introduction: Olfactory and gustative alterations are frequent in the initial stages of
the COVID-19 infection. Vitamin B12 deficiency has been linked to olfactory
dysfunction.
Objective The present study aimed to assess the relationship between vitamin B12
levels and smell affection in COVID-19 patients.
Patients and Methods The present study included 201 laboratory-confirmed COVID19 patients. Smell affection was assessed using self-rated olfactory function. Serum
vitamin B12 levels were assessed using commercial enzyme-linked immunosorbent
assay (ELISA) kits.
Results: According to the smell function assessment, the patients were classified into
three categories: normal smell (n= 77), hyposmia (n = 49), and anosmia (n =75) Four
weeks later, 195 patients (97.0%) had their normal smell function
restored. The remainder 6 patients included 4 anosmia and 2 hyposmia patients.
Patients with hyposmia or anosmia had significantly lower vitamin B12 levels when
Keywords
► COVID-19
► vitamin B12
► olfactory dysfunction
compared with patients with normal smell (median [IQR]: 363.0 [198.0–539.0] versus
337.0 [175.0–467.0] and 491.0 [364.5–584.5] pg./ml, respectively, p < 0.001).
Conclusion Vitamin B12 appears to have some contribution to smell affection in
patients with COVID-19 infection