Elevated serum ferritin level is associated with the incident type 2 diabetes in healthy Korean men: a 4 year longitudinal study

Serum ferritin level and associated factors among uncontrolled adult type II diabetic follow-up patients: comparative based cross-sectional study

BACKGROUND

Uncontrolled type 2 diabetes mellitus (UT2DM) and its associated consequences nowadays have been a global health crisis, especially for adults. Iron has the property to oxidize and reduce reversibly, which is necessary for metabolic processes and excess accumulation of iron indicated by serum ferritin levels could have a significant impact on the pathophysiology of T2DM via generation of reactive oxygen species (ROS). However, no conclusive evidence existed about the association of serum ferritin with the state of glycemic control status. Therefore, this study aimed to evaluate serum ferritin levels and associated factors in uncontrolled T2DM patients and compare them with those of controlled T2DM and non-diabetic control groups.

METHODS

A hospital-based comparative cross-sectional study was conducted among conveniently selected 156 study participants, who were categorized into three equal groups of uncontrolled T2DM, controlled T2DM, and non-diabetic control groups from October 2 to December 29, 2023 at St. Paul's Hospital Millennium Medical College. A pre-tested structured questionnaire was used to collect socio-demographic and diabetes-related information. The laboratory tests were done using an automated chemistry analyzer and IBM-SPSS statistical software (version-27) was utilized for data entry and analysis with a significance level of p < 0.05.

RESULT

The mean serum ferritin level was noticeably higher in uncontrolled T2DM patients as compared to controlled T2DM and control groups (p < 0.001). It was significantly correlated with HbA1c [r = 0.457, p < 0.001], fasting blood sugar (FBs) [r = 0.386, p < 0.001], serum iron [r = 0.430, p < 0.001], and systolic blood pressure (SBP) [r = 0.195, p = 0.047] in T2DM patients. A multivariate logistic regression model revealed that a rise in HbA1c (AOR = 3.67, 95% CI(1.50-8.98), serum iron (AOR = 1.02, 95% CI(1.01-1.04), male gender (AOR = 0.16, 95% CI(0.05-0.57) and being on oral hypoglycemic agent (OHA) monotherapy (AOR = 0.26, 95% CI(0.07-0.95) were key associated factors for the elevated serum ferritin among T2DM patients.

CONCLUSION

The present study demonstrated that T2DM patients had elevated serum ferritin levels which might be related to the existence of long-term hyperglycaemia and that serum ferritin had a significant positive association with HbA1c and FBs, implying that it could be used as an additional biomarker to predict uncontrolled T2DM patients.

Association of Body Iron Metabolism with Type 2 Diabetes Mellitus in Chinese Women of Childbearing Age: Results from the China Adult Chronic Disease and Nutrition Surveillance (2015)

High iron stores have been reported to be associated with type 2 diabetes mellitus (T2DM). However, evidence for the associations of iron metabolism with T2DM is inconsistent, and whether there is a threshold effect remains controversial. In the present study, we aimed to examine the associations between various iron biomarkers and the risk of T2DM as well as impaired glucose metabolism (IGM) and hyperglycemia in Chinese women of childbearing age. A total of 1145 women were divided into three groups (normal blood glucose metabolism group; IGM group; T2DM group). Biomarkers of iron metabolism (serum ferritin (SF), transferrin, soluble transferrin receptor (sTfR), transferrin saturation, serum iron, total body iron, and sTfR-to-lgferritin index) were measured. After adjusting for various confounding risk factors, SF and sTfR were positively associated with the risk of IGM (fourth vs. first quartile: SF odds ratio (OR) = 1.93 (95% CI 1.17-3.20) and sTfR OR = 3.08 (95% CI 1.84-5.14)) and T2DM (SF OR = 2.39 (95% CI 1.40-4.06) and sTfR OR = 3.84 (95% CI 2.53-5.83)). There was a nonlinear relationship between SF and risk of T2DM and hyperglycemia (p for nonlinearity < 0.01). Our findings suggested that SF and sTfR could be independent predictors of T2DM risk.

Association between hepatic iron overload assessed by magnetic resonance imaging and glucose intolerance states in the general population

BACKGROUND AND AIM

While there is evidence that iron overload disorders are associated with type 2 diabetes, the relationship between hepatic iron overload and prediabetes remains unclear. We aimed to investigate the association between hepatic iron overload, as assessed by magnetic resonance imaging (MRI), and different glucose intolerance states in the population-based Study.

