Serum magnesium, iron and ferritin levels in patients with diabetic retinopathy attending Makkah Eye Complex, Khartoum, Sudan

Effect of diabetic macular oedema on serum iron status indicators

CLINICAL RELEVANCE

The role of subclinical inflammation in the pathophysiology of diabetic macular oedema (DME), which is known to be quite complex, is of much interest. Serum ferritin level, which is an indicator of body iron stores, is both an inflammatory marker for various neurodegenerative diseases and an important indicator in the evaluation of iron-induced oxidative stress.

BACKGROUND

Iron metabolism indicators play a role in the formation and development of diabetic retinopathy, which is known to be associated with subclinical inflammation, and may also play a role in the pathogenesis of DME. The aim of this study was to investigate the role of serum iron metabolism markers in the pathogenesis of DME.

MATERIALS AND METHODS

The files of all nonproliferative diabetic retinopathy (NPDR) patients who were scheduled for the first intravitreal injection for DME in the eye clinic between January 2019 and January 2020 were reviewed retrospectively. By examining the files of all diabetes mellitus patients who attended the outpatient eye clinic on the same dates, those without retinopathy and those with NPDR but not DME were recorded. All results, including a comprehensive ophthalmological examination, laboratory data of fasting blood tests, and an internal medicine outpatient examination were collected for analysis.

RESULTS

Of the 157 participants, 44 were NPDR patients with oedema, 50 were NPDR patients without oedema, and 63 were patients without retinopathy. There was a significant difference between the groups in respect of creatinine, high-density lipoprotein, mean corpuscular volume, serum iron and ferritin, total iron binding capacity and transferrin saturation (p < 0.050). Ferritin values were found to be significantly higher in patients with macular oedema. Other iron status markers were found to be significantly lower (p < 0.050).

CONCLUSION

Evaluation of serum iron status indicators in the routine follow-up of diabetic patients may be of diagnostic and/or prognostic benefit in terms of DME.

Reduced serum magnesium is associated with the occurrence of diabetic macular edema in patients with diabetic retinopathy: A retrospective study

Serum magnesium levels have been reported to reflect the risk of diabetic retinopathy (DR); however, the effect of serum magnesium level on diabetic macular edema (DME) remains unclear. Here, we investigated the association between the serum magnesium levels and DME in patients with DR. Patients with DR were recruited between January 2018 and June 2021. A total of 519 such patients were included in this study. All patients underwent a standardized clinical ophthalmic examination by an experienced ophthalmologist, and an assay was conducted to determine the serum magnesium concentration. Compared with the non-DME group, the DME group had a higher proportion of insulin use and a higher level of serum ischemia-modified albumin and fasting plasma glucose. The serum magnesium and calcium levels were lower in the DME group than in the non-DME group (P &lt; 0.05). Higher magnesium levels were negatively associated with DME after adjustment for relevant covariates. Compared with the participants in the lowest magnesium quartile, those in the fourth quartile showed a significantly lower risk of DME after adjustment [odds ratio (OR), 0.294; 95% confidence interval, 0.153–0.566; P &lt; 0.0001]. Considering the potentially different effects of serum magnesium on the development of DME in patients with DR based on age, DR staging and insulin use, stratified analysis was performed by considering these factors. Among insulin-using patients with non-proliferative DR who were &lt; 66 years of age, those in the third and fourth quartile of serum magnesium were less likely to develop DME than those in the lowest quartile of serum magnesium [OR (95% CI), 0.095 (0.014–0.620), 0.057 (0.011–0.305); P = 0.014, 0.001]. Overall, a higher serum magnesium level was associated with a lower risk of DME in patients with DR. Furthermore, patients with DR who used insulin were more likely to develop DME. Long-term studies on oral magnesium supplements are needed to determine whether maintaining the serum magnesium levels in a higher physiological range can reduce the risk of DME in patients with DR.

