Ethnic Differences in Iron Status

Global, regional and national burden of dietary iron deficiency from 1990 to 2021: a Global Burden of Disease study

Although iron deficiency is well documented, less is known about dietary involvement in symptomatic iron deficiency manifesting in medical conditions. In this study, we quantified the global burden of dietary iron deficiency, focusing on where inadequate dietary iron intake leads to clinical manifestations such as anemia. We analyzed data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 to estimate dietary iron deficiency prevalence and disability-adjusted life years (DALYs), stratified by age, sex, geography and socio-demographic index (SDI) across 204 countries. In 2021, global age-standardized prevalence and DALY rates were 16,434.4 (95% uncertainty interval (UI), 16,186.2-16,689.0) and 423.7 (285.3-610.8) per 100,000 population, with rates decreasing by 9.8% (8.1-11.3) and 18.2% (15.4-21.1) from 1990 to 2021. A higher burden was observed in female individual (age-standardized prevalence, 21,334.8 (95% UI, 20,984.8-21,697.4); DALYs, 598.0 (402.6-854.4)) than in male individual ((age-standardized prevalence, 11,684.7 (11,374.6-12,008.8); DALYs, 253.0 (167.3-371.0)). High-SDI countries presented greater improvement, with a 25.7% reduction compared to 11.5% in low-SDI countries. Despite global improvements, dietary iron deficiency remains a major health concern with a global prevalence of 16.7%, particularly affecting female individuals, children and residents in low-SDI countries. Urgent interventions through supplementation, food security measures and fortification initiatives are essential.

Association Between Race and Blood Ferritin Level of Whole Blood Donors

BACKGROUND

 Ferritin serves as a key marker of iron stores, and its levels are influenced by genetic, dietary, and physiological factors. However, racial disparities in ferritin levels among whole blood donors remain underexplored, despite their potential impact on donor health and transfusion practices. This study investigates racial differences in ferritin levels among whole blood donors at a single high-volume center to assess potential disparities and their implications for donor management.

METHODS

 A retrospective cross-sectional analysis was conducted on 26,130 whole blood donors from 2018 to 2021. Donor demographic data, including self-reported race and sex, were extracted from a centralized database. Serum ferritin levels were measured using a chemiluminescent immunoassay, and statistical comparisons were performed using Welch's t-test and ANOVA, with a significance threshold of p < 0.05.

RESULTS

 Significant racial disparities in ferritin levels were observed. Caucasian donors exhibited the lowest ferritin levels, while Asian donors had the highest levels. African American donors displayed relatively lower ferritin levels than expected based on prior literature. Across all racial groups, males had significantly higher ferritin levels than females (p < 0.05).

CONCLUSION

 Racial disparities in ferritin levels suggest the need for race-conscious donor health strategies, including potential pre-donation ferritin screening and tailored donation intervals to mitigate iron depletion risks. Further research is warranted to assess the impact of donation frequency on these disparities.

Characterization of iron status biomarkers and hematological indices among young adults of East Asian or Northern European ancestry: A cross-sectional analysis from the Iron Genes in East Asian and Northern European Adults Study (FeGenes)

BACKGROUND

Excess body iron (Fe) accrual is linked to chronic diseases. East Asian (EA) adults (median age 50 y) were reported to have higher Fe stores compared to other populations despite lacking the mutation that causes Fe overload in Northern European (NE) adults. It is unknown if these differences are evident in a healthy population under 50 y of age.

OBJECTIVES

This cross-sectional study aims to compare Fe-related markers in young adults of EA and NE ancestry and identify determinants of Fe status.

METHODS

Participants were healthy United States males and premenopausal/nonpregnant females of genetically confirmed EA (n = 251) or NE (n = 253) ancestry, aged 18-50 y and without obesity. A complete blood count was obtained. Serum ferritin (SF; μg/L), c-reactive protein, and interleukin-6 were measured by immunoassay, and serum soluble transferrin receptor (mg/L) and transferrin by quantitative immunoturbidimetry. Total body Fe (mg/kg) was calculated. Elevated Fe stores were defined as SF >200 (females) or >300 (males) and c-reactive protein <5 mg/L. Results are shown as the geometric mean 95% confidence interval (CI) or mean ± standard deviation.

RESULTS

The mean age of the population was (26.3 y; 25.6, 26.9 y), with 69.2% of participants aged under 30 y. SF was higher in EA (172; 152, 194) compared with NE (85.3; 76.8, 94.8) males (P < 0.001), and in EA (42.6; 36.7, 49.5) compared with NE (31.9; 27.8, 36.5) females (P = 0.004). The prevalence of elevated Fe stores was 16.7% in EA compared with 0.8% in NE males (P < 0.001) and 1.6% in EA compared with 0% in NE females (P = 0.47). Total body Fe was higher in EA (11.7 ± 2.7) compared with NE (9.1 ± 2.6) males (P < 0.001) and in EA (6.7 ± 3.6) compared with NE (5.6 ± 3.4) females (P = 0.01). All differences persisted after adjustment for confounders (all P < 0.05).

CONCLUSIONS

Individuals of EA ancestry had a significantly greater body Fe burden compared to NE individuals. Of concern, these differences were evident in a cohort primarily consisting of young individuals aged 18-29 y. This trial was registered at clinicaltrials.gov as NCT04198545.

Differences in nonheme iron absorption between healthy adults of East Asian or Northern European ancestry from the Iron Genes in East Asian and Northern European Adults Study (FeGenes): A cross-sectional stable iron isotope study

BACKGROUND

Because humans lack mechanisms for excreting excess iron (Fe), dietary Fe absorption must be tightly regulated to ensure optimal Fe levels. We previously showed that East Asian (EA) individuals have higher Fe stores compared with Northern European (NE) individuals, but the physiological basis for this difference is unknown.

OBJECTIVES

Our aim is to compare nonheme Fe absorption and its regulation in healthy participants of genetically confirmed EA or NE ancestry.

METHODS

Participants of this cross-sectional study were males and premenopausal, nonpregnant females of EA (n = 253) or NE (n = 251) ancestry, aged 18-50 y, and without obesity. Participants ingested a stable 57Fe isotope as a FeSO4 solution mixed with syrup. Percent Fe absorption was calculated based on erythrocyte 57Fe enrichment 2 wk postdosing measured using magnetic sector thermal ionization mass spectrometry and normalized to a fixed serum ferritin (SF) level. Fe status traits (SF, soluble transferrin receptor, total body Fe), hormones (hepcidin, erythropoietin, erythroferrone), and inflammatory markers were evaluated.

RESULTS

SF-corrected % Fe absorption was higher in EA females [27.4 (95% confidence interval (CI): 23.4, 32.0)] and males [19.8 (95% CI: 14.9, 26.4)] compared with NE females [14.8 (95% CI: 11.8, 18.2)] and males [14.9 (95% CI: 11.8, 18.9)], respectively (both P < 0.001). Percent Fe absorption was consistently associated with hepcidin in EA males [β = -0.64; standard error (SE) = 0.24; P = 0.008] and females (β = -0.61; SE = 0.12; P < 0.001), and in NE males (β = -0.63; SE = 0.22; P = 0.005) and females (β = -0.71; SE = 0.14; P < 0.001). Percent Fe absorption was linearly associated with SF in EA females (β = -0.57; SE = 0.09; P < 0.001) and NE males (β = -0.73; SE = 0.21; P < 0.001) and females (β = -0.68; SE = 0.12; P < 0.001), but in EA males, a U-shaped relationship was observed (P = 0.003).

