Alternative Digit Ratios and Their Relationship to Prostate Cancer

Abstract

Background: The ratio of the second to the fourth digits (2D:4D) has been linked to prenatal androgen exposure and prostate cancer (PCa). The use of alternative finger ratios has been shown to be a greater indicator of sexual dimorphism when compared with the traditional 2D:4D ratio. This study aimed to assess the relationship between alternative digit ratios, racial demographics, and clinical/pathologic parameters associated with PCa.

Materials and methods: Digital finger length measurements were made from scanned images of hands from patients with PCa. Race, age, family history, history of metastasis, and Gleason score at diagnosis were assessed in a cross-sectional clinic-based study. Demographic and clinical parameters were analyzed with respect to various alternative finger length ratios.

Results: Hand measurements were obtained in 354 white and 98 African-American patients with PCa. African-American men were more likely to have a smaller 2D:3D (P < .0001) and 2D:4D digit ratio (P < .0001) in both hands. Larger right (R)3D:5D (P = .0005), R4D:5D (P = .0014), and R2T:2D (P = .0501) digit ratios were present in African-Americans compared with whites. In exploratory analyses, African-American men with a smaller left (L)2T:2D ratio were younger at the time of PCa diagnosis (P = .0125). No relationship was found between the various digit ratios and Gleason score, the presence of metastatic disease, or family history.

Conclusion: Various alternative finger length ratios show strong differences between African-American and white men in this study. The potential relationship between the 2T:2D ratio and age at diagnosis in African-Americans needs additional verification.

Keywords: 2D:4D; Androgens; Exploration; Finger length; Race.