Urinary and plasma magnesium and risk of ischemic heart disease

Associations of serum calcium/magnesium ratios with coronary artery disease in diabetes: a cross-sectional study

OBJECTIVE

The early detection of coronary artery disease (CAD) in diabetes mellitus is a major clinical difficulty. The purpose of this paper is to find out a convenient and economical index to help to screen for patients with CAD in diabetes mellitus.

METHOD

From January 2019 to December 2019, a total of 1028 patients hospitalized in the general department of our hospital have been enrolled in our cross-sectional study, of which 190 were diagnosed with CAD and 314 with diabetes. Differences of various factors between the CAD group and the non-CAD group were analyzed. The receiver operating characteristic (ROC) curve and the area under the curve (AUC) were used to evaluate the efficacy of each factor in predicting CAD. The correlation between calcium/magnesium (Ca/Mg) ratio and the prevalence of CAD in diabetic and non-diabetic people was compared, and the cutoff of Ca/Mg ratio to predict the risk of CAD in diabetic patients was calculated.

RESULTS

Logistic regression analysis showed that serum high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, calcium, magnesium, Ca/Mg ratio, hypertension, diabetes, and smoking history were all associated with CAD. Among them, the AUC value of Ca/Mg ratio was the highest of 0.70. Furthermore, in diabetes patients, the AUC value of Ca/Mg ratio to predict the risk of CAD was 0.72, the cutoff was 2.55, the sensitivity was 77.1%, and the specificity was 53.7%. The prevalence rate of CAD was 18.5% below the cutoff, 46.9% higher than the cutoff, and the prevalence rate increased by 153.5%.

CONCLUSION

The Ca/Mg ratio is a good predictor of the risk of CAD in diabetes, higher than the cutoff, the prevalence rate was significantly increased.PLA IN LANGUAGE SUMMARYCAD brings great pain and burden to patient. However, CAD is asymptomatic in quiet a few cases of type 2 diabetes until myocardial infarction or sudden cardiac death occurs. In this study, we explored the association between CAD and various serum factor. We found that the Ca/Mg ratio is of excellent value in screening CAD, especially in diabetes. Moreover, we found that the cutoff of Ca/Mg ratio was 2.55 in diabetic population and the prevalence rate of CAD was 18.5% below the cutoff, 46.9% higher than the cutoff. The Ca/Mg ratio will provide good prediction of the risk of CAD and make early detection easier in diabetes.

Calciprotein Particles Cause Physiologically Significant Pro-Inflammatory Response in Endothelial Cells and Systemic Circulation

Calciprotein particles (CPPs) represent an inherent mineral buffering system responsible for the scavenging of excessive Ca²⁺ and PO₄^3- ions in order to prevent extraskeletal calcification, although contributing to the development of endothelial dysfunction during the circulation in the bloodstream. Here, we performed label-free proteomic profiling to identify the functional consequences of CPP internalisation by endothelial cells (ECs) and found molecular signatures of significant disturbances in mitochondrial and lysosomal physiology, including oxidative stress, vacuolar acidification, accelerated proteolysis, Ca²⁺ cytosolic elevation, and mitochondrial outer membrane permeabilisation. Incubation of intact ECs with conditioned medium from CPP-treated ECs caused their pro-inflammatory activation manifested by vascular cell adhesion molecule 1 (VCAM1) and intercellular adhesion molecule 1 (ICAM1) upregulation and elevated release of interleukin (IL)-6, IL-8, and monocyte chemoattractant protein-1/ C-C motif ligand 2 (MCP-1/CCL2). Among the blood cells, monocytes were exclusively responsible for CPP internalisation. As compared to the co-incubation of donor blood with CPPs in the flow culture system, intravenous administration of CPPs to Wistar rats caused a considerably higher production of chemokines, indicating the major role of monocytes in CPP-triggered inflammation. Upregulation of sICAM-1 and IL-8 also suggested a notable contribution of endothelial dysfunction to systemic inflammatory response after CPP injections. Collectively, our results demonstrate the pathophysiological significance of CPPs and highlight the need for the development of anti-CPP therapies.

The Risk of CVDs from Desalinated Seawater: A Nested Case-Control Study

The aim of this paper was to assess the association between desalinated seawater and cardiovascular diseases (CVDs). We conducted a nested case-control prospective study on a cohort of 7806 subjects who live on an island of China that lacks fresh water. From this cohort, we identified 140 paired CVD cases and matched controls by sex and age during the same period. Questionnaires were used in order to investigate basic sociodemographic information and risk factors for CVDs, and urine samples were collected to measure calcium and magnesium levels. Using these data we developed and tested both univariate and multivariate logistic regression models. We observed no significant differences in risk of CVDs between groups with desalinated seawater and fresh water intake. From multivariate logistic regression, we found that obesity (OR = 5.38, 95% CI: 1.05–27.45), physical activity (OR = 0.35, 95% CI: 0.16–0.75), hypertension (OR = 3.61, 95% CI: 1.58–8.25), alcohol consumption (OR = 2.57, 95% CI: 1.02–6.47), and irritability (OR = 4.30, 95% CI: 1.93–9.60) were associated with an increased risk of CVD. In this population, we found no association between desalinated seawater intake and CVDs; the incidence of CVDs was primarily related to lifestyle.

Associations between the serum magnesium and all-cause or cardiovascular mortality in chronic kidney disease and end-stage renal disease patients: A meta-analysis

BACKGROUND

Some studies have found that hypomagnesemia is associated with vascular calcification, atherosclerosis, and cardiovascular disease, which may lead to increased mortality in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD) who need to maintain hemodialysis (HD). However, the conclusion of these studies remain controversial.

METHODS

Relevant literature was retrieved from the database of Cochrane library, PubMed, EMBASE, and CNKI until December 2020, without any language restrictions. The data was analyzed using the Stata 12.0 software.

RESULTS

A total of 31 studies were included, involving 205436 participants. The results showed that after multivariable adjusted, hypomagnesemia was significant associated with the risk of all-cause mortality in patients with CKD and end-stage renal disease (ESRD) (hazard ratios [HR] 1.955; 95% confidence interval (95% CI) 1.511-2.528; P = .000; hypomagnesemia vs normal magnesium or hypermagnesemia). In contrast, in patients with CKD and ESRD, hypermagnesemia was negatively correlated with all-cause mortality (HR 0.873; 95% CI 0.793-0.960; P = .005) (per unit increase). Moreover, in the adjusted model, it was observed that hypermagnesemia was significantly associated with a reduced risk of cardiovascular death (HR 0.598; 95% CI 0.094-1.102, P = .020). In addition, subgroup analysis found that hypomagnesemia was closely related to the increase of all-cause mortality in HD patients (HR 1.799; 95% CI 1.375-2.354; P = .000) (hypomagnesemia vs normal magnesium or hypermagnesemia).

CONCLUSION

Our results show that hypomagnesemia is significantly associated with cardiovascular and all-cause mortality in maintenance HD patients. Further studies should be conducted to evaluate the benefits of magnesium correction in maintenance dialysis patients with hypomagnesemia.

The Effect of Magnesium Supplementation on Endothelial Function: A Randomised Cross-Over Pilot Study

Evidence supports an association between low magnesium (Mg) intake and coronary heart disease and between Mg intake and endothelial function. The aim of this study was to assess the effect of one week of Mg supplementation on endothelial function, assessed by flow mediated dilatation (FMD). Nineteen healthy men and women completed this cross-over pilot study in which participants were randomised to take an over-the-counter magnesium supplement for one week or to follow their usual diet. Weight, FMD and blood pressure (BP) were taken on completion of each intervention and 24 h urine collections and blood samples were taken to assess compliance. Baseline serum Mg was within normal range for all participants. Urinary Mg and urinary magnesium-creatinine ratio (Mg/Cr) significantly increased between interventions, (p = 0.03, p = 0.005, respectively). No significant differences in FMD or BP were found between the interventions. A significant negative correlation was seen between age and FMD (r = −0.496, p = 0.031). When adjusted for age, saturated fat was negatively associated with FMD (p = 0.045). One week of Mg supplementation did not improve FMD in a healthy population.

Serum Magnesium Is Inversely Associated With Heart Failure, Atrial Fibrillation, and Microvascular Complications in Type 2 Diabetes

OBJECTIVE

We investigated whether serum magnesium (Mg²⁺) was prospectively associated with macro- or microvascular complications and mediated by glycemic control (hemoglobin A_1c [HbA_1c]), in type 2 diabetes (T2D).

RESEARCH DESIGN AND METHODS

We analyzed in 4,348 participants the association of serum Mg²⁺ with macrovascular disease and mortality (acute myocardial infarction [AMI], coronary heart disease [CHD], heart failure [HF], cerebrovascular accident [CVA], and peripheral arterial disease [PAD]), atrial fibrillation (AF), and microvascular complications (chronic kidney disease [CKD], diabetic retinopathy, and diabetic foot) using Cox regression, adjusted for confounders. Mediation analysis was performed to assess whether HbA_1c mediated these associations.