METHODS AND RESULTS

We included data from 1622 individuals with MRI data, who did not have known type 2 diabetes (T2DM). Using an oral glucose tolerance testing, participants were classified as having isolated impaired fasting glucose (i-IFG), isolated impaired glucose tolerance (i-IGT), combined IFG and IGT (IFG + IGT) or previously unknown T2DM. Hepatic iron and fat contents were assessed through quantitative MRI. We undertook linear and multinomial logistic regression models adjusted for potential confounders and MRI-assessed hepatic fat content to examine the association of hepatic iron overload with different glucose intolerance states or continuous markers of glucose metabolism. MRI-assessed hepatic iron overload was positively associated only with both 2-h plasma glucose (β = 0.32; 95%CI 0.04-0.60) and the combined IFG + IGT category (relative risk ratio = 1.87; 95%CI 1.15-3.06). No significant associations were found between hepatic iron overload and other glucose intolerance states or biomarkers of glucose metabolism, independently of potential confounders.

CONCLUSIONS

MRI-assessed hepatic iron overload was associated with higher 2-h glucose concentrations and the combined IFG + IGT category, but not with other glucose intolerance states. Our findings suggest a weak adverse impact of hepatic iron overload on glucose metabolism, but further studies are needed to confirm these findings.

Genome-wide gene and serum ferritin interaction in the development of type 2 diabetes in adults aged 40 years or older

BACKGROUND AND AIMS

Elevated serum ferritin is associated with incident Type 2 diabetes (T2D), but the interactions between serum ferritin and genetic factors which may improve understanding underlying mechanism in the development of T2D are still unclear. We determined the gene-ferritin interactions on the development of T2D by genome-wide gene-ferritin interaction analyses.

METHODS AND RESULTS

A total of 3405 participants from two prospective cohorts of community living residents were included, and the median follow-time was 3.99 years. Genome-wide gene-ferritin interactions were analyzed using the joint test with two degrees of freedom and the interaction test with one degree of freedom. There were 18 SNPs selected in the joint test. Finally, four independent variants [rs355140 (LINC00312), rs4075576 (nearby PDGFA), rs1332202 (PTPRD), and rs713157 (nearby LINC00900)] with low pairwise linkage disequilibrium (r2<0.2) and located at least 1000 kb from the index SNP showed interactions with serum ferritin level. In the association analyses between serum ferritin levels (tertiles of ferritin and ferritin status) and the incidence of T2D according to genotype, the Incidence Rate Ratios (IRRs) in the highest tertile of ferritin level (vs. the lowest tertile) were greater for participants with heterozygotes of risk alleles of each of the four SNP than IRRs for those with wild type. Compared with the normal group, the elevated ferritin group also had a higher risk of T2D for all genetic variants of risk alleles, particularly its homozygotes.

CONCLUSION

Serum ferritin level interacts with genetic variants (rs355140, rs4075576, rs1332202, and rs713157) in the development of T2D.

Blocking effect of ferritin on the ryanodine receptor-isoform 2

Iron, an essential element for most living organism, participates in a wide variety of physiological processes. Disturbance in iron homeostasis has been associated with numerous pathologies, particularly in the heart and brain, which are the most susceptible organs. Under iron-overload conditions, the generation of reactive oxygen species leads to impairment in Ca2+ signaling, fundamentally implicated in cardiac and neuronal physiology. Since iron excess is accompanied by increased expression of iron-storage protein, ferritin, we examined whether ferritin has an effect on the ryanodine receptor - isoform 2 (RYR2), which is one of the major components of Ca2+ signaling. Using the method of planar lipid membranes, we show that ferritin induced an abrupt, permanent blockage of the RYR2 channel. The ferritin effect was strongly voltage dependent and competitively antagonized by cytosolic TEA+, an impermeant RYR2 blocker. Our results collectively indicate that monomeric ferritin highly likely blocks the RYR2 channel by a direct electrostatic interaction within the wider region of the channel permeation pathway.

Vitamin D Rescues Pancreatic β Cell Dysfunction due to Iron Overload via Elevation of the Vitamin D Receptor and Maintenance of Ca2+ Homeostasis

SCOPE

Accumulating evidence indicates that micronutrients are related to metabolic diseases. However, comparatively less attention has been devoted to their influence on each other during the development of metabolic diseases. To investigate the underlying mechanisms, the effects of iron and vitamin D on pancreatic β cell functions are examined.

