The Association of the 2nd to 4th Digit Ratio with the Age of Onset and Metabolic Factors in Korean Patients with Schizophrenia

ABSTRACT

OBJECTIVES: The ratio of second to fourth digit length (2D 4D) could be a potential epigenetic marker of sexual dimorphism reflecting prenatal testosterone exposure. Testosterone is known to affect the development of the brain through an epigenetic mechanism. The purpose of this study was to investigate the effects of exposure to fetal testosterone on the metabolic syndrome based on 2D 4D of schizophrenia patients and the relationship with the age of onset of schizophrenia. METHODS: A total of 214 schizophrenia patients participated in this study. The participant's physical and blood tests were performed according to the American National Cholesterol Education Program's Third Amendment of the Metabolic Syndrome Diagnostic Criteria, and the 2D 4D was measured by the method designed by McFadden. Data were statistically analyzed by t-test, Pearson's correlation analysis and multiple regression model analysis. RESULTS: 2D 4D was significantly higher in female than male in both hands, and there was a statistically significant negative correlation between 2D 4D and the age of onset of schizophrenia in male. However, 2D 4D did not show statistically significant correlation with metabolic factors. CONCLUSIONS: Fetal testosterone suggests the possibility of affecting the age of onset of schizophrenia through the epigenetic mechanism, but there is no clear relationship with metabolic factors.