RESULTS

The average baseline serum Mg²⁺ concentration was 0.80 ± 0.08 mmol/L. During 6.1 years of follow-up, serum Mg²⁺ was inversely associated with major macrovascular, 0.87 (95% CI 0.76; 1.00); HF, 0.76 (95% CI 0.62; 0.93); and AF, 0.59 (95% CI 0.49; 0.72). Serum Mg²⁺ was not associated with AMI, CHD, CVA, and PAD. During 5.1 years of follow-up, serum Mg²⁺ was inversely associated with overall microvascular events, 0.85 (95% CI 0.78; 0.91); 0.89 (95% CI 0.82; 0.96) for CKD, 0.77 (95% CI 0.61; 0.98) for diabetic retinopathy, and 0.85 (95% CI 0.78; 0.92) for diabetic foot. HbA_1c mediated the associations of serum Mg²⁺ with HF, overall microvascular events, diabetic retinopathy, and diabetic foot.

CONCLUSIONS

Serum Mg²⁺ concentration is inversely associated with the risk to develop HF and AF and with the occurrence of CKD, diabetic retinopathy, and foot complications in T2D. Glycemic control partially mediated the association of serum Mg²⁺ with HF and microvascular complications.

Whole-blood magnesium and blood lipids are individually and jointly associated with an elevated likelihood of youngsters being overweight or obese: A matched case-control study using the propensity score

OBJECTIVES

Youngsters who are overweight or obese (YOO) have become an important global health concern. Some micronutrients may be modifiable influential factors. This study aimed to investigate the individual and joint association of whole-blood magnesium (WBMg) and total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), or high-density lipoprotein cholesterol (HDL-C) in YOO.

METHODS

This is a propensity score matching-based case-control study. YOO was defined depending on age- and sex-specific body mass index z-score, calculated with SAS macros (%group_standard and %WHO2007) from the World Health Organization website. WBMg, blood lipids, and covariates were carefully measured by trained technicians using a whole-blood, five-element, basic analyzer and atomic absorption spectrometer or automatic biochemical analyzer. Locally weighted scattered plot smoothing and multivariable conditional logistic regression models were applied to estimate the associations of WBMg and blood lipids in YOO.

RESULTS

WBMg was positively associated with YOO. The adjusted likelihood of YOO significantly increased by 21% (odds ratio: 1.21; 95% confidence interval [CI], 1.10-1.33) with per-interquartile range elevation of WBMg. Compared with the 1st quartile, adjusted odds ratios among youngsters in the 2^nd, 3^rd, and 4^th quartiles of WBMg were 1.11 (95% CI, 0.92-1.35), 1.29 (95% CI, 1.06-1.57), and 1.47 (95% CI, 1.18-1.83), respectively. Furthermore, the relationship between WBMg and YOO was moderated by lipid profiles. Compared with those having lower (< median) WBMg and TC, TG, LDL-C, or higher (≥ median) HDL-C, youngsters with both higher WBMg and TC, TG, LDL-C, or lower HDL-C had higher YOO odds, which averagely increased by 188%, 250%, 339%, and 369%, respectively.

CONCLUSIONS

WBMg was an independent risk factor of YOO, and the associations were stronger among those with unhealthy blood lipids. Our findings can help to guide clinical and public health policies on the relevance of magnesium nutritional status.

Importance of the renal ion channel TRPM6 in the circadian secretion of renin to raise blood pressure

Blood pressure has a daily pattern, with higher values in the active period. Its elevation at the onset of the active period substantially increases the risk of fatal cardiovascular events. Renin secretion stimulated by renal sympathetic neurons is considered essential to this process; however, its regulatory mechanism remains largely unknown. Here, we show the importance of transient receptor potential melastatin-related 6 (TRPM6), a Mg²⁺-permeable cation channel, in augmenting renin secretion in the active period. TRPM6 expression is significantly reduced in the distal convoluted tubule of hypotensive Cnnm2-deficient mice. We generate kidney-specific Trpm6-deficient mice and observe a decrease in blood pressure and a disappearance of its circadian variation. Consistently, renin secretion is not augmented in the active period. Furthermore, renin secretion after pharmacological activation of β-adrenoreceptor, the target of neuronal stimulation, is abrogated, and the receptor expression is decreased in renin-secreting cells. These results indicate crucial roles of TRPM6 in the circadian regulation of blood pressure.

Circadian variation of blood pressure, with higher values in the active period, is associated with the risk of fatal cardiovascular events. Here, we show the importance of renal TRPM6, a Magnesium-permeable cation channel, in raising blood pressure by stimulating renin secretion.

Magnesium Depletion Score (MDS) Predicts Risk of Systemic Inflammation and Cardiovascular Mortality among US Adults

BACKGROUND

Kidney reabsorption of magnesium (Mg) is essential for homeostasis.

OBJECTIVES

We developed and validated models with the kidney reabsorption-related magnesium depletion score (MDS) to predict states of magnesium deficiency and disease outcomes.

METHODS

MDS was validated in predicting body magnesium status among 77 adults (aged 62 ± 8 y, 51% men) at high risk of magnesium deficiency in the Personalized Prevention of Colorectal Cancer Trial (PPCCT) (registered at clinicaltrials.gov as NCT01105169) using the magnesium tolerance test (MTT). We then validated MDS for risk stratification and for associations with inflammation and mortality among >10,000 US adults (weighted: aged 48 ± 0.3 y, 47% men) in the NHANES, a nationally representative study. A proportional hazards regression model was used for associations between magnesium intake and the MDS with risks of total and cardiovascular disease (CVD) mortality.

RESULTS

In the PPCCT, the area under the receiver operating characteristic (ROC) curve (AUC) for magnesium deficiency was 0.63 (95% CI: 0.50, 0.76) for the model incorporating the MDS with sex and age compared with 0.53 (95% CI: 0.40, 0.67) for the model with serum magnesium alone. In the NHANES, mean serum C-reactive protein significantly increased with increasing MDS (P-trend < 0.01) after adjusting for age and sex and other covariates, primarily among individuals with magnesium intake less than the Estimated Average Requirement (EAR; P-trend < 0.05). Further, we found that low magnesium intake was longitudinally associated with increased risks of total and CVD mortality only among those with magnesium deficiency predicted by MDS. MDS was associated with increased risks of total and CVD mortality in a dose-response manner only among those with magnesium intake less than the EAR.

CONCLUSIONS

The MDS serves as a promising measure in identifying individuals with magnesium deficiency who may benefit from increased intake of magnesium to reduce risks of systemic inflammation and CVD mortality. This lays a foundation for precision-based nutritional interventions.

The Acute Effect of Magnesium Supplementation on Endothelial Function: A Randomized Cross-Over Pilot Study

Magnesium (Mg) deficiency might be a catalyst in the process of endothelial dysfunction, an early event in the pathogenesis of atherosclerosis. The aim of this study was to determine the acute effect of an oral Mg supplement as compared to control on endothelial function assessed by flow-mediated dilatation (FMD). Nineteen participants (39 years, body mass index (BMI) 22.9 kg/m²) completed this randomized cross-over study. Blood pressure (BP) and FMD were measured and blood samples were taken before participants drank 200 mL water, with or without an over the counter Mg supplement (450 mg and 300 mg for men and women). Measurements were repeated at 60 and 120 min. There was a statistically significant two-way interaction between treatment and time on serum Mg (p = 0.037). A difference of −0.085 mm in FMD was observed 60-min post drink in the control group, as compared to baseline FMD, and no difference was observed in the supplement group as compared to baseline. Despite the non-significant interaction between treatment and time on FMD, once adjusted for baseline, the difference seen in the control group and the lack of change in the supplement group at 60 min post-drink suggests that Mg might attenuate the reduction in FMD post-prandially.

Magnesium: Biochemistry, Nutrition, Detection, and Social Impact of Diseases Linked to Its Deficiency

Magnesium plays an important role in many physiological functions. Habitually low intakes of magnesium and in general the deficiency of this micronutrient induce changes in biochemical pathways that can increase the risk of illness and, in particular, chronic degenerative diseases. The assessment of magnesium status is consequently of great importance, however, its evaluation is difficult. The measurement of serum magnesium concentration is the most commonly used and readily available method for assessing magnesium status, even if serum levels have no reliable correlation with total body magnesium levels or concentrations in specific tissues. Therefore, this review offers an overview of recent insights into magnesium from multiple perspectives. Starting from a biochemical point of view, it aims at highlighting the risk due to insufficient uptake (frequently due to the low content of magnesium in the modern western diet), at suggesting strategies to reach the recommended dietary reference values, and at focusing on the importance of detecting physiological or pathological levels of magnesium in various body districts, in order to counteract the social impact of diseases linked to magnesium deficiency.

Comparison of two methods for the assessment of intra-erythrocyte magnesium and its determinants: Results from the LifeLines cohort study

BACKGROUND

Direct methods for the assessment of intra-erythrocyte magnesium (dIEM) require extensive sample preparation, making them labor intensive. An alternative, less labor intensive method is indirect calculation of intra-erythrocyte magnesium (iIEM). We compared dIEM and iIEM and studied determinants of dIEM and iIEM, plasma magnesium and 24-h urinary magnesium excretion in a large population-based cohort study.

METHODS

dIEM and iIEM were measured using a validated inductively coupled plasma mass spectrometry (ICP-MS) method in 1669 individuals from the second screening from the LifeLines Cohort Study. We used linear regression analyses to study the determinants of IEM, plasma magnesium and 24-h urinary magnesium excretion.

RESULTS

Mean dIEM and iIEM were 0.20 ± 0.04 mmol/10¹² cells and 0.25 ± 0.04 mmol/10¹² cells, respectively. We found a strong correlation between dIEM and iIEM (r = 0.75). Passing-Bablok regression analyses showed an intercept of 0.015 (95% CI: 0.005; 0.023) and a slope of 1.157 (95% CI: 1.109; 1.210). In linear regression analyses, plasma levels of total- and LDL -cholesterol, and triglycerides were positively associated dIEM, iIEM, and plasma magnesium, while glucose and HbA1c were inversely associated with plasma magnesium.