Reduced Serum Magnesium Levels Are Associated with the Occurrence of Retinopathy in Patients with Type 2 Diabetes Mellitus: a Retrospective Study

The aim of this study is to explore the relationship between serum magnesium (Mg²⁺) level and diabetic retinopathy (DR) in patients with type 2 diabetes mellitus (T2DM). The clinical data of 2222 patients with T2DM, including 713 patients with DR and 1509 patients without DR, between September 2016 and August 2020 in our hospital, were analyzed retrospectively. Further, the role and predictive value of serum Mg²⁺ on the prevalence of DR were determined through logistic regression and the receiver operating characteristic (ROC) curve respectively. The level of serum Mg²⁺ was lower in DR group than that in non-DR group (0.92 vs 0.88 mmol/L, P < 0.001). Stratified serum Mg²⁺ levels into quartiles (Q1-Q4), the first (Q1, Mg²⁺ ≤ 0.85 mmol/L) and fourth quartile (Q4, ≥ 0.96 mmol/L) represented the lowest and highest quartile, respectively. And the incidence of DR was obviously higher in Q1 and Q2 than that in Q3 and Q4 (50.9% and 30.2% vs 23.5% and 21%, respectively). Logistic regression demonstrated that there remained an independent association between lower serum Mg²⁺ levels and the occurrence of DR (OR were 3.907 and 1.709 in Q1 and Q2, respectively) no matter whether the interference of confounding variables. ROC curve showed the best cut-off value of serum Mg²⁺ level in predicting the occurrence of DR was 0.875 mmol/L. Lower Mg²⁺ levels are related with an increased risk of developing DR. Serum Mg²⁺ level can be a potential clinical indicator to help identify DR in patients with T2DM.

Trace elements exposure and risk in age-related eye diseases: a systematic review of epidemiological evidence

This systematic review aimed to evaluate existing evidence on the associations between trace elements exposure and age-related eye diseases. PubMed and Google scholar databases were searched for epidemiological and postmortem studies on the relationship between exposure to trace elements and Age-related eye diseases such as age-related macular degeneration (AMD), cataract, glaucoma and diabetic retinopathy (DR), in population groups aged 40 years and above. Available evidence suggests that cadmium (Cd) exposure may be positively associated with the risks of AMD and cataract. There is also evidence that exposure to lead (Pb) may be positively associated with higher risk of cataract and glaucoma. There is limited number of relevant studies and lack of prospective studies for most of the investigated associations. Evidence for other trace elements is weak and inconsistent, and the number of available studies is small. Likewise, there are very few relevant studies on the role of trace elements in DR. Chemical elements that affect the distribution and absorption of other trace elements have never been investigated. The suggestive but limited evidence motivates large and quality prospective studies to fully characterize the impact of exposure to trace (toxic and essential) elements on age-related eye diseases.

Role of Magnesium in Type 2 Diabetes Mellitus

Magnesium (in its ionized and biologically active form, Mg²⁺) is an essential trace element that participates in numerous physiologic processes. Abnormal Mg²⁺ homeostasis can lead to many metabolic disorders, including diabetes mellitus (DM) and its complications. Mg²⁺ participates in energy generation and is required for DNA and RNA synthesis, reproduction, and protein synthesis. Additionally, Mg²⁺ acts as a calcium antagonist and protects vascular endothelial cells from oxidative stress. Imbalances in Mg²⁺ status, more frequently hypomagnesemia, inhibit glucose transporter type 4 translocation, increase insulin resistance, affect lipid metabolism, induce oxidative stress, and impair the antioxidant system of endothelial cells, In these ways, hypomagnesemia contributes to the initiation and progression of DM and its macrovascular and microvascular complications. In this review, we summarize recent advances in knowledge of the mechanisms whereby Mg²⁺ regulates insulin secretion and sensitivity. In addition, we discuss the future prospects for research regarding the mechanisms whereby Mg²⁺ status impacts DM and its complications.

Serum magnesium and high-sensitivity C-reactive protein as a predictor for gestational diabetes mellitus in Sudanese pregnant women

Background

Gestational diabetes mellitus (GDM) is a big health problem that adversely affects both the maternal and perinatal outcomes. We aimed to predict the development of GDM in the first trimester using high sensitivity C-reactive protein (hs-CRP) and serum magnesium.

