2nd To 4th Digit Ratios Fetal Testosterone And Estradiol Pdf Writer

2nd to 4th digit ratios fetal testosterone and estradiol pdf writer

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Since the ratio of the second-to-fourth finger length was first proposed as a marker for prenatal androgen action in , over studies have been published that have either further tested the association between the digit ratio and prenatal androgens, or employed digit ratios as a marker to investigate the association between prenatal androgens and a variety of outcomes, including behavior, fertility, and disease risks. Despite the clear demand for an adult marker of prenatal androgen action and increased use of digit ratios as such a marker, its validity remains controversial. This review 1 evaluates current evidence for the relationship between digit ratios and prenatal androgens using experimentation with animal models, amniotic testosterone, and congenital adrenal hyperplasia case-control studies , 2 describes opportunities for future validation tests, and 3 compares the potential advantages and disadvantages of digit ratio measures with more established methods for studying the effects of prenatal androgens.

Digit Ratio (2D:4D) and Physical Performance in Female Olympic Athletes

Biomedical and Environmental Sciences, , 31 7 : Biomedical and Environmental Sciences , , 31 7 : Tables Article views PDF downloads 21 Cited by. The ratio of the second-to-fourth digit length 2D:4D has been shown to be sexually dimorphic, with males having lower mean than females [ 1 ] and the ratio relates to masculinity and femininity in adults.

Hormonal modulation during puberty and postnatal sex hormone exposure have minimal effect on 2D:4D because it is slightly affected by puberty and there is a little increase during childhood once it is determined prenatally. This trait is likely to be a viable biological marker of early developmental processes [ 1 ]. From the above, it could be suggested that 2D:4D have an impact on later life phenotypes. Since previous studies have suggested that BMI, WHtR, WC and NC can be a simple screening tool for identifying overweight and metabolic syndrome MetS [ 5 , 6 ] , 2D:4D measure could serve as a simple tool for measuring overweight and metabolic syndrome.

Due to its relationship with fertility and reproductive success, some studies have shown that 2D:4D is related with adult sex hormone concentrations [ 1 , 8 - 10 ] , but others have reported no significant relationship [ 7 , 11 , 12 ].

The purpose of this study is to evaluate the association between 2D:4D, sex hormone levels, and overweight. Written informed consent was obtained from all participants in response to a full description of the study. The study was conducted in accordance with the Declaration of Helsinki, and all the relevant legislation and ethical procedures recommended for assays for human beings.

Participants with unstable hormone level and females on mensuration were excluded. About 1 mL of venous blood was taken from all participants between and approximately five to ten days after onset of menstruation in female participants because sex hormone levels remain relatively stable during this period.

The lengths of the second and fourth digits were directly obtained by measuring the shortest distance in 0. If there was a band of creases at the base of the digit, we measured from the most proximal of these.

This measure was conducted two times at 2- or 4- days interval in 70 subjects to assess measurement repeatability. Parametric Student's t -test was employed to assess difference in normally distributed data, and Cohen's d was used to calculate effect sizes of group differences, while Mann-Whitney U-tests was applied to test differences in variables with a skewed distribution. Correlation coefficient was computed by Pearson's and Spearman test for normal and skewed data respectively.

Partial correlation was also calculated to remove confounding effects of age. For ease of comparison with findings from other studies, parametric statistical analysis for non-normally distributed data was used.

Similar statistical significance in both instances was observed. Reliability and reproducibility of finger length measurement was confirmed with intra-class correlation coefficients ICC two-way mixed, single measures with absolute agreement.

Association between 2D:4D ratio and other parameters Normalized sex steroid levels and overweight was computed using both normal and adjusted logistic regression. Sexual dimorphism was reported in both left and right-hand 2D:4D, as the ratio was significantly higher in female than in male.

This implies that 2D:4D can be used as their predictor. More so, as shown in Supplementary Table S1 available in www. The 2D:4D have been considered to be an indicator of prenatal steroid exposure that affects some of the later phenotypes which include psychological behavior like sex hormone, BMI, masculinity Masc and femininity Fem of an individual in adulthood [ 4 ] , but its relationship with later life reproductive hormone have given several contradictory results [ 7 , 8 , 11 , 12 ].

