Dementia is a chronic and progressive condition that leads to the deterioration of cognitive function. Around 55 million people worldwide live with dementia, and there are around 10 million new cases each year.
In the present study, researchers analyzed health records from 284, 514 individuals from the UK Biobank, including vitamin D levels and incidence of dementia or stroke. The researchers included genetic and neuroimaging data in their analysis.
In the end, they found that vitamin D deficiency was linked to an increased risk for dementia and stroke. Those with vitamin D levels- measured via 25-hydroxy vitamin D (25(OH)D)- of under 25 nmol/L were most likely to develop dementia.
The researchers further found that those with vitamin D levels of 25 nmol/L were 54% more likely to develop dementia than those with vitamin D levels of 50 nmol/L. These results remained after extensive covariate adjustment.
The researchers concluded that their findings suggest that 17% of dementia cases could be prevented by increasing vitamin D levels from 25 nmol/L to 50 nmol/L.
"Dementia is a progressive and debilitating disease that can devastate individuals and families alike," said Prof Elina Hyppönen, Director of the University of South Australia's Australian Centre for Precision Health and senior author of the study.
"If we're able to change this reality through ensuring that none of us is severely vitamin D deficient, it would also have further benefits, and we could change the health and wellbeing for thousands."
"Most of us are likely to be ok, but for anyone who for whatever reason may not receive enough vitamin D from the sun, modifications to diet may not be enough, and supplementation may well be needed."
Sources: Science Daily, The American Journal of Clinical Nutrition