METHODS AND RESULTS

Iron overload is induced in INS-1 rat insulinoma pancreatic β cells and it is found that iron overload dramatically reduce expression of the vitamin D receptor (VDR). Iron overload-induced β cell dysfunction is rescued by 1,25-dihydroxyvitamin D3 (1,25(OH)2 D3 ) cotreatment via restoration of VDR level and the consequent maintenance of Ca2+ homeostasis. Iron accumulation is also observed in the islets of 22-month-old C57BL/6 mice fed with a chow diet (1000 IU vitamin D3 per kg). In contrast, islet iron accumulation and hyperinsulinemia are ameliorated in mice fed with a vitamin D3 -supplemented diet (20 000 IU kg-1 ).

CONCLUSION

The authors show that functional failure of β cells due to iron accumulation is rescued by 1,25(OH)2 D3 , and iron overload significantly reduces VDR levels in β cells. These results suggest that iron and vitamin D inversely influence pancreatic β cell function.

Iron metabolism and type 2 diabetes mellitus: A meta-analysis and systematic review

AIMS/INTRODUCTION

Iron metabolism can directly or indirectly affect the occurrence and development of type 2 diabetes. This meta-analysis and systematic review aimed to analyze the association between serum iron metabolism indicators and type 2 diabetes.

MATERIALS AND METHODS

The databases PubMed and Embase were searched for studies on the correlations between serum iron metabolism indicators (iron, ferritin, transferrin, hepcidin and soluble transferrin receptor) and type 2 diabetes since January 2006. Relevant data were extracted from the included studies, and meta-analysis was carried out.

RESULTS

A total of 12 case-control and cohort studies were analyzed. Of the 12 studies, 11 described the correlation between serum ferritin levels and type 2 diabetes. The median and high serum ferritin concentrations were significantly associated with the risks of type 2 diabetes (odds ratio [OR] 1.20, 95% confidence interval [CI] 1.08-1.33 and OR 1.43, 95% CI 1.29-1.59, respectively). However, the low concentration was not correlated with the risk of type 2 diabetes (OR 0.99, 95% CI 0.89-1.11). No significant association was observed between serum soluble transferrin receptor and type 2 diabetes, whereas the soluble transferrin receptor-to-ferritin ratio was significantly inversely related to the risk of type 2 diabetes in the median and high ratio subgroups (OR 0.71, 95% CI 0.51, 0.99 and OR 0.65, 95% CI 0.45-0.95).

CONCLUSIONS

The elevated serum ferritin was one of the risk factors for type 2 diabetes, and soluble transferrin receptor-to-ferritin ratio was inversely related to the risk of type 2 diabetes. A systematic review showed that serum transferrin and hepcidin might be directly or indirectly related to the development of diabetes.

Impact of Diabetes Control on Subclinical Atherosclerosis: Analysis from Coronary Computed Tomographic Angiography Registry

BACKGROUND

There are limited data on the impact of diabetes control on the risk of subclinical coronary atherosclerosis.

METHODS

We analyzed 6,434 consecutive asymptomatic individuals without previous history of coronary artery disease who underwent coronary computed tomographic angiography (CCTA) (mean age, 53.7±7.6 years and 4,694 men [73.0%]). The degree and extent of subclinical coronary atherosclerosis were assessed by CCTA, and ≥50% diameter stenosis was defined as significant. A cardiac event was defined as a composite of all-cause death, myocardial infarction, unstable angina, or coronary revascularization. Study participants were categorized as normal (n=5,319), controlled diabetes (glycosylated hemoglobin [HbA1c] <7%, n=747), or uncontrolled diabetes (HbA1c ≥7%, n=368), respectively.

RESULTS

Compared with normal individuals, there were no statistically significant differences in the risk of for any atherosclerotic plaque (odds ratio [OR], 1.16; 95% confidence interval [CI], 0.98 to 1.38; P=0.086) and significant coronary artery stenosis (OR, 1.08; 95% CI, 0.82 to 1.42; P=0.583) in controlled diabetic individuals. In contrast, uncontrolled diabetic individuals had consistently higher risks of any atherosclerotic plaque (OR, 2.16; 95% CI, 1.70 to 2.75; P<0.001) and significant coronary artery stenosis (OR, 3.34; 95% CI, 2.52 to 4.43; P<0.001) than normal individuals. During a follow-up of median 5.4 years, there was no significant difference in cardiac events between normal and controlled diabetic individuals (P=0.365). However, uncontrolled diabetes was associated with an increased risk of cardiac events compared with normal individuals (P<0.001) and controlled diabetic individuals (P=0.023).

