New European research provides a causal genetic link between increased vitamin D levels and disease progression.
Getting more sunshine could be key for people living with MS.
Higher vitamin D levels decrease the risk of developing multiple sclerosis, yet less is known about if and how vitamin D levels are related to measures of disease progression.
Now, a new European study, published in the Journal of Neurology, Neurosurgery & Psychiatry, provides the first evidence of a direct, causal role of vitamin D on disease activity.
âVitamin D and MS risk is important, but we are also keen to understand more about the role of UV radiation in the immune system in MS. It seems that there are mechanisms mediated by UV exposure independent of vitamin D production that are also important,â Dr Julia Morahan (PhD), head of research at MS Australia, told The Medical Republic.
Researchers recruited 1600 MS patients prior to starting a first-line disease-modifying therapy and explored how baseline vitamin D levels (and a patientâs genetic predisposition to having naturally higher or lower levels of vitamin D) were associated with disease progression.
After adjusting for seasonal variation in vitamin D levels, higher vitamin D levels at baseline were associated with a higher probability of displaying no evidence of disease activity at the two-year follow-up. Specifically, patients with a baseline vitamin D level below 20ng/ml had 2.36-fold higher odds of displaying new disease progression after two years compared to patients with a baseline vitamin D level above 20ng/ml.
The researchers also found that patients with a genetic predisposition to higher vitamin D levels had a delayed onset of MS. Patients in the top quartile for being genetically predisposed to having higher vitamin D levels had a 31% increase in their odds of showing no disease progression at the two-year mark compared to patients in the bottom quartile.
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Dr Morahan told TMR the results could be explained by vitamin Dâs action on the immune system, which may influence the development of multiple sclerosis.
âWe know that vitamin D has a range of effects on the immune system, including enhancement of innate immunity by activating immune cells like macrophages and natural killer cells and supporting the production of B and T cells,â she said. âVitamin D also has anti-inflammatory properties.â
Additional genetic analysis proved the relationship between vitamin D levels and MS disease progression was causal, with the researchers showing the probability of a patient showing no disease progression after two years of disease-modifying therapy increased with the genetically predicted increase in vitamin D levels at baseline.
âThese findings represent an important step to guide and promote future randomised trials assessing the effect of vitamin D supplementation on disease activity outcomes in a real-world setting,â the researchers concluded.
While Dr Morahan felt it was important for GPs to ensure their patients with MS had adequate vitamin D levels, she agreed the results need to be confirmed in a larger cohort.
Journal of Neurology, Neurosurgery & Psychiatry 2024, online 14 July
