The Relationship Between 2D:4D Ratio and Pulmonary Function of Healthy Young Adults

Abstract

Background: Exposure to sex hormones such as testosterone and oestrogen during prenatal development are known to play an important role in the development of many physiological processes and have also been a topic greatly studied in the last decade. Recorded research results in recent years has shown that a significant correlation exists between the measurements of the second and fourth digit (2D:4D) ratio and pulmonary function. Objectives: To investigate and identify a potential link between 2D:4D ratio and pulmonary function of each participant who enrolled in the study. Methods: 51 healthy participants with no record of cardiovascular or respiratory problems were first enrolled in the study. Following signing the consent form provided, each participant had the lengths of their second and fourth digits measured on both hands using digital callipers. Pulmonary function tests were then carried out on every participant using the Vitalograph Alpha Spirometer. The participants then had their heights measured using a stadiometer. Data was recorded and analysed using Microsoft Excel. Results: The analysis of the results collected in this study included both paired and unpaired t-tests and Pearson’s correlation. These tests were completed using the data analysis functionality available on Microsoft Excel. Examples of results gained from such analysis include the mean digit ratio being higher in females (0.9995) than males (0.9923). Male lung function tests were higher with actual VC (4.91), actual FVC (4.94), actual FEV1 (4.30), than female lung function tests with actual VC (2.97), actual FVC (3.17), actual FEV1 (2.68), with both males and females having the same FEV1/FVC (0.82). Mean digit ratio for white British group was lower (0.995) than the other ethnic subgroup (1.009). Significant positive association was seen between the mean white British height (169.37) and actual FVC (3.721). Smokers lung function tests were higher with actual VC (3.58) and actual FEV1 (3.14) than non-smokers lung function tests with actual VC (3.46) and FEV1 (3.10). Non-smokers had a higher actual FVC (3.65) than smokers (3.50), both smokers and non-smokers had the same actual FEV1/FVC ratio (0.82). Conclusions: From the analysis of the results it was discovered that 2D:4D digit ratio was not related to lung function of healthy individuals aged 18-30. The results of this study oppose those of previous study results, but may show that 2D:4D ratio is a biomarker for male’s lung function as some significant results were found for the male participants. A larger scale study with varying factors being included is needed to gain a better understanding, such factors include varying ages, health conditions, ethnic groups and exercise. Keywords: Digit Ratio, 2D:4D, Pulmonary Function, Prenatal Sex Hormones