Hyperglycaemia enhances renal magnesium excretion in type 1 diabetic patients

Association Between Serum Magnesium and Glycemic Control, Lipid Profile and Diabetic Retinopathy in Type 1 Diabetes

Introduction: Many studies have shown an association between decreased serum magnesium (Mg) levels and poor glycemic control and dyslipidemia in individuals with type 1 diabetes (T1D). Few studies evaluated the association between magnesium (Mg) levels and diabetic retinopathy (DR) in individuals with type 1 diabetes (T1D).

Methods: Retrospective study of adults with T1D, with an ophthalmological evaluation and a serum Mg level determination. According to Mg levels, the individuals were stratified into two groups: normal Mg levels (1.81-2.60 mg/dL) and low Mg levels (≤1.80 mg/dL). Exclusion criteria were individuals on diuretics or proton-pump inhibitors, malabsorption or diarrhea, oral magnesium supplementation in the recent past, pregnancy, or sepsis.

Results: 105 individuals, with median Mg levels of 1.96 (interquartile range 0.23) mg/dL. Hypomagnesemia (≤1.80 mg/dL) was detected in 20.0% individuals and 26.7% had DR. Individuals with hypomagnesemia had higher HbA1c (p = 0.014) and triglycerides (p = 0.024). Mg levels were negatively correlated with systolic blood pressure (r = -0.200, p = 0.041), HbA1c (r = -0.281, p = 0.004) and body mass index (BMI) (r = -0.197, p = 0.041). There was no significant difference between Mg levels or prevalence of hypomagnesemia in individuals with or without DR. Also, there was no significant difference between Mg levels and the severity of DR.

Conclusion: Hypomagnesemia is a common problem in adults with T1D, and it was correlated with poor glycemic control, although we did not find a significant association between Mg levels and prevalence or severity of DR.

Circulating magnesium status is associated with type 2 diabetes remission after Roux-en-Y gastric bypass surgery: a long-term cohort study

BACKGROUND

Low serum magnesium levels predict cardiovascular and all-cause mortality in patients with typ 2 diabetes.

SETTING

Outpatient clinic of obesity and central hospital.

OBJECTIVES

To assess long-term alterations in circulating magnesium status after Roux-en-Y gastric bypass (RYGB) surgery and associations with remission of type 2 diabetes (T2D).

METHODS

Retrospective analysis of 5-year outcomes of plasma magnesium (p-Mg) and glucometabolic statuses in patients who underwent primary RYGB and who completed the annual follow-up program. Data were investigated from 84 patients without diabetes and 62 with T2D before RYGB, who showed either prolonged remission (n = 30), temporary remission (n = 16), or no remission (n = 16) after surgery.

RESULTS

Body mass indexes before RYGB were similar in patients with and without T2D, irrespective of remission. The patients not achieving remission showed longer diabetes durations; higher circulating glucose levels; more intensive antidiabetic drug treatment, including insulin; and significantly lower p-Mg concentrations (.73 [±.08] mmol/L compared with .80-.82 [±.07] mmol/L, respectively; P < .01) than the groups showing remission or without diabetes before surgery. After RYGB, the p-Mg increased similarly, by 10-12% in the groups with T2D before surgery, irrespective of remission; however, the nonremission group did not reach the p-Mg levels registered in the other groups after follow-up. The nonremission group reached .82 (.09) mmol/L, compared with .87 (.06) and .88 (.08) mmol/L (P < .05), respectively, in patients with remission or without a history of diabetes.

CONCLUSION

The p-Mg concentrations increased after RYGB, with similar increments irrespective of T2D remission; however, the nonremission group started from an inferior level and did not reach the p-Mg concentrations seen in the groups achieving remission or without a history of diabetes before surgery.

Association between reduced serum levels of magnesium and the presence of poor glycemic control and complications in type 1 diabetes mellitus: A systematic review and meta-analysis

OBJECTIVE

To evaluate the association between reduced serum magnesium levels and poor glycemic control and/or complications in patients with type 1 diabetes mellitus through a systematic review and meta-analysis.

METHODS

The articles were selected using the Medline/PubMed, Web of Science, Scopus and Scielo databases. Eligibility criteria were cross-sectional, cohort or case-control observational studies that assessed the association between reduced magnesium levels and poor glycemic control and/or complications in patients with type 1 diabetes mellitus.

RESULTS

Nine articles were included in the systematic review and two in the meta-analysis, all articles being cross-sectional. Among the seven studies that were designed to evaluate glycemic control, five showed an association between reduced levels of magnesium and poor glycemic control, and these findings were corroborated by the meta-analysis. Among the two studies in which dyslipidemia was evaluated, both showed higher levels of triglycerides, total cholesterol and LDL cholesterol, and lower levels of HDL cholesterol in patients with lower levels of magnesium as compared to those with higher magnesium levels. The three studies that evaluated diabetes kidney disease and the two studies that evaluated diabetic retinopathy found divergent results.

