Association Between Burning Mouth Syndrome and the Development of Depression, Anxiety, Dementia, and Parkinson Disease.

Importance: Burning mouth syndrome is a chronic oral pain disorder that is characterized by a generalized or localized burning sensation without the presence of any specific mucosal lesions. It remains unclear, however, whether burning mouth syndrome is associated with the development of psychoneurological conditions among patients with the syndrome. Objective: To evaluate the risk of developing psychoneurological conditions, including depression, anxiety, dementia, and Parkinson disease, in patients with burning mouth syndrome. Design, Setting, and Participants: This retrospective population-based cohort study was conducted using a nationwide representative cohort sample from the Korean National Health Insurance Service-National Sample Cohort, which consists of data from approximately 1 million patients in South Korea. The study included 586 patients with burning mouth syndrome (patient group) and 1172 individuals without burning mouth syndrome (comparison group). The patient group included all patients who received inpatient and outpatient care for an initial diagnosis of burning mouth syndrome between January 1, 2002, and December 31, 2012. The comparison group was selected (2 individuals without burning mouth syndrome for each patient with burning mouth syndrome) using propensity score matching for sex, age, location of residence, household income level, and comorbidities. Data were collected and analyzed from January 1, 2002, to December 31, 2013. Main Outcomes and Measures: Death and the incidence of psychopathological diseases. Affective disorder events that occurred among participants during the follow-up period were investigated using survival analysis, a log-rank test, and Cox proportional hazards regression models to estimate the incidence rates, survival rates, and hazard ratios, respectively, of participants who developed psychoneurological conditions. Results: Of 1758 total participants, 1086 (61.8%) were female; 701 participants (39.9%) were younger than 45 years, 667 (37.9%) were aged 45 to 64 years, and 390 (22.2%) were older than 64 years. The overall incidence of depression and anxiety was higher in patients with burning mouth syndrome (n = 586; 30.8 incidents and 44.2 incidents per 1000 person-years, respectively) than in individuals without burning mouth syndrome (n = 1172; 11.7 incidents and 19.0 incidents per 1000 person-years, respectively). The results also indicated a similar incidence of dementia and Parkinson disease between the patient group (6.5 incidents and 2.5 incidents per 1000 person-years, respectively) and the comparison group (4.9 incidents and 1.7 incidents per 1000 person-years, respectively). After adjusting for sociodemographic factors (age, location of residence, household income level, and comorbidities), the adjusted hazard ratios for the development of depression and anxiety among patients with burning mouth syndrome were 2.77 (95% CI, 2.22-3.45) and 2.42 (95% CI, 2.02-2.90), respectively. However, no association was found between burning mouth syndrome and the risk of developing dementia and Parkinson disease. Conclusions and Relevance: Results of this observational study suggest that burning mouth syndrome is associated with increases in the incidence of depression and anxiety but not in the incidence of dementia and Parkinson disease among patients with the syndrome. Clinicians should be aware of this association and be prepared to make referrals to appropriate mental health care professionals.