The link between 2D:4D ratio and pulmonary function of healthy young adults.

Background: 2D:4D ratio is known to be developed during prenatal development and is influenced by sex hormones and homeobox a and d genes. As a result of this 2D:4D ratio is thought to be a common biomarker for a number of physiological and psychological aspects including pulmonary function. Due to this, I investigated if there was a significant relationship between healthy individuals 2D:4D ratio and their lung function Methods and Materials: A total of 51 participants were enrolled in this study and their 2D and 4D measurements were taken from both right and left hand with use of a digital Vernier caliper. The measurements were taken three times with the average used for results and calculations. Participants were also asked to complete a data sheet before having their height and weight measured with a balance and stadiometer. All lung function tests were done through use of a vitalograph alpha where individuals provided a VC and an FEV1. Results: The statistical tests used to analyse results included completing both paired and unpaired t-tests and Pearson’s correlations which were carried out using the functionality available in Microsoft Excel. The outcome of the analysis of the participants right hand 2D:4D ratio against their lung function test provided a weak negative correlation, however, the p values were ≥0.05 providing it to be insignificant (R values, VC= -0.17, FVC= -0.20, FEV1= -0.15, FEV1/FVC= -0.03). The outcome from using the left hand data also provided insignificant results, however, these were mixed of both negative and positive correlations (R values, VC= -0.01, FVC= 0.01, FEV1= 0.09, FEV1/FVC= 0.11). When participants were split into gender subgroups key differences were seen including the female population having a similar 2D:4D ratio on both hands (right hand =0.9997±0.04, left hand= 0.9995±0.04) whereas, with the male population there was a smaller ratio on the right hand compared to the left (right hand = 0.985±0.04, left hand= 1.00±0.04). Males were also shown to have the more improved pulmonary function for VC, FVC and FEV1, however, both genders were similar for FEV1/FVC (FEV1/FVC females=0.82±0.19, males=0.82±0.12). Significant results were found between males 2D:4D of the right hand against FVC, FEV1 and FEV1/FVC (R values, FVC= -0.33, FEV1= -0.36, FEV1/FVC= -0.30). Discussion: It was shown that there was no significant correlation between 2D:4D ratio in healthy individuals between the age of 18-30 and their lung functions. The results of this study do not agree with current literature, however, when broken into gender subgroups there was significant results for males. This may show that 2D:4D is a biomarker for male’s pulmonary function and not females. Keywords: 2D:4D ratio, pulmonary function, sex hormones