Digit Length Ratio Research Articles

Correlation of Hand Digit Length Ratio, Anogenital Distance, and Severity of Hypospadias among Prepubertal Boys.

Antenatal androgen exposure has been suggested as a contributing factor in hypospadias etiology. This study aimed to investigate the correlation between anogenital distance (AGD), index finger-to-ring finger ratio (2D:4D ratio), and hypospadias severity in prepubertal boys, with the goal of exploring these parameters as potential markers of genital anomalies in utero. A cross-sectional observational study was conducted on boys under 8 years old presenting to our outpatient department (April 2020-December 2022). Those with hypospadias were included in the study group, whereas those without hypospadias formed the comparator group. Confounding factors (age, weight, and height) were accounted for using multivariate linear regression analysis. AGD, 2D:4D ratio, and hypospadias severity were measured during clinical visits, with still images taken for precise measurements. Statistical analysis was performed using the Mann-Whitney U and student's t-tests (software: STATA Version 14). Data were collected for 100 cases of hypospadias (26 proximal and 74 distal) and 50 controls. There was no significant difference in mean age between groups (P = 0.90). AGD was slightly lower in cases (3.44 ± 1.13 cm) compared to controls (3.70 ± 1.43) (P = 0.88). 2D:4D ratios were marginally higher in cases compared to controls (P = 0.12 for both hands). Although our study did not find significant associations between AGD and 2D:4D ratios with hypospadias severity, it offers insights into the role of prenatal androgen in genital development. The lack of significance underscores the need for region-specific research, suggesting AGD and 2D:4D ratio may not universally apply as hypospadias markers.

Effects of an App-Based Mindfulness Intervention during Pregnancy on the Infant's Prenatal Androgen Exposure: A Randomized Controlled Pilot Trial.

Prenatal androgen exposure modulates the development of the brain, with lasting effects on its function and behavior over the infant's life span. Environmental factors during pregnancy, in particular maternal stress, have been shown to influence the androgen load of the unborn child. We here addressed the research gap on whether a mindfulness intervention or a pregnancy education administered to pregnant women more affects the androgen exposure of the unborn child (quantified by the proxies of second-to-fourth digit length ratio (2D:4D) and anogenital distance assessed one year after delivery and at delivery, respectively). Moreover, we tested the mindfulness intervention's effects on maternal perceived stress, anxiety, depressiveness, and mindfulness. Pregnant women (gestation weeks 8-14) were randomized to a 15-week app-based mindfulness-oriented intervention (N = 72) or a pregnancy education intervention (control condition; N = 74). The mindfulness-oriented group did not significantly differ from the pregnancy education group in infants' 2D:4D or anogenital distance (partial η2 ≤ 0.01) or in maternal stress, anxiety, depressiveness, or mindfulness. However, the descriptive results indicate that across pregnancy, stress and anxiety decreased and mindfulness increased in both groups. Overall, this study did not show that the mindfulness intervention (relative to the pregnancy education) reduced the prenatal androgen exposure of the unborn children or improved the maternal outcomes significantly.

Investigation of Relationship between Playing the Piano Capability and the Second-to-Fourth Digit (2D:4D) Ratio