CONCLUSIONS

We observed a strong correlation between dIEM and iIEM, suggesting that iIEM is a reliable alternative for the labor intensive dIEM method.

The association between use of proton-pump inhibitors and excess mortality after kidney transplantation: A cohort study

BACKGROUND

Chronic use of proton-pump inhibitors (PPIs) is common in kidney transplant recipients (KTRs). However, concerns are emerging about the potential long-term complications of PPI therapy. We aimed to investigate whether PPI use is associated with excess mortality risk in KTRs.

METHODS AND FINDINGS

We investigated the association of PPI use with mortality risk using multivariable Cox proportional hazard regression analyses in a single-center prospective cohort of 703 stable outpatient KTRs, who visited the outpatient clinic of the University Medical Center Groningen (UMCG) between November 2008 and March 2011 (ClinicalTrials.gov Identifier NCT02811835). Independent replication of the results was performed in a prospective cohort of 656 KTRs from the University Hospitals Leuven (NCT01331668). Mean age was 53 ± 13 years, 57% were male, and 56.6% used PPIs. During median follow-up of 8.2 (4.7-9.0) years, 194 KTRs died. In univariable Cox regression analyses, PPI use was associated with an almost 2 times higher mortality risk (hazard ratio [HR] 1.86, 95% CI 1.38-2.52, P < 0.001) compared with no use. After adjustment for potential confounders, PPI use remained independently associated with mortality (HR 1.68, 95% CI 1.21-2.33, P = 0.002). Moreover, the HR for mortality risk in KTRs taking a high PPI dose (>20 mg omeprazole equivalents/day) compared with patients taking no PPIs (HR 2.14, 95% CI 1.48-3.09, P < 0.001) was higher than in KTRs taking a low PPI dose (HR 1.72, 95% CI 1.23-2.39, P = 0.001). These findings were replicated in the Leuven Renal Transplant Cohort. The main limitation of this study is its observational design, which precludes conclusions about causation.

CONCLUSIONS

We demonstrated that PPI use is associated with an increased mortality risk in KTRs, independent of potential confounders. Moreover, our data suggest that this risk is highest among KTRs taking high PPI dosages. Because of the observational nature of our data, our results require further corroboration before it can be recommended to avoid the long-term use of PPIs in KTRs.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02811835, NCT01331668.

Digital arterial pressure pulse wave analysis and cardiovascular events in the general population: the Prevention of Renal and Vascular End-stage Disease study

Background:

Arterial stiffness influences the contour of the digital pressure pulse wave.

Method:

Here, we investigated whether the digital pulse propagation index (DPPI), based on the digital pressure pulse wave, DPPI is associated with cardiovascular events, heart failure, and mortality in a large population-based cohort. Between 2001 and 2003, DPPI was measured with a PortaPres noninvasive hemodynamic monitoring device (FinaPres Medical Systems, Amsterdam, The Netherlands) in participants of the Prevention of Renal and Vascular End-stage Disease study, a community-based cohort. We assessed the main determinants of the DPPI and investigated associations of DPPI with cardiovascular events and mortality.

Results:

The study included 5474 individuals. Mean age was 52.3 ± 11.8 years and 50.5% was male. Median baseline DPPI was 5.81 m/s (interquartile range 5.47–6.20). Higher age, mean arterial blood pressure, body height, heart rate, current smoking, and lower HDL cholesterol levels and waist circumference were independent determinants of the DPPI (r² = 0.43). After adjustment for heart rate, high_logDPPI was associated with all-cause mortality [hazard ratio: 1.67, 95% confidence interval (1.55–1.81) per SD; P < 0.001], cardiovascular mortality [hazard ratio 1.95 (1.72–2.22); P < 0.001], and incident heart failure with reduced ejection fraction [hazard ratio 1.81 (1.60–2.06); P < 0.001]. These associations remained independent upon further adjustment for confounders. Optimal cutoff values for DPPI ranged between 6.1 and 6.3 m/s for all endpoints. After multivariable adjustment, DPPI was no longer associated with coronary artery disease events or cerebrovascular events.

Conclusion:

The DPPI is associated with an increased risk of development of new onset heart failure with reduced ejection fraction and all-cause and cardiovascular mortality, but not with coronary artery events or cerebrovascular events.

Association between Serum Mg2+ Concentrations and Cardiovascular Organ Damage in a Cohort of Adult Subjects

Magnesium (Mg²⁺) levels are associated with insulin resistance, hypertension, atherosclerosis, and type 2 diabetes (T2DM). We evaluated the clinical utility of physiological Mg²⁺ in assessing subclinical cardiovascular organ damage including increased carotid artery intima- media thickness (c-IMT) and left ventricular mass index (LVMI) in a cohort of well-characterized adult non-diabetic individuals. Age- and gender-adjusted correlations between Mg²⁺ and metabolic parameters showed that Mg²⁺ circulating levels were correlated negatively with body mass index (BMI), fasting glucose, and 2h-oral glucose tolerance test (OGTT) glucose. Similarly, Mg²⁺ levels were significantly and negatively related to c-IMT and LVMI. A multivariate regression analysis revealed that age (β = 0.440; p < 0.0001), BMI (β = 0.225; p < 0.0001), and Mg²⁺ concentration (β = −0.122; p < 0.01) were independently associated with c-IMT. Age (β = 0.244; p = 0.012), Mg²⁺ (β = −0.177; p = 0.019), and diastolic blood pressure (β = 0.184; p = 0.038) were significantly associated with LVMI in women, while age (β = 0.211; p = 0.019), Mg²⁺ (β = −0.171; p = 0.038) and the homeostasis model assessment index of insulin resistance (HOMA-IR) (β = −0.211; p = 0.041) were the sole variables associated with LVMI in men. In conclusion, our data support the hypothesis that the assessment of Mg²⁺ as part of the initial work-up might help unravel the presence of subclinical organ damage in subjects at increased risk of cardiovascular complications.

Environmental heavy metals and cardiovascular diseases: Status and future direction

Cardiovascular disease (CVD) and environmental degradation are leading global health problems of our time. Recent studies have linked exposure to heavy metals to the risks of CVD and diabetes, particularly in populations from low- and middle-income countries, where concomitant rapid development occurs. In this review, we 1) assessed the totality, quantity, and consistency of the available epidemiological studies, linking heavy metal exposures to the risk of CVD (including stroke and coronary heart disease); 2) discussed the potential biological mechanisms underlying some tantalizing observations in humans; and 3) identified gaps in our knowledge base that must be investigated in future work. An accumulating body of evidence from both experimental and observational studies implicates exposure to heavy metals, in a dose-response manner, in the increased risk of CVD. The limitations of most existing studies include insufficient statistical power, lack of comprehensive assessment of exposure, and cross-sectional design. Given the widespread exposure to heavy metals, an urgent need has emerged to investigate these putative associations of environmental exposures, either independently or jointly, with incident CVD outcomes prospectively in well-characterized cohorts of diverse populations, and to determine potential strategies to prevent and control the impacts of heavy metal exposure on the cardiometabolic health outcomes of individuals and populations.

Serum magnesium and the incidence of coronary artery disease over a median 27 years of follow-up in the Atherosclerosis Risk in Communities (ARIC) Study and a meta-analysis

BACKGROUND

Low serum magnesium (Mg) concentrations have been associated with higher coronary artery disease (CAD) risk. A previous Atherosclerosis Risk in Communities (ARIC) Study article that evaluated the Mg-CAD association, based on 319 events occurring over 4-7 y, identified a sex-interaction whereby the inverse Mg-CAD association was much stronger among women than men. More than 1700 additional ARIC CAD events have since accrued.

OBJECTIVE

We aimed to test our hypothesis that serum Mg is inversely and independently associated with long-term CAD risk in ARIC and in a meta-analysis with other prospective studies.

METHODS

A total of 14,446 ARIC study participants (baseline mean ± SD age: 54 ± 6 y, 57% women, 27% African American) were followed for incident CAD through 2017. CAD events were defined by myocardial infarction or CAD mortality. Serum Mg was modeled as quintiles based on mean visit 1 (1987-1989) and visit 2 (1990-1992) concentrations. Cox regression models were used. We also conducted a random-effects meta-analysis incorporating these contemporary ARIC findings.

RESULTS

Over a median follow-up of 27 y, 2131 incident CAD cases accrued. Overall, low serum Mg was associated with higher CAD risk after adjustment for demographics, lifestyle factors, and other CAD risk factors than was higher serum Mg (HR Q1 compared with Q5: 1.28; 95% CI: 1.11, 1.47; P-linear trend <0.001). The association was stronger among women (HR Q1 compared with Q5: 1.53; 95% CI: 1.22, 1.92) than men (HR: 1.11; 95% CI: 0.92, 1.34) (P-interaction = 0.05). In the meta-analysis including 5 studies, the pooled RR (95% CI) for CAD in the lowest compared with the highest circulating Mg category was 1.18 (1.06, 1.31) (I2 = 22%, P-heterogeneity = 0.27).

CONCLUSIONS

In this large community-based cohort and updated meta-analysis, low circulating Mg was associated with higher CAD risk than was higher Mg. Whether increasing Mg concentrations within healthy limits is a useful strategy for CAD prevention remains to be seen.

