Downloaded from http://perspectivesinmedicine.cshlp.org/ on September 25, 2021 - Published by Cold Spring Harbor Laboratory Press The Epidemiology of Deafness Abraham M. Sheffield1 and Richard J.H. Smith2,3,4,5 1Department of Otolaryngology, Head and Neck Surgery, University of Iowa, Iowa City, Iowa 52242 2Molecular Otolaryngology and Renal Research Laboratories (MORL), Department of Otolaryngology, University of Iowa, Iowa City, Iowa 52242 3Department of Molecular Physiology & Biophysics, University of Iowa, Iowa City, Iowa 52242 4Department of Pediatrics, University of Iowa, Iowa City, Iowa 52242 5Department of Internal Medicine, University of Iowa, Iowa City, Iowa 52242 Correspondence:
[email protected] Hearing loss is the most common sensory deficit worldwide. It affects ∼5% of the world population, impacts people of all ages, and exacts a significant personal and societal cost. This review presents epidemiological data on hearing loss. We discuss hereditary hearing loss, complex hearing loss with genetic and environmental factors, and hearing loss that is more clearly related to environment. We also discuss the disparity in hearing loss across the world, with more economically developed countries having overall lower rates of hearing loss compared with developing countries, and the opportunity to improve diagnosis, preven- tion, and treatment of this disorder. earing loss is the most common sensory refer to people with mild-to-moderate (and Hdeficit worldwide, affecting more than half sometimes severe) hearing loss, whereas the a billion people (Smith et al. 2005; Wilson et al. term “deaf” (lower case “d”) is more commonly 2017). Normal hearing is defined as having hear- reserved for those with severe or profound hear- ing thresholds of ≤25 dB in both ears.