We reported that males have lower 2D:4D sexual dimorphism in 2D:4D which is in line earlier studies [ 1 , 4 ]. A recent genetic study buttresses this by reporting that occurrence an essential gene variant associated with obesity FTO gene variant might be predicted by 2D:4D [ 14 ].

Both Spearman correlation and regression model significantly showed that 2D:4D can be used to predict reproductive functions described by adult sex steroids FSH, LH and testosterone levels. Data from this study are congruent with earlier reports that revealed a relationship between 2D:4D and reproductive success with evidence showing that 2D:4D might be a valuable predictor of male reproductive characteristics, number of children and infertility [ 8 , 15 ].

More so, fertility markers like sperm count [ 1 ] , sex drive, level of sexual excitement [ 15 ] and number of sexual partners per individual [ 16 ] were all related to 2D:4D.

Pre-natal testosterone levels reflected in 2D:4D values have also been reported to predict adult testosterone concentration [ 8 ]. Similarly, another report, in males referred for prostate biopsy those with high 2D:4D had lower testosterone serum levels [ 9 ]. Lastly, adult testosterone concentration have been suggested to be a negative correlates of 2D:4D in men attending infertility clinic compromised testicular function but the relationship is weaker among non-overweight subjects [ 10 ].

Thus, they suggested that 2D:4D might be a weak correlate of adult concentrations of testosterone in men who are sampled without regard to fertility. The strong correlations between 2D:4D and sex hormones reported here is in congruent with previous observations [ 1 , 8 , 10 ]. This supported the claim that 2D:4D was an indicator of prenatal sex hormones [ 2 ] , and therefore, it should have influence on adult sex hormone levels.

On the other hand, other studies have reported that 2D:4D was not associated with some adult sex hormone levels [ 7 , 10 - 12 ]. Finally, Bolat et al. This is in line with report by Kelly and Jones [ 17 ] and a study among Korean men [ 18 ]. One possible explanation is the evidence that normal function of reproductive axis in term of gonadal hormonal play a substantial influence on energy balance and regulation of fat storage [ 19 ].

Hence, it may be explained that testosterone levels have different impact on fat storage depending on gender, reducing the storage rate in males and increasing it in females.

A few limitations in this study should be taken into account. First, our results should be replicated in a study in which assessment of adult serum testosterone level would be based on a higher number of samples for each participant over time, since testosterone level can be influenced by many physiological and behavioural factors. Sampling over several periods will lead to more reliable and robust results. Since larger sample size gives better results, it will be essential to confirm this study with increased sample size.

Lastly, measurement variability between assays due to methodology and antibodies employed will not make this an absolute result but rather a guide to the relationship between 2D:4D and adult testosterone level. Thus, validated and robust proof is warranted. Our study has some strengths which include the reliability and reproducibility of our 2D:4D measurement, collection of all female samples before mensuration, as well as objective measures of overweight.

Our results suggest that 2D:4D ratio a possible proxy for the prenatal hormonal environment might have a life-long connection to adult phenotypes like overweight and reproductive fitness, with an impact on testosterone, FSH and LH in both genders. We thank all participants for their cooperation Adebayo S. Authors declare no competing interests. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

All author read and approved the final manuscript. Ltd E-mail: info rhhz. Volume 31 Issue 7 Jul. Turn off MathJax Article Contents. The ratio of 2nd to 4th digit length:a predictor of sperm numbers and concentrations of testosterone, luteinizing hormone and oestrogen. Hum Reprod Oxford, England , ; 13, Developmental basis of sexually dimorphic digit ratios. The ratio of second to fourth digit length and age at first myocardial infarction in men:a link with testosterone?

