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Goździk M, Żelaźniewicz A, Nowak-Kornicka J, Pawłowska-Seredyńska K, Umławska W, Pawłowski B. Autoimmune Hashimoto's Disease and Feminization Level-Testing the Immunocompetence Hypothesis. EVOLUTIONARY PSYCHOLOGY 2024; 22:14747049241259187. [PMID: 39238450 PMCID: PMC11378202 DOI: 10.1177/14747049241259187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2024] Open
Abstract
Morphological femininity depends mainly on estrogen levels at puberty and is perceived as a cue of a woman's biological condition. Due to the immunostimulant properties of estradiol, estradiol-dependent feminine traits are expected to be positively related to immunity. However, heightened immunity in women may increase the risk of autoimmune disease, thus the relationship between femininity and immune quality may be complex. This study aimed to assess the relationship between morphological femininity and both the occurrence and severity of Hashimoto thyroiditis (HT) in women of reproductive age. Moreover, 95 women with HT and 84 without HT (all between 20 and 37 years) participated in the study. Morphological femininity was assessed based on somatic measurements of sexually dimorphic traits (2D:4D ratio, WHR, breast size, facial sexual dimorphism). The occurrence and severity of HT were assessed by serum TPOAb levels. The results showed that only the 2D:4D ratio of the right hand was higher in the HT group, indicating higher femininity in these women. However, there was also a positive relationship between facial femininity and TPOAb level in women with HT, indicating a higher severity of the disease. The results suggest that prenatal and pubertal exposure to estrogens may increase the probability or severity of autoimmune diseases in adulthood, but the relationship is tentative.
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Affiliation(s)
- Malwina Goździk
- Department of Human Biology, University of Wrocław, Wroclaw, Poland
| | | | | | | | - Wioleta Umławska
- Department of Human Biology, University of Wrocław, Wroclaw, Poland
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Butovskaya M, Adam Y, Batsevich V, Shackelford TK, Fink B. Associations between 2D:4D from direct and radiographic measurements with handgrip strength in young adult Tuvans. Early Hum Dev 2024; 193:106037. [PMID: 38743999 DOI: 10.1016/j.earlhumdev.2024.106037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 05/06/2024] [Accepted: 05/07/2024] [Indexed: 05/16/2024]
Abstract
BACKGROUND Digit ratio (2D:4D) - the relative lengths of the index and ring finger - is sexually dimorphic (male < female), possibly because of the sex-differentiated impact of prenatal androgenization on fetal development in the 1st trimester. The sex difference remains stable with age and has been reported in children, adolescents, and adults from industrialized and non-industrialized societies. Handgrip strength (HGS) also is sexually dimorphic (males > females) and correlates negatively with 2D:4D. AIMS To examine in a sample of young adult Tuvans from Siberia (Russian Federation): i) the association between 2D:4D measured directly from the palms with 2D:4D measured from radiographic images of the same individuals and ii) the associations between 2D:4D and HGS in Tuvan men and women. STUDY DESIGN AND SUBJECTS The study was cross-sectional. Participants were Tuvans (n = 185; 80 men; mean age = 21.02 years). 2D:4D was measured with a caliper from the ventral surface of the palm (both hands) and from radiographic images (left hand). HGS of both hands was measured with a digital hand dynamometer. Body height and weight were measured with an anthropometer and a body composition scale. RESULTS 2D:4D ratios and anthropometric measures (including HGS) were sexually dimorphic. Men had lower 2D:4D and higher HGS than women. Direct measures of 2D:4D correlated positively with 2D:4D measured from radiographs. Body mass index (BMI) was a significant predictor of HGS for both sexes. Male right 2D:4D and female right and left 2D:4D correlated negatively with HGS after controlling for the influence of BMI. There were no associations with radiographic measurements of 2D:4D. CONCLUSION Our findings provide evidence of sexual dimorphism in 2D:4D among young adult Tuvans. Together with previous research on Tuvan children and adolescents, these findings provide clear evidence of 2D:4D sexual dimorphism in pre- and postpubertal Tuvans. The small negative association between 2D:4D and HGS corresponds to similar reports across populations, suggesting that 2D:4D is a weak correlate of muscular fitness.
