Effect of vitamin D on the peripheral neuropathy in type 2 diabetic patients

Background: Current therapies for diabetic neuropathy have not been satisfactory despite the frequent attempts made and various medications introduced. Given the lower level of vitamin D in diabetic patients than in normal population, the present study evaluated the role of vitamin D in the treatment of diabetic neuropathy.

Methods: A total of 90 type II diabetic patients with a history of neuropathy for at least one month based on Toronto clinical score system and low level of vitamin D, who had referred to Kermanshah Diabetes Research Center, Iran, were included in this clinical study. The patients underwent treatment with 50000 U vitamin D for three months, once per week. The level of vitamin D, HbA1C and the score of neuropathy were measured before and after three months treatment and the results were analyzed.

Results: After treatment, vitamin D level significantly increased  which was favorable in 85% of the patients. Also, neuropathy level decreased from 9.5±2.5 (before treatment) to 7.0±2.5 (after treatment), which was statistically significant. Moreover, the HbA1C level significantly decreased from 8.6±1.6 to 7.4±1.4. However, no significant correlation was reported between neuropathy level reduction, changes of vitamin D level and HBA1C level. 

Conclusion: The results of the current study indicated that vitamin D has no therapeutic effect on diabetic neuropathy and increase of pain threshold level may be non-specifically due to the placebo effect of vitamin D.