Digit ratio (2D:4D) in primary brain tumor patients: A case-control study

Abstract

BackgroundThe second-to-fourth digit ratio (2D:4D) reflects prenatal estrogen and testosterone exposure, and is established in utero. Sex steroids are implicated in development and progression of primary brain tumors. AimsTo investigate whether there is a link between 2D:4D ratio and primary brain tumors, and age at presentation. MethodsDigital images of the right and left palms of 85 primary brain tumor patients (age 56.96±13.68years; 71% women) and 106 (age 54.31±13.68years; 68% women) gender and age matched controls were obtained. The most common brain tumor diagnoses were meningioma (41%), glioblastoma (20%) and pituitary adenoma (16%). Right and left 2D:4D ratios, and right minus left 2D:4D (Dr-l) were compared between patients and controls, and were correlated with age. ResultsRight and left 2D:4D ratios were significantly lower in primary brain tumor patients relative to controls (t=−4.28, p<0.001 and t=−3.69, p<0.001, respectively). The Dr-l was not different between brain tumor patients and controls (p=0.27). In meningioma and glioma patients, age at presentation correlated negatively with left 2D:4D ratio (rho=−0.42, p=0.01 and rho=−0.36, p=0.02, respectively) and positively with Dr-l (rho=0.45, p=0.009 and rho=0.65, p=0.04, respectively). ConclusionsRight and left hand 2D:4D ratios are lower in primary brain tumor patients relative to healthy individuals suggesting greater prenatal testosterone and lower prenatal estrogen exposure in brain tumor patients. Greater age at presentation is associated with greater Dr-l and with lower left 2D:4D ratio of meningioma and glioma patients. Due to small sample size our results should be considered preliminary and interpreted with caution.