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Affiliation(s)
- Marina Butovskaya
- Institute of Ethnology and Anthropology, Russian Academy of Sciences, Moscow, Russian Federation; Russian State University for the Humanities, Moscow, Russian Federation; National Research University Higher School of Economics, Moscow, Russian Federation.
| | - Yulia Adam
- Institute of Ethnology and Anthropology, Russian Academy of Sciences, Moscow, Russian Federation
| | - Valery Batsevich
- Anuchin Research Institute and Museum of Anthropology, Lomonosov Moscow State University, Moscow, Russian Federation
| | | | - Bernhard Fink
- Department of Evolutionary Anthropology, University of Vienna, Vienna, Austria; Human Evolution and Archaeological Sciences (HEAS), University of Vienna, Vienna, Austria; Biosocial Science Information, Biedermannsdorf, Austria
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Sorokowski P, Kowal M. Relationship between the 2D:4D and prenatal testosterone, adult level testosterone, and testosterone change: Meta-analysis of 54 studies. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 183:20-38. [PMID: 37795916 DOI: 10.1002/ajpa.24852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 08/29/2023] [Accepted: 09/12/2023] [Indexed: 10/06/2023]
Abstract
The ratio between the hands' second to the fourth finger (2D:4D) is commonly hypothesized to result from prenatal testosterone. The 2D:4D has also been hypothesized to relate to adult-level testosterone and, more recently, to the testosterone response to a challenging situation. In the present work, we tested these core assumptions. Drawing from, in total, 54 studies and 8077 participants, we investigated whether the 2D:4D is related to adult level testosterone (44 studies), testosterone change (6 studies), and prenatal testosterone (10 studies). We found no evidence of the relationship between the above testosterone types and digit ratios. Furthermore, there was no relationship between testosterone and the right and left 2D:4D, male and female 2D:4D, and the 2D:4D and testosterone measurement (i.e., measured in blood or saliva). However, we found some evidence that prenatal testosterone measured in amniotic fluid (but not cord blood) might be related to the digit ratios-further studies are necessary to validate this observation. In summary, considering the current state of knowledge, any conclusions drawn from the assumption of the digit ratios as the proxy for testosterone (prenatal, adult level, or testosterone change under a challenging situation) warrant great caution.
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Affiliation(s)
| | - Marta Kowal
- IDN Being Human Lab, University of Wrocław, Wrocław, Poland
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Butovskaya M, Adam Y, Batsevich V, Shackelford TK, Fink B. Direct and radiographic digit ratio (2D:4D) measurements of Tuvan children and adolescents from Southern Siberia: Sex differences and skeletal maturation. Early Hum Dev 2023; 184:105835. [PMID: 37517120 DOI: 10.1016/j.earlhumdev.2023.105835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 07/26/2023] [Accepted: 07/26/2023] [Indexed: 08/01/2023]
Abstract
BACKGROUND In Mongolian-origin ethnic groups digit ratio (2D:4D; a proxy for prenatal sex-steroids) is sexually dimorphic (males < females), as reported for other ethnicities. Most studies measured 2D:4D from soft tissue (directly from the digits, or indirectly from hand scans), or from radiographs. Evidence on the correspondence of 2D:4D measurements from soft tissue with measurements from radiographic images is scarce and has not been reported for a Mongolian-origin sample. In addition, previous research has not considered relationships between 2D:4D and measures of skeletal maturity. AIM To examine (i) associations between 2D:4D measured directly from the palms with those obtained from radiographic images of the same individuals in a sample of children and adolescents from the Tuvan population in Siberia (Russian Federation), and ii) associations between 2D:4D measurements with chronological and skeletal age. SUBJECTS AND METHODS Participants were Tuvan boys and girls aged 7 to 18 years. 2D:4D of the right and left hand was measured from soft tissue (directly from the palm) and compared with radiographic images (left hand only). In addition to finger length 2D:4D, we examined 2D:4D of the phalanges from measurements of radiographs. Skeletal age was assessed using the Tanner-Whitehouse method. RESULTS Sex differences (boys < girls) in measurements of 2D:4D from soft tissue and radiographs were found for total finger length and phalanges. In addition, 2D:4D measurements from radiographs correlated positively and significantly with those obtained from soft tissue. Sex predicted 2D:4D measurements from soft tissue and radiographs, but no effects of chronological/skeletal age and body height were detected. In girls (but not in boys), earlier skeletal maturity (relative to chronological age) was associated with higher 2D:4D in soft tissue measurements of both hands, radiographic 2D:4D, and 2D:4D of the proximal phalanges. CONCLUSION Consistent with reports from other ethnic groups, 2D:4D in young Tuvans was sexually dimorphic, with boys having lower 2D:4D than girls. For girls, higher 2D:4D was found for participants whose skeletal age was more advanced than chronological age. This finding was obtained from direct soft tissue and indirect radiographic measurements. Age and body height were not associated with 2D:4D, which suggests differences in hormone developmental trajectories for 2D:4D and height.
