Incidence of hearing loss following COVID-19 among young adults in South Korea: a nationwide cohort study.

BACKGROUND

The association of COVID-19 with hearing loss (HL) is unclear among young adults and needs to be investigated. This study was conducted to determine the association of COVID-19 with HL and sudden sensorineural hearing loss (SSNHL) in young adults.

METHODS

This nationwide population-based cohort study used data from the Korea Disease Control and Prevention Agency-COVID-19-National Health Insurance Service. The study population consisted of young adult citizens aged 20-39 years without a history of HL. All participants were followed up from July 1, 2022 until HL, death, or December 31, 2022. A positive diagnosis of SARS-CoV-2 infection was determined through laboratory testing employing real-time reverse transcription polymerase chain reaction assays using nasopharyngeal or oropharyngeal swabs. The primary and secondary outcomes were HL and SSNHL, respectively. Age, sex, household income, Charlson comorbidity index, COVID-19 vaccination, hypertension, diabetes, and dyslipidemia-adjusted subdistribution hazard ratios (aSHRs) and 95% confidence intervals (CIs) were evaluated using the Fine-Gray subdistribution hazard regression model, considering overall death as a competing event to compare the aSHRs between COVID-19 positive and negative groups.

FINDINGS

A total of 6,716,879 young adults were eligible for the analyses. During 40,260,757 person-months (PMs) of follow-up, 38,269 cases of HL and 5908 cases of SSNHL were identified. The risk of HL (incidence: 11.9 versus 3.4/10,000 PMs; SHR, 3.51; 95% CI, 3.39-3.63; aSHR, 3.44; 95% CI, 3.33-3.56;  < 0.0001) and SSNHL (incidence: 1.8 versus 0.5/10,000 PMs; SHR, 3.58; 95% CI, 3.29-3.90; aSHR, 3.52; 95% CI, 3.23-3.83;  < 0.0001) was higher in COVID-19 group as compared to no COVID-19 group. In the sensitivity analyses that evaluated HL and SSNHL risks after adopting multiple imputations, utilizing inverse probability of treatment weighting, limiting study population to the cohort with a health screening examination, the results were consistent to the primary analysis.

INTERPRETATION

Our findings suggest a heightened risk of HL and SSNHL following COVID-19 in young adults. Due to study limitations, including the lack of objective audiological data, issues with generalizability to other populations, and the retrospective design, careful interpretation is necessary. Further studies with objective audiological data and a longer follow-up period are warranted.

FUNDING

IITP (Institute for Information & Communications Technology Planning & Evaluation; IITP-2024- RS-00156439) and Jeju National University Hospital Research Fund (2023).