CONCLUSIONS

EA individuals have a greater SF-corrected Fe absorption compared with NE individuals. Increased Fe absorption and resulting excess Fe accumulation suggests that EA individuals may be at greater risk of Fe overload-related diseases. Further studies are needed to evaluate the long-term implications of these findings. This trial was registered at clinicaltrials.gov as NCT04198545.

Iron regulatory hormones and their associations with iron status biomarkers among healthy adults of East Asian or Northern European ancestry: A cross-sectional comparison from the Iron Genes in East Asian and Northern European Adults Study (FeGenes)

BACKGROUND

Individuals of East Asian (EA) ancestry have greater risk of elevated iron (Fe) stores compared with individuals of Northern European (NE) ancestry, but no studies have assessed differences in Fe regulatory hormones between these populations.

OBJECTIVES

This study aimed to evaluate hepcidin, erythropoietin, and erythroferrone as a function of ancestry and examine their associations with Fe status markers in United States adults of genetically confirmed EA or NE ancestry.

METHODS

Participants in this cross-sectional study were healthy EA (n = 251) or NE (n = 253) males and premenopausal, nonpregnant females, aged 18-50 y, and without obesity. Serum hepcidin, erythropoietin, and erythroferrone concentrations were measured using ELISAs. Fe status [serum ferritin (SF), soluble transferrin receptor, total body iron, and transferrin], hematologic (complete blood count), and inflammatory (C-reactive protein and IL-6) markers were measured. Results are shown as the geometric mean (95% CI).

RESULTS

Hepcidin (ng/mL) was significantly higher in EA (43.9; 95% CI: 39.6, 48.7) compared with NE (31.3; 95% CI: 28.4, 34.5) males (P < 0.001) but did not differ between EA (21.8; 95% CI: 19.4, 24.6) and NE (21.3; 95% CI: 19.0, 23.8) females (P = 0.66). Interestingly, the hepcidin:SF ratio was lower in EA males (0.26; 95% CI: 0.23, 0.28) and females (0.51; 95% CI: 0.46, 0.57) compared with NE males (0.37; 95% CI: 0.33, 0.40; P < 0.001) and females (0.65; 95% CI: 0.57, 0.73; P = 0.01), respectively. These differences remained significant after adjustment for C-reactive protein (males: P-adjusted < 0.001; females: P-adjusted = 0.008) or IL-6 (males: P-adjusted < 0.001; females: P-adjusted = 0.006). Erythropoietin did not differ between ancestry groups in males (P = 0.11) or females (P = 0.96). Lastly, erythroferrone (ng/mL) was higher in EA (1.3; 95% CI: 0.8, 1.9) compared with NE (0.6; 95% CI: 0.4, 0.9; P = 0.009) males but did not differ between females (EA: 0.7; 95% CI: 0.5, 1.1; NE: 0.5; 95% CI: 0.3, 0.7; P = 0.11).

CONCLUSIONS

A lower hepcidin:SF ratio in EA compared with NE participants suggests that among EAs, hepcidin concentrations are lower relative to the load of Fe present. Further studies are needed to elucidate the mechanisms underlying the observed differences. This study was registered at clinicaltrials.gov as NCT04198545.

The Interplay Between Vitamin D Deficiency, Iron Status, and Anemia Risk in Moroccan Women of Reproductive Age: A Cross-Sectional Analysis

Background: Vitamin D and iron deficiencies are prevalent among Moroccan women of reproductive age (WRA). Research suggests that Vitamin D deficiency (VDD) may impair iron bioavailability, potentially leading to iron deficiency (ID) and anemia. Objectives: This study investigates associations between vitamin D status, iron levels, and anemia risk in WRA, aged 18-49, from Meknes, Morocco. Methods: A cross-sectional study was conducted among 463 participants, measuring serum 25(OH)D, blood count parameters, iron, ferritin, C-reactive protein, and creatinine. Lifestyle factors, including dietary intake, sun exposure, and physical activity, were assessed through validated questionnaires, and anthropometric data were collected. Linear and logistic regression models analyzed associations, while ROC analysis evaluated VDD's predictive accuracy for ID and anemia. Results: VDD (25(OH)D < 20 ng/mL) was significantly associated with reduced hemoglobin, hematocrit, red blood cells, and ferritin (all p < 0.01), indicating vitamin D's role in erythropoiesis and iron storage. Multivariate logistic regression showed that VDD increased the risk of anemia (OR: 7.17, 95% CI: 3.19-19.28, p < 0.001), ID (OR: 2.20, 95% CI: 1.32-3.77, p = 0.007), and IDA (OR: 4.10, 95% CI: 1.73-12.08, p = 0.004). Dietary iron intake was inadequate, showing minimal protective effects against anemia and ID (β(SE): -0.08(0.03), p = 0.030 and β(SE): -0.05(0.02), p = 0.037). Conclusions: VDD is a significant risk factor for impaired iron status and anemia in Moroccan WRA, highlighting the need for targeted nutritional interventions and further research.

Evaluating utility of routine ferritin testing in blood donors: A hospital-based blood donor centre experience

BACKGROUND AND OBJECTIVES

Iron deficiency (ID) poses a prevalent concern among blood donors, especially impacting young donors, premenopausal females and frequent donors. In alignment with recommendations to address ID, routine ferritin testing was implemented in a hospital-based donor centre.

MATERIALS AND METHODS

Data set, encompassing 26 164 ferritin values from 16 464 blood donors over 33 months, were analysed retrospectively. Ferritin levels were assessed concerning donor characteristics such as sex, age, ethnicity and donation frequency.

RESULTS

Ferritin testing revealed age, sex and ethnicity variations, emphasising the heightened risk of ID in young females meeting all donation criteria under 23 year of age who demonstrated the lowest mean baseline ferritin (41% [CI: 34%-48%] < 26 ng/mL; 20% [CI: 14%-25%] < 15 ng/mL). Postmenopausal females exhibited ferritin levels similar to similarly aged males. Irrespective of sex, donors showcased mean ferritin recovery within 6 months. Analysis of ferritin recovery post-donation showed a five-fold increase in risk (compared with first visit) of ID when donors return at a 2-month interval. 'Regular' donors (≥10 visits) approach a median steady ferritin level (~30-35 ng/mL) by the sixth visit.

CONCLUSION

As reliance on regular blood donors increases, donation policies must strike a balance between blood centre resources and the risks posed to both regular and at-risk donors. Frequent blood donation led to donors attaining a mean steady state ferritin level above the threshold for ID. At-risk groups, particularly premenopausal females, were several times more likely to experience ID after donation but demonstrated recovery rates similar to their group's baseline levels. This valuable information informed the development of new donor deferral policies.

The association between transferrin saturation and all-cause mortality in chronic kidney disease: findings from Korean Cohort Study for Outcome in Patients with Chronic Kidney Disease

BACKGROUND

Transferrin saturation (TSAT) has been used as an indicator of iron deficiency. However, there is no consensus regarding its optimal range for patient with chronic kidney disease (CKD). We aimed to analyze the effect of TSAT on the prognosis of patients with non-dialysis CKD (NDCKD).

