Depressive symptoms and hypomagnesemia in older diabetic subjects.

Background: We undertook this study to assess the hypothesis that hypomagnesemia is associated with depressive symptoms in older people with diabetes.

Methods: A total of 55 type 2 diabetic patients, aged 65 years or older, with depressive symptoms were compared with a control group of diabetic subjects without depressive symptoms in an age- and gender-matched case/control study. A score >or=11 points in the Yesavage's scale was used for defining depressive symptoms, and hypomagnesemia was defined by serum magnesium levels <0.74 mmol/L. Well-known causes for depression as well as diseases and drugs that may cause depressive symptoms or hypomagnesemia were exclusion criteria.

Results: Serum magnesium levels were significantly lower among depressive than control diabetic subjects (0.74 +/- 0.25 vs. 0.86 +/- 0.29 mmol/L, p = 0.02). Twenty four (43.6%) and 7 (12.7%) individuals in the case and control group exhibited low serum magnesium levels (p = 0.0006). The adjusted logistic regression analysis showed an independent association between hypomagnesemia and depressive symptoms (OR 1.79; CI(95%) 1.1-6.9, p = 0.03).

Conclusions: Our results suggest that hypomagnesemia is independently associated with depressive symptoms in older people with diabetes.