No Link Found Between Vitamin D Levels, Age at First MS Symptoms
There is no link between serum vitamin D levels and the age at which an individual develops the first symptoms of multiple sclerosis (MS), a new observational study suggests.
However, a link was found between cerebrospinal fluid antibody levels, serum vitamin D levels, and the age at first MS symptoms, according to the researchers.
The scientists noted that Vitamin D deficiency remains linked to an increased risk of MS.
Thus, “further investigation … is required to understand the role of vitamin D during childhood/adolescence (i.e., before presymptomatic disease) and progression to symptomatic disease onset,” the team wrote.
The study, “Seasonal variability of serum 25-hydroxyvitamin D on multiple sclerosis onset,” was published in Nature Scientific Reports.
Vitamin D is a fat-soluble vitamin that acts as a hormone. Unlike other nutrients that must be obtained from food, the body can produce this vitamin when the person’s skin is exposed to ultraviolet B rays from sunlight. Besides its role in bone health, this vitamin is crucial for immunity and lowering inflammation.
Previous studies have linked low sun exposure and consequent low vitamin D levels with a high risk of early onset MS. However, most of those studies did not consider seasonal changes — important given that the levels of this vitamin typically peak in summer and drop in winter.
A team of scientists now sought to investigate the link between the levels of this vitamin and the age at which the first MS symptoms appear in newly diagnosed individuals, taking seasonal changes into account.
A total of 40 individuals, enrolled from two neurology clinics in Finland between 2000 and 2003, participated in this study. The mean age of the participants was 36.5, 80% were female, and the mean age at first symptom was 33.8. Among them, 95% had relapsing-remitting MS, and the others primary progressive MS.
Serum vitamin D levels — the levels of this vitamin in the blood — in all participants were measured near the start of the disease (disease onset). Samples of the cerebrospinal fluid — which surrounds the brain and spinal cord —were taken to measure immunoglobulin G (a type of antibody) levels.
The vitamin D levels seemed to be higher among participants in remission compared with those relapsing. However, most of the levels in patients in relapse were measured between March and May, when D levels are naturally lower. Notably, after adjusting the results based on seasonality, the vitamin levels measured at relapse were higher than at remission.
There was no link between the serum vitamin levels and age at MS onset, even after adjusting for sex and disease activity.
In contrast, cerebrospinal fluid antibody levels (IgG) were positively linked with these vitamin levels and negatively linked to age at MS onset — meaning that those with higher IgG levels had higher vitamin levels and lower age at disease onset.
“However, this association will require further validation in consideration of both age and disease duration,” the researchers wrote.
Overall, the “findings did not indicate an association between serum [vitamin] D levels and age at MS onset, consistent with previous studies,” the team concluded, adding, however, that “these findings do not fundamentally dismiss the role of vitamin D in MS onset nor the efficacy of vitamin D supplementation.”
According to the team, “it is crucial to correct for seasonal variation of vitamin D to prevent misrepresented conclusions resulting from potential sampling bias.”