Serum magnesium status during lipid-lowering drug treatment in non-insulin-dependent diabetic patients

Serum magnesium concentration (S-Mg) has been reported to be inversely associated with atherogenic lipid fractions and with blood glucose concentrations. In some studies on humans, oral magnesium supplementation has been found to improve the lipoprotein balance. Against this background the present study was undertaken to determine whether reductions in atherogenic lipid fractions are associated with S-Mg alterations. Total S-Mg was measured in 23 patients with non-insulin-dependent diabetes mellitus (NIDDM) treated with the lipid-lowering drugs gemfibrozil and simvastatin in a double-blind cross-over study. The mean S-Mg at the end of the initial placebo period, ie, before active treatment, was 0.80 (SD 0.06) mmol/L. Treatment with gemfibrozil 600 mg twice daily for 4 months decreased S-Mg by 0.02 mmol/L (P =.02), and treatment with simvastatin 10 mg daily for 4 months again decreased S-Mg by 0.02 mmol/L (P =.10; not significant [NS]) The changes in S-Mg during the 2 different treatment periods were closely correlated (r = 0.66, P <.001). Fasting plasma glucose concentrations increased significantly by 17% during both drug regimens. The changes in fasting plasma glucose and S-Mg were significantly correlated both during gemfibrozil treatment (r = -0.56, P <.01) and during treatment with simvastatin (r = -0.44, P <.05). Changes in glucose tolerance or insulin sensitivity did not correlate to changes in S-Mg. The associations between changes in serum very-low-density lipoprotein (VLDL) fractions and S-Mg did not reach statistical significance (r = -0.37, P <.10). Changes in low-density lipoprotein (LDL) cholesterol and S-Mg did not correlate. In conclusion, total S-Mg concentration decreased during treatment with gemfibrozil and simvastatin in patients with NIDDM. During both drug regimens changes in S-Mg status were inversely correlated to changes in plasma glucose concentrations, while changes in lipid status were not significantly correlated with changes in S-Mg.