BACKGROUND
 In the field of piano playing, the suitability of physical characteristics of individuals, especially at the beginner level, is one of the first criteria considered important for educators. In many studies examining the physical fitness of individuals in sports fields, the importance of the relationship between physical fitness and ability has been revealed. In addition, there are studies examining the physical fitness for playing any instrument in the field of music. However, studies examining the physical characteristics of beginner piano players are very limited. Therefore, the purpose of our study was to investigate the relationship between the physical properties of the hand and the ability to play the piano. In addition, our study is the first to examine the relationship between the second digit and fourth digit ratio and the state of being successful in playing the piano. We also intended to contribute to the literature on this subject.
 METHODS
 Among the students who participated in the ballet and piano special talent exam held at Cukurova University State Conservatory in the 2013 and 2015 academic years, students who participated in the piano special talent exam were included in the study. In this exam, the suitability of the candidate to play the piano was evaluated in terms of musical and physical competence. In our study, the second digit and fourth digit length parameters, which include the physical characteristics of the hand, were evaluated. Length measurements were made with a digital display caliper. Students between the ages of 8 and 11 who participated in the piano talent exam were divided into two groups as those who were successful and those who were unsuccessful in the talent test.
 RESULTS
 The number of successful girls was 20 and the average length of the second digit 6.00±0.50 cm, mean fourth digit length; 5.90±0.40 cm, the number of unsuccessful girls was 17, the average of the second length; 5.98±0.48 cm, and the mean fourth digit length was 5.89±0.48 cm. The number of successful men was 15, and the mean length of the second digit; 6.55±0.36 cm, mean fourth digit length; 6.61±0.47 cm, the number of unsuccessful men was 17, the mean length of the second digit; 6.46±0.52 cm, mean fourth digit length; 6.52±0.55 cm were found.
 CONCLUSIONS
 There was no significant relationship between the piano playing ability and the second digit and fourth digit length ratios. We think that this is due to the evaluation of factors such as the level of development of the sensorimotor and neuromuscular system, the level of auditory proficiency, and coordination, not only with the anatomical suitability factors, in the scoring of the talent exam. Therefore, we can say that being successful in playing the piano does not depend only on digit lengths.

Digit Ratio (2D:4D) Is Not Associated with Alzheimer's Disease in the Elderly.

The development of Alzheimer's disease (AD) is influenced by sex hormones-estrogens and androgens in particular. However, the impact of prenatal sex hormone exposure is less clear; very few investigations have examined the relationship between the second-to-fourth digit length ratio (2D:4D), a putative proxy for the ratio of prenatal estrogens to androgens, and AD, with inconsistent results among the few that have. Therefore, we aimed to investigate this relationship using methodologically robust metrics. In a 2 (sex) × 4 (group) MANOVA incorporating 108 participants (30 AD patients, 19 patients with tauopathy but no amyloidopathy, 31 clinical and 28 healthy age- and education-matched controls), the effects of sex and group on the dependent variables right and left 2D:4D were examined. We also explored the association between 2D:4D and the severity of AD symptoms assessed via neuropsychological examination. We did not find any significant differences in the right- and left-hand 2D:4D between patients with AD and the other groups; no significant associations between 2D:4D and neuropsychological task performances were found in the dementia groups. The 2D:4D of healthy women was significantly lower than that of depressed women without AD, i.e., clinical controls, but not significantly different from depressed female patients with AD. This investigation does not support the role of 2D:4D in the development or severity of AD in general, but suggests a potential role of 2D:4D for depression in women. Future studies are warranted to clarify whether 2D:4D can distinguish between early- and late-onset depression in women.

Lower digit length ratio and aggression in adolescents and young adults with boxer's fracture: A case-control study.

Recent evidence shows that a lower second-to-fourth digit ratio (2D:4D), which is a sexually dimorphic trait and the indicator of prenatal testosterone exposure, may be associated with aggressive behaviors. In this cross-sectional, case-control study, we investigated: (1) Are the aggression and impulsivity levels and emotional problems higher? (2) Is the 2D:4D ratio lower in adolescents and young adults who presented with a fifth metacarpal neck fracture (boxer's fracture) compared to controls? (3) Is the digit ratio correlated with aggressive measures in individuals with a fifth metacarpal neck fracture?Seventy-one consecutive patients presented with a fifth metacarpal neck fracture within the age range of 11-25 years old comprised the study group. The control group consisted of 71 age and sex-matched subjects without a history of aggression-related injury. The aggression, impulsiveness, and psychosocial well-being were measured by self-reported questionnaires. 2D:4D was measured by conventional radiography. The 2D:4D ratio was similar between groups, however, when the analyses were conducted separately for sex, females in the study group showed lower 2D:4D than females in the control group (p = 0.001). The aggression level of the study group, measured by the Buss-Perry Aggression Questionnaire was higher than the control group (p = 0.014). The impulsiveness scores on the BarrattImpulsiveness Scale-11were similar (p = 0.60) and the total difficulty score on the Strengths and Difficulties Questionnaire was higher in the study group (p = 0.009).A lower 2D:4D ratio significantly predicted verbal and total aggression scores (p = 0.036, p = 0.032, respectively). Our findings suggest that females with a history of aggression-related injury have lower 2D:4D, and a lower 2D:4D is correlated with higher aggression levels in both sexes. Understanding and addressing aggression in these patients may help prevent further self-inflicted injuries.

