Parkinson’s Disease Foundation - Apr 05 2011
People with a recent diagnosis of Parkinson’s disease (PD) were found to have low blood levels of vitamin D in a study published in the March 2011 issue of Neurology. The study authors suggest that people with PD may not have been getting enough vitamin D for a long time before Parkinson’s symptoms developed, and that vitamin D deficiency may play a role in causing the disease.
In an earlier study, researchers at the Emory University School of Medicine, led by Marian L. Evatt, M.D., M.S. found that people with Parkinson’s are more likely than healthy people or people with Alzheimer's to have vitamin D deficiency. Other studies have reported similar results. Since the body produces vitamin D when skin is exposed to sunlight, scientists have theorized that, as a person’s PD progresses, he or she may tend to stay indoors and be less physically active, leading to a decrease in vitamin D levels.
This time Dr. Evatt and her team studied vitamin D levels measured as (25(OH)D in blood samples only from people with early stage PD who were not taking any PD medications or vitamin D supplements. The samples had been collected and stored as part of another study, during which two samples were drawn, about 18 months apart. Most of the 157 study participants were white, about two-thirds were men and their average age was 61.
- At the beginning of the study nearly 70 percent of participants had lower-than-normal blood levels of vitamin D (less than 30 ng/mL); 26 percent had vitamin D deficiency (less than 20 ng/mL).
*The new study contradicted the expectation that vitamin D levels decrease over time in people with PD: vitamin D levels increased slightly during the course of the study, from 26.3 ng/mL on average to 31.3 ng/mL.
- When the second blood sample was drawn, about 18 months after the first one, about 52 percent of participants had low vitamin D, and 7 percent were vitamin D deficient.
- Participants’ PD symptoms progressed during the interval between blood draws.
What Does it Mean?
This report examines vitamin D levels in a larger group of people with PD than any other study to date. It confirms that low vitamin D levels are common in people with early stage PD and suggests that vitamin D levels do not decrease as PD progresses.
Low vitamin D levels have been associated with multiple neurological disorders, including Parkinson’s disease, Alzheimer’s disease, multiple sclerosis, schizophrenia and mood disorders. More research is needed to explain the association between vitamin D and PD. Most importantly, more research is required to find out whether low levels of vitamin D add to the risk of developing PD.
- - - - -