METHODS

From 2011 to 2016, 2157 NDCKD patients with baseline TSAT measurements were followed for 10 years. Patients were divided into three groups based on baseline TSAT values: <25%, ≥25% and <45%, and ≥45%. All-cause mortality and 4-point major adverse cardiovascular events (MACE) were analyzed using multivariable Cox regression analysis. Other iron biomarkers and mortality were also analyzed.

RESULTS

During a mean follow-up of 7.1 ± 2.9 years, 182 of a total of 2,157 patients (8.4%) died. Compared with the TSAT ≥25% and <45% group, the TSAT <25% group showed significantly increased all-cause mortality (hazard ratio [HR], 1.44; 95% confidence interval (CI), 1.02-2.03; p = 0.04). The occurrence of 4-point MACE was significantly increased in univariable analysis in the TSAT <25% group (HR, 1.48; 95% CI, 1.02-2.15; p = 0.04), but it was not significant in the multivariable analysis (HR, 1.38; 95% CI, 0.89-2.15; p = 0.15). Tertile comparisons of the iron-to-log-ferritin ratio showed increased mortality in the first tertile group.

CONCLUSION

TSAT <25% is an independent risk factor for all-cause mortality in patients with NDCKD and care should be taken to prevent TSAT values of <25%. Other indicators, such as serum iron and iron-to-log-ferritin ratio, may also be used to assess iron deficiency.

Serum Iron Status and Retinal Degenerative Diseases: A Mendelian Randomization Study on AMD, RP, and DR

Background: Observational studies have noted that patients with certain retinal degenerative diseases exhibit iron disturbances in the retina or vitreous compared to healthy controls. However, the connection between serum iron status and these diseases remains unclear. This study aims to explore the potential causal relationship between serum iron status biomarkers and the development of age-related macular degeneration (AMD), retinitis pigmentosa (RP), and diabetic retinopathy (DR). Methods: A two-sample Mendelian randomization (MR) analysis was conducted to investigate the causal relationship between serum iron status and several retinal degenerative diseases. Genome-wide association study (GWAS) summary-level data were extracted from public GWAS databases. Inverse-variance weighting (IVW), MR-Egger regressions, Simple model, Weighted median, and Weight mode were used as MR methods. Sensitivity analysis was conducted to confirm the robustness of the results by examining horizontal pleiotropy and heterogeneity through MR-Egger intercept and leave-one-out analysis. Results: The MR analysis revealed causal relationships between genetically predicted serum iron status biomarkers and various retinal diseases. Transferrin was positively associated with the odds of AMD (whether dry or wet) (OR = 1.167, 95% CI = 1.045-1.304, p = 0.006) and wet AMD (OR = 1.194, 95% CI = 1.018-1.402, p = 0.030). Ferritin was negatively associated with the odds of wet AMD (OR = 0.555, 95% CI = 0.333-0.927, p = 0.024). Serum iron (OR = 0.508, 95% CI = 0.260-0.993, p = 0.048) and transferrin saturation (OR = 0.508, 95% CI = 0.260-0.993, p = 0.048) were negatively associated with the odds of RP. Conclusions: These findings provide evidence supporting a potential causal relationship between serum iron status and various retinal degenerative diseases, highlighting a direction for future research into the underlying mechanisms of these diseases.

Iron Deficiency and Internalizing Symptoms Among Adolescents in the National Health and Nutrition Examination Survey

BACKGROUND

Iron Deficiency (ID) affects two billion people worldwide, predominantly adolescent girls, and may be associated with increased psychopathology. The associations between ID and symptoms of depression and anxiety in adolescents were examined using data from the National Health and Nutrition Examination Survey (NHANES), a cross-sectional survey of a nationally representative sample of non-institutionalized Americans.

METHODS

The current analysis included survey cycles where both iron-related markers and mental health-related outcomes were collected in adolescents 12 to 17 years old. Acute and serious medical conditions, acute inflammation, and abnormal birth weight led to exclusion. Linear multivariable regression analyses examined the association between ID status (defined based on the total body iron model) and (1) total Patient Health Questionnaire (PHQ-9) score, (2) one item examining anxiety severity, and (3) one item examining overall mental well-being. Covariates included age, sex, race and ethnicity, body mass index, household income, head-of-household marital status, and psychotropic medication use. Sensitivity analyses examined the robustness of the findings when ID was defined based on the ferritin model.

RESULTS

In 1990 adolescents (age [mean ± SD]: 14.5 ± 1.7 years; 85.7% females), ID with and without anemia was significantly associated with a higher PHQ-9 score in multiracial adolescents (Cohen's d = 1.09, p = 0.0005 for ID without anemia; d = 0.92, p = 0.0395 for ID with anemia). Moreover, ID with anemia was associated with more severe anxiety (d = 3.00, p = 0.0130) and worse mental well-being (d = 2.75, p = 0.0059) in multiracial adolescents. The findings remained significant after adjusting for psychotropic use and in the sensitivity analyses.

CONCLUSIONS

Iron deficiency is associated with poorer mental health in adolescents of multiracial background. Future studies should confirm these findings prospectively and examine the underlying mechanism.

Iron status in Dutch and Finnish blood donor and general populations: A cross-cohort comparison study

BACKGROUND AND OBJECTIVES

Blood donors are at risk of developing iron deficiency (ID) (ferritin <15 μg/L, World Health Organization definition). Blood services implement different strategies to mitigate this risk. Although in Finland risk group-based iron supplementation is in place, no iron supplementation is provided in the Netherlands. We aim to describe differences in ferritin levels and ID prevalence in donor and general populations in these countries.

MATERIALS AND METHODS

Six cohorts, stratified based on sex, and for women age, in the Netherlands and Finland were used to evaluate differences in ferritin levels and ID between donor populations (Donor InSight-III and FinDonor 10,000) and general populations (Prevention of Renal and Vascular End-Stage Disease [PREVEND], FinRisk 1997 and Health 2000) and newly registered Dutch donors. Multivariable logistic regression was used to quantify associations of various explanatory factors with ID.

RESULTS

In total, 13,443 Dutch and 13,933 Finnish subjects were included. Donors, except for women aged ≤50 years old in Finland, had lower median ferritin levels compared with the general population and new donors. Dutch regular blood donors had higher or similar prevalence of ID as compared with the Dutch general population, including new donors. In contrast, Finnish donors showed similar prevalence of ID compared with the general population, except for a markedly lower prevalence in ≤50-year-old women who routinely receive iron supplements when donating.

CONCLUSION

Iron status in blood donors differs from that in the general population. The Finnish blood service donor management policy, for example, iron supplementation for risk groups, seemingly protects young female blood donors from developing ID.

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.

Iron Metabolic Biomarkers and the Mortality Risk in the General Population: A Nationwide Population-Based Cohort Study

Context

Iron is an essential element in the human body and plays a critical role in many physiological and cellular processes. However, the association between iron status and the risk of all-cause or cause-specific mortality has not been well-investigated. And it is unclear whether the association between iron metabolic biomarkers and the risk of mortality differs between people with and without diabetes mellitus (DM).

