Detection of Frank's sign in the dental setting: A population-based cohort study.

Background: In 1973, Saunders T. Frank described the diagonal earlobe crease (DELC) as a potential marker of cardiovascular disease. However, this anatomical finding is not routinely examined. The aim of this study was to assess the presence of this crease in the general population attending a dental setting and describe its anatomical variations to be able to categorize it as a physical sign.

Methodology: A study group of 1050 white adults were selected, as participants in the framework of the "A Estrada Study of Glycation and Inflammation" (AEGIS), a cross-sectional, population-based descriptive study of a representative sample of the general adult population of the municipality of A Estrada (Pontevedra, Spain). Each participant's age, sex, and preferred head position when sleeping were recorded. Both earlobes were visually inspected and the anatomical variables of the crease were recorded (unilateral or bilateral, length, depth, and presence of secondary creases). The relationship between the study variables was analyzed using the chi-squared test, Student's t-test, the analysis of variance (ANOVA), and the nonparametric tests of Mann-Whitney and Kruskal-Wallis.

Results: The DELC was observed in 65.2% of the participants. In 71.5% of the cases, the sign was complete (occupying the space from the tragus to the posterior edge of the earlobe); in 56.9% of the cases, the sign was bilateral; in 45.1% of the cases it was deep; and in the 43.6% of the cases, accessory creases were identified. Neither sex nor the habitual head position when sleeping were related to the prevalence or characteristics of the DELC. The prevalence, extent and depth of Frank's sign increased significantly with age (p < .001).

Conclusion: The prevalence of the DELC increases significantly with age, and its morphological characteristics are accentuated. This finding, therefore, gains special relevance as a marker of potential cardiovascular disease when observed in young adults.