Hearing impairment and tinnitus: prevalence, risk factors, and outcomes in US service members and veterans deployed to the Iraq and Afghanistan wars.

Hearing loss and tinnitus are the 2 most prevalent service-connected disabilities among veterans in the United States. Veterans of Operations Enduring Freedom, Iraqi Freedom, and New Dawn have been exposed to multiple hazards associated with these conditions, such as blasts/explosions, ototoxic chemicals, and most notably high levels of noise. We conducted a systematic literature review of evidence on 1) prevalence of, 2) risk and protective factors for, and 3) functional and quality-of-life outcomes of hearing impairment and tinnitus in US Operations Enduring Freedom, Iraqi Freedom, and New Dawn veterans and military personnel. We identified studies published from 2001 through 2013 using PubMed, PsycINFO, REHABDATA, Cochrane Library, pearling, and expert recommendation. Peer-reviewed English language articles describing studies of 30 or more adults were included if they informed one or more key questions. A total of 839 titles/abstracts were reviewed for relevance by investigators trained in critical analysis of literature; 14 studies met inclusion criteria. Of these, 13 studies presented data on prevalence and 4 on risk/protective factors, respectively. There were no included studies reporting on outcomes. Findings from this systematic review will help inform clinicians, researchers, and policy makers on future resource and research needs pertaining to hearing impairment and tinnitus in this newest generation of veterans.