CONCLUSION

Asymptomatic uncontrolled diabetes was associated with significant subclinical coronary atherosclerosis with subsequent high risk for cardiac events.

Associations of iron markers with type 2 diabetes mellitus and metabolic syndrome: Results from the prospective SHIP study

AIMS

To assess the role of serum ferritin and transferrin with prevalent and incident type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS) and whether these associations are independent of inflammatory markers and hepatic enzymes.

METHODS

We analyzed data from 3,232 participants aged 20-81 years of the population-based Study of Health in Pomerania (SHIP) from Northeast Germany with a median follow-up time of 10.6 years. Logistic and Cox regression analyses were performed.

RESULTS

Serum ferritin concentrations were associated with a higher prevalence of T2DM (total population OR: 1.16 [95% CI: 1.07, 1.26]; men OR: 1.18 [95% CI: 1.08, 1.30) and MetS (total population OR: 1.27 [95% CI: 1.16, 1.38]; men OR: 1.26 [95% CI: 1.15, 1.38]) in the total population and men independently of inflammatory markers and hepatic enzymes. In longitudinal analyses, baseline ferritin concentrations were associated with a higher risk of incident T2DM in women (HR: 1.38 [95% CI: 1.10, 1.71]), but not in men or in the total population and also with a higher risk of incident MetS (HR: 1.09 [95% CI: 1.01, 1.17]) in the total population. These longitudinal associations attenuated considerably after adjustment for hepatic enzymes but not inflammatory markers. Transferrin was not associated with any of the outcomes.

CONCLUSIONS

Our results suggest a link between ferritin and T2DM and MetS, which might be partially explained by hepatic dysfunction.

Decreased lung function is associated with elevated ferritin but not iron or transferrin saturation in 42,927 healthy Korean men: A cross-sectional study

Objectives

Though elevated ferritin level and decreased lung function both predispose people to cardio-metabolic disease, few reports have investigated the association between them. Furthermore, it remains unclear whether the association reflects a change in iron stores or an epiphenomenon reflecting metabolic stress. Therefore, we looked for possible associations between ferritin, iron, and transferrin saturation (TSAT) and lung function to clarify the role of iron-related parameters in healthy men.

Methods

We conducted a cohort study of 42,927 healthy Korean men (mean age: 38.6 years). Percent predicted forced expiratory volume in one second (FEV1%) and forced vital capacity (FVC%) were categorized into quartiles. Adjusted odds ratios (aORs) and 95% confidence intervals (using the highest quartile as reference) were calculated for hyperferritinemia, high iron, and high TSAT after controlling for potential confounders.

Results

The median ferritin level was 199.8 (141.5–275.6) ng/mL. The prevalence of hyperferritinemia (defined as >300 ng/mL) was 19.3%. Subjects with hyperferritinemia had lower FEV1% and FVC% than those with normal ferritin level with a slight difference, but those were statistically significant (99.22% vs.99.61% for FEV1%, p = 0.015 and 98.43% vs. 98.87% for FVC, p = 0.001). However, FEV1/FVC ratio was not significantly different between groups (P = 0.797). Compared with the highest quartile, the aORs for hyperferritinemia across decreasing quartiles were 1.081 (1.005–1.163), 1.100 (1.007–1.200), and 1.140 (1.053–1.233) for FEV1% (p for trend = 0.007) and 1.094 (1.018–1.176), 1.101 (1.021–1.188), and 1.150 (1.056–1.252) for FVC% (p for trend = 0.001). However, neither FEV1% nor FVC% was associated with iron or TSAT.

Conclusions

Hyperferritinemia was associated with decreased lung function in healthy Korean men, but iron and TSAT were not. Longitudinal follow-up studies are required to validate our findings.

Sex-Specific Association of Circulating Ferritin Level and Risk of Type 2 Diabetes: A Dose-Response Meta-Analysis of Prospective Studies

CONTEXT

Although the role of iron in the development of type 2 diabetes (T2D) has long been a concern, prospective studies directly linking body iron stores to T2D risk in a sex-dependent context have been inconsistent.

OBJECTIVE

A systematic meta-analysis was conducted to explore the sex-specific association of circulating ferritin with T2D risk.

DATA SOURCES

We searched PubMed, Web of Science, and EMBASE databases to identify available prospective studies through 1 August 2018.

