What are the risk factors for sudden sensorineural hearing loss in adults?
Background: Sudden sensorineural hearing loss (SSNHL), commonly defined as sudden hearing impairment of more than 30 dB across three contiguous frequencies in less than three days, affects an estimated five to 20 adults per 100,000 persons each year. Although the majority of risk factors reported in the literature are related to the cardiovascular system, there have been no definitive associations demonstrated.
Study design: Literature review.
Setting: St. Paul’s Rotary Hearing Clinic and Centre for Health Evaluation and Outcome Sciences, St. Paul’s Hospital, Vancouver, British Columbia, Canada; Division of Pediatric Otolaryngology, British Columbia Children’s Hospital, Vancouver; Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, University of Calgary, Alberta, Canada.
Synopsis: The reviewers identified 22 articles that met their inclusion criteria in a search of MEDLINE, Embase and Evidence-Based Medicine Reviews databases. Cardiovascular risk factors, such as smoking and increased alcohol consumption, and a low level of serum folate were associated with a higher risk of developing SSNHL. Factor V Leiden and methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms were found to occur more frequently in patients with SSNHL. The authors said screening of the genetic polymorphisms is unlikely to be cost effective but should be considered in patients with a familial history of thromboembolic events. This review was limited by variable definitions of SSNHL and data heterogeneity. Additionally, the quality of the included studies was variable, and publication and outcome reporting biases may exist.
Bottom line: Many acquired or inherited cardiovascular risk factors were found to have a positive association with SSNHL.
Reference: Lin RJ, Krall R, Westerberg BD, et al. Systematic review and meta-analysis of the risk factors for sudden sensorineural hearing loss in adults. Laryngoscope. 2012; 33(12):624-635.S