Researchers recently conducted a survey of over 2000 adults with multiple sclerosis to determine whether vitamin D supplementation, latitude and/or sun exposure are related to the relapse rate and disease progression of multiple sclerosis (MS).
Multiple sclerosis is a progressive neurodegenerative disease in which the body’s immune system attacks the protective sheath that covers nerves. This damage disrupts the communication between the body and the brain. MS symptoms range depending on the location of the affected nerves. Symptoms may include blurred vision, numbness in the limbs, dizziness and slurred speech.
Clinical trials have recently suggested that vitamin D supplementation has a positive effect on MS. However, the dosage that provides the most benefits remains unclear. Thus, researchers recently assessed the relationship between different dosages of vitamin D and health outcomes of MS. In addition, the researchers looked at latitude and sun exposure.
The researchers surveyed 2301 participates with MS online. The average age was 45 years old. The survey consisted of 163 questions inquiring about socio-demographics, MS diagnosis, level of disability, health related quality of life and symptom severity. They also asked specific questions regarding vitamin D supplementation dosage and sun exposure habits. Here is what the researchers found from analyzing the data:
- A total of 1504 (63%) of participants reported that they intentionally received sun exposure to increase their vitamin D status.
- The majority of participants took vitamin D supplements (81.8%) with an average supplementation regimen between 2000 and 5000 IU daily.
- Deliberate sun exposure and latitude was strongly associated with health related quality of life. Although this relationship disappeared after adjusting for confounding factors.
- Vitamin D supplementation and health related quality of life were significantly related before and after adjusting for confounding factors with a dose-response effect.
- An increase of latitude by one degree (further from the equator) was associated with a 2% increase in odds of moderate disability and a 3% increase in odds of high disability compared to those with no disability or mild disability.
- Relapse rate was also related to latitude. An increase of latitude by one degree was associated with a 1% increase in odds of having more relapses over the previous year.
- Those taking vitamin D supplements had about a one third lower annualized relapse rate compared to those who did not (p < .001).
The researchers concluded,
“We detected significant associations between latitude, deliberate sun exposure and vitamin D supplementation and health outcomes of this large group of people with MS.”
They went on to state the implications of their findings,
“Vitamin D is likely to have a pivotal role in these associations; its role in MS health outcomes urgently requires detailed exploration with well-designed clinical trials.”
These findings provide further support to the extensive research that has found vitamin D plays a role in multiple sclerosis. The high percentage of MS patients who take vitamin D illustrates that MS patients have become aware of the benefits of vitamin D.
There are a few limitations to keep in mind in regards to this study. All measures were self-reported, leaving room for recall bias. Also, vitamin D status was not measured. Lastly, the study is cross-sectional, meaning that we cannot conclude causation.
Citation of article
Tovey A and Cannell JJ. Research provides further evidence that vitamin D and sun exposure play a role in multiple sclerosis. Vitamin D Council Newsletter, August 2015.
Jelinek G., et al. Latitude, sun exposure and vitamin D supplementation: associations with quality of life and disease outcomes in a large international cohort of people with multiple sclerosis. BMC Neurology, 2015.