Objective

This work aimed to investigate associations between iron metabolic biomarkers and all-cause and cause-specific mortality risk in the general population, and heterogeneities in the associations among population with and without DM..

Methods

A total of 29 166 adults from the National Health and Nutrition Examination Survey (NHANES) III and NHANES 1999 to 2010 were included, with linkage to the National Death Index to December 31, 2019. Cox proportional-hazard models and Fine-Gray subdistribution hazard models were used to estimate associations between iron metabolic biomarkers and outcomes.

Results

During a median follow-up of 18.83 years, 9378 deaths were observed, including 3420 cardiovascular disease (CVD) deaths and 1969 cancer deaths. A significant linear association between serum ferritin (SF) and all-cause mortality was observed among the overall population and those without DM. J-shaped associations between transferrin saturation (TSAT) and all-cause and CVD mortality were observed among all populations. In the overall population, compared to the first quartile (Q1) group, the adjusted hazard ratio (HR) (95% CI) for all-cause mortality was 1.07 (1.00-1.15), 1.05 (0.98-1.12), 1.13 (1.05-1.21) in Q2, Q3, and Q4 groups for SF, while the HR was 0.94 (0.88-0.99), 0.92 (0.86-0.97), and 0.93 (0.88-0.99) for TSAT. In individuals without DM, the adjusted HR of the Q4 of SF were 1.19 (1.03-1.37) for CVD mortality and 1.25 (1.05-1.48) for cancer mortality. In individuals with DM, the adjusted HRs of the Q4 of TSAT were 0.76 (0.62-0.93) for CVD mortality and 1.47 (1.07-2.03) for cancer mortality.

Conclusion

Iron metabolism abnormalities increase mortality risk in the general population. The associations of iron status with mortality were significantly different between individuals with and without DM, which indicated tailored strategies for iron homeostasis are needed.

Iron Stress Affects the Growth and Differentiation of Toxoplasma gondii

Iron is an indispensable nutrient for the survival of Toxoplasma gondii; however, excessive amounts can lead to toxicity. The parasite must overcome the host's "nutritional immunity" barrier and compete with the host for iron. Since T. gondii can infect most nucleated cells, it encounters increased iron stress during parasitism. This study assessed the impact of iron stress, encompassing both iron depletion and iron accumulation, on the growth of T. gondii. Iron accumulation disrupted the redox balance of T. gondii while enhancing the parasite's ability to adhere in high-iron environments. Conversely, iron depletion promoted the differentiation of tachyzoites into bradyzoites. Proteomic analysis further revealed proteins affected by iron depletion and identified the involvement of phosphotyrosyl phosphatase activator proteins in bradyzoite formation.

Serum ferritin/C-reactive protein ratio is a simple and effective biomarker for diagnosing iron deficiency in the context of systemic inflammation

BACKGROUND

Diagnosing iron deficiency is challenging in the presence of systemic inflammation.

AIM

To investigate the relationship between plasma C-reactive protein (CRP), serum ferritin (SF) and transferrin saturation (TS), with the objective of establishing a straightforward ratio applicable in the presence of inflammatory syndrome.

DESIGN

Test prospective cohort and validation retrospective cohort.

METHODS

A prospective cohort of inpatients (n = 140) assessed the correlation between CRP and SF/TS levels. The diagnostic performance of a determined ratio was evaluated for identifying iron deficiency (ID) using different definitions and in the presence of inflammation and/or chronic heart and/or kidney failure. A large validation cohort (n = 795) further assessed the predictive power of this ratio.

RESULTS

In a training cohort (median age 76 years [57-84]), a linear relation was observed between SF (µg/l) and CRP (mg/l), unlike with TS. The SF/CRP ratio accurately predicted ID, with receiver operating characteristic-area under the curve (ROC-AUC) values ranging from 0.85 to 0.92 for different ID definitions. A threshold of ≤6 demonstrated the highest Youden index (0.61). In the validation cohort (age 72 years [57-84]), the SF/CRP ratio exhibited an ROC-AUC of 0.88 [95% CI: 0.85-0.90], with an odds ratio of 37.9 [95% CI: 20.3-68.9] for the threshold of ≤6.

CONCLUSION

In this study, we demonstrated that the SF/CRP ratio, with a threshold of ≤6, is a simple and effective biomarker for ID, even in the presence of systemic inflammation or comorbidities. This ratio could potentially replace the complex set of criteria currently recommended by learned societies.

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.

Cohort-Based Reference Values for Serum Ferritin and Transferrin and Longitudinal Determinants of Iron Status in European Children Aged 3-15 Years

BACKGROUND

Reference values of ferritin and transferrin for European children do not exist.

OBJECTIVE

We aimed to provide sex-, age-, and body mass index (BMI)-specific serum ferritin and transferrin reference percentiles of 3-15-y-old children based on cohort data and to investigate determinants of iron status.

METHODS

A total of 3390 ferritin and 3416 transferrin measurements from children residing in 8 European countries participating in the IDEFICS/I.Family cohort (https://www.isrctn.com/ISRCTN62310987) at baseline (W0) and 6 y later (W3) were used to estimate percentiles using the generalized additive model for location, scale and shape. Associations of serum ferritin and transferrin concentrations with total iron intake, total iron intake additionally adjusted for vitamin C intake, and iron from heme sources were investigated separately with adjustment for sex, age, country of residence, parental education, usual energy intake and BMI z-score in regression models using cross-sectional and longitudinal data.

RESULTS

The age-specific ferritin and transferrin 5th and 95th reference percentiles ranged from 10.9 to 81.1 μg/L and 2.23 to 3.56 g/L, respectively. A deficient iron status was observed in 3% of children at W0 and 7% of children and adolescents at W3, respectively. At both waves, a higher iron intake from heme sources was positively associated with serum ferritin {W0: β = 3.21 [95% confidence interval (CI): 0.71, 5.71]; W3: β = 4.48 [95% CI: 2.09, 6.87]}, that is, children consuming one mg more heme iron had a 3.21 and 4.48 μg/L higher ferritin concentration. Adherence to a mainly vegetarian diet was associated with a lower chance for sufficient serum ferritin cross-sectionally at W3 [odds ratio (OR) 0.40 (95% CI: 0.21, 0.81)] and longitudinally [OR 0.35 (95% CI: 0.15, 0.93)].

CONCLUSIONS

Age-, sex-, and BMI-specific reference percentiles of serum ferritin and transferrin concentrations based on cohort data are provided for European children aged 3-15 y and may be used in clinical practice.