RESULTS

Fifteen prospective studies comprising 77,352 participants and 18,404 patients with T2D, aged 20 to 80 years, and with ∼3 to 17 years of follow-up were identified. For each 100-μg/L increment in ferritin levels of overall participants, T2D risk increased by 22% (RR, 1.22; 95% CI, 1.14 to 1.31). Of note, major heterogeneities by sex were identified, with increased ferritin level having an apparently greater effect on T2D risk in women (RR, 1.53; 95% CI, 1.29 to 1.82) than in men (RR, 1.21; 95% CI, 1.15 to 1.27) after exclusion of a study with high heterogeneity (41,512 men and 6974 women for sex-specific analyses; P = 0.020 for sex difference). Further nonlinear analysis between circulating ferritin and T2D risk also showed sex-dimorphic association in that the T2D risk of women was twice as strong in magnitude as that of men at the same ferritin level.

CONCLUSIONS

Greater circulating ferritin levels were independently associated with increased T2D risk, which appeared stronger among women than men. Our findings provide prospective evidence for further testing of the utility of ferritin levels in predicting T2D risk in a sex-specific manner.

Elevated serum ferritin concentration is associated with incident type 2 diabetes mellitus in a Chinese population: A prospective cohort study

AIMS

We aimed to evaluate the association between serum ferritin levels and incident type 2 diabetes mellitus risk in a Chinese population.

METHODS

This cohort study assessed 2225 Chinese individuals aged 25-75 years. Diabetes mellitus was diagnosed using the 1999 World Health Organization definition with a median follow-up period of 20 months. Cox proportional hazard models were used to estimate adjusted hazard ratios and 95% confidence intervals (CI) for incident diabetes when serum ferritin concentrations increased by one standard deviation.

RESULTS

During the follow-up period, 112 cases (62 men and 50 women) of type 2 diabetes mellitus were identified. Baseline serum ferritin levels were higher in the diabetes than the non-diabetes group. After adjusting for age, body mass index, waist circumference, mean arterial pressure, fasting plasma glucose, fasting insulin, hemoglobin A1c, total cholesterol, high-density lipoprotein cholesterol, alanine transaminase and triglyceride levels, family history of diabetes mellitus, pork meat consumption, neutrophil/lymphocyte ratio, education, and annual household income, the hazard ratios for incident diabetes corresponding to one standard deviation increase in serum ferritin levels were 1.17 (95% CI 1.03, 1.34), 1.20 (95% CI 1.003, 1.43), and 1.03 (95% CI 0.82, 1.31) for the total population, men, and women, respectively.

CONCLUSIONS

High serum ferritin levels were associated with a higher risk of incident type 2 diabetes mellitus independent of traditional risk factors in the total population and men.

Investigating Molecular Connections of Non-alcoholic Fatty Liver Disease with Associated Pathological Conditions in West Virginia for Biomarker Analysis

Non-alcoholic fatty liver disease (NAFLD) is a disease characterized by a steatosis of the liver that may progress to more serious pathological conditions including: nonalcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. As the prevalence of NAFLD has increased worldwide in recent years, pathophysiology and risk factors associated with disease progression of NAFLD are at the focus of many studies. NAFLD is related to and shares common serum biomarkers with cardiovascular disease (CVD), type 2 diabetes mellitus (T2DM), obesity, and metabolic syndrome (MetS). West Virginia (WV) is a state with some of the highest rates of CVD, obesity and diabetes mellitus. As NAFLD is closely related to these diseases, it is of particular interest in WV. Currently there is no cost-effective, standardized method used clinically to detect NAFLD prior to the onset of reversible complications. At this time, the diagnosis of NAFLD is made with costly radiologic studies and invasive biopsy. These studies are only diagnostic once changes to hepatic tissue have occurred. The diagnosis of NAFLD by traditional methods may not allow for successful intervention and may not be readily available in areas with already sparse medical resources. In this literature review, we identify a list of biomarkers common among CVD, T2DM, obesity, MetS and NAFLD. From this research we propose the following biomarkers are good candidates for inclusion in a panel of biomarkers for the early detection of NAFLD: adiponectin, AST, ALT, apo-B, CK18, CPS1, CRP, FABP-1, ferritin, GGT, GRP78, HDL-C, IGF-1, IL-1β, 6, 8, 10, IRS-2PAI-1, leptin, lumican, MDA SREBP-1c and TNF-α. Creating and implementing a biomarker panel for the early detection and attenuation of NAFLD, prior to the onset of irreversible complication would provide maximum benefit and decrease the disease burden on the patients and healthcare system of WV.

