Liver iron concentration in dysmetabolic hyperferritinemia: Results from a prospective cohort of 276 patients

Relationship Between Hepatic Iron Concentration and Glycemic Metabolism, Prediabetes, and Type 2 Diabetes: A Systematic Review

CONTEXT

Emerging research has suggested a potential link between high iron levels, indicated by serum ferritin levels, and the development of type 2 diabetes (T2D). However, the role of hepatic iron concentration (HIC) on T2D development and progression is not well understood.

OBJECTIVES

This study aims to systematically review the literature on HIC and/or the degree of hepatic iron overload (HIO) in individuals with prediabetes and/or diagnosed T2D, and to analyze associations between HIC and markers of glucose metabolism.

DATA SOURCES

The databases Medline, PubMed, Embase, CINAHL, and Web of Knowledge were searched for studies published in English from 1999 to March 2024. This review followed the Preferred Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist.

DATA EXTRACTION

Data were extracted following the established eligibility criteria. Study characteristics and biomarkers related to prediabetes, T2D, and HIO were extracted. The risk of bias was analyzed using the Newcastle-Ottawa Scale. Data were stratified by the exposure and analyzed in subgroups according to the outcome. Data regarding the HIC values in controls, individuals with prediabetes, and individuals with T2D and the association estimates between HIC or HIO and markers of glycemic metabolism, prediabetes, or T2D were extracted.

DATA ANALYSIS

A total of 12 studies were identified, and data from 4110 individuals were analyzed. HIO was not consistently observed in prediabetic/T2D populations; however, elevated HIC was frequently observed in prediabetic and T2D individuals, and was associated with the disruption of certain glycemic markers in some cases.

CONCLUSION

The extent of iron overload, as indicated by hepatic iron load, varied among the prediabetic and T2D populations studied. Further research is needed to understand the distribution and regulation of iron in T2D pathology.

Consensus Statement on the definition and classification of metabolic hyperferritinaemia

Hyperferritinaemia is a common laboratory finding that is often associated with metabolic dysfunction and fatty liver. Metabolic hyperferritinaemia reflects alterations in iron metabolism that facilitate iron accumulation in the body and is associated with an increased risk of cardiometabolic and liver diseases. Genetic variants that modulate iron homeostasis and tissue levels of iron are the main determinants of serum levels of ferritin in individuals with metabolic dysfunction, raising the hypothesis that iron accumulation might be implicated in the pathogenesis of insulin resistance and the related organ damage. However, validated criteria for the non-invasive diagnosis of metabolic hyperferritinaemia and the staging of iron overload are still lacking, and there is no clear evidence of a benefit for iron depletion therapy. Here, we provide an overview of the literature on the relationship between hyperferritinaemia and iron accumulation in individuals with metabolic dysfunction, and on the associated clinical outcomes. We propose an updated definition and a provisional staging system for metabolic hyperferritinaemia, which has been agreed on by a multidisciplinary global panel of expert researchers. The goal is to foster studies into the epidemiology, genetics, pathophysiology, clinical relevance and treatment of metabolic hyperferritinaemia, for which we provide suggestions on the main unmet needs, optimal design and clinically relevant outcomes.

Dysmetabolic Iron Overload Syndrome: Going beyond the Traditional Risk Factors Associated with Metabolic Syndrome

Dysmetabolic iron overload syndrome (DIOS) corresponds to the increase in iron stores associated with components of metabolic syndrome (MtS) and in the absence of an identifiable cause of iron excess. The objective of this work was to review the main aspects of DIOS. PUBMED and EMBASE were consulted, and PRISMA guidelines were followed. DIOS is usually asymptomatic and can be diagnosed by investigating MtS and steatosis. About 50% of the patients present altered hepatic biochemical tests (increased levels of γ-glutamyl transpeptidase itself or associated with increased levels of alanine aminotransferase). The liver may present parenchymal and mesenchymal iron overload, but the excess of iron is commonly mild. Steatosis or steatohepatitis is observed in half of the patients. Fibrosis is observed in about 15% of patients. Hyperferritinemia may damage the myocardium, liver, and several other tissues, increasing morbidity and mortality. Furthermore, DIOS is closely related to oxidative stress, which is closely associated with several pathological conditions such as inflammatory diseases, hypertension, diabetes, heart failure, and cancer. DIOS is becoming a relevant finding in the general population and can be associated with high morbidity/mortality. For these reasons, investigation of this condition could be an additional requirement for the early prevention of cardiovascular diseases.

Distribution and Associated Factors of Hepatic Iron-A Population-Based Imaging Study

Hepatic iron overload can cause severe organ damage; therefore, an early diagnosis and the identification of potential risk factors is crucial. We aimed to investigate the sex-specific distribution of hepatic iron content (HIC) in a population-based cohort and identify relevant associated factors from a panel of markers. We analyzed N = 353 participants from a cross-sectional sample (KORA FF4) who underwent whole-body magnetic resonance imaging. HIC was assessed by single-voxel spectroscopy with a high-speed T2-corrected multi-echo technique. A large panel of markers, including anthropometric, genetic, and laboratory values, as well as behavioral risk factors were assessed. Relevant factors associated with HIC were identified by variable selection based on LASSO regression with bootstrap resampling. HIC in the study sample (mean age at examination: 56.0 years, 58.4% men) was significantly lower in women (mean ± SD: 39.2 ± 4.1 s^-1) than in men (41.8 ± 4.7 s^-1, p < 0.001). Relevant factors associated with HIC were HbA1c as well as prediabetes for men and visceral adipose tissue as well as age for women. Hepatic fat, alcohol consumption, and genetic risk score for iron levels were associated with HIC in both sexes. In conclusion, there are sex-specific associations of HIC with markers of body composition, glucose metabolism, and alcohol consumption.