Iron deficiency is associated with increased risk for cardiovascular disease and all-cause mortality in the elderly living in long-term care facilities

Association between essential metals, adherence to healthy lifestyle behavior, and ankle-brachial index

BACKGROUND

Ankle-brachial index (ABI) is a noninvasive diagnostic method for peripheral arterial disease (PAD) and a predictor of cardiovascular events.

OBJECTIVE

The present study aimed to evaluate the association between individual or combined essential metals and ABI, as well as assess the collective impact of essential metals when coupled with healthy lifestyle on ABI.

METHODS

A total of 2865 participants were recruited in Wuhan Tongji Hospital between August 2018 and March 2019. Concentrations of essential metals in urine were measured by inductively coupled plasma mass spectrometer.

RESULTS

The results of general linear regression models demonstrated that after adjusting for confounding factors, there was a positive association between ABI increase and per unit increase of log 10-transformed, creatinine-corrected urinary Cr (β (95 % CI): 0.010 (0.004, 0.016), PFDR = 0.007), Fe (β (95 % CI): 0.010 (0.003, 0.017), PFDR = 0.018), and Co (β (95 % CI): 0.013 (0.005, 0.021), PFDR = 0.007). The WQS regression revealed a positive relationship between the mixture of essential metals and ABI (β (95 % CI): 0.006 (0.003, 0.010), P < 0.001), with Cr and Co contributing most to the relationship (weighted 45.48 % and 40.14 %, respectively). Compared to individuals with unfavorable lifestyle and the lowest quartile of Cr, Fe and Co, those with favorable lifestyle and the highest quartile of Cr, Fe and Co exhibited the most increase in ABI (β (95 % CI): 0.030 (0.017, 0.044) for Cr, β (95 % CI): 0.027 (0.013, 0.040) for Fe, and β (95 % CI): 0.030 (0.016, 0.044) for Co).

CONCLUSION

In summary, our study indicates that adequate essential metal intake together with healthy lifestyle behaviors perform crucial roles in PAD protection.

Associations of iron metabolism and inflammation with all-cause and cardiovascular mortality in a large NHANES community sample: Moderating and mediating effects

BACKGROUND AND AIMS

This study aimed to assess the associations between serum iron concentration, C-reactive protein (CRP) concentration and the risk of all-cause mortality and cardiovascular mortality in the general population and to explore potential mediating and moderating effects.

METHODS AND RESULTS

This study analyzed data from the National Health and Nutrition Examination Survey spanning the years 1999-2010, encompassing 23,634 participants. Cox proportional hazards regression models were employed to investigate the independent associations of serum iron and CRP with all-cause and cardiovascular mortality. Moderation and mediation analyses explored the moderating effect of CRP on the association between the serum iron concentration and all-cause and cardiovascular mortality, and the mediating role of the serum iron concentration in the association between the CRP concentration and all-cause and cardiovascular mortality. After multivariate adjustments in the Cox model, serum iron and CRP levels were independently correlated with both all-cause and cardiovascular mortality risk. Moderation analyses revealed a more pronounced correlation between the serum iron concentration and both all-cause and cardiovascular mortality in participants with higher CRP levels. Mediation analysis indicated that the serum iron concentration partly mediated the impact of CRP on the risk of all-cause mortality (13.79%) and cardiovascular mortality (24.12%).

CONCLUSION

Serum iron and CRP are independently associated with all-cause and cardiovascular mortality. Moreover, the associations between serum iron concentrations and both all-cause and cardiovascular mortality are more pronounced in individuals with elevated CRP. Serum iron partially mediates the effect of CRP on all-cause and cardiovascular mortality.

Predictive value of serum iron on heart failure in patients with acute ST-segment elevation myocardial infarction

BACKGROUND

In clinical practice, heart failure often occurs after acute myocardial infarction, and a new biomarker for its early prediction is urgently needed. The aim of this study was to investigate the relationship between serum iron and heart failure after acute ST-segment elevation myocardial infarction (STEMI).