Methods

The study conducted in the antenatal care clinic of Saad Abualila Hospital (Khartoum, Sudan). Pregnant women were enrolled in this longitudinal cohort study during first trimester ≤14 weeks of gestation. Serum hs-CRP and magnesium concentrations were measured between weeks 11 and 14 of gestation. Glucose tolerance test and fasting plasma insulin (FPI) measurement were performed between 24 and 28 weeks gestational age. To assess insulin sensitivity and β-cell function, Homeostatic Model Assessment Insulin Resistance (HOMA-IR), HOMA-β indices and Quantitative Insulin Sensitivity Check Index (QUICKI) were calculated and used.

Results

Out of the 126 who completed the study 19 (15%) were diagnosed as GDM. The median (interquartile) of FBG was significantly higher in women with GDM [81 (70–95) vs. 67(60–75) mg/dl; P = < 0.001] compared to women without GDM. There was no significant difference in hs-CRP, serum magnesium, HOMA-IR, QUICKI and HOMA- β between women with GDM and women without GDM. No correlation was observed between body mass index (BMI), serum magnesium, hs-CRP, FBG and insulin levels.

Conclusions

First trimester hs-CRP and serum magnesium levels were not correlated with the later development of gestational diabetes in this setting.

Evaluation of Circulating Plasma VEGF-A, ET-1 and Magnesium Levels as the Predictive Markers for Proliferative Diabetic Retinopathy

Diabetic retinopathy (DR) is the most common cause for preventable blindness in India. The onset of micro and macrovascular complications in T2DM is multifactorial and difficult to predict. The status of micronutrients, several inflammatory cytokines, elevated triacylglycerols, oxidative stress etc., are being studied extensively. Hypomagnesemia plays a pivotal role in worsening of insulin resistance. Although, Vascular Endothelial Growth Factor-A (VEGF-A) and Endothelin-1 (ET-1) are known to be elevated in DR, yet few reports cite their role, especially in Indian population. In this study, we included thirty subjects with T2DM in each of the three groups namely, T2DM cases without retinopathy, Non Proliferative DR (NPDR) and Proliferative DR (PDR) retinopathy. The glycemic status, circulating plasma VEGF-A, ET-1 levels, serum magnesium and lipids were estimated and compared among the groups. An ROC was drawn to evaluate VEGF-A, ET-1 and serum magnesium levels as the predictive markers for PDR. On comparison VEGF-A, ET-1 and serum magnesium levels showed a significant difference among the three groups. PDR cases had higher circulating levels of VEGF-A, ET-1 and low serum magnesium levels when compared to others. ROC for VEGF-A and ET-1 showed an optimum cut-off of 1521 ng/ml (AUC 0.975) and 16 pg/ml (AUC 0.96) respectively. A negative ROC was drawn to check the lower cut-off limit for serum magnesium; we documented an optimum cut off of 1.7 mg/dl (AUC 0.837). ET-1, VEGF-A and serum Magnesium levels are significantly altered in PDR and can be used as the predictive markers of PDR.

Serum Magnesium Concentration Is Inversely Associated with Albuminuria and Retinopathy among Patients with Diabetes

Aim. To investigate the association between serum magnesium levels and microvascular complications among patients with diabetes. Methods. Patients with diabetes were recruited between April 2012 and January 2015. All patients received an assay of serum magnesium concentration, were screened for 24 h albumin excretion rate, and underwent nonmydriatic fundus photography. Albuminuria and retinopathy were defined accordingly. A total of 3,100 patients with normal serum magnesium levels were included in this study. Results. Patients with albuminuria and/or retinopathy had lower levels of serum magnesium than patients without these complications (P < 0.001). The prevalence of isolated albuminuria, isolated retinopathy, and combined albuminuria and retinopathy decreased as the concentration of serum magnesium increased. Multiple logistic regression analysis indicated that the odds ratio for isolated albuminuria, isolated retinopathy, and concomitant albuminuria and retinopathy decreased by approximately 20% for every 0.1 mmol/L increase in serum magnesium concentration. Conclusion. Serum magnesium levels were negatively associated with the risk of diabetic microvascular complications among patients with serum magnesium levels within the normal range.