The Link between 2D:4D Ratio and Respiratory Function Parameters.

Prenatal exposure to sex hormones can influence the length of an individual's second and fourth digit (2D:4D ratio). These same sex hormones may also influence physiological processes, such as respiratory function. Consequently, digit ratio could indirectly determine respiratory performance. The premise is that a lower 2D:4D ratio leads to poorer lung function. The aim of this study was to assess the positive relationship between 2D:4D ratio and respiratory function parameters. Furthermore, sexual dimorphism in this relationship was investigated. There were a total of 40 participants analysed in this study (15 males and 25 females), aged between 19-31 years old. Firstly, digital calipers were used to measure the length of each participant's second and fourth digit, and height was measured. Then, lung function tests were carried out using a Vitalograph Compact II. The statistical tests used in this study include paired t-tests, independent t-tests and Pearson's correlations. In general, weak negative correlations were found between digit ratio and lung function (actual VC and FVC: r= 0.24; FEV1: r=0.20; FEV1/FVC: r=0.07). These were all non-significant. When gender was compared, the 2D:4D ratio in males was lower than in females, but this was also non-significant (0.99 ± 0.001 vs 1.00 ± 0.0001). However, the actual respiratory values for males were significantly higher (VC: 4.52 ± 1.04 vs 3.30 ± 0.43; FVC: 4.93 ± 0.74 vs 3.50 ±0.37; FEV1: 4.00 ± 0.52 vs 2.98 ± 0.38, p