METHODS

A total of 41 patients with heart failure after STEMI and 31 controls were included in the study. The demographic variables and baseline clinical characteristics of both groups were analyzed.

RESULTS

There were no significant differences between patients with heart failure and controls in terms of demographic characteristics. There were significant differences in terms of serum iron, N terminal pro-B-type natriuretic peptide levels, left atrial diameter, and left ventricular ejection fraction. Binary logistic regression analyses demonstrated that serum iron (odds ratio [OR]: 0.804, 95% confidence interval [CI]: 0.699-0.924) and Tn-I (OR: 1.072, 95% CI: 1.011-1.137) were independent predictors for heart failure (p < .05, respectively). Receiver operating characteristic analysis showed that the area under the curve for serum iron was 0.808 (95% CI: 0.707-0.908, p < .01). The best cutoff value of serum iron was 11.87 μmol/L (sensitivity: 87.1%; specificity: 68.3%).

CONCLUSIONS

Patients with heart failure after STEMI have lower serum iron levels than patients without heart failure after STEMI. Serum iron levels are a risk factor for heart failure after STEMI.

Maternal iron status in early pregnancy and childhood body fat measures and cardiometabolic risk factors: A population-based prospective cohort

BACKGROUND

Whether maternal iron status during pregnancy is associated with cardiometabolic health in the offspring is poorly known.

OBJECTIVES

We aimed to assess the associations of maternal iron status during early pregnancy with body fat measures and cardiometabolic risk factors in children aged 10 y.

METHODS

In a population-based cohort study among 3718 mother-child pairs, we measured ferritin, transferrin, and transferrin saturation during early pregnancy. We obtained child BMI, fat mass index, and android/gynoid fat mass ratio by DXA, subcutaneous fat index, visceral fat index, pericardial fat index, and liver fat fraction by magnetic resonance imaging and assessed systolic and diastolic blood pressure, serum lipids, glucose, insulin, and CRP at 10 y.

RESULTS

A one-standard deviation score (SDS) higher maternal ferritin was associated with lower fat mass index [difference -0.05 (95% CI: -0.08, -0.02) SDS] and subcutaneous fat index [difference -0.06 (95% CI: -0.10, -0.02) SDS] in children. One-SDS higher maternal transferrin was associated with higher fat mass index [difference 0.04 (95% CI: 0.01, 0.07) SDS], android/gynoid fat mass ratio [difference 0.05 (95% CI: 0.02, 0.08) SDS], and subcutaneous fat index [difference 0.06 (95% CI: 0.02, 0.10) SDS] in children. Iron status during pregnancy was not consistently associated with organ fat and cardiometabolic risk factors at 10 y.

CONCLUSIONS

Maternal lower ferritin and higher transferrin in early pregnancy are associated with body fat accumulation and distribution but are not associated with cardiometabolic risk factors in childhood. Underlying mechanisms and long-term consequences warrant further study.

Prevalence and incidence of iron deficiency in European community-dwelling older adults: an observational analysis of the DO-HEALTH trial

BACKGROUND AND AIM

Iron deficiency is associated with increased morbidity and mortality in older adults. However, data on its prevalence and incidence among older adults is limited. The aim of this study was to investigate the prevalence and incidence of iron deficiency in European community-dwelling older adults aged ≥ 70 years.

METHODS

Secondary analysis of the DO-HEALTH trial, a 3-year clinical trial including 2157 community-dwelling adults aged ≥ 70 years from Austria, France, Germany, Portugal and Switzerland. Iron deficiency was defined as soluble transferrin receptor (sTfR) > 28.1 nmol/L. Prevalence and incidence rate (IR) of iron deficiency per 100 person-years were examined overall and stratified by sex, age group, and country. Sensitivity analysis for three commonly used definitions of iron deficiency (ferritin < 45 μg/L, ferritin < 30 μg/L, and sTfR-ferritin index > 1.5) were also performed.

