Both High and Low Blood Magnesium Levels Linked to Increased Dementia Risk

Summary: A large population study published in Neurology finds that people with either relatively high or relatively low blood magnesium levels have a higher risk of developing dementia compared with those whose magnesium levels fall in the middle range.

Source: AAN.

Study overview

Researchers published results online on September 20, 2017, in the journal Neurology describing an analysis of 9,569 people without dementia at baseline. The study population had an average age of 65 and underwent blood testing for magnesium. Participants were followed for an average of eight years to monitor new diagnoses of dementia, including Alzheimer’s disease.

Main findings

During follow-up, 823 participants were diagnosed with dementia; of those, 662 cases were classified as Alzheimer’s disease. The investigators divided participants into five groups according to their blood magnesium levels. Compared with the group in the middle range, participants in both the lowest and the highest magnesium groups showed a higher risk of developing dementia.

Statistically, people in the low and high magnesium groups had an approximately 30 percent increased risk of dementia compared with those in the middle group. In absolute terms, 160 of the 1,771 people in the low-magnesium group developed dementia, a rate of 10.2 per 1,000 person-years. In the high-magnesium group, 179 of 1,748 people developed dementia, a rate of 11.4 per 1,000 person-years. By comparison, 102 of 1,387 people in the middle group developed dementia, a rate of 7.8 per 1,000 person-years.

Interpretation and context

Study author Brenda C. T. Kieboom, MD, MSc, of Erasmus University Medical Center in Rotterdam, Netherlands, described the results as intriguing but in need of confirmation. The analysis shows an association between magnesium levels and dementia risk but does not prove a causal link. The research team adjusted for multiple potential confounders — including body mass index, smoking, alcohol use and kidney function — and the association remained.

It is also important to note that most participants had magnesium levels within the laboratory reference range; only 108 people had below-normal magnesium and two had above-normal magnesium. The observed differences were seen across the distribution of measured magnesium levels rather than being driven solely by clinically abnormal values.

Dietary sources and practical considerations

Foods that provide dietary magnesium include leafy greens such as spinach, nuts like almonds and cashews, soy and black beans, whole grains, yogurt and avocados. If further research confirms these findings, simple blood tests could potentially help identify individuals at higher risk for dementia who might benefit from targeted investigation or lifestyle interventions. However, because this study is observational, it cannot determine whether changing magnesium intake would alter dementia risk.

Limitations

The investigators acknowledge several limitations. Magnesium was measured only once, so levels may have changed over time. Additionally, blood magnesium concentration may not fully reflect total body magnesium stores or intracellular magnesium status. These factors mean the findings should be interpreted cautiously and warrant replication in other cohorts with repeated measurements and more detailed assessment of magnesium status.

Implications

At present the study adds to a body of research exploring modifiable risk factors for cognitive decline and dementia. Given the limited treatment options for dementia, identifying potentially modifiable risk markers is a public health priority. Future research should focus on confirming this association, clarifying biological mechanisms, and determining whether interventions that adjust magnesium status can influence dementia risk.

Funding and acknowledgements

The research received support from Erasmus University Medical Center, Erasmus University Rotterdam, the Netherlands Organization for Scientific Research, the Netherlands Organization for Health Research and Development, the Research Institute for Diseases in the Elderly, the Netherlands Genomics Initiative, various Dutch ministries, the European Commission and the Municipality of Rotterdam.

Notes

Reporting: Renee Tessman – AAN. Original research: the study appears in Neurology. NeuroscienceNews.com image is in the public domain.