Patients with a history of Bell palsy are at increased risk for depression, according to longitudinal study data published in the Journal of Affective Disorders.
Investigators conducted 2 longitudinal studies using data from the Korean National Health Insurance Service-National Sample Cohort between 2002 and 2013. The cohort database included sociodemographic information, medical examination data, and diagnostic codes according to the International Classification of Diseases, 10th edition (ICD-10). Patients with Bell palsy (n=3526) were identified using the associated ICD-10 code and matched 1:4 by age, sex, income, region of residence, and medical history with 14,104 controls. Additionally, patients with depression (n=61,068) were matched with 244,272 control participants by the same metrics. A Cox proportional hazards model was used to calculate the hazard ratio (HR) of Bell palsy for depression (study I) and depression for Bell palsy (study II). In each study, index date was defined as date of first Bell palsy (study I) or depression (study II) diagnosis. Controls were assumed to have the same index date as their matched patient.
According to study I, the mean (standard deviation) time from index date to depression was 36.5 (32.4) months in patients with Bell palsy, compared with 43.1 (32.3) months in controls. The rate of depression was significantly higher in the Bell palsy group (5.8%) compared with controls (4.1%) (P <.001). The adjusted HR (aHR) for depression was 1.36 (95% CI, 1.16-1.60) in the Bell palsy group (P <.001). The adjusted HRs for depression were highest among women ages 40 to 59 (aHR, 1.45; 95% CI, 1.06-1.99) and in women ≥60 years old (aHR, 1.50; 95% CI, 1.11-2.02; both P <.05). The adjusted HRs for depression were 1.22 (95% CI, 1.02-1.46) and 1.03 (95% CI, 0.99-1.06) in patients with Bell palsy >6 months and >12 months after the index date.
According to study II, the mean time from index date to Bell palsy was 49.9 (35.7) months and 52.9 (36.4) months in the depression and control groups, respectively. The rate of Bell palsy was not higher in patients with depression (0.4%) than in patients without depression (0.4%; P =.11). The rates of ischemic heart disease, cerebral stroke, and anxiety disorder histories were higher in the depression group compared with controls (all P <.05). In all subgroup analyses, aHRs for Bell palsy were not higher in the depression group than in the control group.
These data suggest that a history of Bell palsy increases the risk for depression, although the reverse was not true. The impact of Bell palsy on depression risk was particularly pronounced in older patients. These data may be useful in developing treatment and support strategies for people with Bell palsy.