Association Between Circulating Levels of Magnesium and Metabolic Syndrome: A Systematic Review and Meta-Analysis of Observational Studies with GRADE Assessment.

Context: Evidence on the associations between circulating magnesium (Mg) levels and metabolic syndrome (MetS) is inconclusive.

Objective: In this meta-analysis we examined the relationship between Mg concentrations and MetS.

Data sources: Observational studies were searched through the PubMed, EmBase, ISI Web of Science, and Scopus databases and Google Scholar, without time or language limitations, up to January 2024.

Data extraction: Eligible studies were epidemiological investigations that reported relative risks or odds ratios [ORs] of MetS in relation to serum, plasma, or blood Mg levels. The certainty of each meta-analysis was assessed by use of the grading of recommendations, assessment, development, and evaluation (GRADE) approach.

Data analysis: A total of 11 studies (9 cross-sectional and 2 case-control) were eligible to be included. Pooling estimates of these studies (with 14 188 individuals and 4724 cases with MetS) revealed that compared to individuals with the lowest level of Mg concentration, those with the highest Mg concentration had 46% significantly lower odds of MetS (OR = 0.54; 95% CI: 0.34-0.86). Each 0.5-mg/dL increase in the level of circulating Mg was related to an 11% reduction in the odds of contracting MetS (OR = 0.89; 95% CI: 0.83-0.96). Nonlinear analysis showed a U-shaped curve; the lowest likelihood of MetS was seen at a circulating Mg concentration of 2.5 mg/dL. Certainty of the evidence was high.

Conclusions: In this meta-analysis of epidemiologic studies we documented that circulating Mg levels were inversely associated with MetS. Additional prospective studies are needed to provide more solid evidence for the optimal range of circulating Mg concentrations with respect to prevention of MetS.

Systematic review registration: PROSPERO registration No. CRD42024535236.