIC, haematocrit, and MCV, could indicate tissue hypoxia in obese dogs.

The association between iron metabolism with the change of blood pressure and risk of hypertension: A large cross-sectional study

BACKGROUND

The relationship between iron metabolism and variations in blood pressure and hypertension risk is still not clear. This study aimed to determine whether iron metabolism is associated with changes in blood pressure and hypertension prevalence in the general United States population.

METHODS

The National Health and Nutrition Examination Survey (NAHNES) database contains data on 116876 Americans from 1999 to 2020 years. Data from the NHANES database were used to examine the relationships between iron metabolism (serum iron [SI], serum ferritin [SF], and soluble transferrin receptor [sTfR]) and changes in blood pressure and hypertension prevalence. Generalized linear models and restricted cubic spline (RCS) plot curves were used to estimate the relationship between iron metabolism and hypertension. Further, generalized additive models with smooth functions were used to identify the relationship between iron metabolism and blood pressure. Finally, a stratified subgroup analysis was performed.

RESULTS

A total of 6710 participants were included in our analysis. The RCS plot showed a linear relationship between SI, as well as sTfR, and hypertension prevalence. SF and hypertension prevalence were associated in a J-shape. In addition, the relationship between SI and systolic blood pressure (SBP) and diastolic blood pressure (DBP) decreased initially and then increased. A correlation between SF, SBP, and DBP first decreased, then increased, and finally decreased. A positive linear correlation existed between sTfR and SBP, but it increased and then decreased with DBP.

CONCLUSION

The correlation between SF and hypertension prevalence displayed a J-curve. In contrast, the correlation between SI, as well as sTfR, and hypertension risk was negative and positive, respectively.

Serum Ferritin Levels in Severe Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) has been associated with various acute and chronic inflammatory diseases, as has serum ferritin, an intracellular iron storage protein. Little is known about the relationship between severity of OSA and serum ferritin levels in otherwise healthy subjects. In this study, all polysomnographic recordings, serum levels of ferritin, C-reactive protein (CRP), and hemoglobin, as well as patient files from 90 consecutive, otherwise healthy individuals with suspected OSA who presented to a tertiary sleep medical center were retrospectively analyzed. For comparison, three groups were formed based on apnea-hypopnea index (AHI; none or mild OSA: <15/h vs. moderate OSA: 15-30/h vs. severe OSA: >30/h). Serum ferritin levels were significantly positively correlated with AHI (r = 0.3240, p = 0.0020). A clear trend of higher serum ferritin levels was found when patients with severe OSA were compared to those without or with mild OSA. Serum CRP and serum hemoglobin levels did not differ significantly among OSA severity groups. Age and body-mass index (BMI) tended to be higher with increasing OSA severity. The BMI was significant higher in patients with severe OSA compared to those without or with mild (p < 0.001). Therefore, serum ferritin levels may provide a biochemical surrogate marker for OSA severity.

Plasma Ferritin Concentrations in the General Population: A Cross-Sectional Analysis of Anthropometric, Metabolic, and Dietary Correlates

BACKGROUND

Elevated concentrations of ferritin seem to be detrimental to human health while being quite common in the elderly. Data on dietary, anthropometric, and metabolic correlates of circulating ferritin levels in the elderly are scant.

OBJECTIVES

We aimed to identify a dietary pattern, anthropometric, and metabolic traits associated with plasma ferritin status in an elderly cohort (n = 460, 57% male, age: 66 ± 12 y) from Northern Germany.

METHODS

Plasma ferritin levels were measured by immunoturbidimetry. Reduced rank regression (RRR) yielded a dietary pattern explaining 13% of the variation in circulating ferritin concentrations. Cross-sectional associations of anthropometric and metabolic traits with plasma ferritin concentrations were assessed using multivariable-adjusted linear regression analysis. Restricted cubic spline regression was used to identify nonlinear associations.

RESULTS

The RRR pattern was characterized by a high intake of potatoes, certain vegetables, beef, pork, processed meat, fats (frying and animal fat), and beer and a low intake of snacks, representing elements of the traditional German diet. BMI, waist circumference, and CRP were directly, HDL cholesterol inversely, and age nonlinearly associated with plasma ferritin concentrations (all P < 0.05). After additional adjustment for CRP, only the association of ferritin with age remained statistically significant.

CONCLUSION

Higher plasma ferritin concentrations were associated with a traditional German dietary pattern. The associations of ferritin with unfavorable anthropometric traits and low HDL cholesterol were rendered statistically nonsignificant upon additional adjustment for chronic systemic inflammation (CRP), suggesting that these associations were largely driven by the proinflammatory role of ferritin (an acute-phase reactant). J Nutr 20xx;x:xx.

Is iron status associated with markers of non-communicable disease in adolescent Indian children?

BACKGROUND

High body iron status has been associated with non-communicable diseases (NCD) like diabetes (high fasting blood glucose, FBG), hypertension (HTN) or dyslipidaemia (high total cholesterol, TC) in adults, but this has not been examined in adolescent children. This is relevant to iron supplementation and food iron fortification programs that are directed at Indian children.

METHODS

The association of NCD with Serum Ferritin (SF) was examined using logistic additive models, adjusted for confounders such as age, body mass index, C-Reactive Protein, haemoglobin and sex, in adolescent (10-19 years old) participants of the Indian Comprehensive National Nutrition Survey. The interaction of these associations with wealth and co-existing prediabetes was also examined. A scenario analysis was also done to understand the impact of iron fortification of cereals on the prevalence NCD among adolescents.

RESULTS

The odds ratio (OR) of high FBG, HTN and TC were 1.05 (95% CI: 1.01-1.08), 1.02 (95% CI: 1.001-1.03) and 1.04 (95% CI: 1.01-1.06) respectively for every 10 µg/L increase in SF. The odds for high TC increased with co-existing prediabetes. The scenario analysis showed that providing 10 mg of iron/day by fortification could increase the prevalence of high FBG by 2-14% across states of India. Similar increments in HTN and TC can also be expected.

