Association between Vitamin D Level and Sensorineural Hearing Loss in Adults: Systematic Review and Meta-Analysis.

Sensorineural hearing loss (SNHL) is the most common cause of hearing loss. Several studies have explored the association between vitamin D Levels and the incidence of SNHL. This systematic review and meta-analysis aim to assess the association between vitamin D and the SNHL in adult patients.This meta-analysis was conducted according to PRISMA guidelines. A comprehensive search was performed through PubMed, Embase, Cochrane, and Scopus on November 16, 2024, for all studies assessing the association between vitamin D levels and SNHL. The risk of bias was assessed using the Newcastle-Ottawa Scale (NOS). Meta-analysis was conducted using R software, with heterogeneity being assessed by the I2 statistic. Subgroup analysis was also performed. Five observational studies were included, with a total sample size of 1936 and a mean age of 61.9 years. Vitamin D levels were significantly lower in the SNHL group compared to healthy (MD = -9.50, I2 = 16.9%). The incidence of sufficient vitamin D levels was significantly lower in the SNHL group than in healthy (RR = 0.61, I2 = 85.3%). Subgroup analysis revealed a significantly lower risk ratio of sufficient vitamin D in the Sudden SNHL group than in the other types of SNHL. This meta-analysis suggests a significant association between vitamin D levels and the incidence of SNHL. Lower vitamin D levels were reported among SNHL patients. Further investigations are needed to account for the confounders of this association using less biased methodologies, such as cohort studies and clinical trials.