CONCLUSION

There is an association between reduced levels of magnesium and poor glycemic control in patients with type 1 diabetes mellitus, however, this needs further studies.

Hypomagnesaemia and pregnancy

Hypomagnesaemia is common in pregnancy, particularly in developing countries and low-income communities. Despite the frequent therapeutic use of magnesium in pregnancy, and the evidence regarding the association of hypomagnesaemia with adverse pregnancy outcomes in animal studies, it remains unclear whether hypomagnesaemia is associated with complications in human pregnancy. Three case reports of pregnancies complicated by moderate-severe hypomagnesaemia are presented and magnesium physiology in pregnancy is discussed. The evidence as to whether hypomagnesaemia may represent a direct cause, a consequence of other disease processes or an epiphenomenon in adverse pregnancies outcomes is reviewed.

Increased circulating magnesium concentrations after Roux-en-Y gastric bypass surgery in patients with type 2 diabetes

BACKGROUND

Low circulating magnesium concentrations predict cardiovascular and all-cause mortality in patients with type 2 diabetes (T2D). Epidemiologic and clinical studies have indicated lower extra- and intracellular magnesium concentrations in patients with diabetes.

OBJECTIVE

We aimed to describe alterations, if any, in circulating magnesium concentrations after laparoscopic Roux-en-Y gastric bypass surgery (LRYGB) in patients with obesity and T2D.

SETTING

Outpatient clinic of obesity and central hospital.

METHODS

Retrospective analysis of 1-year outcome of plasma magnesium (p-Mg) and glucometabolic status in all consecutive patients who underwent primary LRYGBP and who completed the follow-up visits, including biochemical test panels 6 and 12 months after surgery.

RESULTS

LRYGBP and complete follow-up visits were performed in 51 patients with T2D and 86 patients without T2D. All patients were given similar dietary advice and multivitamin and mineral supplementation after surgery. Before RYGB, the patients with T2D showed lower p-Mg compared with patients without T2D (.79 ± .06 mM and .82 ± .05 mM, respectively, P<.01). P-Mg was inversely correlated to fasting blood glucose and glycosylated hemoglobin levels. After surgery, mean p-Mg increased by 5.2% in the group with T2D compared with 1.4% in the patients without T2D (P<.01), ending at an equal level of .83 mM. The alterations in p-Mg were inversely related to the changes in fasting glucose and glycosylated hemoglobin concentrations.

CONCLUSION

The lowered p-Mg associated with impaired glucometabolic status in patients with T2D was increased after LRYGBP, reaching similar concentrations as in patients without T2D.

Serum trace elements in insulin-dependent and non-insulin-dependent diabetes: a comparative study

BACKGROUND

Diabetes mellitus is associated with imbalance in body trace elements. The aim of the current investigation was to compare the levels of trace elements (Zn, Mg, Mn, Cu, Na, K, Fe, Ca, Cr, and Se) in insulin dependent (IDDM) and non-insulin dependent (NIDDM) diabetes.

METHODS

A total of 100 patients with diabetes (40 IDDM and 60 NIDDM) and 50 healthy subjects were recruited in the study from both genders. Biochemical measures include glucose, lipids, and HbA1C.

RESULTS

The results showed that Zn, Mg, Cu and Cr were significant lower in patients with diabetes compared to the control group (P<0.01). In addition, Zn and Cr were significantly lower in IDDM than NIDDM (P<0.05). Moreover, Zn and Mg levels were inversely correlated with HbA1c in IDDM and NIDDM (P<0.05). Zn was inversely correlated with fasting blood glucose in IDDM (P<0.05). Finally, no correlation between trace element levels with BMI was found (P>0.05).

CONCLUSION

Disturbance in trace element profile among IDDM and NIDDM is similar.

Increased plasma magnesium concentrations 3 years after biliopancreatic diversion with duodenal switch

BACKGROUND

Biliopancreatic diversion with duodenal switch, BPD-DS, is a surgical procedure for treatment of super obese patients. It renders very good weight results and it strongly reduces the incidence of type 2 diabetes. One important mechanism of weight reduction after BPD-DS is malabsorption. Hypomagnesemia is an established cardiovascular risk factor. While it is well-known that magnesium levels decline after jejuno-ileal bypass and increase after gastric bypass surgery, information on how magnesium status is affected by BPD-DS is scant. The aim of the present study was to evaluate plasma magnesium concentrations (P-Mg) after BPD-DS.

METHODS

Thirty-one patients, all Caucasians (9 diabetics, 12 men, age 38 ± 8 years, weight 159 ± 22 kg, body mass index (BMI) 53.9 ± 5.2 kg/m(2)) underwent BPD-DS. We evaluated weight, glycated hemoglobin levels (HbA1c) and P-Mg preoperatively as well as at 1 and 3 years after surgery. All subjects were treated with vitamin and mineral substitution after surgery, including 100 mg of magnesium salt. P-Mg was analyzed with respect to changes over time, correlation to BMI and HbA1c levels before and 3 years after surgery.