Associations of serum magnesium levels and calcium-magnesium ratios with mortality in patients with coronary artery disease

AIMS

Low magnesium (Mg) and high calcium (Ca) levels are linked to increased cardiovascular disease (CVD) risk in the general population. This prospective study assessed whether there are any independent associations of serum Mg levels and Ca-Mg ratios with mortality in patients with coronary artery disease (CAD).

METHODS

This prospective cohort study included 3380 CAD patients. Cox regression models were used to estimate associations of serum Mg and Ca-Mg ratio with risk of mortality.

RESULTS

A total of 562 deaths (331 due to CVD) were recorded during a 7.59-year (median) follow-up. Spline plots displayed U-shaped associations between serum Mg levels and Ca-Mg ratios and risk of mortality. When compared with a moderate group, adjusted hazard ratios (95% confidence intervals) for low Mg levels and high Ca-Mg ratios were 1.59 (1.30-1.95) and 1.31 (1.06-1.61) for all-cause mortality, and 1.71 (1.32-2.22) and 1.44 (1.09-1.89) for CVD mortality, respectively. There was also a tendency to increase risk of mortality in patients with high serum Mg levels and low Ca-Mg ratios. Associations of low serum Mg and high Ca-Mg ratio with risk of mortality did not change when stratified by gender, body mass index, CAD type, estimated glomerular filtration rate, use of diuretics, or history of diabetes or hypertension.

CONCLUSION

This study demonstrated that a moderate Ca-Mg ratio (range: 3.91-4.70) had the lowest mortality risk, and that low serum Mg and high Ca-Mg ratio were independent risk factors of mortality in CAD patients. Nevertheless, the optimal dose-response of Mg and Ca for mitigating CAD risk still requires further investigation.

Magnesium: An old player revisited in the context of CKD-MBD

Chronic kidney disease (CKD) is associated with a wide number of abnormalities in mineral metabolism. Often, these alterations are the leading players in the development of comorbidities associated with CKD, which are risk factors of mortality. In this context, mineral and bone disorder associated with CKD (CKD-MBD) are highlighted, connecting bone, renal, and cardiovascular disorders. Many studies have been led to propose strategies to avoid, reduce, or slow down CKD-MBD progression using different compositions of metallic elements-based P binders such as aluminum, magnesium, or calcium. Magnesium, the aim of this review, has been used by nephrologists to treat CKD-MBD with a variable acceptation due mainly to different results on bone homeostasis. Nowadays, we have new evidence about the efficacy of magnesium supplementation on vascular calcification, renal function, and bone disorders, suggesting potential beneficial effects of Magnesium in the management of CKD-MBD.

Hypomagnesemia and Short-Term Mortality in Elderly Maintenance Hemodialysis Patients

Background

The relationship between magnesium and mortality in hemodialysis patients has been evaluated in several prospective studies, but few have assessed the risk of all-cause mortality in elderly hemodialysis patients. The aim of this study was to evaluate the association between magnesium levels and the risk of cardiovascular and overall mortality in elderly maintenance hemodialysis patients.

Methods

This was a retrospective study, and patients undergoing maintenance hemodialysis were screened for eligibility at a single dialysis center between July and December 2016. Patients were divided into two groups based on their magnesium levels: a low magnesium level group and a high magnesium level group. Associations between magnesium level and risk of cardiovascular and all-cause mortality were analyzed with a Cox proportional hazards regression model.

Results

In total, 413 patients were included with a median follow-up period of 12 months. We found that compared to patients with high magnesium levels, those with low magnesium levels had significantly lower levels of hemoglobin, urea, creatinine, uric acid, phosphate, potassium, chloride, albumin, and spKt/V (p < 0.05 for each parameter). There was a strong correlation between the baseline mean serum magnesium concentration 1 year prior and the concentration 1 year later (r² = 0.519, p < 0.001). After adjustment for confounding factors, multivariate Cox proportional hazards analysis showed hypomagnesemia to be an independent predictor of all-cause and cardiovascular mortality in chronic hemodialysis patients. Furthermore, subgroup analysis was performed, revealing that serum magnesium levels were still strongly associated with all-cause mortality and cardiovascular mortality in patients older than 60 years, with HR values of 0.020 (95% CI 0.001-0.415) and 0.010 (95% CI 0.000-0.491), respectively. In addition, there were still significant associations between the serum magnesium level and all-cause mortality and cardiovascular mortality in elderly dialysis patients at the 6-month follow-up visit.

Conclusion

Our study indicates that lower serum magnesium levels are strongly associated with cardiovascular and all-cause mortality in maintenance hemodialysis patients, especially in the short term and in those who are elderly. Factors affecting serum magnesium concentrations in hemodialysis patients should be investigated, and correcting hypomagnesemia may benefit elderly hemodialysis patients.

Proton-Pump Inhibitors and Hypomagnesaemia in Kidney Transplant Recipients

Proton-pump inhibitors (PPIs) are commonly used after kidney transplantation and there is rarely an incentive to discontinue treatment. In the general population, PPI use has been associated with hypomagnesaemia. We aimed to investigate whether PPI use is associated with plasma magnesium, 24-h urinary magnesium excretion and hypomagnesaemia, in kidney transplant recipients (KTR). Plasma magnesium and 24-h urinary magnesium excretion were measured in 686 stable outpatient KTR with a functioning allograft for ≥1 year from the TransplantLines Food and Nutrition Biobank and Cohort-Study (NCT02811835). PPIs were used by 389 KTR (56.6%). In multivariable linear regression analyses, PPI use was associated with lower plasma magnesium (β: −0.02, P = 0.02) and lower 24-h urinary magnesium excretion (β: −0.82, P < 0.001). Moreover, PPI users had a higher risk of hypomagnesaemia (plasma magnesium <0.70 mmol/L), compared with non-users (Odds Ratio (OR): 2.12; 95% confidence interval (CI) 1.43–3.15, P < 0.001). This risk tended to be highest among KTR taking high PPI dosages (>20 mg omeprazole Eq/day) and was independent of adjustment for potential confounders (OR: 2.46; 95% CI 1.32–4.57, P < 0.005). No interaction was observed between PPI use and the use of loop diuretics, thiazide diuretics, tacrolimus, or diabetes (P_interaction > 0.05). These results demonstrate that PPI use is independently associated with lower magnesium status and hypomagnesaemia in KTR. The concomitant decrease in urinary magnesium excretion indicates that this likely is the consequence of reduced intestinal magnesium absorption. Based on these results, it might be of benefit to monitor magnesium status periodically in KTR on chronic PPI therapy.

Dietary intervention reduces left atrial enlargement in dogs with early preclinical myxomatous mitral valve disease: a blinded randomized controlled study in 36 dogs

Background

Myxomatous mitral valve disease (MMVD), the most common naturally-occurring heart disease in dogs, is associated with alterations in energy metabolism, oxidative stress and inflammation. Energy deprivation plays a causal role in the development of heart failure. This study was designed to determine if a cardiac protection blend (CPB) of nutrients containing medium-chain triglycerides as an alternative energy source, fish oil to reduce inflammation, antioxidants, and other key nutrients important to cardiac health and function could slow or prevent MMVD progression. Nineteen dogs with early stage MMVD and 17 breed-, age-, and sex-matched healthy dogs were enrolled for a 6-month blinded, placebo-controlled study. Dogs in each cardiac health group were randomly assigned to either control diet (CON) or CPB-supplemented diet. Echocardiography was performed at baseline, 3 months and 6 months.

Results

No changes were found in healthy dogs. While MMVD-CON dogs had an average 10% increase over baseline in left atrial diameter (LAD) and left atrial to aortic root ratio (LA/Ao) at 6 months, MMVD-CPB dogs showed 3% decreases, resulting significant diet by time interactions (P = 0.037, P = 0.005, respectively). More MMVD-CON dogs progressed from stage B1 to B2 during the study. A positive correlation was found between 6-month changes in LAD and blood pressures in MMVD-CPB dogs (systolic: P = 0.050, diastolic: P = 0.035) but not MMVD-CON dogs.

Conclusions

Our results demonstrated efficacy of CPB-based dietary intervention in reducing LA size and mitral regurgitation, and in slowing or preventing the progression of early MMVD in dogs.

Anabolic effects of vitamin D and magnesium in aging bone

Decreased bone mass and an increased risk of bone fractures become more common with age. This condition is often associated with osteoporosis and is caused by an imbalance of bone resorption and new bone formation. Lifestyle factors that affect the risk of osteoporosis include alcohol, diet, hormones, physical activity, and smoking. Calcium and vitamin D are particularly important for the age-related loss of bone density and skeletal muscle mass, but other minerals, such as magnesium, also have an important role. Here, we summarize how optimal magnesium and vitamin D balance improve health outcomes in the elderly, the role of magnesium and vitamin D on bone formation, and the implications of widespread deficiency of these factors in the United States and worldwide, particularly in the elderly population.

Effects of magnesium citrate, magnesium oxide and magnesium sulfate supplementation on arterial stiffness in healthy overweight individuals: a study protocol for a randomized controlled trial

Background

Arterial stiffness is closely related to the process of atherosclerosis, an independent cardiovascular risk factor, and predictive of future cardiovascular events and mortality. Recently, we showed that magnesium citrate supplementation results in a clinically relevant improvement of arterial stiffness. It remained unclear whether the observed effect was due to magnesium or citrate, and whether other magnesium compounds may have similar effects. Therefore, we aim to study the long-term effects of magnesium citrate, magnesium oxide and magnesium sulfate on arterial stiffness. In addition, we aim to investigate possible underlying mechanisms, including changes in blood pressure and changes in gut microbiota diversity.