RESULTS

Out of 2157 participants, 2141 had sTfR measured at baseline (mean age 74.9 years; 61.5% women). The prevalence of iron deficiency at baseline was 26.8%, and did not differ by sex, but by age (35.6% in age group ≥ 80, 29.3% in age group 75-79, 23.2% in age group 70-74); P < 0.0001) and country (P = 0.02), with the highest prevalence in Portugal (34.5%) and the lowest in France (24.4%). As for the other definitions of iron deficiency, the prevalence ranged from 4.2% for ferritin < 30 µg/L to 35.3% for sTfR-ferritin index > 1.5. Occurrences of iron deficiency were observed with IR per 100 person-years of 9.2 (95% CI 8.3-10.1) and did not significantly differ by sex or age group. The highest IR per 100 person-years was observed in Austria (20.8, 95% CI 16.1-26.9), the lowest in Germany (6.1, 95% CI 4.7-8.0). Regarding the other definitions of iron deficiency, the IR per 100 person-years was 4.5 (95% CI 4.0-4.9) for ferritin < 45 µg/L, 2.4 (95% CI 2.2-2.7) for ferritin < 30 µg/L, and 12.2 (95% CI 11.0-13.5) for sTfR-ferritin index > 1.5.

CONCLUSIONS

Iron deficiency is frequent among relatively healthy European older adults, with people aged ≥ 80 years and residence in Austria and Portugal associated with the highest risk.

Iron Status is Associated with Mood, Cognition, and Functional Ability in Older Adults: A Cross-Sectional Study

Several conditions are risk factors for iron deficiency (ID), some of which are highly prevalent in older individuals. Despite the amount of evidence pointing for a role of ID in cognition, mood and physical functional ability, the research addressing these associations in older individuals is still scarce. In the present study, 162 older community-dwelling individuals (29.53% classified as ID) were enrolled in a cross-sectional analysis and characterized regarding cognition, mood, functional ability, general nutritional intake and iron status. Assessment of iron status was performed using several blood biomarkers. Storage and erythropoiesis dimensions were positively associated with memory, along with an interaction (moderator effect) between iron storage and nutritional status. A more depressed mood was negatively associated with (iron) transport, transport saturation and erythropoiesis dimensions, and functional tiredness was positively associated with the erythropoiesis dimension. These observations indicate that lower iron status is associated with depressive mood, functional tiredness and poorer memory ability, with the latter moderated by nutritional status. These findings suggest that using iron as a continuous variable may be useful in finding associations with iron homeostasis, eventually missed when iron levels are considered within the usual classification groups.

Low serum iron levels and risk of cardiovascular disease in high risk elderly population: Nested case-control study in the PREvención con DIeta MEDiterránea (PREDIMED) trial

BACKGROUND & AIMS

Epidemiological data on iron status and cardiovascular disease (CVD) are still controversial. The aim of this study was to determine whether low serum iron (SI) levels are associated with an increased odds of first CVD event in a population at high cardiovascular risk.

METHODS

Case-control study design nested within the "PREvención con DIeta MEDiterránea" (PREDIMED) trial. A total of 207 participants diagnosed with CVD (myocardial infarction, stroke or cardiovascular death) during follow-up period (2003-2010) were matched by sex, age and intervention group to 436 controls by incidence density sampling. Median time between serum sample collection and subsequent CVD event occurrence was 0.94 years. Inductively coupled plasma mass spectrometry analysis was used to determine SI levels. In-person interviews, medical record reviews, and validated questionnaires were used to assess covariates. Multivariable-adjusted odds ratios (ORs) of CVD were calculated with conditional logistic regression.

RESULTS

Mean SI levels were higher in men than in women (1224.0 μg/L vs. 1093.8 μg/L; p < 0.001). Among women, but not in men, the mean SI concentration was lower in cases than in controls (1008.5 μg/L vs. 1132.9 μg/L; p = 0.030). There was a gradual decrease in the multivariable-adjusted ORs of CVD with increasing SI levels (highest vs. lowest quartile: OR = 0.55, 95% CI: 0.32-0.93; p_trend = 0.020). This inverse relationship was more pronounced among women (highest vs. lowest quartile: OR = 0.15, 95% CI: 0.03-0.69; p_trend = 0.011).