Br J Cardiol, ; 8, Sexual dimorphism in ratio of second and fourth digits and its relationship with metabolic syndrome indices and cardiovascular risk factors. J Res Med Sci, ; 19, The 2nd-4th digit ratio 2D:4D and neck circumference:implications for risk factors in coronary heart disease.

Int J Obes Lond , ; 30, The metabolic syndrome-a new worldwide definition. The Lancet, ; , The relationship between the second-to-fourth digit ratios and lifelong premature ejaculation:a prospective, comparative study.

Andrology, ; 5, Digit ratio 2D:4D as an indicator of body size, testosterone concentration and number of children in human males.

Ann Hum Biol, ; 41, Second to fourth digit ratio, adult testosterone level and testosterone deficiency. BJU International, ; , Second to fourth digit ratio 2D:4D and testosterone in men. Asian J Androl, ; 6, Digit ratio 2D:4D does not correlate with daily 17beta-estradiol and progesterone concentrations in healthy women of reproductive age. Am J Hum Biol, ; 27, Second to fourth digit length ratio 2D:4D and adult sex hormone levels:New data and a meta-analytic review.

Psychoneuroendocrinology, ; 32, Behav Res Methods, ; 41, Journal of obesity, ; Am J Hum Biol, ; 20, Psychoneuroendocrinology, ; 31, Testosterone and obesity.

Obes Rev, ; 16, Cross-sectional association between testosterone, sex hormone-binding globulin and metabolic syndrome:The Healthy Twin Study. Clin Endocrinol, ; 87, Sex differences in obesity:X chromosome dosage as a risk factor for increased food intake, adiposity and co-morbidities. Physiol Behav, ; , Get Citation. Article Metrics. Proportional views. All correlations reported are two-tailed. CA Controlled for age. SP: Spearman's rho.

The second-to-fourth digit ratio correlates with aggressive behavior in professional soccer players

Whether this aggressive behavior is the result of innate factors or acquired elements is a matter for debate. Animal studies have indicated a link between incidents of aggression and the individual level of circulating testosterone. However, results in relation to primates, particularly humans, are less clear cut and are at best only suggestive of a positive association in certain contexts 1. It has been observed in male athletes that testosterone levels before a competition exhibit an increase that precedes the start of the competition and reflects the quality of the performance. In fact, testosterone levels measured in athletes with high-level performances are increased compared with those detected in low-level athletes 2. It must be emphasized, nevertheless, that several studies in humans did not observe any correlation between testosterone and aggression 3 — 5. However, even if there is an effect of testosterone on aggression at extremely high doses, this does not necessarily suggest that testosterone is effective at physiological concentrations.

Background: The second to fourth digit ratio 2D:4D ratio is suggested to be a negative correlate of prenatal testosterone. Little is known about the role of the 2D:4D ratio in relation to serum and urinary androgens for physical performance in female athletes. We aimed to compare the 2D:4D ratio in female Olympic athletes with sedentary controls, and to investigate the 2D:4D ratio in relation to serum and urinary androgens and physical performance in the athletes. Methods: This cross-sectional study included Swedish female Olympic athletes participating in power, endurance and technical sports and sedentary controls. The 2D:4D ratio was calculated using direct digit measurements.


Accepted by Cornelia Pechmann, Editor; Associate Editor, Rui (Juliet) Zhu. Received 4 quently, digit ratio (typically measured as the second-to-fourth digit ratio, or Given that the ratio of prenatal estrogen to testosterone promotes sex drive.


The digit ratio (2D:4D) and economic preferences: no robust associations in a sample of 330 women

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Biomedical and Environmental Sciences, , 31 7 : Biomedical and Environmental Sciences , , 31 7 : Tables Article views PDF downloads 21 Cited by. The ratio of the second-to-fourth digit length 2D:4D has been shown to be sexually dimorphic, with males having lower mean than females [ 1 ] and the ratio relates to masculinity and femininity in adults.

The use of digit ratios as markers for perinatal androgen action

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PDF | The ratio of length between the second (index) and fourth (ring) 2D:4D; Digit ratio; Estradiol; Prenatal sex hormones; Testosterone. 2. 1.

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