Associations of Serum Iron Status with MAFLD and Liver Fibrosis in the USA: a Nationwide Cross-Section Study

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a new terminology characterized by liver steatosis. Iron status is related to many metabolic diseases. However, the researches on the associations of serum iron status with MAFLD are limited. The objective of this study was to investigate the associations of serum iron status biomarkers with MAFLD and liver fibrosis. A total of 5892 adults were enrolled in the current cross-sectional study using the 2017-March 2020 National Health and Nutrition Examination Survey. Liver steatosis and liver fibrosis were defined by the median values of controlled attenuation parameter ≥ 274 dB/m and liver stiffness measurement ≥ 8 kPa, respectively. The multivariable logistic/linear regression and restricted cubic spline analysis were conducted. After adjusting for potential confounders, higher ferritin levels were associated with higher odds of MAFLD (OR 4.655; 95% CI 2.301, 9.418) and liver fibrosis (OR 7.013; 95% CI 3.910, 12.577). Lower iron levels were associated with a higher prevalence of MAFLD (OR 0.622; 95% CI 0.458, 0.844) and liver fibrosis (OR 0.722; 95% CI 0.536, 0.974). Lower transferrin saturation (TSAT) was associated with a higher prevalence of MAFLD (OR 0.981; 95% CI 0.970, 0.991) and liver fibrosis (OR 0.988; 95% CI 0.979, 0.998). Higher ferritin levels, lower iron levels, and TSAT were associated with a higher prevalence of MAFLD and liver fibrosis. This study extended the knowledge of modifying iron status to prevent MAFLD and liver fibrosis. More prospective and mechanism studies were warranted to confirm the conclusions.

Metformin alleviates hepatic iron overload and ferroptosis through AMPK-ferroportin pathway in HFD-induced NAFLD

Metformin prevents progression of non-alcoholic fatty liver disease (NAFLD). However, the potential mechanism is not entirely understood. Ferroptosis, a recently recognized nonapoptotic form of regulated cell death, has been reported to be involved in the pathogenesis of NAFLD. Here, we investigated the effects of metformin on ferroptosis and its potential mechanism in NAFLD. We found that metformin prevented the progression of NAFLD, and alleviated hepatic iron overload (HIO), ferroptosis and upregulated ferroportin (FPN) expression in vivo and in vitro. Mechanically, metformin reduced the lysosomal degradation pathway of FPN through activation AMPK, thus upregulated the expression of FPN protein, alleviated HIO and ferroptosis, and prevented progression of NAFLD. These findings discover a mechanism of metformin, suggesting that targeting FPN may have the therapeutic potential for treating NAFLD and related disorders.

Excess adiposity and iron-deficient status in Colombian women of reproductive age

OBJECTIVE

Information about excess adiposity markers different from BMI and iron status is limited and more so about the shape of these associations. This study evaluated the relationship between three adiposity markers and iron-deficient status in reproductive-age women.

METHODS

Cross-sectional analysis in 6357 non-pregnant women from the Colombian nutritional health survey (ENSIN) 2010. Exposures were the following: waist circumference (WC), waist-to-height ratio (W-HtR), BMI, and WC > 80 cm, W-HtR > 0.5, and BMI ≥ 25 and ≥30. Outcomes were the following: iron deficiency (ID) as serum ferritin <15 μg/L, ID as ferritin <30 μg/L, anemia, and continuous values of ferritin and hemoglobin. Logistic and linear regressions adjusted for sociodemographic/inflammation covariates were conducted.

RESULTS

All the adiposity markers, continuous or categorical, were inversely and significantly associated with both ID thresholds in fully adjusted models (p < 0.05). W-HtR reported stronger effect estimates for ID (odds ratios < 0.5) and for prediction of log-ferritin levels (fully adjusted β-coefficient [95% CI] 0.61 [0.39-0.82], p < 0.01) and was also inversely associated with anemia (p < 0.05). In cubic splines analyses, W-HtR, WC, and BMI were linearly associated with ID from values closer to international thresholds of general or central obesity, and the patterns of WC and BMI tended toward flatness. A significant decline in the likelihood of anemia was steeper by increasing W-HtR than by increasing BMI. After exclusion of women with C reactive protein >  5 mg/L or adjustment for C reactive protein, adiposity markers remained significantly related to ferritin levels and W-HtR with anemia.

CONCLUSIONS

Women with higher adiposity were less likely to have an iron-deficient status. W-HtR was the strongest and most consistently associated marker. Inflammation would not be involved in the associations found.

Empagliflozin effects on iron metabolism as a possible mechanism for improved clinical outcomes in non-diabetic patients with systolic heart failure

Sodium-glucose co-transporter-2 (SGLT2) inhibitors improve clinical outcomes in patients with heart failure (HF), but mechanisms of action are incompletely understood. In the EMPA-TROPISM trial, empagliflozin reversed cardiac remodeling and increased physical capacity in stable non-diabetic patients with systolic HF. Here we explore, post hoc, whether treatment effects in this cohort, comprising patients who had a high prevalence of iron deficiency, were related to iron metabolism. Myocardial iron content estimated by cardiac magnetic resonance T2* quantification increased after initiation of empagliflozin but not placebo (treatment effect: P = 0.01). T2* changes significantly correlated with changes in left ventricular volumes, mass and ejection fraction, peak oxygen consumption and 6-minute walking distance; concomitant changes in red blood cell indices were consistent with augmented hematopoiesis. Exploratory causal mediation analysis findings indicated that changes in myocardial iron content after treatment with empagliflozin may be an important mechanism to explain its beneficial clinical effects in patients with HF.ClinicalTrials.gov: NCT03485222 .

Cardiovascular Manifestations of Hemochromatosis: A Review of Pathophysiology, Mechanisms, and Treatment Options

Hemochromatosis is a genetic disorder characterized by excessive absorption and accumulation of iron in the body. It is one of the most common inherited disorders. The excess iron deposition can cause damage to various organs, including the liver, heart, pancreas, and joints. If left untreated, hemochromatosis can lead to serious complications such as cirrhosis, diabetes, heart failure, and increased risk of certain cancers. Iron overload in hemochromatosis significantly affects the cardiovascular system, leading to morbidity and mortality. This article reviews the current literature describing the pathogenesis and various cardiovascular manifestations of hemochromatosis, including dilated cardiomyopathy, conduction abnormalities, heart failure, cardiac fibrosis, myocardial infarction, and valvular heart disease. This article aims to provide a detailed understanding of the cardiovascular manifestations associated with hemochromatosis and their underlying mechanisms through a review of current literature in publicly available databases.

Association between iron status markers and kidney outcome in patients with chronic kidney disease

Several studies conducted in patients with various stages of chronic kidney disease (CKD) have investigated the association of iron status markers, such as transferrin saturation (TSAT) and serum ferritin, with kidney outcomes. However, the associations were inconsistent and remain strongly debated. Therefore, we aimed to investigate whether TSAT and serum ferritin levels were associated with kidney outcome in such a population. In this study, 890 patients who were admitted for the evaluation of and education for CKD were prospectively followed. Primary kidney outcome was a composite of doubling of serum creatinine, end-stage kidney disease, or death due to kidney failure. Participants were divided into quartiles (Q1-Q4) according to TSAT or serum ferritin levels. During a median follow-up period of 2.8 years, kidney events occurred in 358 patients. In the multivariable Cox analyses, compared with Q3 of TSAT, the hazard ratios (95% confidence intervals) for Q1, Q2, and Q4 were 1.20 (0.87, 1.66), 1.38 (1.01, 1.87), and 1.14 (0.82, 1.59), respectively. Compared with Q2 of serum ferritin, lower and higher quartiles had a significantly increased risk for kidney outcome; hazard ratios (95% confidence intervals) for Q1, Q3, and Q4 were 1.64 (1.18, 2.27), 1.71 (1.24, 2.37), and 1.52 (1.10, 2.10), respectively. A Fine-Gray model with death before kidney events as a competing risk showed results similar to the above. In CKD, lower and higher ferritin levels were independent risk factors for kidney disease progression.

