Hand digit ratio (2d:4d) and gastric cancer risk: a cross-sectional study among southeastern Brazilians

Abstract

Background: The ratio between the length of the second and fourth digit, known as digit ratio or 2D:4D, has been used as a biomarker for several diseases, clinical conditions and human’s phenotypes, including cancer occurrence. We aimed to investigate whether there is a link between digit ratio and gastric cancer (GCA) risk among southeastern Brazilians. Methods: This was a cross-sectional research, performed with 240 subjects (120 cases and 120 controls). Data source derived from the Oncology Department of Santa Casa Hospital, Montes Claros, Brazil. Digital measurements were performed with a digital Vernier caliper and the digit ratios in both hands were collected; plus, we calculated de difference between the ratios found in the right and the left hand (R-L). Baseline characteristics of both groups, such as smoking status, and alcohol consumption status, were compared between the two groups using Chi-square test. Shapiro-Wilk’s test was used to check sample distribution. Subsequently, a Student’s t -test for unpaired samples was performed to compare the means of 2D:4D ratios and R-L among groups were performed. All analyses included a 5% level of significance. Results: Subjects at the case group had the highest digit ratio, especially on the right hand, when observing the overall average and for the female gender. Regarding the R-L, patients with GCA had higher differences than the control group, most DR-L consequently high levels of estrogen and low testosterone levels. Left digit ratio did not differed significantly between cases and controls; however, R2D:4D and R-L were (P=0.0013). Conclusions: The results suggest that the main reason why a higher estrogen exposure in utero causes higher cancer risk among women still need to be established.