CONCLUSIONS

High SF is significantly associated with NCD in adolescents, dependent on wealth and co-existing prediabetes. This should be considered when enhancing iron intake in anaemia prevention programs, and the NCD relationship with body iron stores should be studied.

Interaction between Butyrate and Tumor Necrosis Factor α in Primary Rat Colonocytes

Butyrate, a short-chain fatty acid, is utilized by the gut epithelium as energy and it improves the gut epithelial barrier. More recently, it has been associated with beneficial effects on immune and cardiovascular homeostasis. Conversely, tumor necrosis factor alpha (TNFα) is a pro-inflammatory and pro-hypertensive cytokine. While butyrate and TNFα are both linked with hypertension, studies have not yet addressed their interaction in the colon. Here, we investigated the capacity of butyrate to modulate a host of effects of TNFα in primary rodent colonic cells in vitro. We measured ATP levels, cell viability, mitochondrial membrane potential (MMP), reactive oxygen species (ROS), mitochondrial oxidative phosphorylation, and glycolytic activity in colonocytes following exposure to either butyrate or TNFα, or both. To address the potential mechanisms, transcripts related to oxidative stress, cell fate, and cell metabolism (Pdk1, Pdk2, Pdk4, Spr, Slc16a1, Slc16a3, Ppargc1a, Cs, Lgr5, Casp3, Tnfr2, Bax, Bcl2, Sod1, Sod2, and Cat) were measured, and untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) was employed to profile the metabolic responses of colonocytes following exposure to butyrate and TNFα. We found that both butyrate and TNFα lowered cellular ATP levels towards a quiescent cell energy phenotype, characterized by decreased oxygen consumption and extracellular acidification. Co-treatment with butyrate ameliorated TNFα-induced cytotoxicity and the reduction in cell viability. Butyrate also opposed the TNFα-mediated decrease in MMP and mitochondrial-to-intracellular calcium ratios, suggesting that butyrate may protect colonocytes against TNFα-induced cytotoxicity by decreasing mitochondrial calcium flux. The relative expression levels of pyruvate dehydrogenase kinase 4 (Pdk4) were increased via co-treatment of butyrate and TNFα, suggesting the synergistic inhibition of glycolysis. TNFα alone reduced the expression of monocarboxylate transporters slc16a1 and slc16a3, suggesting effects of TNFα on butyrate uptake into colonocytes. Of the 185 metabolites that were detected with LC-MS, the TNFα-induced increase in biopterin produced the only significant change, suggesting an alteration in mitochondrial biogenesis in colonocytes. Considering the reports of elevated colonic TNFα and reduced butyrate metabolism in many conditions, including in hypertension, the present work sheds light on cellular interactions between TNFα and butyrate in colonocytes that may be important in understanding conditions of the colon.

Percent Body Fat-Related Disparities of Serum Ferritin on the Risk of Lipid Metabolism Abnormalities in Children and Adolescents

OBJECTIVE

This study examined the association between serum ferritin and dyslipidemia in children and adolescents with different degrees of obesity.

METHOD

In this multi-stage, stratified, randomized, sampling cross-section cohort study, demographic data were collected by questionnaire from 4320 children and adolescents (aged 6-17 years) in Shanghai, China. Anthropometric measures and percent body fat (PBF) were recorded. Serum lipid parameters were detected by an automatic biochemical method, and ferritin levels were measured by an automatic immunoassay.

RESULTS

Our results showed 70.6%, 13.9%, and 15.5% of participants had a healthy body fat, low fat, and overweight/obese, respectively. Increasing ferritin quartiles were independently associated with a greater hazard of dyslipidemia, especially in overweight/obese participants, and the OR (95% CI) was 3.01 (1.29-7.00), 3.58 (1.59-8.04), and 5.66 (2.57-12.46) across the ferritin quartiles after adjustment for confounders. Ferritin was only a predictive value for dyslipidemia in overweight/obese participants (AUC = 0.64) and was consistent in boys (AUC = 0.61) and girls (AUC = 0.68). The significant positive correlation between ferritin value and lipid abnormalities profiles (except for low HDL-C) mainly appeared in the overweight/obesity group.

CONCLUSION

The results showed that serum ferritin can be considered an independent risk factor for dyslipidemia in children and adolescents with obesity.

HIGHLIGHTS

Ferritin overload had a greater risk of dyslipidemia, especially in children and adolescents with overweight/obesity.

The association between serum ferritin and blood pressure in adult women: a large cross-sectional study

BACKGROUND

Studies on the relationships between ferritin and blood pressure remain limited, especially in adult women. The aim of the present study was to investigate the associations between serum ferritin and blood pressure among adult women.

METHODS

Using the National Health and Nutrition Examination Survey, a cross-sectional study, including 5521 adult women, was performed. Weighted multivariate regressions, subgroup analyses, threshold effect analyses, and sensitivity analysis were used.

RESULTS

The authors found that serum ferritin was independently and positively correlated to diastolic blood pressure (DBP), and this positive correlation kept present among women who are 26-30 years old, non-pregnant women, Mexican American women, and women of other races in the subgroup analyses. Additionally, no significant association was found between serum ferritin and systolic blood pressure (SBP), except in women aged 26-30, Mexican American women, and women of other races. In pregnant women, the association between serum ferritin and SBP was an inverted U-shaped curve with an inflection point at 39.5 ng/mL.

CONCLUSIONS

The authors demonstrated that serum ferritin was positively correlated to DBP in adult women, which may provide a novel reference for clinical management.

