Association between the 2D:4D ratio and schizophrenia

Association of second and fourth digit (2D:4D) ratios with metabolic syndrome and cardiovascular disease risk

BACKGROUND

The study aimed to investigate the association of second and fourth-digit (2D:4D) ratios with metabolic syndrome (MS) and cardiovascular disease risk (CVR).

METHOD

This case-control study was conducted between February and March 2024 with 200 participants (100 patients +100 controls). Biochemical parameters (glucose, total cholesterol, HDL, LDL, triglycerides, haemogram, HbA1C) were recorded. All participants were evaluated in terms of MS diagnostic criteria. CVR was calculated with the ESC CVD Risk Calculator. Second-digit and fourth-digit measurements were performed and the 2D:4D ratio of both hands and the difference between 2D:4D of both hands (Dr-l) were obtained. The relationship between 2D:4D and MS, CVR, and gender was evaluated. p < .05 was considered statistically significant.

RESULTS

Forty-one percent of the study participants were male. The right-hand 2D:4D (R2D:4D) ratio was 1.009 ± 0.04 and the left-hand 2D:4D (L2D:4D) ratio was 0.991 ± 0.04 (p < .001). R2D:4D ratio was 1.010 ± 0.04 in women and 0.985 ± 0.03 in men (p = .019). R2D:4D (p < .001), Dr-l (p = .001), and CVR (p < .001) were significantly higher in men with MS (+) compared to MS (-).

CONCLUSION

In our study, the R2D:4D ratio was found to be associated with MS and CVR in men. Low intrauterine androgen exposure may affect the development of MS, but this effect is more prominent in males.

Association of 2D:4D finger length ratio of People Working in different professions with personality traits

Background

The ratio of the index finger (2nd finger) to the ring finger (4th finger) (2D:4D) can give information about harmony between personality and career of individuals. The developing technology makes it difficult to choose a profession.

Aim

This study aims to contribute to the career choice of individuals by analyzing the relationship between the 2D:4D finger digit ratio and personality traits of individuals working in different professions (Educator, Worker, Housewife, Civil servant, Healthcare professional/EWHCH).

Method

The participants were three hundred twenty-five individuals living in the province of Malatya. The SPSS 26.0 software was utilized in the data analysis. The p value of 0.05 was accepted as significance level in comparison tests.

Results

A statistically significant difference was determined between the participants, who had the 2D shorter than the 4D in right hand, in terms of professional groups (p < 0.05). In healthcare workers, a low level (r = 0.305) positive correlation was found between right hand 2D4D and both control (r = 0.264) and curiosity and left hand 2D:4D, and a low level (r = 0.255) negative correlation was found between Conscientiousness and right hand 2D:4D in housewives. There was a statistically significant difference between the groups (educator, worker, housewife, civil servant, healthcare professional) in terms of total score of the Five-Factor Personality Inventory (FFPI) and scores of extroversion, agreeableness, conscientiousness, neuroticism, and openness to experience subscales (p < 0.05). A weak positive statistically significant correlation was detected between the healthcare professionals' score of Career Adapt-abilities Scale (CAAS) control subscale and the right-hand 2D:4D ratio. Conclusions: It is suggested to investigate the 2D:4D ratio over different professional groups. The present study is important since it gives information about personality and associates such information with the 2D:4D ratio.

Investigating the correlation between 2D:4D finger digit ratios and attention gathering skills of 60-72 month-old children

BACKGROUND

Digit ratio 2D:4D is used to follow children's development process and examine behaviours and abilities.

AIM

The aim of this study is to determine the correlation between the 2D:4D digit ratios of 60-72 month-old children and their attention gathering skills, as well as whether the 2D:4D digit ratio and attention gathering skills of children differ based on independent variables.

METHOD

The sample of the study, designed in the correlational survey model, consisted of a total of 112 children aged 60-72 months who were attending preschool education in Malatya province in Turkey. The data were analysed using SPSS packaged software.

RESULTS

It was determined that there was a positive low significant correlation between attention gathering skills and the right hand 2D:4D digit ratio in 60-72 month-old children. In addition to, no significant difference was found between the children's FTF-K scores and the right hand 2D:4D digit ratio in terms of the variable of mother's status of exercising, but there was a significant difference between their FTF-K scores and the left hand 2D:4D digit ratio in terms of the variable of the mother's status of exercising.

CONCLUSIONS

The findings of the study demonstrate the importance of the study for revealing clues about children's attention gathering/concentration levels from their early periods, and promoting their attention gathering skills and generally their cognitive development.

Investigating the reliability and sex differences of digit lengths, ratios, and hand measures in infants

Hands and digits tend to be sexually dimorphic and may reflect prenatal androgen exposure. In the past years, the literature introduced several hand and digit measures, but there is a lack of studies in prepubertal cohorts. The available literature reports more heterogeneous findings in prepubertal compared to postpubertal cohorts. The comparability of the available studies is further limited by the study design and different measurement techniques. The present study compared the reliability and sex differences of available hand and digit measures, namely digit lengths of 2D, 3D, 4D, 5D, digit ratios 2D:4D, 2D:5D, 3D:4D, 3D:5D, 4D:5D, relative digit lengths rel2, rel3, rel4, rel5, directional asymmetry of right and left 2D:4D (Dr-l), hand width, length, and index of 399 male and 364 female 6-month-old German infants within one study using only indirect and computer-assisted measurements. The inter-examiner reliability was excellent while the test-retest reliability of hand scans was only moderate to high. Boys exhibited longer digits as well as wider and longer hands than girls, but smaller digit ratios, with ratios comprising the fifth digit revealing the largest effect sizes. Other hand and digit ratios revealed sex differences to some extent. The findings promote the assumption of sexual dimorphic hand and digit measures. However, by comparing the results of the available literature, there remains an uncertainty regarding the underlying hypothesis. Specifically in prepubertal cohorts, i.e. before the influence of fluctuating hormones, significant effects should be expected. It seems like other factors than the influence of prenatal androgens contribute to the sexual dimorphism in hand and digit lengths.