Serum ionized magnesium in diabetic older persons

Abstract Objective Several alterations of magnesium metabolism have been associated with type 2 diabetes pathophysiology, a condition particularly frequent in older persons. We aimed to evaluate serum total (Mg-tot) and serum ionized magnesium (Mg-ion) in older persons with type 2 diabetes in order to explore clinically applicable methods for the detection of magnesium deficit. Material/Methods Mg-tot and Mg-ion were measured in 105 fasting subjects with type 2 diabetes (mean age: 71.1 ± 0.8 years; M/F: 45/60) and in 100 age-matched non-diabetic control persons (mean age: 72.2 ± 0.8 years; M/F: 42/58). Results Mg-ion concentrations were significantly lower in diabetic persons compared with controls (0.49 ± 0.05 mmol/L vs. 0.55 ± 0.05 mmol/L; p < 0.001). Mg-tot was also slightly but significantly lower in diabetic patients (0.82 ± 0.007 mmol/L vs. 0.84 ± 0.006 mmol/L; p < 0.05). There was an almost complete overlap in the values of Mg-tot in older diabetic patients and controls; conversely, 44.8% of diabetic patients had Mg-ion values below 0.47 mmol/L, while none of the controls did. After adjustment for age, sex, BMI, and triglycerides, Mg-tot was significantly associated with FBG in all the participants (p < 0.05) and Mg-ion was significantly associated with FBG in all the participants (p < 0.01) and with HbA1c in diabetic participants (p < 0.001). Conclusions Alterations of magnesium serum concentrations are common in type 2 diabetic older adults; Mg-ion evaluation may help to identify subclinical magnesium depletion (i.e. in patients with normal Mg-tot); the close independent associations of Mg-tot and Mg-ion with FBG and with HbA1c reinforce the possible link between magnesium homeostasis and altered glucose metabolism.