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Affiliation(s)
- Marina Butovskaya
- Institute of Ethnology and Anthropology, Russian Academy of Sciences, Moscow, Russian Federation; National Research University Higher School of Economics, Moscow, Russian Federation; Russian State University for the Humanities, Moscow, Russian Federation
| | - Yulia Adam
- Institute of Ethnology and Anthropology, Russian Academy of Sciences, Moscow, Russian Federation
| | - Valery Batsevich
- Anuchin Research Institute and Museum of Anthropology, Lomonosov Moscow State University, Moscow, Russian Federation
| | | | - Bernhard Fink
- Department of Evolutionary Anthropology, University of Vienna, Vienna, Austria; Human Evolution and Archaeological Sciences (HEAS), University of Vienna, Vienna, Austria; Biosocial Science Information, Biedermannsdorf, Austria.
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Lupu DC, Monedero I, Rodriguez-Ruiz C, Pita M, Turiegano E. In support of 2D:4D: More data exploring its conflicting results on handedness, sexual orientation and sex differences. PLoS One 2023; 18:e0280514. [PMID: 37607180 PMCID: PMC10443882 DOI: 10.1371/journal.pone.0280514] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 12/28/2022] [Indexed: 08/24/2023] Open
Abstract
In the last few years, several studies have questioned the value of the second-to-fourth digit ratio (2D:4D) as a measure of exposure to sex hormones before birth. Controversy has also extended to the 2D:4D association with individual features previously related to this exposure such as handedness and sexual orientation. Given that it has been argued that sex differences in 2D:4D could be a consequence of body-size differences, we have tested in a large sample the allometric relationship between finger lengths and body size. Our results show that the association is either allometric or isometric, depending on the analyses performed. In any case, the deviation from isometry is not large enough to explain the typically observed sex difference in this trait. We have also tested the association between sexual orientation and 2D:4D, finding a relationship between 2D:4D and sexual orientation in men but not in women. We attribute this discordance with previously published meta-analysis to differences in genetic background, a variable that has gained relevance in recent years in studies involving 2D:4D. Finally, we did not find any relationship between 2D:4D and handedness, evaluated through self-reported preference and hand performance. Our main conclusion is that 2D:4D shows differences between sexes beyond their disparity in body size. In our opinion, 2D:4D can be used cautiously as an indicator of intrauterine exposure to sex hormones taking into account some considerations, such as analysing a very large sample and taking careful measurements of the ethnicity of the sample.
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Affiliation(s)
| | - Ignacio Monedero
- Departamento de Fisiología, Universidad Autónoma de Madrid, Madrid, España
| | | | - Miguel Pita
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, España
| | - Enrique Turiegano
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, España
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Richards G, Tan DW, Whitehouse AJO, Chris McManus I, Beaton AA, Hickey M, Maybery MT, Licari MK, Lawson L. A longitudinal examination of perinatal testosterone, estradiol and vitamin D as predictors of handedness outcomes in childhood and adolescence. Laterality 2022; 27:547-580. [PMID: 35938410 DOI: 10.1080/1357650x.2022.2109656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The developmental origins of handedness remain elusive, though very early emergence suggests individual differences manifesting in utero could play an important role. Prenatal testosterone and Vitamin D exposure are considered, yet findings and interpretations remain equivocal. We examined n = 767 offspring from a population-based pregnancy cohort (The Raine Study) for whom early biological data and childhood/adolescent handedness data were available. We tested whether 18-week maternal circulatory Vitamin D (25[OH]D), and testosterone and estradiol from umbilical cord blood sampled at birth predicted variance in direction of hand preference (right/left), along with right- and left-hand speed, and the strength and direction of relative hand skill as measured by a finger-tapping task completed at 10 (Y10) and/or 16 (Y16) years. Although higher concentrations of Vitamin D predicted more leftward and less lateralized (regardless of direction) relative hand skill profiles, taken as a whole, statistically significant findings typically did not replicate across time-point (Y10/Y16) or sex (male/female) and were rarely detected across different (bivariate/multivariate) levels of analysis. Considering the number of statistical tests and generally inconsistent findings, our results suggest that perinatal testosterone and estradiol contribute minimally, if at all, to subsequent variance in handedness. Vitamin D, however, may be of interest in future studies.