CONCLUSIONS

The present findings are consistent with previously reported inverse associations between SI and CVD. SI levels as an independent marker of short-term cardiovascular risk may be useful for risk assessment in older populations.

TRIAL REGISTRATION

www.controlled-trials.com; International Standard Randomized Controlled Trial Number (ISRCTN): 35,739,639. Registered 5 October 2005. Retrospectively registered.

[Trend in the prevalence of anemia in Mexican women of childbearing age from 2006-2016. Ensanut MC 2016]

OBJECTIVE

To describe the anemia prevalence among women from 20 to 49 years from 2016-Halfway National Health and Nutrition Survey (Ensanut MC 2016) and compare the trends in 2006, 2012 and 2016 surveys, as well as its association with dietary iron and sociodemographic factors.

MATERIALS AND METHODS

The methodological design of Ensanut MC is fully comparable with Ensanut 2006 and 2012. Capillary hemoglobin (Hb) was obtained and those values <120 g/L were classified as anemic. Pregnant women were excluded from the analysis.

RESULTS

Anemia prevalence is higher in Ensanut MC 2016 when compared with Ensanut 2012 (p<0.001), differences can be found by age-groups, locality (urban-rural) and country region (North, Center, Mexico City and South). Logistic model showed an increase in anemia prevalence in 2016.

CONCLUSIONS

Anemia decreas from 2006 to 2012 was followed by an increas in 2016. It is necessary to identify potential risk factors that could be promoting anemia prevalence rising as well as estimate the iron-rich foods intake whit 24 hours recall.

Consequences of Inadequate Intakes of Vitamin A, Vitamin B12, Vitamin D, Calcium, Iron, and Folate in Older Persons

Purpose of Review

This review broadly discusses the consequences of inadequate consumption, by deficit or excess, of selected micronutrients on the quality of life and morbidity during aging, specifically considering increases in life expectancy and the costs of care in the older persons.

Recent Findings

A literature review of the periods 2012 to 2018, focusing on vitamins A, B₁₂, and D, calcium, iron and folate, was completed as these micronutrients are found to significantly affect the aging process. Causation and application of these micronutrients to disorders related to aging are controversial and mixed. This review highlights research needs and controversial points on the role of these micronutrients.

Summary

Micronutrient deficiencies are a common and avoidable contributor to decreased quality of life and healthcare costs in the older persons. Further research is needed to determine adequate intakes and innovative uses, including appropriate thresholds for improved health outcomes for this population.

Ferritin levels and risk of heart failure-the Atherosclerosis Risk in Communities Study

AIMS

Severe iron overload is associated with cardiac damage, while iron deficiency has been related to worse outcomes in subjects with heart failure (HF). This study investigated the relationship between ferritin, a marker of iron status, and the incidence of HF in a community-based cohort.

METHODS AND RESULTS

We examined 1063 participants who were free of heart failure from the Atherosclerosis Risk in Communities (ARIC) Study in whom ferritin serum levels were measured at baseline (1987-1989). The participants (mean age 52.7 ± 5.5 years, 62% women), were categorized in low (<30 ng/mL; n = 153), normal (30-200 ng/mL in women and 30-300 ng/mL in men; n = 663), and high (>200 ng/mL in women and >300 ng/mL in men; n = 247) ferritin levels. Multivariable Cox proportional hazards models were used to evaluate the relationship between ferritin and incident HF. After 21 ± 4.6 years of follow-up, HF occurred in 144 (13.5%) participants. When compared with participants with normal ferritin levels, participants with low ferritin levels had a higher risk of HF [hazard ratio (HR) = 2.24, 95% confidence interval (CI) 1.15-4.35; P = 0.02] as did those with high ferritin levels (HR = 1.81, 95% CI 1.01-3.25; P = 0.04), after adjusting for potential confounders. Notably, low ferritin levels remained associated with incident HF even after excluding subjects with anaemia (HR = 2.28, 95% CI 1.11-4.68; P = 0.03).