The association between serum ferritin levels and the risk of new-onset type 2 diabetes mellitus: A 10-year follow-up of the Chinese Multi-Provincial Cohort Study

AIMS

To investigate the association of serum ferritin levels and ferritin level changes with the 10-year risk of new-onset type 2 diabetes mellitus (T2DM).

METHODS

Among 2359 subjects without T2DM at baseline in 2002, 1956 subjects were re-examined in 2007, and 1660 subjects were invited to be re-examined in 2012. Serum ferritin (ng/ml) levels were measured by latex-enhanced turbidimetric immunoassay. Five-year serum ferritin changes were categorized into four groups using the median as the cut-off point. Multivariate logistic regression was performed to examine the independent association of serum ferritin levels and 5-year ferritin level changes with 10-year new-onset T2DM.

RESULTS

At the 10-year follow-up, 205 (12.3%) subjects had developed new-onset T2DM. After adjusting for traditional risk factors and high-sensitivity C-reactive protein, 10-year new-onset T2DM risk was significantly increased in subjects in the highest tertile of baseline serum ferritin levels [odds ratio (OR)=1.80, 95% confidence interval (CI): 1.17-2.79] and in subjects with high serum ferritin levels in both 2002 and 2007 (OR=1.54, 95% CI: 1.01-2.34). After adjusting for baseline fasting blood glucose, the effect was attenuated and became borderline or non-significant.

CONCLUSIONS

Serum ferritin levels and ferritin level changes were associated with 10-year new-onset T2DM risk in the Chinese population, whereas the independent effect awaits validation from studies with larger sample sizes.

Plasma ferritin, C-reactive protein, and risk of incident type 2 diabetes in Singapore Chinese men and women

AIMS

Ferritin is postulated to be involved in diabetogenesis as a marker of iron stores. We prospectively examined the association between ferritin levels and type 2 diabetes (T2D) risk in a Chinese population.

METHODS

Plasma ferritin concentrations were assayed among 485 diabetes cases and 485 controls nested within the Singapore Chinese Health Study. Cases and controls were matched on age, gender, date of blood collection, and dialect group. Participants were free of diagnosed diabetes, cardiovascular disease, and cancer at blood collection (1999-2004). Incident self-reported T2D cases were identified at follow-up II interview (2006-2010). Multivariable conditional logistic regression models were used to compute the odds ratio (OR) and the corresponding 95% confidence intervals (CIs).

RESULTS

After adjusting for T2D risk factors, including high-sensitivity C-reactive protein (hs-CRP), adiponectin, triglycerides, HDL cholesterol and alanine aminotransferase, the OR comparing the highest versus lowest quartile of ferritin levels was 1.87 (95% CI 1.10-3.19) (P-trend=0.004). When the analysis was limited to participants with hs-CRP<1.5mg/L (below median; n=482), the OR comparing extreme quartiles of ferritin levels was 1.16 (95% CI 0.62-2.16; P-trend=0.63); while the corresponding OR was 2.51 (95% CI 1.31-4.79; P-trend<0.001) when confined to those with hs-CRP≥1.5mg/L (n=488; P-interaction=0.022). Compared to participants with both ferritin and hs-CRP levels below median, those with both levels above median had markedly increased T2D risk (P-interaction for multiplicative scale=0.037).

CONCLUSIONS

The elevation of blood ferritin levels, in the presence of raised hs-CRP, was significantly associated with increased risk of T2D.

Prediabetes is not a risk factor for subclinical coronary atherosclerosis

BACKGROUND

There are limited data regarding the influence of glycemic status on the risk of subclinical coronary atherosclerosis on coronary computed tomographic angiography (CCTA) in asymptomatic individuals.

METHODS

We analyzed 6434 asymptomatic individuals who underwent CCTA. The degree and extent of subclinical coronary atherosclerosis were assessed by CCTA, and ≥50% diameter stenosis was defined as significant. Of study participants, 2197 (34.1%), 3122 (48.5%), and 1115 (17.3%) were categorized as normal, prediabetic and diabetic individuals, respectively.

