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. 2025 Aug;32(8):e70336.
doi: 10.1111/ene.70336.

Risk Factors Associated With Bell's Palsy: A Real-World Analysis of 281,600 Patients

Norbert Neckel  1 , Susanne Nahles  1 , Max Heiland  1 , Heinrich Audebert  2 , Anna Zdunczyk  3 , Orlando Guntinas-Lichius  4 , Robert Preissner  5 , Saskia Preissner  1
Affiliations

Risk Factors Associated With Bell's Palsy: A Real-World Analysis of 281,600 Patients

Norbert Neckel et al. Eur J Neurol. 2025 Aug.

Abstract

Introduction: Bell's palsy is the most common cause of peripheral facial paralysis, with an annual incidence of 5-50 per 100,000 cases worldwide. Its etiology remains largely unknown, though risk factors such as herpes simplex virus reactivation, diabetes, depression, and pregnancy-related complications have been suggested. Understanding these risk factors is critical for improving diagnosis, prevention, and treatment strategies.

Methods: A retrospective analysis of the TriNetX database included over 25 million patients. Two cohorts of approximately 140,800 patients each, matched for age and sex, were analyzed for associations between BP and herpes simplex virus, diabetes, depression, and pregnancy. Odds ratios (OR) and confidence intervals (CI) were calculated, with p < 0.05 indicating significance.

Results: Herpes simplex virus showed the strongest association with Bell's palsy (OR: 6.49, 95% CI: 5.96-7.05); followed by diabetes (OR: 2.4, CI: 2.36-2.46) and depression (OR: 2.05, CI: 2.0-2.1). Pregnancy was inversely correlated (OR: 0.76, CI: 0.73-0.78).

Conclusion: Herpes simplex virus reactivation appears to be a major risk factor, suggesting a potential role of antiviral therapies in select cases. The associations with diabetes and depression highlight a need for metabolic and mental health evaluations in patients with Bell's palsy. The inverse correlation with pregnancy warrants further investigation into pregnancy-related conditions. These findings emphasize the multifactorial nature of this condition and the importance of individualized approaches to reduce its idiopathic classification.

Keywords: Bell's palsy; depression; herpes; pregnancy; risk factors.

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Conflict of interest statement

The authors declare no conflicts of interest.

Figures

FIGURE 1
FIGURE 1
Modified CONSORT diagram for the performed analysis.
FIGURE 2
FIGURE 2
Results of the risk analysis for herpes simplex, herpes zoster (ICD‐10: B00 or B02).
FIGURE 3
FIGURE 3
Results of the risk analysis for diabetes (ICD‐10: E08‐E13).
FIGURE 4
FIGURE 4
Results of the risk analysis for depression (ICD‐10: F32).
FIGURE 5
FIGURE 5
Results of the risk analysis for pregnancy, childbirth, and puerperium (ICD‐10: O00‐O9A).
See this image and copyright information in PMC

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