Assessment Of 2D:4D ratios amongst federal polytechnic Ekowe students, Bayelsa State, Nigeria

Humans, primates, birds and reptiles have demonstrated sexually dimorphism in the length of their 2nd and 4th digits otherwise known as 2D:4D, with males on the average having lower values than females. This difference has been associated with the differential exposure of prenatal testosterone relative to estrogen during intrauterine life. This present study assesses the 2d:4d ratio amongst students of the federal Polytechnic Ekowe, Bayelsa state of Nigeria. A total of 299 students (males n=150 and females n=149) participated in the study. The length of 2nd and 4th digits were measured with digital Vernier caliper from the basal crease to the tip of the finger, and 2nd digit length (2D) was divided by 4th digit (4D) to obtain 2D:4D ratio. The results of this study showed no significant difference between 2D right and left and 4D right and left for same sex (0.98±0.04 and 0.98±0.04 for males and 0.96±0.05 and 0.96±0.05 for female). Sexual dimorphism exits between sexes which is an indication that prenatal hormones have played a fundamental role on humans, during developmental stages.

Sex, population origin, age and average digit length as predictors of digit ratio in three large world populations

Recently, a number of authors have claimed that sexual dimorphism in the second-to-fourth digit ratio (2D:4D) is simply dependent on digit length and is an artifact of allometry. The goal of our study is to verify the validity of these assumptions. The study sample comprised 7,582 individuals (3,802 men and 3,780 women) from three large world populations: Europeans (n = 3043), East Africans (n = 2844), and Central Asians (n = 1695). The lengths of the second and fourth digits on both hands were measured. Digit ratios were computed according to standard procedures. Analyses were conducted separately for each hand for the whole sample and in succession for the three large populations. Additionally, we separately tested four age cohorts (≤ 13, 14–18, 19–30, and 31 ≥ years) to test the effect of developmental allometry. The second and fourth digits showed strong positive linear relationships on both hands, and demonstrated an increase with age; digit length in women from the youngest age cohort was longer or equal to that of men, and shorter than men in older age cohorts. However, the 2D:4D magnitude and its sexual dimorphism remained stable throughout the ontogeny. To test for an allometric effect on 2D:4D, the average digit lengths were calculated. Both sex and population origin were permanent reliable predictors of 2D:4D, whereas average digit length was not. Height was applied as another measure of allometric effect on the limited sample (≤ 30 years) from the European population, along with sex and age. No allometric effect was observed in this case. We conclude that sex differences in 2D:4D are not an artifact of allometry.

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

Assessment of 2D:4D ratio for the early diagnosis of caries and malocclusion in 7-15-year-old children

Background: The ratio between 2nd and 4th digit length is termed as hormonal fingerprintand is used as an indirect marker in many medical diseases.Dental studies pertaining to theimportance of hormonal fingerprint on oral health are very sparse. Aim and objectives: Tostudy the correlation of dental caries and malocclusion with hormonal fingerprints. Materialsand Methods: A total of 100 children of age group 7-15 years and both genders were randomlyselected and included in the present study. The hormonal fingerprint (2D:4D ratio) wasdone bymeasuring the length ratio of the index and ring finger with the help of digital vernier caliper.Caries assessment wascarried out using standard mouth mirrors and Community PeriodontalIndex probes. WHO assessment form (1997) was followed for assessment of dentitionstatus and treatment need.Occlusal characteristics evaluated were molar relation, anteriorand posterior crossbite, open bite, deep bite and lower anterior crowding. The subjects weredivided into high 2D:4D, equal 2D:4D digit ratio and low 2D:4D. All the measurements weredone by two investigators. The data collected were tabulated and statistically analyzed usingChi-square and ANOVA test. Results: Out of 100 children, 34% were males and 66% werefemales. Most of the participants were 7-8 years old (12 males and 15 females). Majority of theparticipants (87% for the right hand and 80% for left hand) had low 2D:4D ratio, only 6% forright and 11% for the left hand had high 2D:4D ratio and the remaining had equal 2D:4D ratio.Statistically insignificantcorrelation between 2D:4D ratio and deft/DMFT score and occlusalstatus of an individualwere found. Conclusion:The insignificant results of 2D:4D ratio with allthe parameters assessed validates that hormonal fingerprints could not be employed as an earlypredictor of caries and malocclusion in an individual. Bangladesh Journal of Medical Science Vol.20(1) 2021 p.154-158

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

Treatment of Multiple Digit Amputation in an Infant Using an Abdominal Pocket Combined with Composite Grafts of the Amputated Distal Phalanxes and Nails

Retention of the distal phalanxes is important in the treatment of multiple digit amputations in infants to preserve the digit length and nail for functional and cosmetic reasons. We report the case of a 22-month-old boy with multiple digit amputations of his left index, middle, and ring fingers, which were severely mangled and not suitable for replantation. We propose the usefulness of the abdominal pocket method combined with composite grafts of the amputated phalanxes and nails and report the outcome of our case, with 2-year follow-up.