Role of Iron in Aging Related Diseases

Iron progressively accumulates with age and can be further exacerbated by dietary iron intake, genetic factors, and repeated blood transfusions. While iron plays a vital role in various physiological processes within the human body, its accumulation contributes to cellular aging in several species. In its free form, iron can initiate the formation of free radicals at a cellular level and contribute to systemic disorders. This is most evident in high iron conditions such as hereditary hemochromatosis, when accumulation of iron contributes to the development of arthritis, cirrhosis, or cardiomyopathy. A growing body of research has further identified iron’s contributory effects in neurodegenerative diseases, ocular disorders, cancer, diabetes, endocrine dysfunction, and cardiovascular diseases. Reducing iron levels by repeated phlebotomy, iron chelation, and dietary restriction are the common therapeutic considerations to prevent iron toxicity. Chelators such as deferoxamine, deferiprone, and deferasirox have become the standard of care in managing iron overload conditions with other potential applications in cancer and cardiotoxicity. In certain animal models, drugs with iron chelating ability have been found to promote health and even extend lifespan. As we further explore the role of iron in the aging process, iron chelators will likely play an increasingly important role in our health.

Hepcidin is potential regulator for renin activity

An association between genetic variants in the genes HFE, HJV, BMP4 and arterial hypertension has been shown earlier. Proteins encoded by these genes participate in the signalling routes leading eventually to the production of the peptide hormone hepcidin. Mutations in these genes have been associated with the abnormal production of hepcidin in the body. This finding led to studies exploring the possible role of hepcidin in regulating the activity of blood pressure related renin-angiotensin system enzymes. We used molecular modelling to find out if it is possible for hepcidin to bind to the active site of the renin-angiotensin system enzymes, especially renin. Fluorometric assays were used to evaluate the inhibitory effect of hepcidin on renin as well as angiotensin converting enzymes 1 and 2. Finally, bio-layer interferometry technique was used to study hepcidin binding to renin. The molecular modelling showed that hepcidin seems to have similar binding properties to the renin active site as angiotensinogen does. Based on fluorometric enzyme activity assay, hepcidin has an inhibitory effect on renin in vitro, too. However, angiotensin converting enzymes 1 and 2 were not inhibited remarkably by hepcidin-25. In bio-layer interferometry analysis hepcidin-renin binding was concentration dependent. Our results suggest that hepcidin could act as an inhibitor to the renin. Nowadays, there is no known biological inhibitor for renin in vivo and our finding may thus have important clinical implications.

Maternal Iron Status in Early Pregnancy and Blood Pressure Throughout Pregnancy, Placental Hemodynamics, and the Risk of Gestational Hypertensive Disorders

BACKGROUND

In nonpregnant populations, higher serum ferritin, which reflects high iron stores, is associated with an increased risk of hypertension. We hypothesized that a dysregulated maternal iron status in early pregnancy may lead to impaired gestational hemodynamic adaptations, leading to an increased risk of gestational hypertensive disorders.

OBJECTIVES

We examined the associations of maternal iron status with maternal blood pressure, placental hemodynamic parameters, and the risks of gestational hypertensive disorders.

METHODS

In a population-based prospective cohort study among 5983 pregnant women, we measured maternal serum ferritin, transferrin saturation, serum iron, and transferrin concentrations at a median of 13.2 weeks gestation (95% range, 9.6-17.6). Maternal blood pressure was measured in early pregnancy, mid pregnancy, and late pregnancy, and placental hemodynamic parameters in mid pregnancy and late pregnancy were measured by ultrasound. Information on gestational hypertensive disorders was collected from medical records. We examined the associations of maternal early pregnancy iron status with maternal systolic and diastolic blood pressure, placental hemodynamic parameters, and the risks of gestational hypertensive disorders using linear and logistic regression models.

RESULTS

Higher maternal early pregnancy serum ferritin concentrations were associated with higher systolic and diastolic blood pressure throughout pregnancy in the basic models (P values < 0.05). After adjustment for maternal inflammation, sociodemographic and lifestyle factors, higher maternal early pregnancy serum ferritin concentrations were only associated with a higher early pregnancy diastolic blood pressure [0.27 (95% CI, 0.03-0.51) mmHg per SD score increase in serum ferritin] and with a higher mid pregnancy umbilical artery pulsatility index (P < 0.05). No associations with the risk of gestational hypertensive disorders were present.

CONCLUSIONS

No consistent associations were present of maternal iron status in early pregnancy with gestational hemodynamic adaptations or the risks of gestational hypertensive disorders. Further studies are needed to examine the potential role of iron metabolism in the development of gestational hypertensive disorders within higher-risk populations.

Cardiovascular Disease Complicating COVID-19 in the Elderly

SARS-CoV-2, a single-stranded RNA coronavirus, causes an illness known as coronavirus disease 2019 (COVID-19). The highly transmissible virus gains entry into human cells primarily by the binding of its spike protein to the angiotensin-converting enzyme 2 receptor, which is expressed not only in lung tissue but also in cardiac myocytes and the vascular endothelium. Cardiovascular complications are frequent in patients with COVID-19 and may be a result of viral-associated systemic and cardiac inflammation or may arise from a virus-induced hypercoagulable state. This prothrombotic state is marked by endothelial dysfunction and platelet activation in both macrovasculature and microvasculature. In patients with subclinical atherosclerosis, COVID-19 may incite atherosclerotic plaque disruption and coronary thrombosis. Hypertension and obesity are common comorbidities in COVID-19 patients that may significantly raise the risk of mortality. Sedentary behaviors, poor diet, and increased use of tobacco and alcohol, associated with prolonged stay-at-home restrictions, may promote thrombosis, while depressed mood due to social isolation can exacerbate poor self-care. Telehealth interventions via smartphone applications and other technologies that document nutrition and offer exercise programs and social connections can be used to mitigate some of the potential damage to heart health.

Prevalence of nutritional deficiencies in bariatric surgery candidates and its effect on metabolic status

BACKGROUND

Nutritional deficiencies are common among obese individuals and constitute one of the main concerns in the bariatric field. The aim of this study was to investigate nutritional status in bariatric surgery candidates, comparing individuals with and without metabolic syndrome (MetS) and to explore possible associations between nutritional and metabolic status.