CONCLUSION

Derangements in iron metabolism, either low or high ferritin serum levels, were associated with higher risk of incident HF in a general population, even without concurrent anaemia. These findings suggest that iron imbalance might play a role in the development of HF.

Serum ferritin and risk for new-onset heart failure and cardiovascular events in the community

AIMS

Heart failure (HF) is a common manifestation of patients with primary and secondary causes of iron overload, whereas in patients with established HF iron deficiency impairs outcome. Whether iron stores, either depleted or in overload, amplify the risk for new-onset HF among healthy individuals is unknown. The present study aimed to assess whether markers of iron status or the iron-regulatory hormone hepcidin are associated with new-onset HF or cardiovascular (CV) events in the general population.

METHODS AND RESULTS

In 6386 subjects from the Prevention of REnal and Vascular ENd-stage Disease (PREVEND) trial, a prospective, community-based, cohort study, markers of iron status and the iron-regulatory hormone hepcidin were measured. Mean age was 53.1 ± 12.0 years, and 50.7% of the cohort was female. During a median follow-up of 8.3 (interquartile range 7.8-8.9) years, 199 subjects (3.1%) were newly diagnosed with HF, 456 (7.1%) experienced a CV event, and 356 (5.6%) died from all causes. A higher annual HF incidence per ferritin quartile was observed in women (P < 0.001), but not in men (P for interaction 0.032). Multivariable analyses demonstrated ferritin levels to remain independently predictive for new-onset HF in women only (P = 0.024). This association persisted within strata defined by markers of the metabolic syndrome, markers of inflammation, or other markers of iron homeostasis, including hepcidin. No association between ferritin or hepcidin and incident CV events or all-cause mortality was observed in either sex.

CONCLUSIONS

Increased serum ferritin levels independently amplify the risk for new-onset HF in women in the community.

Inverse relationship between body mass index and mortality in older nursing home residents: a meta-analysis of 19,538 elderly subjects

Body mass index (BMI) and mortality in old adults from the general population have been related in a U-shaped or J-shaped curve. However, limited information is available for elderly nursing home populations, particularly about specific cause of death. A systematic PubMed/EMBASE/CINAHL/SCOPUS search until 31 May 2014 without language restrictions was conducted. As no published study reported mortality in standard BMI groups (<18.5, 18.5-24.9, 25-29.9, ≥30 kg/m(2)), the most adjusted hazard ratios (HRs) according to a pre-defined list of covariates were obtained from authors and pooled by random-effect model across each BMI category. Out of 342 hits, 20 studies including 19,538 older nursing home residents with 5,223 deaths during a median of 2 years of follow-up were meta-analysed. Compared with normal weight, all-cause mortality HRs were 1.41 (95% CI = 1.26-1.58) for underweight, 0.85 (95% CI = 0.73-0.99) for overweight and 0.74 (95% CI = 0.57-0.96) for obesity. Underweight was a risk factor for higher mortality caused by infections (HR = 1.65 [95% CI = 1.13-2.40]). RR results corroborated primary HR results, with additionally lower infection-related mortality in overweight and obese than in normal-weight individuals. Like in the general population, underweight is a risk factor for mortality in old nursing home residents. However, uniquely, not only overweight but also obesity is protective, which has relevant nutritional goal implications in this population/setting.

Is Correction of Iron Deficiency a New Addition to the Treatment of the Heart Failure?