Systematical assessment of digit ratio in a female masculinization disease: polycystic ovary syndrome.

In recent years, the right ratio of 2nd and 4th digit length (2D:4D) is regarded as an anatomical marker of prenatal testosterone exposure. Polycystic ovary syndrome (PCOS) is a female masculinized disease and is determined by prenatal testosterone exposure. Whether the ratio in the right hand of PCOS women is reduced or not compared with non-PCOS women is under debate. To further investigate the relationship between PCOS and digit ratio, we systematically measured all the digit ratios. We recruited 34 non-PCOS women, 116 PCOS women, and 40 men and systematically measured all the ratios of digit length (2D:3D, 2D:4D, 2D:5D, 3D:4D, 3D:5D, and 4D:5D) of right hands and left hands. Left 2D:3D, 2D:4D, and 2D:5D in men were significantly lower than those in non-PCOS women. Significantly lower digit ratios of left 2D:3D and 2D:4D were observed in PCOS compared with non-PCOS women. In the subgroup analysis, the left ratio of digit length in 2D:3D and 2D:5D of the hyperandrogenism subgroup was lower than that of the non-hyperandrogenism subgroup without statistical significance. The logistic regression model of PCOS revealed that 2D:3D, 2D:4D, 2D:5D, and 3D:4D of left hands were statistically related to the diagnosis of PCOS among all the digit ratios. Not only 2D:4D but also other digit ratios, such as 2D:3D and 2D:5D, are a marker of prenatal testosterone exposure and may be an anatomical marker of PCOS. The majority of these significant differences included left 2D, with the following order: non-PCOS women > PCOS women > men.

2D:4D biomarker reliability and validity in a within-subject pregnancy-childhood-adolescence cohort

BackgroundA lot of studies use the second-to-fourth digit length ratio (2D:4D) as a biomarker for intrauterine androgen load to predict behavioral and mental health problems. Thus, knowledge of 2D:4D's metric properties, namely reliability and validity, is essential. Method2D:4D handscans were available from 149 adolescents (M = 13.32 years, SD = 0.35) and their mothers. For 88 adolescents, there were also primary-school age handscans (M = 7.87 years, SD = 0.68). Prenatal risks for the 1st to 3rd trimesters were recorded during the 3rd trimester of pregnancy (alcohol exposition: meconium biomarker and maternal self-report; nicotine exposition: maternal self-report; maternal depressive symptoms and subjective stress: questionnaires). ResultsThe 2D:4D ratio was highly stable from childhood to early adolescence. However, both developmental and sex effects were present: The 2D:4D ratio increased with age and was higher in adolescent girls vs. boys. Significant 2D:4D mother-child associations were found for girls. Significant main effects could be found for the prenatal risk factors alcohol (self-report) and nicotine consumption. ConclusionIn line with earlier studies, the 2D:4D biomarker proved to be an inter-individually stable measure with an intra-individual increase from childhood to early adolescence. Sex differences in adolescence and associations with maternal prenatal health behaviour underline the validity of the biomarker. Findings on heritability emphasize the importance of interpreting 2D:4D results in a sex-specific manner.

Sex-specific association between prenatal androgenization (second-to-fourth digit length ratio) and frontal brain volumes in adolescents