RESULTS

Compared with normal individuals, there were no statistically differences in the adjusted odds ratios of prediabetic individuals for significant coronary artery stenosis (0.98, 95% confidence interval [CI] 0.80-1.22, p=0.888), any plaque (0.96, 95% CI 0.86-1.07, p=0.483), calcified plaque (0.90, 95% CI 0.79-1.01, p=0.080), non-calcified plaque (1.02, 95% CI 0.88-1.17, p=0.803), and mixed plaque (1.00, 95% CI 0.82-1.22, p=0.983). However, adjusted odds ratios for significant coronary artery stenosis (1.71, 95% CI 1.34-2.19, p<0.001), any plaque (1.45, 95% CI 1.26-1.68, p<0.001), calcified plaque (1.35, 95% CI 1.15-1.57, p<0.001), non-calcified plaque (1.33, 95% CI 1.11-1.59, p=0.002), and mixed plaque (1.64, 95% CI 1.30-2.07, p<0.001) of diabetic individuals were significantly higher than those of the normal individuals.

CONCLUSION

In asymptomatic individuals, diabetic individuals had a higher risk for subclinical coronary atherosclerosis, but prediabetic individuals were not associated with an increased risk of subclinical coronary atherosclerosis.

Circulating ferritin concentrations and risk of type 2 diabetes in Japanese individuals

AIMS/INTRODUCTION

Higher iron storage has been linked to an increased risk of type 2 diabetes, but little is known about the mediator of this association. Here, we prospectively investigated the association between circulating ferritin, a marker of iron storage, and the incidence of type 2 diabetes among Japanese individuals.

MATERIALS AND METHODS

The participants were 4,754 employees who attended a comprehensive health check-up in 2008-2009 and donated blood for the study. During 5 years of follow up, diabetes was identified based on plasma glucose, glycated hemoglobin and self-report. Two controls matched to each case on sex, age and date of check-up were randomly chosen using density sampling, giving 327 cases and 641 controls with ferritin measurement. Cox proportional hazards regression was used to estimate the hazard ratio while adjusting for a series of potential confounders or mediators.

RESULTS

Elevated serum ferritin levels were associated with a significantly increased risk of type 2 diabetes, with the hazard ratio adjusted for known risk factors in the highest vs lowest quartile of 1.42 (95% confidence interval: 1.03-1.96). This association was unchanged after adjustment for C-reactive protein and adiponectin, but attenuated after adjustment for liver enzyme and insulin resistance (hazard ratio 1.04). The ferritin-diabetes association was confined to non-obese participants.

CONCLUSIONS

These results suggest that elevated iron storage is associated with increased risk of type 2 diabetes in normal weight individuals, and that this association is partly mediated through liver dysfunction and resulting insulin resistance.

Association of Multiple Biomarkers of Iron Metabolism and Type 2 Diabetes: The EPIC-InterAct Study

OBJECTIVE

Observational studies show an association between ferritin and type 2 diabetes (T2D), suggesting a role of high iron stores in T2D development. However, ferritin is influenced by factors other than iron stores, which is less the case for other biomarkers of iron metabolism. We investigated associations of ferritin, transferrin saturation (TSAT), serum iron, and transferrin with T2D incidence to clarify the role of iron in the pathogenesis of T2D.

RESEARCH DESIGN AND METHODS

The European Prospective Investigation into Cancer and Nutrition-InterAct study includes 12,403 incident T2D cases and a representative subcohort of 16,154 individuals from a European cohort with 3.99 million person-years of follow-up. We studied the prospective association of ferritin, TSAT, serum iron, and transferrin with incident T2D in 11,052 cases and a random subcohort of 15,182 individuals and assessed whether these associations differed by subgroups of the population.

RESULTS

Higher levels of ferritin and transferrin were associated with a higher risk of T2D (hazard ratio [HR] [95% CI] in men and women, respectively: 1.07 [1.01-1.12] and 1.12 [1.05-1.19] per 100 μg/L higher ferritin level; 1.11 [1.00-1.24] and 1.22 [1.12-1.33] per 0.5 g/L higher transferrin level) after adjustment for age, center, BMI, physical activity, smoking status, education, hs-CRP, alanine aminotransferase, and γ-glutamyl transferase. Elevated TSAT (≥45% vs. <45%) was associated with a lower risk of T2D in women (0.68 [0.54-0.86]) but was not statistically significantly associated in men (0.90 [0.75-1.08]). Serum iron was not associated with T2D. The association of ferritin with T2D was stronger among leaner individuals (Pinteraction < 0.01).

CONCLUSIONS

The pattern of association of TSAT and transferrin with T2D suggests that the underlying relationship between iron stores and T2D is more complex than the simple link suggested by the association of ferritin with T2D.

