Influence of vitamin D on muscle strength and botulinum toxin dosage through surface electromyography.

To evaluate the influence of patients' serum vitamin D levels on muscle strength characteristics and whether it impacts the durability of botulinum toxin (BT) treatment. The muscle strength of the frontal and corrugator muscles was evaluated before and after the application of TB with pre- and post-application control measurements, and at weeks 2, 5 and 12. The effect of vitamin D on muscle strength and its interaction with BT were investigated in 20 patients. The muscle contraction force was measured by surface electromyography. The results revealed statistically significant differences between the frontal measurement groups at weeks 2 and 5, as well as for the corrugator in the same weeks and at week 12. Regarding vitamin D, significant differences were observed only in the initial group with vitamin D > 30 ng/mL compared to < 30 ng/mL for the frontal muscles. Patients with higher levels of vitamin D had higher average muscle strength compared to those with lower levels in all evaluations. It was observed that vitamin D influences muscle strength and the necessary dosage of BT.