Methods

In this randomized, double-blind, placebo-controlled trial, a total of 162 healthy overweight and slightly obese men and women will be recruited. During a 24-week intervention, individuals will be randomized to receive: magnesium citrate; magnesium oxide; magnesium sulfate (total daily dose of magnesium for each active treatment 450 mg); or placebo. The primary outcome of the study is arterial stiffness measured by the carotid–femoral pulse wave velocity (PWV_c–f), which is the gold standard for quantifying arterial stiffness. Secondary outcomes are office blood pressure, measured by a continuous blood pressure monitoring device, and gut microbiota, measured in fecal samples. Measurements will be performed at baseline and at weeks 2, 12 and 24.

Discussion

The present study is expected to provide evidence for the effects of different available magnesium formulations (organic and inorganic) on well-established cardiovascular risk markers, including arterial stiffness and blood pressure, as well as on the human gut microbiota. As such, the study may contribute to the primary prevention of cardiovascular disease in slightly obese, but otherwise healthy, individuals.

Trial registration

ClinicalTrials.gov, NCT03632590. Retrospectively registered on 15 August 2018.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3414-4) contains supplementary material, which is available to authorized users.

Association between parity and persistent weight gain at age 40-60 years: a longitudinal prospective cohort study

OBJECTIVES

Physiological metabolic adaptations occur in the pregnant woman. These may persist postpartum and thereby contribute to an unfavourable cardiovascular disease (CVD) risk profile in parous women. The aim of the current study is to assess time-dependent changes of cardiometabolic health in parous women compared with nulliparous women.

DESIGN AND SETTING

We studied data of 2459 women who participated in the Prevention of Renal and Vascular End-stage Disease study, a population-based prospective longitudinal cohort for assessment of CVD and renal disease in the general population.

PARTICIPANTS

We selected women ≥40 years at the first visit, who reported no new pregnancies during the four follow-up visits. All women were categorised in parity groups, and stratified for age.

OUTCOME MEASURES

We compared body mass index (BMI), high-density lipoprotein (HDL) cholesterol, blood pressure as continuous measurements and as clinical relevant CVD risk factors among parity groups over the course of 6 years using generalised estimating equation models adjusted for age.

RESULTS

The BMI was significantly higher in women para 2 or more in all age categories: per child, the BMI was 0.6 kg/m² higher. corresponding with 1.5-2.0 kg weight gain per child. HDL cholesterol was significantly lower in women para 2 or more aged 40-49 and 50-59 years: per child, the HDL cholesterol was up to 0.09 mmol/L lower. Blood pressure did not differ among parity groups in any of the age categories.

CONCLUSIONS

Higher parity is associated with higher BMI, lower HDL cholesterol and a higher prevalence of cardiovascular risk factors, which is constant over time. These findings warrant for prospective research assessing determinants of cardiometabolic health at earlier age to understand the role of pregnancy in the development of CVD in women.

Association between serum magnesium and blood count: influence of type 2 diabetes and central obesity

The relationship between serum Mg and blood cell counts in Chinese adult diabetes or central obesity was assessed by investigating 8163 subjects with China Health and Nutrition Survey (mean age 59⋅6 years, 54⋅9 % men). Participants were classified according to blood Mg (below 0⋅65 mmol/l, or 0⋅66–0⋅94 mmol/l or above 0⋅95 mmol/l), type 2 diabetes (yes/no) and central obesity (yes/no). Leucocytes, erythrocytes, platelets (PLT), Hb and glycated Hb (HbA1c) were determined using standardised methods and conditions. HbAc1, leucocytes and PLT were significantly higher among subjects with central obesity than without central obesity (P &lt; 0⋅05). A significant increase for Hb, erythrocytes, PLT, but not leucocytes, across progressive Mg groups was observed in subjects without diabetes (P &lt; 0⋅05). Hb, erythrocytes and HbAc1 were significantly higher among subjects with higher Mg than in subjects with lower Mg with diabetes (P &lt; 0⋅05). Central obesity disturbed the positive association between PLT count and serum Mg. Type 2 diabetes caused metabolism disorder in serum Mg, blood sugar and blood cell count. Hb, erythrocytes and PLT, but not leucocytes, are positively correlated with serum Mg, but this association is somehow disturbed by type 2 diabetes or central obesity.

Serum magnesium, mortality, and cardiovascular disease in chronic kidney disease and end-stage renal disease patients: a systematic review and meta-analysis

BACKGROUND

Previous studies reported that magnesium deficiency was associated with vascular calcifications, atherosclerosis and cardiovascular disease, which might play an independent pathogenic role in chronic kidney disease (CKD) and end-stage renal disease (ESRD) patients. However, the results of these studies were somewhat underpowered and inconclusive.

METHODS

Literature was identified by searching PubMed, EMBASE, Web of Science and the Cochrane Central Register of Controlled Trials (CENTRAL). We included studies that investigated the association between serum magnesium with mortality risk in CKD and ESRD patients. Unadjusted and adjusted hazard ratios (HRs) with 95% confidence intervals (95% CIs) were pooled.

RESULTS

Twenty studies involving 200,934 participants were included, and the results showed that there was a strong association between hypomagnesemia and the risk of all-cause mortality in patients with CKD and ESRD (HR 1.32; 95% CI 1.19-1.47; p < 0.00001) (hypomagnesemia vs. normal magnesium or hypermagnesemia) after multivariable adjusted. On the contrary, hypermagnesemia was inversely associated with all-cause mortality in patients with CKD and ESRD (HR 0.86; 95% CI 0.79-0.94; p = 0.001) (per unit increase). Moreover, a significant association between hypermagnesemia and decreased risk of cardiovascular mortality was observed (HR 0.71; 95% CI 053-0.97, p = 0.03) in the adjusted model. In addition, subgroup analysis found that hypomagnesemia was strongly associated with increased all-cause mortality in hemodialysis patients (HR 1.29; 95% CI 1.12-1.50; p = 0.0005) (hypomagnesemia vs. normal magnesium or hypermagnesemia).

CONCLUSIONS

Our results indicate that hypomagnesemia is significantly associated with cardiovascular and all-cause mortality in patients with CKD and ESRD. Further studies evaluating benefits of magnesium correction in CKD and dialysis patients with hypomagnesemia should be performed.

Lower Plasma Magnesium, Measured by Nuclear Magnetic Resonance Spectroscopy, is Associated with Increased Risk of Developing Type 2 Diabetes Mellitus in Women: Results from a Dutch Prospective Cohort Study

Background: Low circulating magnesium (Mg) is associated with an increased risk of developing type 2 diabetes mellitus (T2DM). We aimed to study the performance of a nuclear magnetic resonance (NMR)-based assay that quantifies ionized Mg in EDTA plasma samples and prospectively investigate the association of Mg with the risk of T2DM. Methods: The analytic performance of an NMR-based assay for measuring plasma Mg was evaluated. We studied 5747 subjects free of T2DM at baseline in the Prevention of Renal and Vascular End-stage Disease (PREVEND) study. Results: Passing–Bablok regression analysis, comparing NMR-measured ionized Mg with total Mg measured by the Roche colorimetric assay, produced a correlation of r = 0.90, with a slope of 1.08 (95% CI: 1.00–1.13) and an intercept of 0.02 (95% CI: −0.02–0.08). During a median follow-up period of 11.2 (IQR: 7.7–12.0) years, 289 (5.0%) participants developed T2DM. The association of NMR-measured ionized Mg with T2DM risk was modified by sex (P_interaction = 0.007). In women, we found an inverse association between Mg and the risk of developing T2DM, independent of adjustment for potential confounders (HR: 1.80; 95% CI: 1.20–2.70). In men, we found no association between Mg and the risk of developing T2DM (HR: 0.90; 95%: 0.67–1.21). Conclusion: Lower NMR-measured plasma ionized Mg was independently associated with a higher risk of developing T2DM in women, but not in men.

Chronic magnesium deficiency and human disease; time for reappraisal?

Numerous epidemiological, experimental and clinical studies over the last 30 years have consistently shown that chronic magnesium deficiency is associated with and/or exacerbates a number of major disorders (Table 1). Yet chronic magnesium deficiency is not widely recognized and a major reason for this failure is that serum magnesium levels do not accurately reflect body magnesium stores. Specifically, in chronic magnesium deficiency, serum magnesium levels are often within the normal reference range (usually lowest quartile) and may not progress to overt hypomagnesaemia. This raises serious questions namely (i) should chronic magnesium deficiency be considered in high-risk patients irrespective of serum magnesium, even when 'normal'? and (ii) if recognized, should oral magnesium supplement be given to restore body stores? Appreciating the vital role of magnesium for normal cellular function and bone health may help in formulating a well-considered and justifiable approach to these questions. Pragmatic tests for assessing magnesium status in the adult are suggested and discussed.

