Lower Serum Zinc Levels in Patients with Multiple Sclerosis Compared to Healthy Controls.

OBJECTIVE: Diminished blood levels of zinc have been reported to be associated with T-cell-mediated autoimmunity, which has been implicated in multiple sclerosis (MS). We aimed to compare the distribution of serum zinc status in MS patients with that in healthy controls (HCs) and to investigate a potential correlation with clinical state, through analysis of serum zinc concentration in MS patients suffering from different disease subtypes. METHODS: Serum zinc concentrations of 133 patients with relapsing (RMS) and 18 patients with the progressive form of MS (PMS), according to the McDonald criteria of 2010, were measured. Clinical status was quantified using the Expanded Disability Status Scale (EDSS). Zinc concentrations were also determined in the sera of 50 HCs, matched for age and sex at a group level. RESULTS: MS patients showed significantly lower zinc concentrations (mean (SD)) than HCs (12.5 (2.1) µmol/L vs. 14.6 (2.3) µmol/L, p < 0.001). In contrast, we did not find any difference between RMS (12.4 (2.0) µmol/L) and PMS (13.0 (3.0) µmol/L) cases (p = 0.8). Patients receiving disease-modifying treatment showed lower mean (SD) serum zinc levels than untreated cases (12.3 (1.9) µmol/L vs. 13.5 (3.2) µmol/L, p < 0.03). Zinc levels were not related to disease duration, EDSS, annual relapse rate, or the median number of relapses. CONCLUSIONS: The data suggest that a diagnosis of MS is related to lower serum zinc concentrations than in HCs, and concentrations were lower still under disease-modifying therapy. However, zinc levels did not predict disease subtypes or disability status.