Objective: Temporal population-based data on tinnitus are lacking. We used a representative older population-based cohort to establish 5-yr incidence, persistence, and progression of tinnitus symptoms.
Design: Two thousand six participants of the Blue Mountains Hearing Study (1997-1999) had complete tinnitus data, and of these, 1214 participants were followed up at 5-yr examinations in 2002-2004. Presence of prolonged tinnitus was assessed by a positive response to a single question administered by an audiologist. Incident tinnitus was defined in participants who were free of tinnitus symptoms at the baseline study in 1997-1999 but who reported tinnitus symptoms at the 5-yr follow-up in 2002-2004. Progression of tinnitus was defined as the increase in annoyance of tinnitus symptoms from baseline to the 5-yr follow-up study. Persistence of tinnitus symptoms was defined as the presence of tinnitus symptoms at both the baseline and follow-up examinations. Hearing impairment was measured as the pure-tone average (PTA) of audiometric hearing thresholds at 500, 1000, 2000, and 4000 Hz (PTA0.5-4 kHz), defining bilateral hearing loss as PTA0.5-4 kHz >25 dB HL.
Results: Five-year incidence of tinnitus was 18.0%. A significant age trend was observed for the 5-yr incidence (p = 0.005), with incident tinnitus decreasing with age. Hearing loss increased the risk of developing incident tinnitus, age-sex adjusted odds ratio 2.13 (95% confidence interval, 1.40 to 3.24). Most (55.5%) incident tinnitus cases reported symptoms that were only mildly annoying. Tinnitus at baseline persisted in 81.6% of participants. Of those reporting mildly annoying tinnitus at baseline, 39.6% progressed to moderately annoying and 5.9% to severely annoying tinnitus. At the follow-up, a higher frequency of participants with persistent tinnitus (old cases) reported their symptoms as very/extremely annoying compared with the new (incident) cases of tinnitus (p = 0.01). A high proportion (85.2%) of subjects receiving tinnitus treatment (mainly medications and hearing aid) at baseline still reported tinnitus at 5-yr examinations.
Conclusions: Incident tinnitus was frequent, with nearly one in five older adults suffering from this condition after 5 yrs. Tinnitus symptoms persisted in more than three-quarters of the cohort, during the 5 yrs. Longitudinal data are an important contribution to the research evidence base to support timely intervention and effective management of this frequent symptom.