Challenges in the Diagnosis of Magnesium Status

Magnesium is a critical mineral in the human body and is involved in ~80% of known metabolic functions. It is currently estimated that 60% of adults do not achieve the average dietary intake (ADI) and 45% of Americans are magnesium deficient, a condition associated with disease states like hypertension, diabetes, and neurological disorders, to name a few. Magnesium deficiency can be attributed to common dietary practices, medications, and farming techniques, along with estimates that the mineral content of vegetables has declined by as much as 80⁻90% in the last 100 years. However, despite this mineral's importance, it is poorly understood from several standpoints, not the least of which is its unique mechanism of absorption and sensitive compartmental handling in the body, making the determination of magnesium status difficult. The reliance on several popular sample assays has contributed to a great deal of confusion in the literature. This review will discuss causes of magnesium deficiency, absorption, handling, and compartmentalization in the body, highlighting the challenges this creates in determining magnesium status in both clinical and research settings.

Association between serum magnesium and blood lipids: influence of type 2 diabetes and central obesity

To assess the changes in the relationship between serum Mg and blood lipids of Chinese adults with type 2 diabetes (T2D) or central obesity, a total of 8163 subjects (mean age 59·6 years, 54·9 % men) were analysed. Participants were classified according to blood Mg (below 0·65 mmol/l, 0·65-0·95 mmol/l and above 0·95 mmol/l), T2D (yes/no) and central obesity (yes/no). Blood lipids (TAG, total cholesterol (TC), HDL-cholesterol and LDL-cholesterol) were determined by standardised methods and conditions. A significant increase in blood lipids, with the exception of HDL-cholesterol, across progressive Mg groups in all subjects was noted (P0·05). TAG, TC, HDL-cholesterol and LDL-cholesterol were significantly higher among subjects with T2D than those without T2D (P<0·05). Multivariable models for TAG and LDL-cholesterol failed to attain statistical significance in diabetics, by using a generalised linear or parsimonious model. TAG, TC, HDL-cholesterol and LDL-cholesterol were significantly higher among subjects with T2D or central obesity. Blood lipids, with the exception of HDL-cholesterol, were associated with serum Mg, but this association was somehow influenced by T2D in LDL-cholesterol. In addition, multivariable models for both TAG and LDL-cholesterol failed to attain statistical significance among subjects with T2D, different from subjects without T2D.

Serum magnesium and risk of incident heart failure in older men: The British Regional Heart Study

To examine the association between serum magnesium and incident heart failure (HF) in older men and investigate potential pathways including cardiac function, inflammation and lung function. Prospective study of 3523 men aged 60–79 years with no prevalent HF or myocardial infarction followed up for a mean period of 15 years, during which 268 incident HF cases were ascertained. Serum magnesium was inversely associated with many CVD risk factors including prevalent atrial fibrillation, lung function (FEV₁) and markers of inflammation (IL-6), endothelial dysfunction (vWF) and cardiac dysfunction [NT-proBNP and cardiac troponin T (cTnT)]. Serum magnesium was inversely related to risk of incident HF after adjustment for conventional CVD risk factors and incident MI. The adjusted hazard ratios (HRs) for HF in the 5 quintiles of magnesium groups were 1.00, 0.72 (0.50, 1.05), 0.85 (0.59, 1.26), 0.76 (0.52, 1.11) and 0.56 (0.36, 0.86) respectively [p (trend) = 0.04]. Further adjustment for atrial fibrillation, IL-6, vWF and FEV₁ attenuated the association but risk remained significantly reduced in the top quintile (≥ 0.87 mmol/l) compared with the lowest quintile [HR 0.62 (0.40, 0.97)]. Adjustment for NT-proBNP and cTnT attenuated the association further [HR 0.70 (0.44, 1.10)]. The benefit of high serum magnesium on HF risk was most evident in men with ECG evidence of ischaemia [HR 0.29 (0.13, 0.68)]. The potential beneficial effect of high serum magnesium was partially explained by its favourable association with CVD risk factors. Further studies are needed to investigate whether serum magnesium supplementation in older adults may protect from the development of HF.

Higher Dietary Magnesium Intake and Higher Magnesium Status Are Associated with Lower Prevalence of Coronary Heart Disease in Patients with Type 2 Diabetes

In type 2 diabetes mellitus (T2D), the handling of magnesium is disturbed. Magnesium deficiency may be associated with a higher risk of coronary heart disease (CHD). We investigated the associations between (1) dietary magnesium intake; (2) 24 h urinary magnesium excretion; and (3) plasma magnesium concentration with prevalent CHD in T2D patients. This cross-sectional analysis was performed on baseline data from the DIAbetes and LifEstyle Cohort Twente-1 (DIALECT-1, n = 450, age 63 ± 9 years, 57% men, and diabetes duration of 11 (7-18) years). Prevalence ratios (95% CI) of CHD by sex-specific quartiles of magnesium indicators, as well as by magnesium intake per dietary source, were determined using multivariable Cox proportional hazard models. CHD was present in 100 (22%) subjects. Adjusted CHD prevalence ratios for the highest compared to the lowest quartiles were 0.40 (0.20, 0.79) for magnesium intake, 0.63 (0.32, 1.26) for 24 h urinary magnesium excretion, and 0.62 (0.32, 1.20) for plasma magnesium concentration. For every 10 mg increase of magnesium intake from vegetables, the prevalence of CHD was, statistically non-significantly, lower (0.75 (0.52, 1.08)). In this T2D cohort, higher magnesium intake, higher 24 h urinary magnesium excretion, and higher plasma magnesium concentration are associated with a lower prevalence of CHD.

Dietary Magnesium and Cardiovascular Disease: A Review with Emphasis in Epidemiological Studies

Magnesium (Mg) is an essential dietary element for humans involved in key biological processes. A growing body of evidence from epidemiological studies, randomized controlled trials (RCTs) and meta-analyses have indicated inverse associations between Mg intake and cardiovascular diseases (CVD). The present review aims to summarize recent scientific evidence on the topic, with a focus on data from epidemiological studies assessing the associations between Mg intake and major cardiovascular (CV) risk factors and CVD. We also aimed to review current literature on circulating Mg and CVD, as well as potential biological processes underlying these observations. We concluded that high Mg intake is associated with lower risk of major CV risk factors (mainly metabolic syndrome, diabetes and hypertension), stroke and total CVD. Higher levels of circulating Mg are associated with lower risk of CVD, mainly ischemic heart disease and coronary heart disease. Further, RCTs and prospective studies would help to clarify whether Mg intake and Mg circulating levels may also protect against other CVDs and CVD death.

Dietary Protein Intake and Overall Diet Quality Are Associated with Handgrip Strength in African American and White Adults

OBJECTIVE

To determine the association of handgrip strength (HS) with protein intake, diet quality, and nutritional and cardiovascular biomarkers in African American and White adults.

DESIGN

Cross-sectional wave 3 (2009-2013) of the cohort Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study.

PARTICIPANTS

Socioeconomically diverse urban population of 2,468 persons aged 33 to 71 years.

MEASUREMENTS

Socio-demographic correlates, dietary intakes and biomarkers, HS, physical performance measures were collected. HS was measured using a dynamometer with the dominant hand. Functional measures included chair, tandem, and single leg stands. Two 24-hour recalls were collected using the US Department of Agriculture Automated Multiple Pass Method. The total protein intake and diet quality, evaluated by adherence to the DASH eating plan and Healthy Eating Index-2010, were calculated. Biomarkers included nutritional anemia, and serum levels of albumin, cholesterol, magnesium, and glucose.

RESULTS

The mean ±SE age of the sample was 52.3±0.2 years. Approximately 61% were African American and 57% were women. The mean ±SE HS of women was 29.1±0.2kg and for men was 45.9±0.4 kg. Protein, gm, per kg body weight for the women was 0.94±0.02 compared to 1.16 ±0.02 for men. After adjusting for socio-demographic factors, hypertension, and diabetes, HS/BMI ratio was significantly associated with protein intake per kg body weight (p<0.001) and diet quality, assessed by either the DASH adherence (p=0.009) or Health Eating Index-2010 (p=0.031) scores. For both men and women, participants in the upper tertile of HS maintained a single leg and tandem stances longer and completed 5 and 10 chair stands in shorter time compared to individuals in the lower HS tertile. Of the nutritional status indicators, the percent of men in the upper HS tertile with low serum magnesium and albumin, was significantly lower than those in the lower HS tertile [magnesium,7.4% vs 16.1%; albumin, 0.4% vs 4.5%]. The only difference observed for women was a lower percent of diabetes (14.4% for the upper HS tertile compared to 20.5% for the lower HS tertile.

CONCLUSIONS

The findings confirm the role of protein and a healthful diet in the maintenance of muscle strength. In this community sample, HS was significantly associated with other physical performance measures but did not appear to be strongly associated with indicators of nutritional risk. These findings support the use of HS as a proxy for functional status and indicate the need for research to explore its role as a predictor of nutritional risk.

Kidney Function After a Hypertensive Disorder of Pregnancy: A Longitudinal Study

BACKGROUND

Registry-based studies report an increased risk for end-stage kidney disease after hypertensive disorders of pregnancy (HDPs). It is unclear whether HDPs lead to an increased incidence of chronic kidney disease (CKD) and/or progression of kidney function decline.

STUDY DESIGN

Subanalysis of the Prevention of Renal and Vascular Endstage Disease (PREVEND) Study, a Dutch population-based cohort with follow-up of 5 visits approximately 3 years apart.

SETTING & PARTICIPANTS

Women without and with patient-reported HDPs (non-HDP, n=1,805; HDP, n=977) were identified. Mean age was 50 years at baseline and median follow-up was 11 years.

FACTOR

An HDP.