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Affiliation(s)
- Gareth Richards
- School of Psychology, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Diana Weiting Tan
- School of Psychological Science, University of Western Australia, Perth, Australia.,Telethon Kids Institute, University of Western Australia, Perth, Australia.,School of Education, Macquarie University, Sydney, Australia
| | | | - I Chris McManus
- Research Department of Clinical, Education and Health Psychology, Division of Psychology and Language Sciences, Faculty of Brain Sciences, School of Life and Medical Sciences, University College London, London, UK.,Research Department for Medical Education, University College London Medical School, School of Life and Medical Sciences, University College London, London, UK
| | - Alan A Beaton
- Department of Psychology, School of Human & Health Sciences, Swansea University, Swansea, UK.,Department of Psychology, Aberystwyth University, Aberystwyth, UK
| | - Martha Hickey
- Department of Obstetrics and Gynaecology, University of Melbourne and the Royal Women's Hospital, Victoria, Australia
| | - Murray T Maybery
- School of Psychological Science, University of Western Australia, Perth, Australia
| | - Melissa K Licari
- Telethon Kids Institute, University of Western Australia, Perth, Australia
| | - Lauren Lawson
- Olga Tennison Autism Research Centre, La Trobe University, Melbourne, Australia.,Cooperative Research Centre for Living with Autism (Autism CRC), Long Pocket, Brisbane, Australia
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Maternal Age and Behavior during Pregnancy Affect the 2D:4D Digit Ratio in Polish Children Aged 6–13 Years. BIOLOGY 2022; 11:biology11091286. [PMID: 36138765 PMCID: PMC9527011 DOI: 10.3390/biology11091286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/23/2022] [Accepted: 08/27/2022] [Indexed: 11/16/2022]
Abstract
Background: The length of the second and fourth finger calculated as a ratio (2D:4D) is a marker of prenatal exposure to sex hormones. Higher exposure to testosterone is related to a lower 2D:4D digit ratio, and inversely, higher exposure to estrogen is related to a higher 2D:4D. The digit ratio in humans (prenatally determined by sex hormone levels and androgen receptor activity) is associated with multiple biological, cognitive, and behavioral traits, as well as health in later life. The aim of this study was to verify if maternal traits during pregnancy are associated with 2D:4D among their children. Methods: We investigated 537 boys, 646 girls, and their mothers. The investigation consisted of a questionnaire and a measurement part. In the questionnaire, we included questions about maternal traits during pregnancy such as: illnesses, active and passive smoking, work activity, psychological trauma (death or serious illness of a loved one, divorce, job loss), and age. We performed length measurements of the second and fourth fingers on both hands for both study groups. Results: The GLM analysis showed that children of smoking mothers were characterized by a higher 2D:4D R as compared to their peers whose mothers did not smoke (β = 0.10, p = 0.0008). In turn, the offspring of women who worked during pregnancy exhibited lower 2D:4D R values than the children of women who did not work (β = −0.07, p = 0.0233). It should be noted, however, that the effects of those maternal factors were small, as each of them explained less than 1% of 2D:4D R in the population, adjusted for child age and sex. Pearson’s linear correlation revealed that maternal age was negatively correlated with 2D:4D R in daughters (r = −0.11, p = 0.0137), but not in sons (r = 0.02, p = 0.6908). The negative correlation of 2D:4D R with maternal age indicates that the daughters of older mothers exhibited lower values of that ratio relative to the same-age daughters of younger mothers. Conclusions: For both study groups, the right-hand digit ratio was positively correlated with maternal smoking and negatively with maternal work during pregnancy. Maternal age during pregnancy was negatively related to right hand 2D:4D only among girls.
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Digit ratio (2D:4D) and maternal testosterone-to-estradiol ratio measured in early pregnancy. Sci Rep 2022; 12:13586. [PMID: 35945232 PMCID: PMC9363442 DOI: 10.1038/s41598-022-17247-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 07/22/2022] [Indexed: 11/09/2022] Open
Abstract
The ratio of index to ring finger (2D:4D) has been hypothesised to indicate prenatal androgen exposure, yet evidence for its validity is lacking. We report the first pre-registered study to investigate mothers' early pregnancy sex hormone concentrations in relation to their children's digit ratios measured at 18-22-month follow-up. Although the testosterone (T) to estradiol (E) ratio correlated negatively with right hand digit ratio (R2D:4D) and directional asymmetry (right-minus-left) in digit ratio (D[R-L]), neither effect remained statistically significant once demographic and obstetric covariates were controlled for. Nevertheless, the multivariate level of analysis did reveal that T correlated positively with left hand digit ratio (L2D:4D) and negatively with D[R-L]. However, the first of these effects is in the opposite direction to that predicted by theory. Taken together, the results of our study suggest research with larger samples is required to determine whether digit ratios are valid proxies for maternal sex hormone exposure.