METHODS

Patients accepted for gastric sleeve surgery between 2010 and 2015 were included and anthropometric and metabolic parameters were recorded before surgery. Univariate and multivariate analyses were applied in order to find possible associations between MetS, nutritional, anthropometric, and metabolic parameters.

RESULTS

A total of 330 patients were evaluated (285 females, mean age of 41.88 ± 10.4 years old, mean body mass index 43.91 ± 6.2 kg/m²) and MetS was present in 47% of them. Patients without MetS presented a higher prevalence of folate deficiency (12 vs. 2%, p < 0.001). Male gender, older age, lower magnesium levels, and higher BMI and calcium levels were predictors of a greater number of MetS components. Male gender, a greater number of MetS components, and lower magnesium were predictors of higher homeostatic model assessment for insulin resistance (HOMA-IR).

CONCLUSIONS

The rising prevalence of obesity is causing a parallel increase in the use of bariatric surgery. The high occurrence of preoperative nutritional deficiencies can impair metabolic status and contribute to a worse outcome after surgery. Nutritional assessment and improvement before surgery may be crucial to optimize patient status, and future studies should explore the effect of the correction of these deficiencies in the metabolic status of these patients.

Ferritin in the coronavirus disease 2019 (COVID-19): A systematic review and meta-analysis

OBJECTIVE

The coronavirus disease 2019 (COVID-19) has rapidly developed into a pandemic. Increased levels of ferritin due to cytokine storm and secondary hemophagocytic lymphohistiocytosis were found in severe COVID-19 patients. Therefore, the aim of this study was to determine the role of ferritin in COVID-19.

METHODS

Studies investigating ferritin in COVID-19 were collected from PubMed, EMBASE, CNKI, SinoMed, and WANFANG. A meta-analysis was performed to compare the ferritin level between different patient groups: non-survivors versus survivors; more severe versus less severe; with comorbidity versus without comorbidity; ICU versus non-ICU; with mechanical ventilation versus without mechanical ventilation.

RESULTS

A total of 52 records involving 10 614 COVID-19-confirmed patients between December 25, 2019, and June 1, 2020, were included in this meta-analysis, and 18 studies were included in the qualitative synthesis. The ferritin level was significantly increased in severe patients compared with the level in non-severe patients [WMD 397.77 (95% CI 306.51-489.02), P < .001]. Non-survivors had a significantly higher ferritin level compared with the one in survivors [WMD 677.17 (95% CI 391.01-963.33), P < .001]. Patients with one or more comorbidities including diabetes, thrombotic complication, and cancer had significantly higher levels of ferritin than those without (P < .01). Severe acute liver injury was significantly associated with high levels of ferritin, and its level was associated with intensive supportive care, including ICU transfer and mechanical ventilation.

CONCLUSIONS

Ferritin was associated with poor prognosis and could predict the worsening of COVID-19 patients.

Serum Transferrin Predicts New-Onset Type 2 Diabetes in Koreans: A 4-Year Retrospective Longitudinal Study

BACKGROUND

It is well known that high serum ferritin, a marker of iron storage, predicts incident type 2 diabetes. Limited information is available on the association between transferrin, another marker of iron metabolism, and type 2 diabetes. Thus, we investigated the association between transferrin and incident type 2 diabetes.

METHODS

Total 31,717 participants (mean age, 40.4±7.2 years) in a health screening program in 2005 were assessed via cross-sectional analysis. We included 30,699 subjects who underwent medical check-up in 2005 and 2009 and did not have type 2 diabetes at baseline in this retrospective longitudinal analysis.

RESULTS

The serum transferrin level was higher in the type 2 diabetes group than in the non-type 2 diabetes group (58.32±7.74 μmol/L vs. 56.17±7.96 μmol/L, P&lt;0.001). Transferrin correlated with fasting serum glucose and glycosylated hemoglobin in the correlational analysis (r=0.062, P&lt;0.001 and r=0.077, P&lt;0.001, respectively) after full adjustment for covariates. Transferrin was more closely related to homeostasis model assessment of insulin resistance than to homeostasis model assessment of β cell function (r=0.042, P&lt;0.001 and r=-0.019, P=0.004, respectively) after full adjustment. Transferrin predicted incident type 2 diabetes in non-type 2 diabetic subjects in a multivariate linear regression analysis; the odds ratio (95% confidence interval [CI]) of the 3rd tertile compared to that in the 1st tertile of transferrin for incident diabetes was 1.319 (95% CI, 1.082 to 1.607) after full adjustment (P=0.006).

CONCLUSION

Transferrin is positively associated with incident type 2 diabetes in Koreans.

Ferritin modifies the relationship between inflammation and arterial stiffness in hypertensive patients with different glucose tolerance

Background

Ferritin, a crucial element for iron homeostasis, is associated with chronic diseases characterized by subclinical inflammation such as essential arterial hypertension and type 2 diabetes mellitus (T2DM), showing a prognostic value in different clinical settings. We investigated whether ferritin is associated with arterial stiffness (AS), an early indicator of atherosclerosis, and if it could act as effect modifier on the relationship between inflammation and AS in hypertensive patients with different glucose tolerance.

Methods

We enrolled 462 newly diagnosed untreated hypertensive (HT) patients. All subjects underwent an oral glucose tolerance test. Insulin sensitivity was assessed by MATSUDA index and ferritin levels were estimated by immunoradiometric assay. AS was defined by carotid-femoral pulse wave velocity (PWV).

Results

Out of 462 patients, 271 showed normal glucose tolerance (HT/NGT), 146 impaired glucose tolerance (HT/IGT) and 45 were diabetic (HT/T2DM). Iron levels significantly decreased and transferrin and ferritin significantly increased from the first to the third group. PWV values were significantly higher in HT/IGT and HT/T2DM patients. PWV was related directly with ferritin, high sensitivity C reactive protein (hs-CRP), transferrin, and inversely with MATSUDA index. Ferritin resulted the strongest determinant of PWV explaining a 14.9% of its variation; moreover it was a strong modifier of the relationship between hs-CRP and PWV. The estimated augmentation in PWV portended by a fixed increase in hs-CRP, was higher across increasing values of ferritin.

