The 2D:4D Ratio and Sex Difference in Circulating Liver Enzymes in Adulthood: A Cross-sectional Study in Ghana

Aims: The second-to-fourth digit ratio (2D:4D) and the right-left difference (Dr-l) are the putative markers of prenatal hormone exposure. These digit ratios are sexually dimorphic and are said to be positive and negative correlates, respectively, of circulating testosterone and estrogen in adulthood. There is also a sex difference in liver function in adulthood which may be due to sex differences in plasma liver enzyme activity or concentration. The observed sex difference in liver function has been attributed to the sex difference in circulating testosterone and estrogen. The study sought to determine whether prenatal hormone exposure, as indexed by the 2D:4D or Dr-l, may partly account for sex differences in circulating liver enzyme levels in adulthood.

Study Design: The study was cross-sectional.

Place and Duration of Study: The study was conducted from June to December 2021 at the University for Development Studies.

Methodology: There were 190 participants (females=94 and males=96), between the ages of 18 and 32 years. The right-hand (2D:4DR), and the left-hand (2D:4DL) digit ratios were measured using computer-assisted analysis. The right-left hand difference (Dr-l) was then calculated. Venous blood samples were collected and assayed for aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and gamma-glutamyl transferase (GGT).

Results: The adjusted odds ratio (AOR) and 95% confidence interval (CI) showed that males had greater odds of higher plasma GGT than females [AOR=1.035 (95%CI: 1.004-1.067), P=0.025]. However, there were no interactions between sex and digit ratio on adult plasma liver enzymes.

Conclusion: The 2D:4D ratio or Dr-l may not account for sex differences in plasma liver enzyme levels in adulthood. Further studies are however recommended.