OUTCOMES

(1) The incidence of CKD using Cox regression and (2) the course of kidney function (estimated glomerular filtration rate [eGFR] and 24-hour albuminuria) over 5 visits using generalized estimating equation analysis adjusted for age, mean arterial pressure, and renin-angiotensin system (RAS) blockade. CKD was defined as eGFR<60mL/min/1.73m² and/or 24-hour albuminuria with albumin excretion > 30mg, and end-stage kidney disease was defined as receiving dialysis or kidney transplantation.

RESULTS

During follow-up, none of the women developed end-stage renal disease and the incidence of CKD during follow-up was similar across HDP groups (HR, 1.04; 95% CI, 0.79-1.37; P=0.8). Use of RAS blockade was higher after HDP at all visits. During a median of 11 years, we observed a decrease in eGFR in both groups, with a slightly steeper decline in the HDP group (98±15 to 88±16 vs 99±17 to 91±15mL/min/1.73m²; P_group<0.01, P_group*visit<0.05). The group effect remained significant after adjusting for mean arterial pressure, but disappeared after adjusting for RAS blockade. The 24-hour albuminuria did not differ between groups.

LIMITATIONS

No obstetric records available. HDPs defined by patient report rather than health records.

CONCLUSIONS

HDPs did not detectably increase the incidence of CKD. During follow-up, we observed no differences in albuminuria, but observed a marginally lower eGFR after HDP that was no longer statistically significant after adjusting for the use of RAS blockers. In this population, we were unable to identify a significant risk for kidney function decline after patient-reported HDP.

Genome-Wide Meta-Analysis Unravels Interactions between Magnesium Homeostasis and Metabolic Phenotypes

Magnesium (Mg²⁺) homeostasis is critical for metabolism. However, the genetic determinants of the renal handling of Mg²⁺, which is crucial for Mg²⁺ homeostasis, and the potential influence on metabolic traits in the general population are unknown. We obtained plasma and urine parameters from 9099 individuals from seven cohorts, and conducted a genome-wide meta-analysis of Mg²⁺ homeostasis. We identified two loci associated with urinary magnesium (uMg), rs3824347 (P=4.4×10^-13) near TRPM6, which encodes an epithelial Mg²⁺ channel, and rs35929 (P=2.1×10^-11), a variant of ARL15, which encodes a GTP-binding protein. Together, these loci account for 2.3% of the variation in 24-hour uMg excretion. In human kidney cells, ARL15 regulated TRPM6-mediated currents. In zebrafish, dietary Mg²⁺ regulated the expression of the highly conserved ARL15 ortholog arl15b, and arl15b knockdown resulted in renal Mg²⁺ wasting and metabolic disturbances. Finally, ARL15 rs35929 modified the association of uMg with fasting insulin and fat mass in a general population. In conclusion, this combined observational and experimental approach uncovered a gene-environment interaction linking Mg²⁺ deficiency to insulin resistance and obesity.

Oral magnesium supplementation improves endothelial function and attenuates subclinical atherosclerosis in thiazide-treated hypertensive women

BACKGROUND

Epidemiological studies demonstrate an inverse association between serum magnesium and incidence of cardiovascular disease. Diuretics commonly cause hypomagneseamia.

METHOD

We evaluated effects of magnesium supplementation on blood pressure (BP) and vascular function in thiazide-treated hypertensive women in a randomized, double-blind, clinical trial. Hypertensive women (40-65 years) on hydrochlorothiazide and mean 24-h BP at least 130/80 mmHg were divided into placebo and supplementation (magnesium chelate 600 mg/day) groups. Patients were evaluated for nutritional and biochemical parameters, office and ambulatory blood pressure monitoring, brachial flow-mediated dilatation (FMD), peripheral arterial tonometry, assessment of carotid intima-media thickness, central hemodynamic parameters and pulse wave velocity at inclusion and after 6-month follow-up.

RESULTS

The magnesium group had a significant reduction in SBP (144 ± 17 vs. 134 ± 14 mmHg, P = 0.036) and DBP (88 ± 9 vs. 81 ± 8 mmHg, P = 0.005) at 6 months, without effect on plasma glucose, lipids, or arterial stiffness parameters. The placebo group showed a significant increase in carotid intima-media thickness (0.78 ± 0.13 vs. 0.89 ± 0.14 mm, P = 0.033) without change in the magnesium group (0.79 ± 0.16 vs. 0.79 ± 0.19 mm, P = 0.716) after 6 months. The magnesium group demonstrated a significant increase in variation of FMD vs. the placebo group (+3.7 ± 2.1 vs. 2.4 ± 1.2%, P = 0.015). There was a significant correlation between the intracellular magnesium variation and FMD (r = 0.44, P = 0.011).

CONCLUSION

Magnesium supplementation was associated with better BP control, improved endothelial function and amelioration of subclinical atherosclerosis in these thiazide-treated hypertensive women.

Circulating magnesium levels and incidence of coronary heart diseases, hypertension, and type 2 diabetes mellitus: a meta-analysis of prospective cohort studies

BACKGROUND

Data on the associations between circulating magnesium (Mg) levels and incidence of coronary heart diseases (CHD), hypertension, and type 2 diabetes mellitus (T2DM) are inconsistent and inconclusive. The aim of this study was to examine circulating Mg levels in relation to incidence of CHD, hypertension, and T2DM.

METHODS

Prospective cohort studies published before May 2017 were searched through PubMed, EmBase, SCOPUS, and Google Scholar. A total of 11 studies that reported multivariable-adjusted associations of interest were identified. Information on the characteristics of study and participants, exposure, main outcomes, risk estimates, and cofounders was extracted and analyzed.

RESULTS

Of the 11 included studies, 5 reported results on CHD (38,808 individuals [4437 cases] with an average 10.5-year follow-up), 3 on hypertension (14,876 participants [3149 cases] with a 6.7-year follow-up), and 4 on T2DM (31,284 participants [2680 cases] with an 8.8-year follow-up). Comparing the highest to the lowest category of circulating Mg concentration, the pooled relative risks [RRs] (95% confidence intervals [CIs]) were 0.86 (0.74, 0.996), 0.91 (0.80, 1.02), and 0.64 (0.50, 0.81) for incidence of CHD, hypertension, and T2DM, respectively. Every 0.1 mmol/L increment in circulating Mg levels was associated with 4% (RR, 0.96; 95% CI: 0.94, 0.99) reduction in hypertension incidence. No significant linear association was found between circulating Mg levels and incidence of CHD (RR, 0.89; 95% CI: 0.77, 1.03) and T2DM (RR, 0.90; 95% CI: 0.81, 1.002). The observed associations of interest were sensitive to exclusion of individual studies.

CONCLUSIONS

Findings in this meta-analysis suggest that circulating Mg levels are inversely associated with incidence of CHD, hypertension, and T2DM. Additional studies are needed to provide more solid evidence and identify the optimal range of circulating Mg concentration with respect to primary prevention of CHD, hypertension, and T2DM.

Serum magnesium concentrations and all-cause, cardiovascular, and cancer mortality among U.S. adults: Results from the NHANES I Epidemiologic Follow-up Study

BACKGROUND

Few studies have examined the associations of serum magnesium (Mg) concentrations with total and cause-specific mortality in a nationally representative sample of US adults. We investigate the dose-response relationships of baseline serum Mg concentrations with risk of mortalities in a large, nationally representative sample of US adults.

METHODS

We analyzed prospective data of 14,353 participants aged 25-74 years with measures of serum Mg concentrations at baseline (1971-1975) from the National Health and Nutrition Examination Survey I Epidemiologic Follow-up Study (NHEFS). Mortality data was linked through December 31, 2011. We estimated the mortality hazard ratios (HRs), for participants within serum Mg categories of <0.7, 0.7-0.74, 0.75-0.79, 0.8-0.89 (referent), 0.9-0.94, 0.95-0.99, and ≥1.0 mmol/L using weighted multivariate-adjusted Cox proportional hazards models.

RESULTS

During a median follow-up of 28.6 years, 9012 deaths occurred, including 3959 CVD deaths, 1923 cancer deaths, and 708 stroke deaths. The multivariate-adjusted HRs (95% CIs) of all-cause mortality across increasing categories of Mg were 1.34 (1.02, 1.77), 0.94 (0.75, 1.18), 1.08 (0.97, 1.19), 1.00 (referent), 1.05 (0.95, 1.16), 0.96 (0.79, 1.15), and 0.98 (0.76, 1.26). Similar trends were observed for cancer (HRs for serum Mg < 0.7: 1.39, 95% CI: 0.83, 2.32) and CVD mortality (HRs for serum Mg < 0.7: 1.28, 95% CI: 0.81, 2.02) but were not statistically significant. An elevated risk for stroke mortality was observed among participants with serum Mg < 0.70 mmol/L (HR: 2.55, 95% CI: 1.18, 5.48).

CONCLUSIONS

Very low serum Mg concentrations were significantly associated with an increased risk of all-cause mortality in US adults.

