Vitamin D deficiency leads to dementia – Neuroscience News

Summary: Researchers have found an association between low vitamin D levels and reduced brain volume. A drop in vitamin D was also linked to an increased risk of stroke and dementia. Up to 17% of dementia cases could be prevented by increasing vitamin D.

Source: University of South Australia

Dementia is one of the leading causes of disability and dependency in older people worldwide, affecting thinking and behaviors as you age. What if you could stop this degenerative disease in its tracks?

A world-first study from the University of South Australia could make that a reality, as new genetic research shows a direct link between dementia and a lack of vitamin D.

Investigating the association between vitamin D, neuroimaging characteristics, and the risk of dementia and stroke, the study found:

  • low vitamin D levels were associated with lower brain volumes and increased risk of dementia and stroke
  • genetic analyzes have supported a causal effect of vitamin D deficiency and dementia.
  • in some populations, up to 17% of dementia cases could be prevented by bringing everyone to normal levels of vitamin D (50 nmol/L).

Dementia is a chronic or progressive syndrome that leads to deterioration of cognitive functions. Around 487,500 Australians live with dementia and it is the second leading cause of death in the country. Globally, more than 55 million people have dementia and 10 million new cases are diagnosed each year.

Supported by the National Health and Medical Research Council, the genetic study analyzed data from 294,514 participants from the UK Biobank, examining the impact of low levels of vitamin D (25 nmol/L) and the risk of dementia and diabetes. ‘stroke. Nonlinear Mendelian (MR) randomization – a method of using measured variation in genes to examine the causal effect of modifiable exposure on disease – has been used to test the underlying causality of neuroimaging findings , dementia and stroke.

Lead researcher and director of UniSA’s Australian Center for Precision Health, Professor Elina Hyppönen, says the findings are important for the prevention of dementia and for appreciating the need to abolish vitamin D deficiency.

“Vitamin D is a hormone precursor whose widespread effects, including on brain health, are increasingly recognized, but until now it has been very difficult to examine what would happen if we could prevent a vitamin D deficiency,” says Professor Hyppönen.

Low vitamin D levels were associated with lower brain volumes and an increased risk of dementia and stroke. Image is in public domain

“Our study is the first to examine the effect of very low levels of vitamin D on the risk of dementia and stroke, using robust genetic analyzes in a large population.

“In some settings, where vitamin D deficiency is relatively common, our findings have important implications for dementia risk. Indeed, in this UK population, we observed that up to 17% of dementia cases could have been prevented by raising vitamin D levels to within a normal range.

The results are incredibly significant given the high prevalence of dementia around the world.

“Dementia is a progressive and debilitating disease that can devastate individuals and families,” says Professor Hyppönen.

“If we are able to change this reality by ensuring that none of us are seriously deficient in vitamin D, that would also have other benefits and we could change the health and well-being of thousands of people. .”

“Most of us are probably fine, but for anyone who, for whatever reason, is not getting enough vitamin D from sunlight, dietary changes may not be enough and supplementation may be necessary.”

About This Vitamin D and Dementia Research News

Author: Annabel Mansfield
Source: University of South Australia
Contact: Annabel Mansfield – University of South Australia
Image: Image is in public domain

Original research: Free access.
“Vitamin D and Brain Health: A Mendelian Observational Randomization Study” by Elina Hyppönen et al. American Journal of Clinical Nutrition


Summary

Vitamin D and brain health: a Mendelian randomized observational study

Background

See also

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Higher vitamin D status has been suggested to have beneficial effects on the brain.

Goals

Studying the association between 25-hydroxyvitamin D [25(OH)D]neuroimaging features and risk of dementia and stroke.

Methods

We used prospective data from the UK Biobank (age 37–73 at baseline) to examine the association between 25(OH)D concentrations and neuroimaging outcomes (NOT = 33,523) and the risk of dementia and stroke (NOT = 427690; 3414 and 5339 incident cases, respectively). Observational analyzes were adjusted for age, sex, ethnicity, month, center and socioeconomic factors, lifestyle, sun behavior and disease-related factors. Nonlinear Mendelian randomization (MR) analyzes were used to test the underlying causality of neuroimaging findings (NOT = 23,901) and dementia and stroke (NOT = 294514; 2399 and 3760 cases, respectively).

Results

Associations between 25(OH)D and total, gray matter, white matter, and hippocampus volumes were not linear, with lower volumes for low and high concentrations (adjusted P-nonlinear ≤ 0.04). 25(OH)D had an inverse association with white matter hyperintensity volume [per 10 nmol/L 25(OH)D; adjusted β: –6.1; 95% CI: –11.5, –7.0]. Vitamin D deficiency was associated with an increased risk of dementia and stroke, with the strongest associations for those with 25(OH)D <25 nmol/L (compared to 50–75.9 nmol /L; adjusted RR: 1.79; 95% CI: 1.57, 2.04 and HR: 1.40; 95% CI: 1.26, 1.56, respectively).

Nonlinear MR analyzes confirmed the threshold effect of 25(OH)D on dementia, with a 54% higher predicted risk (95% CI: 1.21, 1.96) for participants at 25 nmol /L versus 50 nmol/L. 25(OH)D was not associated with neuroimaging findings or stroke risk in MRI scans. The potential impact fraction suggests that 17% (95% CI: 7.22; 30.58) of dementia could be prevented by increasing 25(OH)D to 50 nmol/L.

conclusion

Low vitamin D status was associated with neuroimaging findings and risk of dementia and stroke, even after extensive adjustment for covariates. MR analyzes support a causal effect of vitamin D deficiency on dementia, but not on stroke risk.

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