Serum vitamin B12 levels and tinnitus severity: a prospective observational study in adults with chronic subjective tinnitus

Abstract Chronic tinnitus affects 10–33% of adults and significantly impairs their quality of life. Vitamin B12 deficiency may contribute to tinnitus through demyelination and impaired Central auditory inhibition; however, evidence remains limited. This study aimed to evaluate The association between serum vitamin B12 levels and tinnitus severity in adults with chronic Tinnitus. Methods This prospective observational study was conducted over 18 months (January 2022–June 2023) at a tertiary care hospital in India. Fifty adults (≥ 18 years) with chronic subjective Tinnitus (> 3 months duration) were enrolled. The exclusion criteria included objective or Pulsatile tinnitus, vascular causes (e.g. carotid stenosis), non-B12-related anaemia, recent B12 supplementation (< 6 months), and severe psychiatric illnesses. All participants Underwent pure-tone audiometry, serum vitamin B12 assay (chemiluminescent microparticle Immunoassay), and tinnitus severity assessment using the Tinnitus Handicap Inventory (THI) And visual analogue scale (VAS). Statistical analyses included Pearson’s correlation, one-way ANOVA, and descriptive statistics (SPSS v26.0). Results The cohort included 29 males (58%) and 21 females (42%), with a mean age of 44.2 ± 15.3 Years old. Vitamin B12 deficiency (< 200 pg/mL) was present in five participants (10%), 44 (88%) had normal levels (200–900 pg/mL), and one (2%) had supranormal levels (> 900 Pg/mL). Mean THI and VAS scores were 47.62 ± 12.47 and 4.32 ± 1.04, respectively; 40% Reported severe tinnitus (THI > 50). No statistically significant correlation was observed Between serum B12 levels and the THI (r = 0.006, p = 0.969) or VAS scores (r = − 0.197, p = 0.169). However, B12-deficient participants exhibited higher mean THI (42.8 vs. 48.1) and VAS (4.6 vs. 4.3) scores, though the difference was not statistically significant. Conclusions This study found no significant association between serum vitamin B12 levels and tinnitus Severity in a predominantly B12-replete cohort. Nevertheless, a consistent trend toward greater symptom burden in deficient individuals supports targeted screening and justifies future interventional trials with B12 supplementation in patients with tinnitus with deficiency.