A new risk factor? Diagonal earlobe crease (Frank's sign) associated with intracranial aneurysms: a case–control study

To evaluate the association of diagonal earlobe crease (DELC, Frank's sign), laterality, and type of DELC with the presence of intracranial arterial aneurysms (IAA). The authors conducted a hospital-based case–control study involving 130 patients diagnosed with IAA and 130 age-grouped and sex-matched controls who had no arterial intracranial aneurysms. This study aimed to evaluate a potential association between IAA and DELC, the laterality of DELC, and the type of DELC. Multivariable logistic regression models were applied to identify correlations between cases and controls. DELC was identified in 96 patients of the IAA group (73.8 %) and 45 in the control group (34.6 %). There was a significant association between IAA and DELC (OR 7.92, 95 % CI 3.96–15.83, p < 0.001), unilateral and bilateral DELC (OR 7.36, 95 % CI 2.96–18.31, p < 0.001, and OR 8.17, 95 % CI 3.90–17.14, p < 0.001, respectively), and type 2, type 3, and type 4 DELC (OR 5.66, 95 % CI 2.17–14.77, p < 0.001, OR 5.73, 95 % CI 1.95–16.83, p 0.001, and OR 39.45, 95 % CI 12.40–125.50, p < 0.001, respectively). Type 1 DELC was not associated with IAA (p 0.079). This study demonstrates a significant association between DELC and the presence of IAA. Laterality was not a limiting factor. Complete and deep features in DELC are associated with IAA, whereas superficial incomplete DELC is not. Hypertension also showed an association with IAA. DELC should be considered a risk factor for IAA. DELC could serve as a crucial candidate risk factor for determining prognosis and screening protocols for patients with IAA; this may enable timely interventions to improve outcomes.