Vitamin D deficiency increases the risk of dementia

Researchers argue that raising rates could prevent about 17% of cases. (Photo: First Pilot Jensen Stidham/Public Images)

In addition to the already known negative effects on bone health, vitamin D deficiency has been linked in several studies to effects on the brain and cardiovascular disease. Now, new work published in The American Journal of Clinical Nutrition was the first to use genetic analysis and found a causal link between low levels of the compound and a 54% risk of developing dementia.

Conducted by researchers at the University of South Australia, the study analyzed information from nearly 295,000 participants available in the UK Biobank, the UK’s health database. The aim was to understand the effects of suboptimal (25 nmol/L) vitamin D levels for the diagnosis of dementia and stroke.

“Vitamin D is a hormone that is increasingly being recognized for its widespread effects, including on brain health, but until now it has been very difficult to examine what would happen if we could prevent deficiency. Our study is the first to examine the effect of very low levels of vitamin D. Vitamin D on the risk of dementia and stroke using robust genetic analyzes in a large population.

The innovative method the scientists use blends genetic analysis with traditional epidemiology, called the Mendelian randomization (MR) method. The approach starts from the variation of genes with known functions to assess causal links between a risk factor and disease. For example, if a gene that specifically acts on what could be the greatest risk is also associated with the problem, this indicates a causal relationship.

Disease prevention

In the new study, researchers used this technology for the first time to test this relationship between low vitamin D and dementia and stroke outcomes. The conclusion was that lower levels, of 25 nmol/L, were associated with smaller brain volumes and an increased risk of both health problems, but only directly with dementia.

This is because genetic analysis of the images showed that the risk of dementia, which was increased by 54%, was a direct result of a deficiency of the compound. According to those responsible for the study, this indicates that an intervention to raise the level of vitamin D from 25 to 50 nmol/L could prevent cases of the disease.

“In the UK population, we have observed that up to 17% of cases of dementia can be prevented by increasing vitamin D levels to stay within the normal range,” Elena says.

Last year, the World Health Organization (WHO) issued an alert stating that the world was failing to fight dementia – of which Alzheimer’s disease is a leading cause – and highlighted that the diagnosis could reach 139 million people. 2050.

In the analysis of stroke and smaller brain volume, although the observation of the data indicated an increase in cases in people with low vitamin D, genetic evaluation did not indicate a cause-and-effect association.

However, the answer to the exact relationship may lie in another study published at the end of last year by the same team of researchers, in the European Heart Journal.

In it, scientists used genetic analysis technology in nearly 270,000 participants and concluded that low vitamin D generally increases the risk of cardiovascular disease, although in a shyer way than that seen with dementia. In the work, the researchers argued that raising the rate of the compound could prevent 6% of cases of heart disease.

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