Carpal tunnel syndrome (CTS) is a painful neuropathy disorder which occurs due to compression of nerves travelling through the wrist. Individuals with this condition experience pain, numbness and loss of strength in the wrists and hands. These symptoms can lead to significant decline in quality of life.
The most common cause of CTS is an underlying medical condition, such as diabetes mellitus, impaired thyroid function and rheumatoid arthritis. Some risk factors include obesity, pregnancy and frequent wrist activity, such as using a keyboard and typing.
Previous research has connected vitamin D to diabetic neuropathy. Furthermore, studies have shown vitamin D helps treat or mediate pain in conditions including osteoarthritis, chronic widespread pain and fibromyalgia. Researchers from this study aimed to investigate the relationship between vitamin D and pain severity in patients with mild CTS.
A total of 76 individuals between the ages of 18 and 45 were included in the study. About half of the participants were diagnosed with mild CTS, while the remaining half did not have CTS. The researchers measured the patients’ vitamin D levels and pain using serum 25(OH)D draws and the visual analog scale (VAS), a tool used to measure the intensity and frequency and symptoms, respectively. The researchers also wanted to compare vitamin D levels to the severity of CTS; therefore, they assessed the severity with an electromyograph (EMG). Based on their EMG tests, participants were either placed into a no CTS or mild CTS group.
This is what the researchers found:
- Vitamin D levels were significantly lower in patients with CTS (p=0.003).
- There was no correlation between pain and vitamin D in the no CTS group, but there was a significant association between low vitamin D levels (<20 ng/ml) and pain in the mild CTS group (p=0.002).
Below is a table which shows the distribution of vitamin D levels in correlation with VAS scores in healthy and CTS individuals:
The researchers concluded that lower vitamin D levels may increase the severity of pain in patients with CTS. While the findings were significant, the study was limited by its observational design and small study population. In addition, the researchers acknowledged that the lack of a vitamin D intervention makes it impossible to determine if vitamin D supplementation may affect pain severity in CTS patients. The researchers called for larger-scale, interventional studies to explore the effect of vitamin D replacement in patients with CTS.
Peterson, R. & Cannell, JJ. Low vitamin D levels associated with increased pain in patients with carpal tunnel syndrome. The Vitamin D Council Blog & Newsletter, 2017.
Demiryurek BE, Gundogdu AA, The Effect of Vitamin D Levels on Pain In Carpal Tunnel Syndrome, Orthopaedics and Traumatology: Surgery and Research (2017), http://dx.doi.org/10.1016/j.otsr.2017.05.003