Investigating the Relationship between Respiratory Function and the 2D:4D Ratio in Healthy 18-30 Year Olds

Abstract

Background: Prenatal exposure to hormones such as androgens has been found to be linked to the development of the lungs, as well as of the fingers, in the womb. Androgens such as testosterone have been found to play an important role in both these aspects of the developing foetus, with visible consequences being found in adulthood. It has been suggested that when lung function is considered relative to scale, females outperform males. This suggests that lower levels of so called ‘male hormones’ in the androgen group, may be linked to an improved lung function. Similarly, assessing the ratio between the second and fourth digit, has been found to give indications in adulthood about the hormonal conditions experienced in the womb during pregnancy. The research conducted in these areas suggests that there may be a link between respiratory function and 2D:4D ratio, although current research on this topic is limited. Objectives: The aim of this study was to assess the relationship between respiratory function and 2D:4D ratio by measuring the second and fourth digits of participants using digital calipers and assessing their lung function using a Vitalograph Alpha. Data was analysed using Microsoft Excel, and comparisons were made between factors such as dominant/non-dominant hand and male/female. Methodology: The study consisted of 21 participants, all of 18-30 years of age. The participants were all asked to complete a questionnaire, giving demographic information such as ethnicity as well as information confirming they meet the inclusion/exclusion criteria (such as smoking status). Subjects were grouped male (n=8) and female (n=13), Caucasian (n=19) and non-Caucasian (n=2), and non-smoker (n=18) and ex-smoker (n=3). Results: The results of the study showed no significant correlation between the 2D:4D ratio and respiratory function of participants in any of the populations studied. All paired T-tests conducted to analyse the relationship between the 2D:4D ratios and each of the respiratory parameters produced a p value larger than 0.05, and so are therefore not significant. Similarly, an unpaired T-test produced p values more than 0.05 when analysing the various demographic groups (with the exception of ex/non-smokers). Caucasian/non-Caucasian p=0.44, and ≤5 hours of exercise a week/>5 hours of exercise a week p=0.12. The only significance was found in ex/non-smokers (p=0.006). Conclusion: The results of this study do not support the hypothesis that there is a prenatal hormonal link between lung function and finger length, as the respiratory parameters tested did not show any correlation with the 2D:4D ratios calculated. Other similar studied have had more significant results so therefore these results may have arisen due to limitations in our study