Hemoglobin distributions and prevalence of anemia in a multiethnic United States pregnant population

BACKGROUND

Few normative longitudinal hemoglobin data are available to estimate the prevalence and risk factors for anemia among a multiethnic United States pregnant population.

OBJECTIVES

The aim of this study was to characterize hemoglobin distributions and prevalence of anemia in a pregnant population receiving care at a large urban medical center.

METHODS

A retrospective medical chart review was undertaken in 41,226 uncomplicated pregnancies of 30,603 pregnant individuals who received prenatal care between 2011 and 2020. Mean hemoglobin concentrations and anemia prevalence in each trimester and incidence of anemia during pregnancy in a subset of 4821 women with data in each trimester were evaluated in relation to self-reported race and ethnicity and other possible risk factors. Risk ratios (RRs) of anemia were determined using generalized linear mixed-effects models. Smoothed curves describing changes in hemoglobin across pregnancy were created using generalized additive models.

RESULTS

The overall prevalence of anemia was 26.7%. The observed fifth percentiles of the hemoglobin distributions were significantly lower than the United States CDC anemia cutoffs in the second and third trimesters (T3). The RR (95% CI) of anemia were 3.23 (3.03, 3.45), 6.18 (5.09, 7.52), and 2.59 (2.48, 2.70) times higher in Black women than that in White women in each trimester, respectively. Asian women recorded the lowest risk of anemia compared with other racial groups in T3 (compared with White womenRR: 0.84; 95% CI: 0.74, 0.96). Hispanic women presented a higher risk of anemia in T3 than non-Hispanic women (RR: 1.36; 95% CI: 1.28, 1.45). In addition, adolescents, individuals with higher parity, and those carrying multiple fetuses experienced a higher risk of developing anemia in late gestation.

CONCLUSIONS

Anemia was evident in more than one-quarter of a multiethnic United States pregnant population despite current universal prenatal iron supplementation recommendations. Prevalence of anemia was higher among Black women and lowest among Asian and White women.

Diagnosing anemia: Challenges selecting methods, addressing underlying causes, and implementing actions at the public health level

Accurate and affordable tools for diagnosing anemia and its main determinants are essential for understanding the magnitude and distribution of the problem and the appropriate interventions needed for its timely prevention and treatment. The objective of this review is to address methods, equipment, and sample-related and quality control aspects of hemoglobin measurement for anemia diagnosis. Also, other iron-, infectious-, and genetic-related causes of anemia are addressed in individuals and populations. The best practice for hemoglobin determination is the use of venous blood, analyzed on automated hematology analyzers, with high-quality control measures in place. The importance of a correct anemia diagnosis is highlighted by the cost of a misdiagnosis. A false-negative diagnosis may result in missing out and not treating anemia, its causes, and its adverse effects. On the other hand, a false-positive diagnosis may result in the provision of unneeded treatment or referral for expensive laboratory tests to determine a cause of anemia, wasting valuable resources and risking causing harm. At the individual level, clinicians must understand the causes of absolute and functional anemia to diagnose and treat anemia at the clinical level. Actions toward anemia diagnosis and control at public health levels require global, regional, and country actions that should cover general and context-specific characteristics.

Ancient DNA suggests anaemia and low bone mineral density as the cause for porotic hyperostosis in ancient individuals

Porotic hyperostosis (PH) is a disease that had high prevalence during the Neolithic. Several hypotheses have been suggested to explain the origin of the disease, such as an iron deficiency diet, low B12 intake, malaria caused by Plasmodium spp., low haemoglobin levels or low vitamin D levels. None of these hypotheses have been tested genetically. Here, I calculated different genetic scores to test each hypothesis. Additionally, I calculated a genetic score of bone mineral density as it is a phenotype that seems to be selected in ancient Europeans. I apply these genetic scores on 80 ancient samples, 33 with diagnosed PH. The results seem to suggest anaemia and low bone mineral density as the main cause for this disease. Additionally, Neolithic individuals show the lowest genetic risk score for bone mineral density of all other periods tested here, which may explain the highest prevalence of the porotic hyperostosis during this age.

Relevant Membrane Transport Proteins as Possible Gatekeepers for Effective Pharmacological Ascorbate Treatment in Cancer

Despite the increasing number of newly diagnosed malignancies worldwide, therapeutic options for some tumor diseases are unfortunately still limited. Interestingly, preclinical but also some clinical data suggest that the administration of pharmacological ascorbate seems to respond well, especially in some aggressively growing tumor entities. The membrane transport and channel proteins are highly relevant for the use of pharmacological ascorbate in cancer therapy and are involved in the transfer of active substances such as ascorbate, hydrogen peroxide, and iron that predominantly must enter malignant cells to induce antiproliferative effects and especially ferroptosis. In this review, the relevant conveying proteins from cellular surfaces are presented as an integral part of the efficacy of pharmacological ascorbate, considering the already known genetic and functional features in tumor tissues. Accordingly, candidates for diagnostic markers and therapeutic targets are mentioned.

Ferritin in pediatric critical illness: a scoping review

This scoping review aimed to elucidate and summarize the predictive role of serum ferritin in critical pediatric illness. The Preferred Reporting Items for Systematic reviews and Meta-Analyses methodology was employed to conduct a scoping review of 5 databases (MEDLINE, CENTRAL, ProQuest, ScienceDirect, and Epistemonikos) from the date of inception through January 24, 2022. Primary research studies involving subjects aged <18 years and serum ferritin levels were screened and reviewed independently following an a priori defined protocol. Of the 1,580 retrieved studies, 66 were analyzed. Summary statistics of serum ferritin levels for overall and condition-specific studies were reported in 30 (45.4%) and 47 studies (71.2%), respectively. The normal range was defined in 16 studies (24.2%), whereas the threshold was determined in 43 studies (65.1%). A value of <500 ng/mL was most often the upper limit of the normal range. Serum ferritin as a numerical variable (78.9%) was usually significantly higher (80.8%) in the predicted condition than in controls, while as a categorical variable with preset thresholds, ferritin was a significant predictor in 84.6% of studies. A total of 22 predictive thresholds predicted mortality (12 of 46 [26.1%]), morbidity (18 of 46 [39.1%]), and specific (16 of 46 [34.8%]) outcomes in 15 unique conditions. Increased precision in serum ferritin measures followed by close attention to the threshold modeling strategy and reporting can accelerate the translation from evidence to clinical practice.

