Association Between Serum Magnesium Levels and Alzheimer's Disease or Mixed Dementia Patients: A Population-Based Retrospective Controlled Study

High magnesium intake has been associated with a decreased risk of dementia. In contrast, other research has found that both low and high serum magnesium levels were associated with an increased risk of Alzheimer's disease and mixed dementia. Hence, presently the role of magnesium levels in dementia is unclear.

To investigate a possible association between serum magnesium concentrations and dementia in a large population-based sample.

Maccabi Healthcare Service in Israel provides healthcare to over 2 million citizens. Maccabi maintains a registry with approximately 26,000 diagnosed dementia patients. We focused on patients of both sexes with Alzheimer's disease or mixed dementia aged 65 or older, excluding patients with clinical diagnoses that could affect serum magnesium level, or with other causes of cognitive decline. Our control group consisted of patients of the same age and sex without dementia.

No significant differences were found in mean, mode, and median magnesium levels between the dementia and control groups. However, there were marginally but significantly more cases with low magnesium levels among dementia patients than among controls: A total of 9.4% of tests done in patients with dementia and 7.81% done in non-dementia subjects were hypomagnesemic (p <  0.00001).

Despite similar means and medians of serum magnesium in dementia and controls, the proportion of lower than normal magnesium test results was slightly higher among dementia patients. It is possible that patients with dementia have more episodes of hypomagnesemia than controls, despite similar overall mean levels of magnesium.