Prenatal androgenization associates sex-dependently with behavior and mental health in adolescence and adulthood, including risk-taking, emotionality, substance use, and depression. However, still little is known on how it affects underlying neural correlates, like frontal brain control regions. Thus, we tested whether prenatal androgen load is sex-dependently related to frontal cortex volumes in a sex-balanced adolescent sample. In a cross-sectional magnetic resonance imaging study, we examined 61 adolescents (28 males, 33 females; aged 14 or 16 years) and analyzed associations of frontal brain region volumes with the second-to-fourth digit length ratio (2D:4D), an established marker for prenatal androgenization, using voxel-based morphometry in a region-of-interest approach. Lower 2D:4D (indicative of higher prenatal androgen load) correlated significantly with smaller volumes of the right anterior cingulate cortex (r-ACC; β = 0.45) in male adolescents and with larger volumes of the left inferior frontal gyrus orbital part (l-IFGorb; β = – 0.38) in female adolescents. The regression slopes of 2D:4D on the r-ACC also differed significantly between males and females. The study provides novel evidence that prenatal androgenization may influence the development of the frontal brain in a sex- and frontal brain region-specific manner. These effects might contribute to the well-known sex differences in risk-taking, emotionality, substance use, and depression. Future research is needed to elucidate the role of prenatal androgenization within the biopsychosocial model.

The Ratio of Second and Fourth Digit Length: A Biomarker for Methamphetamine Dependence?

The ratio of 2nd and 4th digit length (2D:4D) is considered to be a sexually dimorphic trait. Low 2D:4D is implicated in alcohol dependence and heroin dependence and correlated with psychological traits such as aggression, physical aggression, and sensation. The purpose of this study is to compare the 2D:4D between methamphetamine (METH) dependence and controls and the 2D:4D ratio that is a potential biomarker for METH dependence. In this study, 40 patients diagnosed with METH dependence in Eulji University Gangnam Eulji Hospital and 50 healthy volunteers were all employees in the same hospital. Images of participants' hands were created using a scanning device. The images contained both the right and left hands; computer software was used to measure the 2D:4D ratio for both hands. We compared the ratios, analyzed by t test, between the METH dependence group and the control group. The mean 2D:4D values were 0.941 (right hand) and 0.943 (left hand) for the patients with METH dependence; in contrast, they were 0.961 (right hand) and 0.961 (left hand) for the control group. These values were significantly smaller than the control in patients' right hands (p = 0.003) and left hands (p = 0.012). Patients with METH dependence had smaller 2D:4D ratios than those in the control group, which is similar to the results from the previous substance use disorder studies. Thus, elevated prenatal testosterone levels during the gonadal period could be related to future METH problems. Furthermore, the 2D:4D ratio is a potential marker for the prediction of METH dependence.

Born to be wild: Second-to-fourth digit length ratio and risk preferences

The second-to-fourth digit length ratio of an individual’s hand (digit ratio) is a putative biomarker for prenatal exposure to testosterone. We examine the hypothesized negative association between the digit ratio and the preference for risk taking within a large U.S. population survey. Our statistical framework provides a cardinal proxy for the true digit ratio based on ordinal digit ratio measurements and accounts for measurement error under the assumptions of Gaussianity and time-invariant true digit ratios. Our empirical findings support the hypothesis and suggest a meaningful biological basis for risk preferences.

Mood States and Performance in Elite Canoe Polo Players: The Mediating Role of Stress.

Sport performance is characterized by competitive stressful conditions that elicit emotional states. The purpose of the study was to examine whether stress mediated the relationship between mood states and performance. Thirty-two elite canoe polo players from four different Italian teams (16 senior males and 16 senior females), aged between 29 and 38 years old (M = 32.3, SD = 2.71), participated in the study. Measures included level of psychological stress, six mood dimensions, and performance outcome. We also detected the digit ratio—the lower second-to-fourth digit length (2D:4D) ratio—as it was demonstrated to be correlated to high sports performance. The assessment took place one day before the first game of the national competition “ITALY CUP”. Male athletes reported lower scores on dysfunctional emotion-related states and on 2D:4D ratio than female athletes. The results of the mediation analysis showed that psychological stress plays a mediating role between moods and performance. Overall, given the limited literature, the findings supported an integrative approach to the study of the linkage between emotion and action in canoe polo.

