Biochemical analysis of serum mineral and vitamin levels in benign essential blepharospasm

Background/Aim: Benign essential blepharospasm (BEB) is a type of focal dystonia characterized by involuntary periocular muscle spasms, resulting in partial or complete eyelid closure. Though BEB has been linked to a variety of mineral and vitamin D deficiencies, its association with serum vitamin B12 has never been studied. We intended to determine the association between vitamin B12, serum calcium, magnesium, phosphorus, and 25-(OH) vitamin D levels, and BEB severity and frequency. Methods: This retrospective case-control study included 20 BEB patients who were followed-up and treated periodically with botulinum toxin injections in Afyonkarahisar Health Sciences University Department of Ophthalmology’s Oculoplastic and Reconstructive Surgery Unit between January 2019 and January 2021. Twenty age- and gender-matched healthy individuals were also included. The Jankovic rating scale was used to determine the severity and frequency of BEB. Acquired data were assessed retrospectively in terms of age, gender, serum minerals, 25 (OH)-Vitamin D and Vitamin B12 levels. Results: In this study, 20 BEB patients (F:M=14:6) and 20 healthy individuals (F:M=12:8) (P=0.321) were investigated. The mean ages of BEB patients and healthy individuals were 64.37 (4.21) and 63.83 (3.13) years, respectively (P=0.239). Compared to healthy individuals, BEB patients had significantly lower serum levels of 25-(OH) vitamin D (P=0.037), vitamin B12 (P=0.014) and calcium (P=0.011). In BEB patients, serum levels of 25-(OH) vitamin D (r=-0.375, P=0.043), calcium (r=-0.319, P=0.039), and vitamin B12 (r=-0.408, P=0.027) were all strongly negatively correlated with the Jankovic severity score. Conclusion: A strong negative correlation between disease severity and decreased vitamin B12, 25-(OH) vitamin D, and calcium in BEB patients indicated that, among other things, BEB may be a rare form of vitamin B12 deficiency. In the absence of an obvious cause for BEB, serum vitamin B12 testing, in addition to serum minerals and 25-(OH) vitamin D, may be useful.