Conclusion

Ferritin represents an independent risk factor of arterial stiffness in our study population and a strong effect modifier on the relationship between inflammation and PWV. However, further studies are needed to fully elucidate the potential role of this biomarker in human atherosclerosis.

Associations of iron status with apolipoproteins and lipid ratios: a cross-sectional study from the China Health and Nutrition Survey

Background

Iron overload has been found to be related with various cardiometabolic disorders, like dyslipidemia, metabolic syndrome, and diabetes. The disturbance of the iron status and lipid metabolism can contribute to organ damage such as atherosclerotic plaque growth and instability. An assessment on the associations of iron status with apolipoproteins and lipid ratios would be informative for maintenance of metabolic homeostasis and hinderance of disease progression. Hence, this study aims to establish the relationships of iron status with apolipoproteins and lipid ratios.

Methods

A cross-sectional study of 7540 adult participants from the China Health and Nutrition Survey 2009 was conducted. Logistic regression analyses were used to investigate the relationships between indicators of iron status and the prevalence of unfavorable apolipoprotein profiles. Multivariate linear regression models were constructed to assess the dose-response correlations between serum ferritin and lipid parameters.

Results

After adjustment for confounding factors, in both sexes, the subjects in the top quartile of ferritin had the highest prevalence of an elevated apolipoprotein B (men: odds ratio (OR) 1.97, 95% confidence interval (CI) 1.50–2.62; women: OR 2.13, 95% CI 1.53–2.97) and an elevated apolipoprotein B/apolipoprotein A1 ratio (men: OR 2.00, 95% CI 1.50–2.66; women: OR 1.41, 95% CI 1.04–1.92) when compared with individuals in the lowest quartile. Hemoglobin were also independently associated with unfavorable apolipoprotein B and apolipoprotein B/apolipoprotein A1 ratio both in men and women. However, transferrin (men: OR 0.74, 95% CI 0.56–0.99; women: OR 0.73, 95% CI 0.56–0.95) and soluble transferrin receptor (men: OR 0.75, 95% CI 0.57–0.99; women: OR 0.71, 95% CI 0.55–0.91) were found to be negatively associated with a decreased apolipoprotein A1. Moreover, after controlling for potential confounders, the ferritin concentrations were significantly associated with the levels of lipid ratios including TG/HDL-C, non-HDL-C/HDL-C, TC/HDL-C, apoB/apoA1, and LDL-C/HDL-C ratio in men (β coefficient = 0.147, 0.061, 0.043, 0.038, 0.032, respectively, all P values < 0.001) and in women (β coefficient = 0.074, 0.034, 0.025, 0.020, 0.018, respectively, all P values < 0.05).

Conclusions

The indicators of iron status are significantly associated with unfavorable apolipoprotein profiles. Serum ferritin concentrations are positively correlated with the levels of lipid ratios. The management on the modifiable iron status and lipid metabolism has a clinical significance. The atherosclerotic lipid profiles of the patients with iron overload deserve special clinical concerns.

Markers of iron status, blood pressure and incident hypertension among Chinese adults

BACKGROUND AND AIMS

The evidence on the relationship between markers of iron, blood pressure and hypertension are limited and inconsistent. This prospective cohort study aimed to investigate the relationship of serum ferritin (SF), transferrin, soluble transferrin receptor (sTFR) and haemoglobin on blood pressure and incident hypertension in the China Health and Nutrition Survey (CHNS) study.

METHODS AND RESULTS

We studied 8337 adults aged 18 years old or above from CHNS in 2009 to investigate the association of markers of iron and blood pressure (BP). Among them, 4509 non-hypertensive participants who completed follow up were included to investigate the association of markers of iron and hypertension development. Linear regression model was used to assess the association between markers of iron and BP. Cox regression model was used to examine the association of markers of iron and hypertension development. SF and serum sTFR concentration had a non-significant effect on incident hypertension. Transferrin and haemoglobin concentrations were positively associated with incident hypertension. Compared to the participants with the lowest tertile of transferrin, those with the highest tertile had a higher risk of developing hypertension [HR: 1.26, 95% CI (1.04, 1.53), P = 0.017]. Similarly, participants with the highest tertile of haemoglobin had a significantly higher risk of incident hypertension [HR: 1.27, 95% CI (1.01, 1.59), P = 0.038].

CONCLUSION

The current study found that haemoglobin and transferrin levels were positively associated with blood pressure and incident hypertension. Further research in different ethnic groups is required to confirm the association of the full range of markers of iron with BP and incident hypertension.

Association between serum ferritin and hypertension according to the working type in Korean men: the fifth Korean National Health and nutrition examination survey 2010-2012

Background

Several studies suggest that serum ferritin concentrations reflect systemic inflammation, and high ferritin levels can increase the risk of hypertension in adult men. Shift work is also known to increase the risk of hypertension; however, there has been no study about the relationship between serum ferritin levels and the prevalence of hypertension according to the working type.

Methods

This cross-sectional study included 4,442 male participants (3,651 daytime workers and 791 shift workers) who participated in the fifth Korean National Health and Nutrition Examination Survey. Hypertension was defined as a systolic blood pressure greater than or equal to 140 mmHg, a diastolic blood pressure greater than or equal to 90 mmHg or the current use of antihypertensive medications regardless of blood pressure values. For the statistical analyses, serum ferritin levels were reclassified into quartiles, and complex sample analyses were used to evaluate the relationship between serum ferritin levels and the prevalence of hypertension according to the working type in this study.

Results

Serum ferritin and shift work were positively associated with the prevalence of hypertension. The effect of interaction was above multiplicative. When compared to participants in the lowest serum ferritin quartile, the odds ratio for hypertension for participants in the highest serum ferritin quartile was 1.372 (1.027–1.833) in daytime workers and 2.009 (1.042–3.873) in shift workers after adjustment.

