Serum ionized magnesium in diabetic older persons.
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.


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.
Geriatric Unit, Dept. of Internal Medicine and Specialties, University of Palermo, Italy. Electronic address: mario.barbagallo@unipa.it.
Mario
M
Barbagallo
Geriatric Unit, Dept. of Internal Medicine and Specialties, University of Palermo, Italy.
Giovanna
G
Di Bella
Geriatric Unit, Dept. of Internal Medicine and Specialties, University of Palermo, Italy.
Virna
V
Brucato
Geriatric Unit, Dept. of Internal Medicine and Specialties, University of Palermo, Italy.
Daniela
D
D'Angelo
Geriatric Unit, Dept. of Internal Medicine and Specialties, University of Palermo, Italy.
Provvidenza
P
Damiani
Geriatric Unit, Dept. of Internal Medicine and Specialties, University of Palermo, Italy.
Alfredo
A
Monteverde
Geriatric Unit, Dept. of Internal Medicine and Specialties, University of Palermo, Italy.
Mario
M
Belvedere
Geriatric Unit, Dept. of Internal Medicine and Specialties, University of Palermo, Italy.
Ligia J
LJ
Dominguez
D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008274:Magnesium / Q000097:blood*; D008297:Male
D001786:Blood Glucose; D006442:Glycated Hemoglobin; D008274:Magnesium; C517652:hemoglobin A1c protein, human
Aging; Diabetes; Hypertension; Ionized magnesium; Magnesium