A recent study published in the journal Nutrients investigates the role of vitamin D in the management of carpal tunnel syndrome (CTS).
Study: The role of vitamin D in the treatment of carpal tunnel syndrome: clinical and electroneuromyographic responses. Image credit: Alliance Images / Shutterstock.com
What is CTS?
CTS is one of the most common peripheral neuropathies affecting the anatomy of the wrist. It causes compression of the median nerve, a large nerve that innervates the arm, forearm and hand. This compression causes the sufferer to experience pain, numbness, or tingling along the area of the upper limb affected by the pressure. In addition, CTS often results in impaired grip and hand function.
Obesity, diabetes, repetitive stress injury, rheumatoid inflammation, pregnancy, and genetic factors interact to increase the risk of CTS. CTS usually affects people between the ages of 40 and 60. However, the condition can also affect people of other ages. Women are twice as likely to have CTS than men, with 193 and 88 women and men affected for every 1,000,000, respectively.
Vitamin D and CTS
Vitamin D is a fat-soluble vitamin that regulates calcium and phosphorus metabolism and immune function. It is also vital for endocrine, cardiovascular, skeletal and skin health and is associated with metabolic and antioxidant/anti-inflammatory properties.
Thus, vitamin D deficiency could enhance several neuropathic or pain syndromes associated with increased inflammation. Vitamin D deficiency also enhances the severity of symptoms in CTS.
To date, it remains unclear how vitamin D supplementation might help in the management of CTS.
About the study
The present study included 14 patients with CTS from two centers. All study participants had CTS in one or both wrists and low levels of vitamin D. None of the study participants had consumed vitamins for six months prior to the study period, and none of the participants had a history of medical or surgical treatment for CTS.
Study participants were screened for other conditions that could cause CTS or similar symptoms, including neuropathies, inflammatory syndromes, trauma to the affected limb, poorly managed diabetes, thyroid and parathyroid disease, cervical problems, and obesity. All study participants were women with an average age of 51 years.
Participants were randomized to receive either corticosteroid therapy alone or corticosteroids with vitamin D supplementation. Block randomization was used to ensure homogeneity within the cohort.
Graphic Summary
What did the study show?
Among CTS patients with low vitamin D levels, adding vitamin D to corticosteroid therapy resulted in improved pain relief, reduced symptom severity, and some electromyography (EMG) parameters.
At baseline, Phalen and Tinel tests were performed in all patients, with 86% and 71% positivity rates, respectively. When stratified by group, the intervention group had 100% Phalen positivity at baseline, which decreased to 75% at three months. In comparison, Phalen positivity rates in the corticosteroid-only group were 67% and 33%, respectively.
At baseline, corticosteroid-only recipients had 50% Tinel test positivity, which decreased to 33% by three months. Compared to baseline levels of 88%, vitamin D supplementation resulted in 75% Tinel test positivity at three months.
Pain relief was greater in the intervention group than in controls, which corresponds to increased vitamin D concentrations. Symptom severity decreased in both groups without significant improvement in functional status.
By EMG, motor delay of the median nerve and sensitive driving speed improved in the intervention group.
conclusions
Previous studies have shown that vitamin D deficiency increases the risk of CTS and the severity of symptoms. The current study confirms these results and suggests that vitamin D supplementation in CTS patients with low vitamin D levels may reduce levels of innervation and hypersensitivity, thereby reducing pain sensation and nerve tingling. Lower vitamin D levels were associated with greater symptom severity, which improved after three months of supplementation alongside corticosteroid treatment.
Vitamin D protects against neuropathies such as CTS by suppressing L-type calcium channel expression and upregulating vitamin D receptors and their antioxidant activity.
Vitamin D supplementation improves pain severity in CTS. In addition, it affects the reduction of symptom severity in CTS patients, but does not affect their functional status.”
Both the Tinel and Phalen tests, although usually used for diagnosis rather than treatment monitoring, showed clinical improvement in both groups. Thus, the current study also demonstrates a monitoring role for these tests.
Future studies with larger sample sizes, longer follow-up, and other assessment tools are indicated to validate and extend the results of this experiment.
Journal Reference:
- Andrade, AVD, Martins, DGS, Rocha, GS, et al. (2024). The role of vitamin D in the treatment of carpal tunnel syndrome: clinical and electroneuromyographic responses. Nutrients. doi:10.3390/nu16121947.