Digits Angle and Digits Length Ratio in Japanese Quail (Coturnix coturnix Japonica)

Background: Digit lengths are dimorphic in some other creatures as in humans. In particular, gender analysis can be done using the ratio between the second finger (D2) and the fourth finger (D4). The aim of this study is to examine whether the ratio of foot fingers is related to gender in Japanese quail (Coturnix coturnix japonica).Methods: In this study, 60 adults (30 female and 30 male) Japanese quail foot digit length ratios were examined in relation to gender. The ratios of the lengths of the second finger (D2), the third finger (D3) and the fourth finger (D4) to each other were taken on the computer. Result: In addition, geometrical analysis of base posture positions between female and male individuals were made and shape differences were revealed. It was observed that the second finger (D2) of male birds was more introverted than in females. It was seen that Principal component analysis (PCA1) explained 53.07% of the total variation between female and male groups. PCA2 explained 17.6% of the total variation and PCA3 announced 11.83%. In statistical morphometric analysis, the difference in shape between the male and female was statistically insignificant. D2:D3, D2:D4 and D3:D4 ratios were higher in males. It was observed that the lateral angle in both genders was higher than medial angle. This difference was statistically significant (p less than 0.001). While the average of the lateral angle was 50.89% in all individuals, the average of the medial angle was 42.81%. The highest length in all individuals belonged to the third finger. It was observed that the ratio of D2:D4 among females used in the study was 0.867 in females and 0.877 in males.

Digit ratio (2D:4D) and amniotic testosterone and estradiol: an attempted replication of Lutchmaya etal. (2004).

The ratio of length between the second (index) and fourth (ring) fingers (digit ratio or 2D:4D) is frequently employed as a retrospective marker of prenatal sex hormone exposure. Lutchmaya etal. (2004) reported that the ratio of testosterone (T) to estradiol (E) present in second-trimester amniotic fluid was negatively correlated with digit ratios for the right hand (but not the left hand) in a sample of 29 children at 2-year follow-up. This observation is frequently cited as evidence for the measure's validity but has not been replicated. We therefore present the findings of another study of amniotic T and E that did not find evidence for these effects at 4½-year follow-up. The confidence intervals were large, the direction of correlations observed was generally erratic, and the overall findings question the premise that second-trimester sex hormones affect the development of digit length ratios in humans.

Correlation between Second and Fourth Digit Length Ratio with Height, Body Mass Index and Axial Length of Eyeball in Adult Population of Burdwan, West Bengal, India

Introduction: Studies are being conducted to correlate second (2D) to fourth digit (4D) length ratio as an anthropometric marker of prenatal sex steroid exposure with human body. As 2nd digit: 4th digit(2D:4D)ratio is an anthropometric window into the interplay of sex hormones in-utero, this tool may be tested to note if there is any correlation between the sexual dimorphism of axial length and the Digit length ratio. Aim: To find a correlation between digit length ratio (2D:4D) with physical parameters like height, BMI and axial length of eyeball in the adult population of South Bengal presenting in a tertiary care hospital, in Burdwan, West Bengal, India. Materials and Methods: A cross-sectional study with simple random sampling was conducted on 500 patients (age ≥20 years) from March 2016 to February 2017 in the Departments of Anatomy and Ophthalmology Out Patients Department (OPD) of a tertiary care Hospital and Medical College in West Bengal, India. Height, weight, axial length of eyeball were measured and the BMI was computed for the study population. Statistical analysis was done with Statistical Package for Social Sciences(SPSS) version 16.0. Unpaired t-test was used for determining possible group differences in 2D:4D length ratios. Pearson’s correlation coefficients were used to find a correlation between second and fourth digit length ratio (2D:4D) with height, BMI and axial length of eyeball in the study population. The p-value <0.05 was considered significant. Results: The study included 280 males and 220 females with a minimum age above 20 years and most of the patients belonged to the age group of 50-69 years. A 2D:4D length ratio was significantly lower in males compared to females (For Right hand t=34.91, p<0.001, and for left hand t=14.30, p<0.001). Correlation analysis of 2D:4D length ratio of right and left hands with height of males revealed significant negative correlation (Right hand: r=-0.679, p<0.001; Left hand: r=-0.0463, p<0.001). In females, the result was positively significant for both hands (Right hand: r=0.313, p<0.05; left hand: r=0.21, p<0.05). A 2D:4D length ratio and BMI of males showed significant positive correlation for both Right hand (r=0.18, p<0.05) as well as for the left hand (r=0.137 p<0.05). In case of females, however 2D:4D ratio and BMI showed weakly negative correlation for both hands but the values were not significant. Correlation of 2D:4D length ratio of right and left hands on axial length of eyeball in males revealed significant negative correlation (right hand: r=-0.706, p<0.001; left hand: r=-0.25, p<0.05) but in females, there was significant positive correlation for the right hand (r=0.145, p <0.05*) and positive but non-significant correlation for the left hand at 95% CI (r=0.087, p>0.05) Conclusion: In this study, we have tried to establish that 2D:4D ratio (which is significantly higher in females) can be used as a putative non-invasive anthropometric marker to differentiate between males and females, which presumably is prenatally determined by in-utero sex steroid hormone exposure. By correlation studies, we have also tried to prove that this parameter correlates well with other anthropometric measurements like height, BMI and ocular axial length which are already known to be significantly different in males and females

