The Association Between Head Trauma and BPPV: A Nested Case-Control Study Using a National Health Screening Cohort

Background/Objectives: Benign paroxysmal positional vertigo (BPPV) is one of the most common vestibular disorders and is characterized by transient but very severe vertigo, increasing fall risk, especially in older people. While many risk factors have been reported, there are still contradicting papers and evidence from large-scale studies remains limited. Methods: This nationwide, nested case-control study utilized Korean National Health Insurance Service-Health Screening Cohort data to investigate possible risk factors for BPPV. In particular, it examined the association between prior head trauma and BPPV, proposing prior head trauma as a plausible and clinically relevant risk factor. From an initial cohort of 514,866 participants, 29,467 BPPV cases were matched 1:4 with 117,868 controls based on age, sex, income, region, and index date. Conditional logistic regression, with overlap weighting, assessed the risk of BPPV associated with head trauma and other potential factors. Results: Head trauma was modestly more prevalent in the BPPV group (2.29% vs. 1.83%) and was significantly associated with BPPV (adjusted OR 1.28, 95% CI 1.17-1.40, p < 0.001). The corresponding Absolute Risk Increase (ARI) was 0.82 percentage points over the entire follow-up and 0.66 percentage points within 1 year. The association persisted across most subgroups including both demographic and clinical factors except underweight individuals and those with high comorbidity scores. Conclusions: This large-scale analysis reinforces head trauma as a significant risk factor for BPPV, providing population-level evidence that may guide clinical assessment and prevention strategies.