RESULTS

The plasma magnesium concentrations increased by 15 % from 0.77 ± 0.07 to 0.88 ± 0.09 mmol/l over 3 years (p < 0.001). The weight loss was 71 ± 25 kg. No patient had diabetes at follow-up. No correlations between P-Mg and BMI or HbA1c were seen.

CONCLUSIONS

Although exerting much of its weight-reducing effect by a malabsorptive mechanism, BPD-DS yields a rise in P-Mg 3 years postoperatively, possibly contributing to the improved metabolic state after this operation.

Serum magnesium and atherogenic lipid fractions in type II diabetic patients of Lahore, Pakistan

This study was conducted to determine the prevalence of hypomagnesemia and its effect on the lipid profile of local type II diabetic patients. For this purpose, 219 diabetic patients and 100 age-matched control subjects were enrolled. Blood samples of the subjects were analyzed for fasting glucose, Mg, triglyceride, total cholesterol, HDL-cholesterol, and LDL-cholesterol. Results showed that mean serum values of these parameters were differing in diabetic patients as compared to control subjects. The reference range of serum magnesium in healthy controls was 1.2-4.4 mg/dl. Mean serum magnesium in diabetic patients was significantly lower as compared to healthy subjects (1.6 ± 0.23 mg/dl vs. 2.8 ± 0.8 mg/dl). Among diabetic patients, 143 (65.3%) had serum magnesium level below 1.7 mg/dl (hypomagnesemia). The corresponding figure for control subjects was 11 (11%). The difference was significant (p < 0.01). Diabetes mellitus patients with current hyperglycemic status had significantly lower serum Mg as compared to euglycemic patients (p = 0.05). Serum Mg in diabetic patients was correlated with all lipid parameters. Among them, HDL-cholesterol was significantly (p < 0.05) positively correlated (r = 0.34), while total cholesterol and LDL-cholesterol was negatively correlated, albeit non-significantly, with serum Mg. These results demonstrate that hypomagnesemia is accompanied by atherogenic alterations in the lipid profiles of type II diabetic patients of Lahore, Pakistan.

Physiology of epithelial Ca2+ and Mg2+ transport

Ca2+ and Mg2+ are essential ions in a wide variety of cellular processes and form a major constituent of bone. It is, therefore, essential that the balance of these ions is strictly maintained. In the last decade, major breakthrough discoveries have vastly expanded our knowledge of the mechanisms underlying epithelial Ca2+ and Mg2+ transport. The genetic defects underlying various disorders with altered Ca2+ and/or Mg2+ handling have been determined. Recently, this yielded the molecular identification of TRPM6 as the gatekeeper of epithelial Mg2+ transport. Furthermore, expression cloning strategies have elucidated two novel members of the transient receptor potential family, TRPV5 and TRPV6, as pivotal ion channels determining transcellular Ca2+ transport. These two channels are regulated by a variety of factors, some historically strongly linked to Ca2+ homeostasis, others identified in a more serendipitous manner. Herein we review the processes of epithelial Ca2+ and Mg2+ transport, the molecular mechanisms involved, and the various forms of regulation.

Measurement of magnesium absorption and retention in type 2 diabetic patients with the use of stable isotopes

BACKGROUND

Magnesium deficiency has been associated with type 2 diabetes and may reduce insulin sensitivity and impair glucose tolerance. The etiology of magnesium depletion in diabetes is unclear. Animal studies suggest that diabetes may impair magnesium absorption; however, there are no published data on magnesium absorption in humans with diabetes.

OBJECTIVE

Magnesium absorption from a test meal and the excretion and retention of magnesium were compared between patients with type 2 diabetes and healthy control subjects.

DESIGN

A meal labeled with 10 mg (26)Mg isotopic label was administered, and stool and urine samples were collected for 10 and 6 d, respectively. Apparent absorption was calculated as the difference between the oral dose of (26)Mg isotopic label and the total amount of the isotopic label excreted in the feces. Magnesium retention was calculated from the apparent absorption and urinary excretion of (26)Mg isotopic label in the 6 d after administration.

RESULTS

Mean (+/- SD) values for fractional magnesium absorption in the diabetic patients and the control subjects were 59.3 +/- 7.0% and 57.6 +/- 8.5%, respectively (NS). Mean (+/- SD) urinary magnesium excretion values in the diabetic patients and the control subjects were 11.2 +/- 2.6% and 11.7 +/- 3.8%, respectively (NS); retention values were 54.2 +/- 7.1% and 51.4 +/- 6.1%, respectively (NS).

CONCLUSION

Dietary magnesium absorption and retention are not impaired in patients with reasonably well-controlled type 2 diabetes.