Elevated Plasma Vitamin D Levels are Associated with Pain Characteristics and Duration in Patients with Postherpetic Neuralgia

BACKGROUND: Aim is to analyze the correlation between plasma vitamin D (VD) level and pain characteristics and duration in patients with postherpetic neuralgia (PHN). METHODS: 116 patients with PHN were prospectively collected as the PHN group, and another 102 non-PHN patients were selected as the control group. The plasma VD levels were detected by enzyme-linked immunosorbent assay. The factors affecting the plasma VD levels of PHN patients were analyzed by one-way and logistic regression analysis. The correlation between the plasma VD levels of the PHN patients with pain characteristics and duration was analyzed by Pearson correlation. RESULTS: Plasma VD levels [(26.63 ± 2.95) ng/mL] in patients in the PHN group were significantly lower compared with those in the control group [(31.39 ± 2.98) ng/mL] (p < 0.001). Plasma VD level was associated with LANSS score (OR = 1.302), pain type (OR = 3.218) and pain duration (OR = 1.392) in patients with PHN (all p < 0.01). Plasma VD levels were negatively correlated with LANSS score (r = -0.346) and pain duration (r =- 0.381) in patients with PHN. CONCLUSIONS: Plasma VD levels are significantly lower in patients with PHN, and plasma VD levels determine pain characteristics and duration.