The Saudi Journal of Medical Insights

Background: Vitamin D receptors in inner ear tissues suggest a potential link between vitamin D status and auditory
function. This systematic review synthesizes current evidence on the association between vitamin D deficiency and hearing
loss, and evaluates supplementation efficacy.
Methods: A systematic search of PubMed/MEDLINE, Scopus, Embase, and Web of Science (2021–2026) identified
observational studies and randomized controlled trials examining serum 25-hydroxyvitamin D levels and audiometric
outcomes. Quality was assessed using Newcastle-Ottawa Scale and Cochrane RoB 2.0. A narrative synthesis was performed
due to heterogeneity.
Results: Eight studies were included (four cross-sectional, one prospective cohort, one retrospective case-control, two
RCTs). Observational studies consistently found significant associations between low vitamin D (<20 ng/mL) and hearing
impairment (adjusted ORs: 1.45–2.02), particularly for bilateral sensorineural low-frequency loss. Associations were
stronger in males (OR: 1.638) and younger adults (<30 years, deficiency rate: 60%). Two RCTs reported significant hearing
recovery with adjunctive vitamin D supplementation (82.0% vs 52.9% effective rate, p<0.001), but one cohort found no
benefit from post-diagnosis intervention, suggesting chronic maintenance may be more critical than acute supplementation.
Conclusion: Evidence supports a significant association between vitamin D deficiency and hearing loss, with plausible
mechanisms involving cochlear calcium homeostasis and immunomodulation. While supplementation may benefit deficient
sudden sensorineural hearing loss patients, optimal timing remains unclear. Routine serum 25(OH)D screening is advisable
for at-risk populations, including the elderly, young adults with sudden hearing loss, and males. Future prospective studies
with standardized protocols are needed to establish causality and refine clinical recommendations.