Nearly half of people with Friedreich’s ataxia (FA) in the U.K. have insufficient vitamin D levels, although these levels were not associated with measures of disease severity, a new analysis shows.
In addition, nearly 30% of patients had vitamin D levels in the deficiency range, meaning their levels were even lower.
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Low vitamin D levels highlight need for screening in FA patients
Considering the established benefits of vitamin D supplementation, particularly for bone health, along with its low cost and good safety profile, the researchers noted that “vitamin D deficiency should be screened for and actively managed in all [FA] patients.”
The study, “An Exploration of Vitamin D Deficiency and Clinical Status in Friedreich’s Ataxia Patients in the UK,” was published in Movement Disorders.
FA is caused by mutations in the FXN gene that result in abnormally low levels of frataxin, a protein vital for the function of mitochondria, the cell’s energy production centers. Muscle and nerve cells are particularly vulnerable to low energy levels, leading to FA symptoms such as ataxia (coordination and balance difficulties), heart problems, and other neurological issues.
Vitamin D deficiency has been associated with several neurodegenerative conditions. In FA, vitamin D supplementation has been shown to increase frataxin levels in some patients, and eating vitamin D-rich foods, such as dairy products, may support bone health.
In this study, researchers aimed to assess vitamin D status among people with FA in the U.K. To do this, they analyzed records from 56 FA patients (33 women) enrolled in the London arm of the European Friedreich’s Ataxia Consortium of Translational Studies (EFACTS) database.
Participants had a median age of 30 years and a median disease duration of 17 years. The majority used a wheelchair (55.4%) and most reported falls (81.1%). Additionally, 17.9% were able to walk but used a wheelchair regularly, and 26.8% were fully able to walk.
The median score on the Scale for the Assessment and Rating of Ataxia (SARA), a clinician-administered measure of ataxia severity, was 22 points.
Analysis finds vitamin D deficiency common in FA patients
Results showed that the median vitamin D level was 31.8 nanomoles per liter (nmol/L). According to the U.K. National Institute for Health and Care Excellence definitions, 48% of patients had insufficient vitamin D levels (below 50 nmol/L), and 29% had vitamin D deficiency (below 25 nmol/L). Although there were no statistically significant differences between men and women, the median vitamin D level in men was at the deficiency threshold (25 nmol/L), while women were in the insufficiency range (34.7 nmol/L).
The vitamin D levels found in this FA group were similar to those reported in U.K. individuals with multiple sclerosis (38 nmol/L), another neurological condition that affects young adults.
Compared with median vitamin D levels in adults ages 19–64 in the National Diet and Nutrition Survey — 49.7 nmol/L in women and 44 nmol/L in men — the researchers hypothesized that FA patients may be at higher risk of vitamin D deficiency than the general adult population.
Vitamin D deficiency was not associated with any of the clinical measures assessed, including the SARA score, patients’ ability to walk, disease duration, age at disease onset or evaluation, falls, or the presence and severity of leg muscle weakness.
“Since the assumption is that deficiency is primarily linked to limited sunlight exposure, which one would expect with higher levels of disability, this finding requires further explanation,” the researchers wrote.
