This study determined whether there is an increased risk of tinnitus in patients with temporomandibular joint (TMJ). We used information from health insurance claims obtained from Taiwan National Health Insurance (TNHI). Patients aged 20 years and older who were newly diagnosed with TMJ disorder served as the study cohort. The demographic factors and comorbidities that may be associated with tinnitus were also identified, including age, sex, and comorbidities of hearing loss, noise effects on the inner ear, and degenerative and vascular ear disorders. A higher proportion of TMJ disorder patients suffered from hearing loss (5.30 vs. 2.11 %), and degenerative and vascular ear disorders (0.20 vs. 0.08 %) compared with the control patients. The crude hazard ratio (HR) of tinnitus in the TMJ disorder cohort was 2.73-fold higher than that in the control patients, with an adjusted HR of 2.62 (95 % CI = 2.29-3.00). The comorbidity-specific TMJ disorder cohort to the control patients' adjusted HR of tinnitus was higher for patients without comorbidity (adjusted HR = 2.75, 95 % CI = 2.39-3.17). We also observed a 3.22-fold significantly higher relative risk of developing tinnitus within the 3-year follow-up period (95 % CI = 2.67-3.89). Patients with TMJ disorder might be at increased risk of tinnitus.
Keywords: Comorbidity; Insurance; Retrospective cohort study; Temporomandibular disorder; Tinnitus.