Conclusions

The prevalence of hypertension increased as ferritin levels increased in individuals, especially in shift workers.

Trace minerals intake: Risks and benefits for cardiovascular health

Minerals play a major role in regulating cardiovascular function. Imbalances in electrolyte minerals are frequent and potentially hazardous occurrences that may lead to the development of cardiovascular diseases (CVDs). Transition metals, such as iron, zinc, copper and selenium, play a major role in cell metabolism. However, there is controversy over the effects of dietary and supplemental intake of these metals on cardiovascular risk factors and events. Since their pro-oxidant or antioxidant functions can have different effects on cardiovascular health. While deficiency of these trace elements can cause cardiovascular dysfunction, several studies have also shown a positive association between metal serum levels and cardiovascular risk factors and events. Thus, a J- or U-shaped relationship between the transition minerals and cardiovascular events has been proposed. Given the existing controversies, large, well-designed, long-term, randomized clinical trials are required to better examine the effects of trace mineral intake on cardiovascular events and all-cause mortality in the general population. In this review, we discuss the role of dietary and/or supplemental iron, copper, zinc, and selenium on cardiovascular health. We will also clarify their clinical applications, benefits, and harms in CVDs prevention.

Serum ferritin and obstructive sleep apnea-epidemiological study

PURPOSE

Ferritin is an intracellular iron storage protein and a marker of inflammation. Studies have shown that subjects with obstructive sleep apnea (OSA) have higher levels of circulating pro-inflammatory cytokines, but little is known about the association between ferritin and OSA. The aims of the study were to evaluate serum ferritin (S-Ferritin) levels in OSA patients compared to levels in the general population and also examine the effect of obesity level and treatment with positive airway pressure (PAP) on S-Ferritin levels.

METHODS

The OSA subjects (n = 796) were part of the Icelandic Sleep Apnea Cohort. The control subjects (n = 637) were randomly chosen Icelanders who participated in an epidemiological study. Propensity score (PS) methodologies were employed to minimize selection bias and strengthen causal inferences when comparing non-randomized groups. S-Ferritin levels were measured and all participants answered the same detailed questionnaire about sleep and health. Only OSA patients underwent a sleep study and were re-invited for a 2-year follow-up.

RESULTS

S-Ferritin levels were significantly higher in OSA males than controls (213.3 vs. 197.3 μg/L, p = 0.007). However, after adjusting for confounders and using our PS methodology, no significant difference was found. S-Ferritin levels were not correlated with severity of OSA, obesity level, or clinical symptoms. Also, no significant change in S-Ferritin levels was found with 2 years of PAP treatment.

CONCLUSIONS

S-Ferritin levels are comparable in OSA patients and controls and do not change consistently with obesity level or PAP treatment in our sample.

Association of serum ferritin with insulin resistance, abdominal obesity, and metabolic syndrome in Korean adolescent and adults: The Korean National Health and Nutrition Examination Survey, 2008 to 2011

This study aimed to evaluate the associations of serum ferritin with insulin resistance indices, body fat mass/percentage, and all the components of metabolic syndrome (MetS), as well as the risk for MetS according to serum ferritin levels in Korean adolescents and adults.A total of 15,963 Korean males and females aged 16 to 80 years were analyzed using data from the Korean National Health and Nutrition Examination Survey, 2005 to 2011.The median serum ferritin concentration was 98.82 ng/mL for males and 38.60 ng/mL for females (P < 0.001). Increased risks of greater waist circumference and elevated glucose levels, elevated triglyceride levels, and reduced high-density lipoprotein cholesterol levels were noted across the serum ferritin quartiles after adjustment for confounders in both genders (P ≤ 0.012 for trend). Insulin resistance indices and abdominal obesity (trunk fat mass/percent) increased across the ferritin concentration quartiles after adjustment for confounders in males and females (P ≤ 0.011 for trend), and the risk of MetS increased across the ferritin quartiles in males (P < 0.001 for trend) and females (P = 0.001 for trend). The highest serum ferritin quartile exhibited a 1.62-fold increased risk of MetS (95% CI, 1.28-2.12) in males and a 1.36-fold increased risk of MetS (95% CI, 1.09-1.69) in females compared with the lowest quartile after adjustment for confounders.Our results suggest that ferritin is associated with insulin resistance and abdominal obesity.

Association of serum ferritin levels with metabolic syndrome and insulin resistance in a Chinese population

AIMS

Increased iron is associated with type 2 diabetes, dyslipidemia, and high blood pressure. Therefore, serum ferritin may be a suitable biomarker to detect metabolic syndrome (MetS). We investigated the relationship between serum ferritin, and the prevalence of MetS and insulin resistance (IR).

METHODS

This cross-sectional study assessed 2,786 Chinese participants, aged 25-75 years. MetS was defined using the 2006 International Diabetes Federation guidelines. IR was assessed with homeostasis model assessment estimated IR (HOMA-IR). Regression analysis was used to estimate the association between serum ferritin and the prevalence of MetS and IR.

RESULTS

MetS prevalence within each serum ferritin quartile (Q1-4) was 31.7%, 37.1%, 43.6%, and 55.4%, respectively in men (P<0.001), and 30.1%, 34.8%, 48.2%, and 66.9%, respectively in women (P<0.001). Increased serum ferritin correlated with the number of MetS components (P<0.001). The odds ratio for MetS in the ferritin Q4 group was 1.95 (1.39-2.73) for men and 1.66(1.12-2.47) for women, compared with Q1. Serum ferritin correlated positively with HOMA-IR in men (regression coefficient: 0.058, P=0.009) and women (regression coefficient: 0.082, P=0.001).

CONCLUSION

MetS prevalence increased with elevated serum ferritin levels, and serum ferritin levels were independently associated with MetS and IR.