Anemia is present in about 40% of heart failure (HF) patients. Iron deficiency (ID) is present in about 60% of the patients with anemia (about 24% of all HF patients) and in about 40% of patients without anemia (about 24% of all HF patients). Thus ID is present in about half the patients with HF. The ID in HF is associated with reduced iron stores in the bone marrow and the heart. ID is an independent risk factor for severity and worsening of the HF. Correction of ID with intravenous (IV) iron usually corrects both the anemia and the ID. Currently used IV iron preparations are very safe and effective in treating the ID in HF whereas little information is available on the effectiveness of oral iron. In HF IV iron correction of ID is associated with improvement in functional status, exercise capacity, quality of life and, in some studies, improvement in rate of hospitalization for HF, cardiac structure and function, and renal function. Large long-term adequately-controlled intervention studies are needed to clarify the effect of IV iron in HF. Several heart associations suggest that ID should be routinely sought for in all HF patients and corrected if present. In this paper we present our approach to diagnosis and treatment of iron deficiency in heart failure.

Homocysteine, iron and cardiovascular disease: a hypothesis

Elevated circulating total homocysteine (tHcy) concentrations (hyperhomocysteinemia) have been regarded as an independent risk factor for cardiovascular disease (CVD). However, several large clinical trials to correct hyperhomocysteinemia using B-vitamin supplements (particularly folic acid) have largely failed to reduce the risk of CVD. There is no doubt that a large segment of patients with CVD have hyperhomocysteinemia; therefore, it is reasonable to postulate that circulating tHcy concentrations are in part a surrogate marker for another, yet-to-be-identified risk factor(s) for CVD. We found that iron catalyzes the formation of Hcy from methionine, S-adenosylhomocysteine and cystathionine. Based on these findings, we propose that an elevated amount of non-protein-bound iron (free Fe) increases circulating tHcy. Free Fe catalyzes the formation of oxygen free radicals, and oxidized low-density lipoprotein is a well-established risk factor for vascular damage. In this review, we discuss our findings on iron-catalyzed formation of Hcy from thioethers as well as recent findings by other investigators on this issue. Collectively, these support our hypothesis that circulating tHcy is in part a surrogate marker for free Fe, which is one of the independent risk factors for CVD.

Total and cause-specific mortality by moderately and markedly increased ferritin concentrations: general population study and metaanalysis

BACKGROUND

Previous population-based studies of plasma ferritin concentration have not revealed a relationship with total mortality. We tested the possible association of increased ferritin concentrations with increased risk of total and cause-specific mortality in the general population.

METHODS

We examined total and cause-specific mortality according to baseline plasma ferritin concentrations in a Danish population-based study (the Copenhagen City Heart Study) of 8988 individuals, 6364 of whom died (median follow-up 23 years). We also included a metaanalysis of total mortality comprising population-based studies according to ferritin quartiles or tertiles.

RESULTS

Multifactorially adjusted hazard ratios (HRs) for total mortality for individuals with ferritin ≥200 vs <200 μg/L were 1.1 (95% CI 1.1-1.2; P = 0.0008) overall, 1.1 (1.0-1.2; P = 0.02) in men, and 1.2 (1.0-1.3; P = 0.03) in women. Stepwise increasing concentrations of ferritin were associated with a stepwise increased risk of premature death overall (log rank, P = 2 × 10(-22)), with median survival of 55 years at ferritin concentrations ≥600 μg/L, 72 years at 400-599 μg/L, 76 years at 200-399 μg/L, and 79 years at ferritin <200 μg/L. The corresponding HR for total overall mortality for ferritin ≥600 vs <200 μg/L was 1.5 (1.2-1.8; P = 0.00008). Corresponding adjusted HRs for ferritin ≥600 vs <200 μg/L were 1.6 (1.1-2.3; P = 0.01) for cancer mortality, 2.9 (1.7-5.0; P = 0.0001) for endocrinological mortality, and 1.5 (1.1-2.0; P = 0.01) for cardiovascular mortality. The metaanalysis random effects odds ratio for total mortality for ferritin upper vs reference quartile or tertile was 1.0 (0.9-1.1; P = 0.3) (P heterogeneity = 0.5).

CONCLUSIONS

Moderately to markedly increased ferritin concentrations represent a biological biomarker predictive of early death in a dose-dependent linear manner in the general population.

Nut consumption and 5-y all-cause mortality in a Mediterranean cohort: the SUN project

OBJECTIVE

The aim of this study was to assess the association between nut consumption and all-cause mortality after 5-y follow-up in a Spanish cohort.

