Researchers from The University of South Australia has found a link between vitamin D deficiency and an increased risk of dementia and stroke.
Vitamin D plays an important role in the body, primarily helping the absorption of calcium and phosphorus. Most of the vitamin D consumed by humans enters the body not with food, but with the sun, since the skin produces it in response to exposure to ultraviolet radiation.
Unfortunately, it is estimated that up to a billion people worldwide are deficient in vitamin D. This can lead not only to weakening of muscles and bones, but also to an increase in the number of other conditions, such as certain cancers, autoimmune diseases and opioid addiction. Studies even suggest that pregnant women with vitamin D deficiency are at risk of having children who will develop schizophrenia or autism later in life.
In a new study, Australian scientists have added new diseases to this list. The team analyzed data from 294,514 people from the British Biobank, comparing vitamin D levels with the manifestation of dementia symptoms and stroke cases. They used a method called nonlinear Mendelian randomization to study whether variations in genes have a causal effect on diseases, while taking into account factors such as age, gender, ethnicity, lifestyle and health status.
The team found that low vitamin D levels – less than 25 nmol/L — or half of what is considered normal, was associated with lower brain volumes, as well as an increased risk of dementia and stroke. Genetic analysis showed a causal relationship between vitamin D deficiency and dementia, in people with a concentration of this vitamin at 25 nmol/l, the risk was 54% higher than in people with a concentration of 50 nmol/L.