Born to Be Wild: Second-to-Fourth Digit Length Ratio and Risk Preferences

The second-to-fourth digit length ratio of an individual’s hand (digit ratio) is a putative biomarker for prenatal exposure to testosterone. We are examining the hypothesized negative association between the digit ratio and the preference for risk taking within a large U.S. population survey. Our statistical framework provides a cardinal proxy for the true digit ratio based on ordinal digit ratio measurements and accounts for measurement error under the assumptions of Gaussianity and time-invariant true digit ratios. Our empirical findings support the hypothesis and suggest a meaningful biological basis for risk preferences.

Digit ratio (2D:4D) and transgender identity: new original data and a meta-analysis

Previously reported associations between second-to-fourth digit length ratio (2D:4D), a proxy for prenatal androgen load, and transgender identity have been inconsistent. The objectives of the present study were to provide additional original data and an updated meta-analysis concerning this association. In a study of 464 participants, we compared the 2D:4D of transgender individuals with age- and sex-matched controls. Patients were recruited at a specialized psychiatrist’s medical office, whereas controls were hired via flyers, advertisements, and as convenience sample. A random-effects meta-analysis of the literature (17 samples, n = 3674) also quantifies the overall magnitude of the difference in 2D:4D between transgender individuals and controls. In our study providing new original data, we found a significantly higher (i.e. feminized) left-hand 2D:4D in the male-to-female transgender (MtF) identity [mean age: 32.3 (18; 61)] than in the male control group [mean age: 34.5 (18; 65)] with a Cohen’s d = 0.271. Concordantly, the meta-analytic results suggest a significant difference in 2D:4D among MtF individuals compared to male controls [g = 0.153; 95% CI (0.063; 0.243)], which was even more pronounced when individuals had been diagnosed by a clinician instead of self-identified as transgender [g = 0.193; 95% CI (0.086; 0.300)]. In both studies, no significant results were revealed for female-to-male transgender individuals [mean age: 26.1 (18; 53)] versus female controls [mean age: 27.2 (18; 55)]. This original investigation and the updated meta-analysis clarify the association between transgender identity and 2D:4D indicating the influence of prenatal androgen on the development of gender identity in subjects born as males.

Sexual dimorphism in digit length ratios of the second to fourth digits (2D:4D) in two species of green toads (Pelobates syriacus Boettger, 1889 and Bufo viridis (Laurenti, 1768))

Sexual dimorphism in digit length ratios of the second to fourth digits (2D:4D) in two species of green toads (Pelobates syriacus Boettger, 1889 and Bufo viridis (Laurenti, 1768))

Association between the 2D:4D ratio and schizophrenia.