METHODS

The SUN (Seguimiento Universidad de Navarra, University of Navarra Follow-up) project is a prospective cohort study, formed by Spanish university graduates. Information is gathered by mailed questionnaires collected biennially. In all, 17 184 participants were followed for up to 5 y. Baseline nut consumption was collected by self-reported data, using a validated 136-item semi-quantitative food frequency questionnaire. Information on mortality was collected by permanent contact with the SUN participants and their families, postal authorities, and the National Death Index. The association between baseline nut consumption and all-cause mortality was assessed using Cox proportional hazards models to adjust for potential confounding. Baseline nut consumption was categorized in two ways. In a first analysis energy-adjusted quintiles of nut consumption (measured in g/d) were used. To adjust for total energy intake the residuals method was used. In a second analysis, participants were categorized into four groups according to pre-established categories of nut consumption (servings/d or servings/wk). Both analyses were adjusted for potential confounding factors.

RESULTS

Participants who consumed nuts ≥2/wk had a 56% lower risk for all-cause mortality than those who never or almost never consumed nuts (adjusted hazard ratio, 0.44; 95% confidence intervals, 0.23-0.86).

CONCLUSION

Nut consumption was significantly associated with a reduced risk for all-cause mortality after the first 5 y of follow-up in the SUN project.

Iron status in the elderly

Iron deficiency anaemia is prevalent in older age, particularly after the age of 80. Serum ferritin concentrations also decline, although there is no evidence to suggest that changes in iron stores are an inevitable consequence of ageing. Chronic inflammation is a common condition in older people, making the measurement of iron status difficult, and it is likely that elevated levels of circulating hepcidin are responsible for changes in iron metabolism that result in systemic iron depletion. Other contributory factors are poor diet and some medications, such as aspirin. Anaemia in older age has undesirable health outcomes, including increased susceptibility to falling and depression. However, there are concerns about possible adverse effects of iron supplements, either in relation to pro-inflammatory effects in the gut or inappropriate tissue iron deposition. Brain iron levels are increased with age-related degenerative diseases, but it is not known if this is the cause or a consequence of the disease, and genetic factors are likely to play a role. In order to maintain body iron within the normal range a personalised approach is required, taking into account all of the factors that may affect iron metabolism and the available strategies for preventing iron deficiency or overload.

Iron status and survival in diabetic patients with coronary artery disease

OBJECTIVE

To investigate the impact of iron status on survival in patients with type 2 diabetes and coronary artery disease (CAD).

RESEARCH DESIGN AND METHODS

Serum ferritin, transferrin saturation (Tsat), and soluble transferrin receptor (sTfR) were measured in 287 patients with type 2 diabetes and stable CAD (65 ± 9 years of age, 78% men).

RESULTS

During a mean follow-up of 45 ± 19 months, there were 59 (21%) deaths and 60 (21%) cardiovascular hospitalizations. Both serum ferritin and sTfR strongly predicted 5-year all-cause mortality rates, independently of other variables (including hemoglobin, measures of renal function, inflammation, and neurohormonal activation). There was an exponential relationship between sTfR and mortality (adjusted hazard ratio [HR] per 1 log mg/L: 4.24 [95% CI 1.43-12.58], P = 0.01), whereas the relationship between ferritin and mortality was U-shaped (for the lowest and the highest quintiles vs. the middle quintile [reference group], respectively: adjusted HR 7.18 [95% CI 2.03-25.46], P = 0.002, and adjusted HR 5.12 [1.48-17.73], P = 0.01). Similar patterns were observed for the composite outcome of all-cause mortality or cardiovascular hospitalization, and in these multivariable models, low Tsat was related to unfavorable outcome.

CONCLUSIONS

Both low and high serum ferritin (possibly reflecting depleted and excessive iron stores, respectively) along with high serum sTfR (reflecting reduced metabolically available iron) identify patients with type 2 diabetes and CAD who have a poor prognosis.