Integrated Assessment of Pharmacological and Nutritional Cardiovascular Risk Management: Blood Pressure Control in the DIAbetes and LifEstyle Cohort Twente (DIALECT)

Cardiovascular risk management is an integral part of treatment in Type 2 Diabetes Mellitus (T2DM), and requires pharmacological as well as nutritional management. We hypothesize that a systematic assessment of both pharmacological and nutritional management can identify targets for the improvement of treatment quality. Therefore, we analysed blood pressure (BP) management in the DIAbetes and LifEstyle Cohort Twente (DIALECT). DIALECT is an observational cohort from routine diabetes care, performed at the ZGT Hospital (Almelo and Hengelo, The Netherlands). BP was measured for 15 minutes with one minute intervals. Sodium and potassium intake was derived from 24-hour urinary excretion. We determined the adherence to pharmacological and non-pharmacological guidelines in patients with BP on target (BP-OT) and BP not on target (BP-NOT). In total, 450 patients were included from August 2009 until January 2016. The mean age was 63 ± 9 years, and the majority was male (58%). In total, 53% had BP-OT. In those with BP-NOT, pharmacological management was suboptimal (zero to two antihypertensive drugs) in 62% of patients, and nutritional guideline adherence was suboptimal in 100% of patients (only 8% had a sodium intake on target, 66% had a potassium intake on target, 3% had a sodium-to-potassium ratio on target, and body mass index was <30 kg/m² in 35%). These data show pharmacological undertreatment and a low adherence to nutritional guidelines. Uncontrolled BP is common in T2DM, and our data show a window of opportunity for improving BP control, especially in nutritional management. To improve treatment quality, we advocate to incorporate the integrated monitoring of nutritional management in quality improvement cycles in routine care.

Magnesium Counteracts Vascular Calcification: Passive Interference or Active Modulation?

Over the last decade, an increasing number of studies report a close relationship between serum magnesium concentration and cardiovascular disease risk in the general population. In end-stage renal disease, an association was found between serum magnesium and survival. Hypomagnesemia was identified as a strong predictor for cardiovascular disease in these patients. A substantial body of in vitro and in vivo studies has identified a protective role for magnesium in vascular calcification. However, the precise mechanisms and its contribution to cardiovascular protection remain unclear. There are currently 2 leading hypotheses: first, magnesium may bind phosphate and delay calcium phosphate crystal growth in the circulation, thereby passively interfering with calcium phosphate deposition in the vessel wall. Second, magnesium may regulate vascular smooth muscle cell transdifferentiation toward an osteogenic phenotype by active cellular modulation of factors associated with calcification. Here, the data supporting these major hypotheses are reviewed. The literature supports both a passive inorganic phosphate-buffering role reducing hydroxyapatite formation and an active cell-mediated role, directly targeting vascular smooth muscle transdifferentiation. However, current evidence relies on basic experimental designs that are often insufficient to delineate the underlying mechanisms. The field requires more advanced experimental design, including determination of intracellular magnesium concentrations and the identification of the molecular players that regulate magnesium concentrations in vascular smooth muscle cells.

The inverse association of HDL-cholesterol with future risk of hypertension is not modified by its antioxidant constituent, paraoxonase-1: The PREVEND prospective cohort study

BACKGROUND AND AIMS

High-density lipoprotein cholesterol (HDL-C), an established risk marker for atherosclerotic cardiovascular disease (CVD), has been shown to be inversely and independently associated with incident hypertension. Paraoxonase-1 (PON-1) is an HDL-bound esterase enzyme associated with CVD, but its relationship with incident hypertension has not been previously investigated. We aimed at evaluating the prospective association between PON-1 and hypertension risk.

METHODS

PON-1 arylesterase activity was measured in serum at baseline in 3988 participants without pre-existing hypertension in the Prevention of Renal and Vascular End-stage Disease (PREVEND) prospective population-based study. During a median follow-up of 10.7 years, 1206 participants developed hypertension.

RESULTS

In age- and sex-adjusted analysis, the hazard ratio (95% CI) for incident hypertension per 1 standard deviation increase in PON-1 was 1.01 (0.96-1.07; p = 0.656), which remained non-significant after adjustment for several established hypertension risk factors and other potential confounders (0.99, 0.93 to 1.05; p = 0.764). The association was also non-existent on further adjustment for HDL-C (1.00 (0.94-1.06; p = 0.936)) and did not importantly vary across several clinical subgroups. In analyses in the same set of participants, HDL-C was continuously inversely and independently associated with hypertension risk; the association persisted after further adjustment for PON-1 activity and was not modified by PON-1 activity.

CONCLUSIONS

In this Caucasian cohort of men and women, HDL-C, but not its anti-oxidant constituent - PON-1, is inversely, continuously and independently associated with future risk of hypertension. The association is independent of and not modified by PON-1.

Data from Controlled Metabolic Ward Studies Provide Guidance for the Determination of Status Indicators and Dietary Requirements for Magnesium

Determination of whether magnesium (Mg) is a nutrient of public health concern has been hindered by questionable Dietary Recommended Intakes (DRIs) and problematic status indicators that make Mg deficiency assessment formidable. Balance data obtained since 1997 indicate that the EAR and RDA for 70-kg healthy individuals are about 175 and 250 mg/day, respectively, and these DRIs decrease or increase based on body weight. These DRIs are less than those established for the USA and Canada. Urinary excretion data from tightly controlled metabolic unit balance studies indicate that urinary Mg excretion is 40 to 80 mg (1.65 to 3.29 mmol)/day when Mg intakes are <250 mg (10.28 mmol)/day, and 80 to 160 mg (3.29 to 6.58 mmol)/day when intakes are >250 mg (10.28 mmol)/day. However, changing from low to high urinary excretion with an increase in dietary intake occurs within a few days and vice versa. Thus, urinary Mg as a stand-alone status indicator would be most useful for population studies and not useful for individual status assessment. Tightly controlled metabolic unit depletion/repletion experiments indicate that serum Mg concentrations decrease only after a prolonged depletion if an individual has good Mg reserves. These experiments also found that, although individuals had serum Mg concentrations approaching 0.85 mmol/L (2.06 mg/dL), they had physiological changes that respond to Mg supplementation. Thus, metabolic unit findings suggest that individuals with serum Mg concentrations >0.75 mmol/L (1.82 mg/L), or as high as 0.85 mmol/L (2.06 mg/dL), could have a deficit in Mg such that they respond to Mg supplementation, especially if they have a dietary intake history showing <250 mg (10.28 mmol)/day and a urinary excretion of <80 mg (3.29 mmol)/day.

Is heart disease a risk factor for low dementia test battery scores in older persons with Down syndrome? Exploratory, pilot study, and commentary

OBJECTIVES

Certain heart conditions and diseases are common in Down syndrome (DS; trisomy 21), but their role in early onset dementia that is prevalent in older adults with DS has not been evaluated. To address this knowledge gap, we conducted a study of risk factors for low neurocognitive/behavioral scores obtained with a published dementia test battery (DTB). Participants were adults with DS living in New York (N = 29; average age 46 years). We asked three questions. 1. Does having any type of heart disease affect the association between DTB scores and chronological age? 2. Does thyroid status affect the association between heart disease and DTB scores? 3. Are the E4 or E2 alleles of apolipoprotein E (APOE) associated with DTB scores or with heart disease?

METHOD

The study was retrospective, pilot, and exploratory. It involved analysis of information in a database previously established for the study of aging in DS. Participants had moderate intellectual disability on average. Information for each person included: gender, age, a single DTB score obtained by combining results from individual subscales of the DTB, the presence or absence of heart disease, thyroid status (treated hypothyroidism or normal), and APOE genotype. Trends were visualized by inspection of graphs and contingency tables. Statistical methods used to evaluate associations included Pearson correlation analysis, Fisher's exact tests (2-tailed), and odds ratio analysis. P values were interpreted at the 95% confidence level without Bonferroni correction. P values >.05<.1 were considered trends.

RESULTS

The negative correlation between DTB scores and age was significant in those with heart disease but not in those without. Heart disease was significantly associated with DTB scores >1 SD below the sample mean; there was a strong association between heart disease and low DTB scores in those with treated hypothyroidism but not in those with normal thyroid status. The APOE genotype was weakly associated with heart disease (E4, predisposing; E2, protective) in males.

CONCLUSIONS

On the basis of the potentially important findings from the present study, large prospective studies are warranted to confirm and extend the observations. In these, particular heart conditions or diseases and other medical comorbidities in individuals should be documented.

Effects of long-term magnesium supplementation on endothelial function and cardiometabolic risk markers: A randomized controlled trial in overweight/obese adults

Long-term magnesium supplementation improves arterial stiffness, a cardiovascular disease risk marker. Effects on endothelial function may be another mechanism whereby increased magnesium intakes affect cardiovascular risk. Therefore, a 24-week, randomized, double-blind, placebo-controlled trial was performed to examine effects of magnesium supplementation on endothelial function and cardiometabolic risk markers. Fifty-two overweight and obese subjects (30 men and 22 women, age 62 ± 6 years) were randomized to receive either three times daily magnesium (total dose: 350 mg) or placebo capsules. Endothelial function was assessed at the start and at the end of the study. Cardiometabolic risk markers were measured at baseline, after 12 weeks, and at week 24. Brachial artery flow-mediated vasodilation did not change following long-term magnesium supplementation (0.49 pp; 95% CI: −0.38 to 1.36 pp; P = 0.26). Changes in reactive hyperemia index, retinal microvascular caliber and plasma markers for microvascular endothelial function (sVCAM-1, sICAM-1 and sE-selectin) were also not different. In addition, no effects on serum lipids, plasma glucose, insulin sensitivity, and low-grade systemic inflammation were observed. In conclusion, a daily magnesium supplement of 350 mg for 24 weeks does not improve endothelial function and cardiometabolic risk markers in overweight and obese middle-aged and elderly adults.