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2D:4D digit ratio and its relationship to BMI, sporting choices and physiological predispositions among women. ANTHROPOLOGICAL REVIEW 2022. [DOI: 10.18778/1898-6773.85.2.07] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The 2D:4D digit ratio has been established as a biomarker of the level of exposure to prenatal sex hormones’ balancebetween prenatal testosterone (PT) and estrogenne levels. Higher 2D:4D indicates lower PT exposure and vice versa. Data suggests that PT exposure is linked to a risk-taking attitude and physical aggressiveness, both of which are requirements in contact sport. A possible correlation between 2D:4D and human body mass index has also been identified. The aim of the study was to examine the relation between 2D:4D ratio and choice of sport. It was assumed that female soccer players who choose a contact sport would have a lower 2D:4D ratio (thus experiencing higher exposure to PT) than female volleyball players (selecting non-contact sport). The analysis was also aimed at identifying whether a correlation between prenatal testosterone level and BMI exists. The participant sample consisted of 103 women – 36 volleyball players, 33 soccer players and a control group (N=34). Measurements were collected in 2019–2020. The results suggest that 2D:4D was significantly different in women practicing various sports (contact and non-contact sports). Women engaged in contact sports had lower 2D:4D than women engaged in non-contact sports, and vice versa (p<0.05). 2D:4D correlated positively with BMI and body weight – the higher the 2D:4D ratio, the higher the BMI and body weight (and vice versa) (p<0.05). Low 2D:4D (high PT exposure) may predict the choice of more risky, aggressive contact sports, and vice versa. High 2D:4D may predict a higher BMI and body weight, and vice versa.
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Babarro I, Andiarena A, Fano E, García-Baquero G, Lebeña A, Arranz-Freijo EB, Ibarluzea J. Do prepubertal hormones, 2D:4D index and psychosocial context jointly explain 11-year-old preadolescents' involvement in bullying? Biol Psychol 2022; 172:108379. [PMID: 35690279 DOI: 10.1016/j.biopsycho.2022.108379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 05/11/2022] [Accepted: 06/03/2022] [Indexed: 11/02/2022]
Abstract
BACKGROUND Bullying is a type of aggressive behavior that occurs repeatedly and intentionally in school environments and where there is a power imbalance. The main objective of this study was to analyze the association that hormones and the psychosocial context jointly have with bullying behavior. METHOD Participants were 302 11-year-old preadolescents from the Gipuzkoan cohort of the INMA Project. Bullying was assessed using the Olweus Bully/victim Questionnaire. Prenatal sexual hormones were assessed by calculating 2D:4D ratio and in order to measure prepubertal testosterone and cortisol levels saliva samples were collected within a week of each other. Additionally, various psychosocial factors were evaluated: executive function, family context, school environment and social context. To analyze our complex hypothesis, six metamodels were tested using structural equation modeling. RESULTS In relation to victims, results showed that victimization was related to worse school environment' perception in boys, and higher stress and conflict in the family in girls. In the case of their involvement in bullying as a bully, lower salivary cortisol levels, worse school environment' perception and lower peers and social support was related to being more frequently involved as a bully in boys, while having more family stress and conflict was related with being a bully in girls. CONCLUSIONS This approach makes it possible not only to explore the different biological and psychosocial factors affect bullying behavior, but also to explore associations between the predictor variables.
