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

Abstract

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.

Keywords: Coronary heart disease; Hypertension; Magnesium; Meta-analysis; Type 2 diabetes.

Fig. 1

Study selection process. Articles were identified by searches of PubMed (http://www.ncbi.nlm.nih.gov/pubmed), EmBase (http://www.elsevier.com/online-tools/embase), SCOPUS (https://www.scopus.com/) and Google Scholar (http://scholar.google.com)

Fig. 2

Multivariable-adjusted RRs (95% CIs) for incidence of CHD comparing highest to lowest, or per 0.1 mmol/L increment in circulating Mg levels from prospective cohort studies. The summary estimate was obtained by using a random-effects model. The dots indicate the adjusted RRs. The size of the shaded square is proportional to the weight of each study. The horizontal lines represent 95% CIs. The diamond markers indicate the pooled RRs. Abbreviations: CHD, coronary heart disease; CI, confidence interval; RR, relative risk

Fig. 3

Multivariable-adjusted RRs (95% CIs) for incidence of hypertension comparing highest to lowest, or per 0.1 mmol/L increment in serum Mg levels from prospective cohort studies. The summary estimate was obtained by using a random-effects model. The dots indicate the adjusted RRs. The size of the shaded square is proportional to the weight of each study. The horizontal lines represent 95% CIs. The diamond markers indicate the pooled RRs. Abbreviations: CI, confidence interval; RR, relative risk

Fig. 4

Multivariable-adjusted RRs (95% CIs) for incidence of T2DM comparing highest to lowest, or per 0.1 mmol/L increment in serum Mg levels from prospective cohort studies. The summary estimate was obtained by using a random-effects model. The dots indicate the adjusted RRs. The size of the shaded square is proportional to the weight of each study. The horizontal lines represent 95% CIs. The diamond markers indicate the pooled RRs. Abbreviations: CI, confidence interval; RR, relative risk; T2DM, type 2 diabetes mellitus