A New Artificial Intelligence Approach Using Extreme Learning Machine as the Potentially Effective Model to Predict and Analyze the Diagnosis of Anemia

The procedure to diagnose anemia is time-consuming and resource-intensive due to the existence of a multitude of symptoms that can be felt physically or seen visually. Anemia also has several forms, which can be distinguished based on several characteristics. It is possible to diagnose anemia through a quick, affordable, and easily accessible laboratory test known as the complete blood count (CBC), but the method cannot directly identify different kinds of anemia. Therefore, further tests are required to establish a gold standard for the type of anemia in a patient. These tests are uncommon in settings that offer healthcare on a smaller scale because they require expensive equipment. Moreover, it is also difficult to discern between beta thalassemia trait (BTT), iron deficiency anemia (IDA), hemoglobin E (HbE), and combination anemias despite the presence of multiple red blood cell (RBC) formulas and indices with differing optimal cutoff values. This is due to the existence of several varieties of anemia in individuals, making it difficult to distinguish between BTT, IDA, HbE, and combinations. Therefore, a more precise and automated prediction model is proposed to distinguish these four types to accelerate the identification process for doctors. Historical data were retrieved from the Laboratory of the Department of Clinical Pathology and Laboratory Medicine, Faculty of Medicine, Public Health, and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia for this purpose. Furthermore, the model was developed using the algorithm for the extreme learning machine (ELM). This was followed by the measurement of the performance using the confusion matrix and 190 data representing the four classes, and the results showed 99.21% accuracy, 98.44% sensitivity, 99.30% precision, and an F1 score of 98.84%.

Eligibility Considerations for Female Whole Blood Donors: Hemoglobin Levels and Iron Status in a Nationally Representative Population

Blood collection from minority populations improves the transfusion support of patients with sickle cell disease and thalassemia, but efforts are challenged by high deferral rates for hemoglobin (Hb) eligibility thresholds. This study sought to evaluate hemoglobin and iron status of a representative US female population to assess the suitability of 12.0 g/dL as minimum hemoglobin. Data were extracted from the National Health and Nutrition Examination Surveys (NHANES), 1999-2010. A national sample designed to reflect potential female blood donors (weight ≥110 lbs, not pregnant, no infectious marker reactivity, and no blood donation in past year) aged 16 to 49 years was analyzed for Hb and serum ferritin (SF) measures by race/ethnicity (N = 6937). Mean Hb and SF and the prevalence of iron deficiency ([ID] SF<12 ng/mL and SF<26 ng/mL) and low Hb (<12.5 g/dL and <12.0 g/dL) were estimated. Multivariable modified Poisson regression compared the prevalence for ID or low Hb at each cutoff by race/ethnicity. Mean SF values were higher and ID prevalence was lower in Non-Hispanic (NH) White (SF = 45.3 ng/mL, SF<12 ng/mL = 8.2%) than NH Black (SF = 39.6 ng/mL, SF<12 ng/mL = 14.2%) and Hispanic (SF = 36.5 ng/mL, SF<12 ng/mL = 12.7%) females. Compared to NH White females (13.7 g/dL), mean Hb was lower in NH Black (12.6 g/dL) and Hispanic females (13.4 g/dL). The percentage with Hb<12.5 g/dL was >4 times greater in NH Black (39.1%) and >2 times greater in Hispanic females (16.5%) compared to NH White (8.6%). Within 0.5 g/dL incremental categories of Hb, NH Black had higher mean SF levels and lower prevalence of SF<12 ng/mL or <26 ng/mL compared to NH White and Hispanic females. At Hb of 12.0 to 12.4g/dL, NH Black females had better measures of iron status (SF = 39.1 ng/mL, %SF<12 ng/mL = 12.0%) than NH White (SF = 33.6 ng/mL, %SF<12 ng/mL=15.8%) and Hispanic (SF = 30.4 ng/mL, %SF<12 ng/mL=15.5%) females whose Hb was 12.5 to 12.9 g/dL. Adjusting for age and Hb, the prevalence ratio for low SF was significantly lower in NH Black compared to NH White females at both SF<26 ng/mL (adjusted prevalence ratio [aPR] = 0.83, 95%CI = 0.76-0.92) and SF<12 ng/mL (aPR = 0.66, 95%CI = 0.52-0.83). NH Black females with Hb 12.0 to 12.4g/dL have better iron stores than NH White and Hispanic females whose Hb is 12.5 to 12.9 g/dL. The distribution of Hb and iron may support the safe collection of blood for female donors below the current Hb eligibility requirement of 12.5 g/dL.

Association of ferritin and transferrin saturation with all-cause mortality, and the effect of concurrent inflammation: a danish cohort study

The association between ferritin and transferrin saturation (TS), respectively, and all-cause mortality is unclear. Furthermore, the influence of concurrent inflammation has not been sufficiently elucidated. We investigated these associations and the effect of concurrently elevated C-reactive protein (CRP), and accordingly report the levels associated with lowest all-cause mortality for females and males with and without inflammation.Blood test results from 161,921 individuals were included. Statistical analyses were performed in sex-stratified subpopulations, with ferritin or TS level as continuous exposure variables, and were adjusted for age, co-morbidity and inflammation status using CRP. An interaction was used to investigate whether the effect of ferritin or TS on all-cause mortality was modified by inflammation status (CRP ≥ 10 mg/L or CRP < 10 mg/L). Low and high ferritin and TS levels were respectively associated with increased all-cause mortality in females and in males. These associations persisted with concurrent CRP ≥ 10 mg/L. The ferritin level associated with lowest mortality was 60 µg/L for females and 125 µg/L for males with CRP < 10 mg/L. It was 52 µg/L for females and 118 µg/L for males with CRP ≥ 10 mg/L. The TS level associated with lowest mortality was 33.9% for females and 32.3% for males with CRP < 10 mg/L. It was 28.7% for females and 30.6% for males with CRP ≥ 10 mg/L.Our findings can nuance clinical interpretation and further aid in defining recommended ranges for ferritin and TS.

Positive or U-Shaped Association of Elevated Hemoglobin Concentration Levels with Metabolic Syndrome and Metabolic Components: Findings from Taiwan Biobank and UK Biobank

Iron overnutrition has been implicated with a higher risk of developing metabolic and cardiovascular diseases, including metabolic syndrome (MetS), whereas iron deficiency anemia exacerbates many underlying chronic conditions. Hemoglobin (Hb) concentration in the blood, which reflects a major functional iron (i.e., heme iron) in the body, may serve as a surrogate of the nutritional status of iron. We conducted sex-specific observational association studies in which we carefully titrated the association between Hb deciles and MetS and its components among the Taiwanese Han Chinese (HC) from the Taiwan Biobank and Europeans of White ancestry from the UK Biobank, representing two large ethnicities. Our data show that at higher-than-normal levels of Hb, increasing deciles of Hb concentration were significantly associated with MetS across all sex subgroups in both ethnicities, with the highest deciles resulting in up to three times greater risk than the reference group [Taiwanese HC: OR = 3.17 (95% CI, 2.75-3.67) for Hb ≥ 16.5 g/dL in men, OR = 3.11 (2.78-3.47) for Hb ≥ 14.5 g/dL in women; European Whites: OR = 1.89 (1.80-1.98) for Hb ≥ 16.24 g/dL in men, OR = 2.35 (2.24-2.47) for Hb ≥ 14.68 g/dL in women]. The association between stronger risks and increasing Hb deciles was similarly observed with all metabolic components except diabetes. Here we found that both the highest Hb decile groups and contrarily the lowest ones, with respect to the reference, were associated with higher odds of diabetes in both ethnic groups [e.g., Taiwanese HC men: OR = 1.64 (1.33-2.02) for Hb ≥ 16.5 g/dL, OR = 1.71 (1.39-2.10) for Hb ≤ 13.5 g/dL; European Whites women: OR = 1.39 (1.26-1.45) for Hb ≥ 14.68 g/dL, OR = 1.81 (1.63-2.01) for Hb ≤ 12.39 g/dL]. These findings confirm that elevated Hb concentrations, a potential indicator of iron overnutrition, may play a role in the pathophysiology of MetS and metabolic components.