Oxidative stress, oxidative balance score, and hypertension among a racially diverse population

Hypertension is a risk factor for several vascular diseases. Evidence suggests that oxidative stress (OS) plays a significant role in its pathophysiology. Human studies have shown inconsistent results, varying based on the OS biomarker and study population. In a racially diverse population, examine the association between: (1) blood pressure or hypertension and four markers of OS and (2) blood pressure or hypertension and oxidative balance score (OBS). Using data (n = 317) from the cross-sectional study on race, stress, and hypertension, an OBS was constructed from various measures of pro-oxidant and antioxidant exposures. OS was assessed by four biomarkers: fluorescence oxidative products, F2-isoprostanes, mitochondrial DNA copy number, and gamma tocopherol. Multivariate linear and logistic regression analyses were used to estimate the associations of interest. None of the adjusted associations between hypertension and OS markers was statistically significant. OBS was inversely associated with hypertension after adjusting for study covariates. Persons with higher OBS have lower odds of having hypertension; however, the evidence on the relationship between OS markers and blood pressure remains unconvincing.

High serum ferritin level is an independent risk factor for metabolic syndrome in a Chinese male cohort population

BACKGROUND

Elevated serum ferritin levels have been reported to contribute to metabolic syndrome (MetS). We examined the association of serum ferritin levels with the development of MetS in a representative sample of Chinese male adult population.

METHOD

The data came from the 2009-2013 Fangchenggang Area Males Health and Examination Survey (FAMHES). We combined a cross-sectional study of 2417 males and a longitudinal study of 857 males who participated in the FAMHES.

RESULT

The serum ferritin level of MetS was higher than that of nonMetS (median and percentiles 25-75: 447.4 (294.1-612.4) vs. 302.4 (215.0-435.8) ng/ml, p < 0.01). A positive correlation between ferritin concentrations and blood pressure (Systolic BP: R = 0.110, Diastolic BP: R = 0.158), waist circumference (R = 0.333), fasting glucose (R = 0.089), triglyceride (R = 0.315) and low high-density lipoprotein cholesterol (R = 0.130) was significant (all p < 0.001). Compared with the level of ferritin in the group with no MetS component, the group with all five MetS components had a higher ferritin level (554.7 (340.1-606.4) vs. 274.2 (198.2-384.4) ng/ml). The odd radio (OR) was higher for MetS in the highest ferritin quartile (OR = 2.29, 95% CI = 1.47-3.54) compared with the lowest ferritin quartile after adjustment for multi-factors. After 4-year follow up, 79 subjects newly diagnosed with MetS in 857 cohort male participants in 2013. Compared with the lowest ferritin quartile, the RR of the highest ferritin quartile was 2.55 (95% CI = 1.30-5.00) after multiple adjustments (p < 0.01).

CONCLUSION

Our findings confirm that the serum ferritin level is associated with the independent components of MetS, and elevated ferritin level is an independent risk factor for MetS development in the Chinese male population during the 4-year follow-up period.

Elevated serum ferritin and mercury concentrations are associated with hypertension; analysis of the fourth and fifth Korea national health and nutrition examination survey (KNHANES IV-2, 3, 2008-2009 and V-1, 2010)

The impact of simultaneously elevated serum ferritin and mercury concentrations on hypertension in the general population is not known. To determine the association of serum ferritin and mercury concentrations with hypertension, 6213 subjects (3060 men and 3153 women) over 20 years of age from 2008 to 2010 Korea National Health and Nutrition Examination Survey were divided into tertiles according to serum ferritin and mercury concentrations in each gender. Serum ferritin (258.2 vs. 94.8 pmol/L) and mercury concentrations (28.4 vs. 19.9 nmol/L) were higher in men than in women. Serum ferritin (men; P = 0.029, women; P < 0.001) and mercury (men; P < 0.001, women; P = 0.003) concentrations were significantly associated with the prevalence of hypertension. In addition, significant correlation between serum ferritin and mercury concentrations in both men (r = 0.193, P < 0.001) and women (r = 0.145, P < 0.001) were found. Also, the increase of serum ferritin concentrations were more prominent in men (P < 0.001) than in women (P = 0.017) as the serum mercury tertiles increased after proper adjustments. Furthermore, significantly higher odds ratios of hypertension were found in the second (OR = 1.86, 95% CI; 1.05-3.30), and third (OR = 1.84, 95% CI; 1.01-3.36) tertiles of serum ferritin with the top tertile of serum mercury in men. The current study indicate that serum ferritin and mercury concentrations are associated with the prevalence of hypertension and that simultaneously elevated serum ferritin and mercury concentrations are related to the risk for hypertension in men.

Disease risk factors identified through shared genetic architecture and electronic medical records

Genome-wide association studies have identified genetic variants for thousands of diseases and traits. We evaluated the relationships between specific risk factors (for example, blood cholesterol level) and diseases on the basis of their shared genetic architecture in a comprehensive human disease-single-nucleotide polymorphism association database (VARIMED), analyzing the findings from 8962 published association studies. Similarity between traits and diseases was statistically evaluated on the basis of their association with shared gene variants. We identified 120 disease-trait pairs that were statistically similar, and of these, we tested and validated five previously unknown disease-trait associations by searching electronic medical records (EMRs) from three independent medical centers for evidence of the trait appearing in patients within 1 year of first diagnosis of the disease. We validated that the mean corpuscular volume is elevated before diagnosis of acute lymphoblastic leukemia; both have associated variants in the gene IKZF1. Platelet count is decreased before diagnosis of alcohol dependence; both are associated with variants in the gene C12orf51. Alkaline phosphatase level is elevated in patients with venous thromboembolism; both share variants in ABO. Similarly, we found that prostate-specific antigen and serum magnesium levels were altered before the diagnosis of lung cancer and gastric cancer, respectively. Disease-trait associations identify traits that could serve as future prognostics, if validated through EMR and subsequent prospective trials.

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.

