Low serum magnesium levels are associated with depressive symptoms in elderly diabetic patients, a finding that has potentially therapeutic implications, investigators reported.
“Whether hypomagnesemia is a risk factor for depression or merely an associated epiphenomenon in older people with diabetes cannot be ascertained. Interventional studies with magnesium supplementation are needed in order to convincingly demonstrate a cause-effect relationship,” wrote Lázaro Barragan-Rodríguez and colleagues from the Mexican Social Security Institute's Medical Research Unit in Clinical Epidemiology, and the Research Group on Diabetes and Chronic Illnesses, both in Durango, Mexico.
The authors studied 110 type 2 diabetic subjects, aged 65 years or older, who had no previous diagnosis of either depression or hypomagnesemia. A total of 55 subjects (40 women and 15 men) screened positive for depressive symptoms (a score of 11 points or more on the Yesavage Geriatric Depression Scale) and were included as cases, whereas the other 55 subjects (43 women and 12 men) with no depressive symptoms served as the control group. The mean depression score was 17 for subjects in the case group, compared with 6 for controls.
Venous whole blood samples were collected under fasting conditions to identify hypomagnesemia, which was defined as a serum magnesium level of less than 0.74 mmol/L. Serum magnesium levels were significantly lower in the case group, compared with controls. In the case group, 44% of subjects exhibited hypomagnesemia, compared with 13% in the control group.
After adjusting for age, gender, duration of diabetes, hemoglobin A1c, concomitant physical illness, serum triglycerides, albumin, and creatinine levels, the odds ratio (OR) between hypomagnesemia and depressive symptoms was calculated as 1.79. After lowering the cut-off point of serum magnesium to 0.66 mmol/L or less, hypomagnesemia still remained significantly associated with depressive symptoms (OR 1.74), noted the authors (Arch. Med. Res. 2007;38:752–6).