ObjectiveTo investigate the potential association between the ratio of the second digit length to the fourth digit length (2D:4D) and schizophrenia, to provide evidence regarding the pathogenesis of schizophrenia.MethodsIn this study, we enrolled 843 patients with schizophrenia (387 men and 456 women), all of whom met the diagnostic criteria of the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV), and 1050 normal healthy controls (477 men and 573 women). The digit lengths of both hands were measured in all subjects and the 2D:4D ratio was analyzed.ResultsIn the healthy controls, the 2D:4D ratio was sexually dimorphic, with a larger value in women than in men. In addition, the 2D:4D ratio in the schizophrenia patients was significantly larger than in the healthy controls. The 2D:4D ratio of the right hand was more sexually dimorphic than the left hand. Furthermore, the difference in 2D:4D ratios between the male patients and male controls was significantly larger than in their female counterparts.ConclusionsBy analyzing the 2D:4D ratio and considering alternative factors related to schizophrenia, our findings support the hypothesis that there are abnormal cerebral conditions in schizophrenia patients.

Comparison of anthropometric profile and handgrip strength between inter-university volleyball players and a reference group

Summary Study aim: In a volleyball game, multiple elements can influence competitive success, e.g. height, arm span and other anthropometric variables. The present cross-sectional study was undertaken to find out whether any differences exist between Indian inter-university male and female volleyball players as well as between players and a reference group in terms of anthropometry and handgrip strength. Materials and methods: The present cross-sectional research was conducted on 114 randomly selected Indian inter-university male (n = 50) and female (n = 64) volleyball players aged 18–25 years. An equal number of reference group individuals who did not participate in any exercise or training programme were also taken. Height, body weight, body mass index (BMI) (kg/m2), hand length, hand breadth, second digit length, fourth digit length, second and fourth digit ratio (2D/4D ratio), upper arm length, forearm length, total arm length, upper arm circumference, hip circumference; humerus and femur biepicondylar diameters, handgrip strength (dominant/non-dominant), arm muscle area, arm area, arm fat area, arm fat index, % body fat, and % lean body mass were measured with equipment including an anthropometer, sliding caliper, handgrip dynamometer and skinfold caliper using standard techniques. The data were analysed using SPSS version 17.0. Student’s t-test was applied for the comparison of data between players and the reference group. Differences between the groups were analysed using the oneway ANOVA test. Bonferroni post hoc test was applied after application of the ANOVA test. Effect size was also calculated. Statistical significance (p < 0.05) was indicated using a 5% level of probability. Results: Male volleyball players had higher mean values in height, body weight, hand length, hand breadth, second and fourth digit length, dominant and non-dominant handgrip strength, humerus and femur biepicondylar diameter, upper arm length, forearm length and total arm length, arm muscle area, arm area and percent lean body mass than the reference group. Similar findings were observed between female players and the reference group also. Statistically significant differences (p < 0.05–0.001) were also observed between male and female players except BMI, 2D/4D ratio, and arm fat area. These findings were supported by the effect size (η) calculations. Conclusion: Volleyball players had better height, weight, hand and arm anthropometrics, handgrip strength and % lean body mass as compared to the reference group. Significant differences were found in anthropometry and handgrip strength between players and reference group individuals, suggesting that these findings could be very useful for player selection and talent identification in sports.

Increased hand digit length ratio (2D:4D) is associated with increased severity of hypospadias in pre-pubertal boys.

Hypospadias is a common congenital male disorder, with much research focusing on prenatal androgen exposure as a causative factor. Whilst digit length ratios were apparent in sexual dimorphism since the nineteenth century, their role in hypospadias remains unknown. The objective of our study was to determine the correlation between digit length (2D:4D) ratio, hypospadias severity, and anogenital distance. Pre-pubertal boys (<3years old) seen intra/postoperatively following hypospadias repair (June 2018-January 2019 inc.) were included. These were age-matched to non-hypospadias controls. Anthropomorphic measurements of digit lengths, penile/glans width, and anogenital distance were measured using digital calipers. Data measurements were collected for 105 boys with hypospadias (60 distal; 45 proximal) and 55 controls. There were significant differences in 2D:4D ratios in each hand (p < 0.001), as well as individual digits (p < 0.001), and a reduced anogenital distance (p < 0.001), when comparing the proximal group with distal or control groups. There were no significant differences in glans width, or between term- and preterm births. This study is the first to demonstrate increased 2D:4D ratios with proximal hypospadias, which also correlate with a shortened anogenital distance. This may provide a non-invasive, potentially antenatal, anthropomorphic measurement, as an indirect indicator of aberrant urogenital development.