Poorly controlled type 2 diabetes is accompanied by significant morphological and ultrastructural changes in both erythrocytes and in thrombin-generated fibrin: implications for diagnostics

We have noted in previous work, in a variety of inflammatory diseases, where iron dysregulation occurs, a strong tendency for erythrocytes to lose their normal discoid shape and to adopt a skewed morphology (as judged by their axial ratios in the light microscope and by their ultrastructure in the SEM). Similarly, the polymerization of fibrinogen, as induced in vitro by added thrombin, leads not to the common ‘spaghetti-like’ structures but to dense matted deposits. Type 2 diabetes is a known inflammatory disease. In the present work, we found that the axial ratio of the erythrocytes of poorly controlled (as suggested by increased HbA1c levels) type 2 diabetics was significantly increased, and that their fibrin morphologies were again highly aberrant. As judged by scanning electron microscopy and in the atomic force microscope, these could be reversed, to some degree, by the addition of the iron chelators deferoxamine (DFO) or deferasirox (DFX). As well as their demonstrated diagnostic significance, these morphological indicators may have prognostic value.

The Relationship between Serum Ferritin and Insulin Resistance in Different Glucose Metabolism in Nonobese Han Adults

The exact mechanism through which elevated serum ferritin promotes the development of type 2 diabetes is unknown. This study showed that ferritin concentration in impaired glucose regulation and newly diagnosed diabetes mellitus subjects of nonobesity already significantly increased when compared with normal glucose tolerant subjects of nonobesity. Elevated serum ferritin levels are associated with insulin resistance and may be not associated with the decline of insulin beta cells in different status of glucose tolerance in nonobese Han adults.

Serum ferritin, diabetes, diabetes control, and insulin resistance

AIMS

The present study aims to investigate the association between serum ferritin and diabetes, diabetes control, and insulin resistance (IR) and examine whether gender is a modifier for these associations in a community-based sample.

METHODS

A cross-sectional survey of 8,235 participants was conducted in 2009. Serum ferritin, glucose, hemoglobin A1c (HbA1c), insulin, inflammatory markers, and lipid markers were measured. IR was estimated with a Homeostasis Model Assessment (HOMA-IR) equation. Multiple logistic and linear regression models were applied to evaluate these associations.

RESULTS

The numbers of diabetic patients and non-diabetic participants in the present study were 644 (7.8 %) and 7,591 (92.2 %). After adjusting for multiple confounders, the odds ratios (ORs) and 95 % confidence intervals (CIs) for diabetes were 1.48 (1.31-1.69) in men and 1.43 (1.24-1.65) in women for one-unit increase in log-transformed serum ferritin levels. Likewise, ORs (95 % CIs) for poor diabetes control (HbA1c ≥7.5 %) were 1.58 (1.21-2.05) and 1.37 (1.07-1.77) in men and women, respectively. As for HOMA-IR, the respective betas (P value) for one-unit increase in log-transformed serum ferritin were 0.07 (P < 0.0001) and 0.06 (P < 0.0001) in men and women.

CONCLUSIONS

In conclusion, elevated serum ferritin levels were associated with higher risks of diabetes, higher levels of HbA1c, and HOMA-IR independent of several confounders.

Serum ferritin is an important inflammatory disease marker, as it is mainly a leakage product from damaged cells

"Serum ferritin" presents a paradox, as the iron storage protein ferritin is not synthesised in serum yet is to be found there. Serum ferritin is also a well known inflammatory marker, but it is unclear whether serum ferritin reflects or causes inflammation, or whether it is involved in an inflammatory cycle. We argue here that serum ferritin arises from damaged cells, and is thus a marker of cellular damage. The protein in serum ferritin is considered benign, but it has lost (i.e. dumped) most of its normal complement of iron which when unliganded is highly toxic. The facts that serum ferritin levels can correlate with both disease and with body iron stores are thus expected on simple chemical kinetic grounds. Serum ferritin levels also correlate with other phenotypic readouts such as erythrocyte morphology. Overall, this systems approach serves to explain a number of apparent paradoxes of serum ferritin, including (i) why it correlates with biomarkers of cell damage, (ii) why it correlates with biomarkers of hydroxyl radical formation (and oxidative stress) and (iii) therefore why it correlates with the presence and/or severity of numerous diseases. This leads to suggestions for how one might exploit the corollaries of the recognition that serum ferritin levels mainly represent a consequence of cell stress and damage.

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

BACKGROUND/AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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