Dementia is one of the major causes of disability and dependency among older people worldwide. However, the latest research suggests that there may be a link to Vitamin D deficiency.
The world-first study from the University of South Australia found:
- Low levels of vitamin D were associated with lower brain volumes and an increased risk of dementia and stroke.
- Genetic analyses supported a causal effect of vitamin D deficiency and dementia.
- In some populations as much as 17 per cent of dementia cases might be prevented by increasing everyone to normal levels of vitamin D (50 nmol/L).
Dementia is a chronic or progressive syndrome that leads to deterioration in cognitive function. Globally, more than 55 million people have dementia with 10 million new cases diagnosed every year.
Supported by the National Health and Medical Research Council, the genetic study analysed 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 stroke. Nonlinear Mendelian randomisation (MR) – a method of using measured variation in genes to examine the causal effect of a modifiable exposure on disease – was used to test for underlying causality for neuroimaging outcomes, dementia, and stroke.
Senior investigator and Director of UniSA’s Australian Centre for Precision Health, Professor Elina Hyppönen, said the findings are important for the prevention of dementia and appreciating the need to abolish vitamin D deficiency.
“Vitamin D is a hormone precursor that is increasingly recognised for widespread effects, including on brain health, but until now it has been very difficult to examine what would happen if we were able to prevent vitamin D deficiency,” Prof Hyppönen commented.
“Our study is the first to examine the effect of very low levels of vitamin D on the risks of dementia and stroke, using robust genetic analyses among a large population.
“In some contexts, where vitamin D deficiency is relatively common, our findings have important implications for dementia risks. Indeed, in this UK population we observed that up to 17 per cent of dementia cases might have been avoided by boosting vitamin D levels to be within a normal range.”