Sex-Specific Association Between Vitamin D Insufficiency and Burning Pain in Herpetic Neuralgia: A Prospective Cohort Study.

Purpose: Vitamin D is important for host immunity and a large proportion of herpes zoster patients experience vitamin D insufficiency (VDI). However, the role of vitamin D in herpetic neuralgia (HN) remains controversial. This study aims to explore the potential relationship between vitamin D status and HN characteristics. Patients and methods: This prospective observational cohort study was conducted from February 2024 to November 2024 with 160 HN patients within 12 weeks after rash onset. Demographic and clinical data of patients were collected. The serum 25-hydroxyvitamin D level, triglyceride and other laboratory parameters were measured at patients' admission. Comprehensive pain evaluations including the Brief Pain Inventory (BPI), 11-point Numerical Rating Scale (NRS) and Douleur Neuropathique 4 questionnaires were performed at admission, as well as 1, 2, and 3 months after treatment. Results: VDI was prevalent (121 VDI, 39 VDS) in the cohort. Although no significant correlation emerged between vitamin D levels and BPI or NRS scores, Female (n = 82, odds ratio [OR] 2.80, 95% CI 1.30-6.33, P < 0.05) and high serum triglyceride level (OR 3.20, 95% CI 1.41-8.86, P < 0.05) were identified as independent predictors of VDI. Female patients exhibited a significant negative correlation between vitamin D status and burning pain (Spearman's ρ = -0.347, P < 0.001) and a concomitantly lower early pain relief rate compared to males, in whom the correlation was non-significant (n = 78, ρ = 0.7, P > 0.05). Conclusion: Low vitamin D levels are common in HN patients. The sex-specific association between VDI and burning pain, as well as short-term prognosis, Triglyceride levels served as a predictive indicator for VDI in HN patients. Future studies are needed to elucidate the underlying mechanisms of the pain-vitamin D association specifically in female patients.