The incidental relationship between serum ferritin levels and hypertension

BACKGROUND AND OBJECTIVE

Although several studies have shown an association between ferritin level and hypertension, only a few studies have investigated the longitudinal relationship between them. Thus, we evaluated the incidental risk for hypertension according to baseline ferritin level.

PATIENTS AND METHODS

A total of 7104 healthy Korean men matched by a propensity score, who had participated in a medical health check-up program in 2005, were followed up from 2005 to 2010. They were divided into four groups according to baseline serum ferritin level (first quartile-fourth quartile). The incidence of hypertension was compared among the four groups, and the Cox-proportional hazard model was used to assess whether the development of hypertension was associated with higher baseline serum ferritin level.

RESULTS

A total of 1252 (17.6%) cases had newly developed hypertension during the 26,339.5 person-years of follow-up between 2006 and 2010. The adjusted hazard ratios (HRs) (95% confidence intervals, CIs) for incident hypertension were 1.00 (reference), 1.09 (0.91-1.30), 1.21 (1.01-1.45) and 1.28 (1.07-1.52), respectively (P for trend=0.003) through the quartiles of serum ferritin levels, respectively, after adjusting for multiple confounders. For the log-transformed serum ferritin levels as a continuous variable, adjusted HRs and 95% CIs for HTN were 1.15 (1.02-1.29).

CONCLUSIONS

Elevated serum ferritin level was independently associated with the incidental risk for hypertension in Korean men. This finding suggests the value of elevated ferritin level as an early predictor of hypertension.

High serum ferritin levels increase the risk of hyperuricemia: a cross-sectional and longitudinal study

BACKGROUND/AIMS

To examine the cross-sectional and longitudinal associations of serum ferritin levels with hyperuricemia.

METHODS

A cross-sectional and subsequently prospective study was performed among the employees of Zhenhai Refining and Chemical Company, Ningbo, China. In a cross-sectional study, the association between serum ferritin levels and the prevalence of hyperuricemia was analyzed. Subjects who were free of hyperuricemia at baseline were followed up annually to explore the prospective association between serum ferritin levels and hyperuricemia incidence.

RESULTS

Of the 10,074 subjects enrolled at baseline, 1,731 (17.18%) fulfilled the diagnostic criteria of hyperuricemia. Subjects with hyperuricemia presented significantly higher serum ferritin levels, and the levels were positively correlated with the prevalence of hyperuricemia. During a total of 22,367 person-years of follow-up, 502 subjects developed hyperuricemia. The overall incidence of hyperuricemia for 1,000 person-years of follow-up was 22.4, ranging from 17.6 in subjects with baseline serum ferritin levels in the first quintile to 19.2, 21.7, 23.9, and 30.7 in subjects in quintiles 2, 3, 4, and 5, respectively (p for trend < 0.001). Cox regression analyses showed that serum ferritin levels were positively associated with the risk of incident hyperuricemia.

CONCLUSIONS

Our cross-sectional and longitudinal results indicate that high serum ferritin levels increase the risk of hyperuricemia.

Association between serum ferritin and microalbuminuria in Type 2 diabetes in Taiwan

AIMS

Serum ferritin has been found closely related with diabetes and glucose metabolism, but its impact on diabetic nephropathy remains unknown. This study aimed to explore the association between serum ferritin and microalbuminuria in Type 2 diabetes.

METHODS

Eight hundred and fifty-one subjects with Type 2 diabetes were selected from a cohort participating in a glycaemic control study in Taiwan in 2008. We used urine albumin:creatinine ratio to define microalbuminuria; serum ferritin was divided into quartiles for analysis. Logistic regression and trend tests were used to delineate the association between serum ferritin and microalbuminuria.

RESULTS

Subjects with diabetes with higher ferritin tended to have more metabolic disorders, higher high-sensitivity C-reactive protein and higher prevalence of microalbuminuria. Compared with those in the lowest quartile, subjects with diabetes in the highest ferritin quartile were 55% (P = 0.029) more likely to have microalbuminuria. After controlling for demographics, metabolic profiles and other inflammatory markers, the association between serum ferritin levels and microalbuminuria remained significant (P for trend < 0.001). This independent relationship was not changed either for those who had better glycaemic control or those who had not used an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker.

CONCLUSIONS

The current study shows hyperferritinemia may be an independent risk factor of nephropathy in patients with Type 2 diabetes.

Endocrinopathies in transfusion-associated iron overload

BACKGROUND

Transfusional iron overload primarily results in reticuloendothelial iron accumulation, which is considered to be less harmful than parenchymal iron accumulation. However, systematic and comprehensive data on endocrine function in transfusion-associated haemochromatosis are limited.

METHODS

We examined 25 aplastic anaemia patients (11 men and 14 women) diagnosed with transfusion-associated haemochromatosis at a single institution. Pituitary function was determined with a combined pituitary function test. On a different day, a 75-g oral glucose tolerance test was performed. The bone mineral density (BMD) of the lumbar spine and total hip was assessed with dual-energy X-ray absorptiometry.

RESULTS

Twenty-two (88%) of these 25 patients had at least one endocrine abnormality, and 12 had more than one abnormality. The most common pituitary hormonal deficiency involved the pituitary-gonadal axis; 54% of the total subjects had hypogonadotropic hypogonadism. Two patients had an insufficient cortisol response to corticotrophin-releasing hormone stimulation. No patient had a deficiency of growth hormone or thyroid-stimulating hormone. Twelve (48%) had diabetes mellitus, and these patients tended to have higher concentrations of ferritin, alanine aminotransferase and γ-glutamyl transferase. Osteoporosis (T-score <-2·5 SD) was observed in 48% of patients. The reduction in BMD was more pronounced in the lumbar spine than in the total hip. The patients with osteoporosis were accompanied by hypogonadism, which predominantly affected the trabecular bone.

CONCLUSIONS

Our observations suggest that endocrinopathies are common in transfusion-associated haemochromatosis.