Dietary Approaches to Iron Deficiency Prevention in Childhood-A Critical Public Health Issue

Iron is an essential nutrient, and individual iron status is determined by the regulation of iron absorption, which is driven by iron requirements. Iron deficiency (ID) disproportionately affects infants, children, and adolescents, particularly those who live in areas with unfavorable socioeconomic conditions. The main reason for this is that diet provides insufficient bioavailable iron to meet their needs. The consequences of ID include poor immune function and response to vaccination, and moderate ID anemia is associated with depressed neurodevelopment and impaired cognitive and academic performances. The persistently high prevalence of ID worldwide leads to the need for effective measures of ID prevention. The main strategies include the dietary diversification of foods with more bioavailable iron and/or the use of iron-fortified staple foods such as formula or cereals. However, this strategy may be limited due to its cost, especially in low-income countries where biofortification is a promising approach. Another option is iron supplementation. In terms of health policy, the choice between mass and targeted ID prevention depends on local conditions. In any case, this remains a critical public health issue in many countries that must be taken into consideration, especially in children under 5 years of age.

Estimates of West African Ancestry in African Americans Using Alleles of Iron-Related Genes HJV, SLC40A1, and TFR2

Background: Few studies have estimated African ancestry of African Americans (AA). In sub-Saharan West African (WA) Blacks, some nonancestral alleles of iron-related genes HJV, SLC40A1, and TFR2 are common, whereas in European Americans (EA) the same alleles are rare. These alleles have not been used to estimate WA Black ancestry in AA. Methods: We estimated WA Black ancestry in AA (M) using published HJV c.929C>G (rs7540883), SLC40A1 c.744G>T (rs11568350), and TFR2 c.713C>T (rs34242818) allele frequencies in WA Blacks, AA, and EA. We computed standard error (SE) and one-sided 95% confidence intervals (CI) for each M. Results: The combined representation of WA Blacks from The Gambia and Nigeria was 79-89%. Aggregate HJV, SLC40A1, and TFR2 allele frequencies in WA Blacks were 0.1025 [95% CI: 0.0835-0.1253] (n = 405), 0.0517 [0.0469-0.0569] (n = 3839), and 0.1432 [0.1202-0.1697] (n = 405), respectively. Aggregate HJV, SLC40A1, and TFR2 allele frequencies in AA were 0.0718 [0.0648-0.0797] (n = 2352), 0.0557 [0.0506-0.0613] (n = 3590), and 0.1224 [0.1132-0.1322] (n = 2352), respectively. Aggregate HJV, SLC40A1, and TFR2 allele frequencies in 4449 EA were 0.0002 [0-0.0009], 0.0003 [0.0001-0.0010], and 0.0004 [0.0001-0.0012], respectively. M (SE [one-sided 95% CI]) for HJV, SLC40A1, and TFR2 alleles was 0.7006 (0.0818 [0.5402-1.0000]), 1.0000 (0.0752 [0.9306-1.0000]), and 0.8546 (0.0810 [0.6959-1.0000]), respectively. Mean of these M is 0.8777 (87.8%). Conclusions: The mean proportional WA Black ancestry in AA of 87.8% using HJV c.929C>G, SLC40A1 c.744G>T, and TFR2 c.713C>T allele frequencies is consistent with that of previous studies that used other autosomal markers and methods.

Revisiting the malaria hypothesis: accounting for polygenicity and pleiotropy

The malaria hypothesis predicts local, balancing selection of deleterious alleles that confer strong protection from malaria. Three protective variants, recently discovered in red cell genes, are indeed more common in African than European populations. Still, up to 89% of the heritability of severe malaria is attributed to many genome-wide loci with individually small effects. Recent analyses of hundreds of genome-wide association studies (GWAS) in humans suggest that most functional, polygenic variation is pleiotropic for multiple traits. Interestingly, GWAS alleles and red cell traits associated with small reductions in malaria risk are not enriched in African populations. We propose that other selective and neutral forces, in addition to malaria prevalence, explain the global distribution of most genetic variation impacting malaria risk.

Iron Deficiency in Heart Failure: Mechanisms and Pathophysiology

Iron is an essential micronutrient for a myriad of physiological processes in the body beyond erythropoiesis. Iron deficiency (ID) is a common comorbidity in patients with heart failure (HF), with a prevalence reaching up to 59% even in non-anaemic patients. ID impairs exercise capacity, reduces the quality of life, increases hospitalisation rate and mortality risk regardless of anaemia. Intravenously correcting ID has emerged as a promising treatment in HF as it has been shown to alleviate symptoms, improve quality of life and exercise capacity and reduce hospitalisations. However, the pathophysiology of ID in HF remains poorly characterised. Recognition of ID in HF triggered more research with the aim to explain how correcting ID improves HF status as well as the underlying causes of ID in the first place. In the past few years, significant progress has been made in understanding iron homeostasis by characterising the role of the iron-regulating hormone hepcidin, the effects of ID on skeletal and cardiac myocytes, kidneys and the immune system. In this review, we summarise the current knowledge and recent advances in the pathophysiology of ID in heart failure, the deleterious systemic and cellular consequences of ID.

New Era in the Treatment of Iron Deficiency Anaemia Using Trimaltol Iron and Other Lipophilic Iron Chelator Complexes: Historical Perspectives of Discovery and Future Applications

The trimaltol iron complex (International Non-proprietary Name: ferric maltol) was originally designed, synthesised, and screened in vitro and in vivo in 1980–1981 by Kontoghiorghes G.J. following his discovery of the novel alpha-ketohydroxyheteroaromatic (KHP) class of iron chelators (1978–1981), which were intended for clinical use, including the treatment of iron deficiency anaemia (IDA). Iron deficiency anaemia is a global health problem affecting about one-third of the world’s population. Many (and different) ferrous and ferric iron complex formulations are widely available and sold worldwide over the counter for the treatment of IDA. Almost all such complexes suffer from instability in the acidic environment of the stomach and competition from other dietary molecules or drugs. Natural and synthetic lipophilic KHP chelators, including maltol, have been shown in in vitro and in vivo studies to form stable iron complexes, to transfer iron across cell membranes, and to increase iron absorption in animals. Trimaltol iron, sold as Feraccru or Accrufer, was recently approved for clinical use in IDA patients in many countries, including the USA and in EU countries, and was shown to be effective and safe, with a better therapeutic index in comparison to other iron formulations. Similar properties of increased iron absorption were also shown by lipophilic iron complexes of 8-hydroxyquinoline, tropolone, 2-hydroxy-4-methoxypyridine-1-oxide, and related analogues. The interactions of the KHP iron complexes with natural chelators, drugs, metal ions, proteins, and other molecules appear to affect the pharmacological and metabolic effects of both iron and the KHP chelators. A new era in the treatment of IDA and other possible clinical applications, such as theranostic and anticancer formulations and metal radiotracers in diagnostic medicine, are envisaged from the introduction of maltol, KHP, and similar lipophilic chelators.