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Affiliation(s)
- Izaro Babarro
- Faculty of Psychology of the University of the Basque Country (UPV/EHU), 20018 Donostia/San Sebastian, Spain; Biodonostia Health Research Institute, Group of Environmental Epidemiology and Child Development, 20014 Donostia/San Sebastian, Spain.
| | - Ainara Andiarena
- Faculty of Psychology of the University of the Basque Country (UPV/EHU), 20018 Donostia/San Sebastian, Spain; Biodonostia Health Research Institute, Group of Environmental Epidemiology and Child Development, 20014 Donostia/San Sebastian, Spain
| | - Eduardo Fano
- Faculty of Psychology of the University of the Basque Country (UPV/EHU), 20018 Donostia/San Sebastian, Spain; Biodonostia Health Research Institute, Group of Environmental Epidemiology and Child Development, 20014 Donostia/San Sebastian, Spain
| | - Gonzalo García-Baquero
- Biodonostia Health Research Institute, Group of Environmental Epidemiology and Child Development, 20014 Donostia/San Sebastian, Spain; Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Andrea Lebeña
- University of Linköping, Department of Biomedical and Clinical Science, Linköping, Sweden
| | - Enrique B Arranz-Freijo
- Faculty of Psychology of the University of the Basque Country (UPV/EHU), 20018 Donostia/San Sebastian, Spain; Biodonostia Health Research Institute, Group of Environmental Epidemiology and Child Development, 20014 Donostia/San Sebastian, Spain
| | - Jesus Ibarluzea
- Faculty of Psychology of the University of the Basque Country (UPV/EHU), 20018 Donostia/San Sebastian, Spain; Biodonostia Health Research Institute, Group of Environmental Epidemiology and Child Development, 20014 Donostia/San Sebastian, Spain; Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Instituto de Salud Carlos III, 28029 Madrid, Spain; Ministry of Health of the Basque Government, Sub-Directorate for Public Health and Addictions of Gipuzkoa, 20013 Donostia/San Sebastian, Spain
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Smoliga JM, Fogaca LK, Siplon JS, Goldburt AA, Jakobs F. Giving science the finger-is the second-to-fourth digit ratio (2D:4D) a biomarker of good luck? A cross sectional study. BMJ 2021; 375:e067849. [PMID: 34911738 PMCID: PMC8672321 DOI: 10.1136/bmj-2021-067849] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVES To explore whether random chance, weak research methodology, or inappropriate reporting can lead to claims of statistically significant (yet, biologically meaningless) biomarker associations, using as a model the relation between a common surrogate of prenatal testosterone exposure, second-to-fourth digit ratio (2D:4D), and a random indicator of good luck. DESIGN Cross sectional study. SETTING University sports performance laboratory in the United States. Data were collected from May 2015 to February 2017. PARTICIPANTS 176 adults (74 women, 102 men), including university students, faculty, and staff with no history of injuries, disease, or medical conditions that would affect digit length. MAIN OUTCOME MEASURES 2D:4D, body composition parameters potentially influenced by androgens (bone mineral content, bone mineral density, body fat percentage), and good luck (using poker hands from randomly selected playing cards as a surrogate). RESULTS 2D:4D significantly correlated with select body composition parameters (Spearman's r s range -0.26 to 0.23; P<0.05), but the correlations varied by sex, participant hand measured, and the method of measuring 2D:4D (by photocopy or radiography). However, the strongest correlation observed was between right hand 2D:4D in men measured by radiograph and poker hand rank (r s=0.28, P=0.004). CONCLUSIONS Greater prenatal exposure to testosterone, as estimated by a lower 2D:4D, significantly increases good luck in adulthood, and also modulates body composition (albeit to a lesser degree). While these findings are consistent with a wealth of research reporting that 2D:4D is related to many seemingly disparate outcomes, they are not meant to provide confirmatory evidence that 2D:4D is a universal biomarker of nearly everything. Instead, the associations between 2D:4D and good luck are simply due to chance, and provide a "handy" example of the reproducibility crisis within medical and scientific research. Biologically sound hypotheses, pre-registration of trials, strong methodological and statistical analyses, transparent reporting of negative results, and unbiased interpretation of data are all necessary for biomarker studies and other areas of clinical research.
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Affiliation(s)
- James M Smoliga
- Department of Physical Therapy, High Point University, High Point, NC, USA
| | - Lucas K Fogaca
- Department of Physical Therapy, High Point University, High Point, NC, USA
| | - Jessica S Siplon
- Department of Physical Therapy, High Point University, High Point, NC, USA
| | - Abigail A Goldburt
- Department of Physical Therapy, High Point University, High Point, NC, USA
| | - Franziska Jakobs
- Department of Physical Therapy, High Point University, High Point, NC, USA
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Banyeh M, Amidu N, Quaye L. The relationship between offspring's 2D:4D ratio and postpartum maternal circulating testosterone, estradiol, and their indices in a Ghanaian population. Am J Hum Biol 2021; 34:e23684. [PMID: 34558765 DOI: 10.1002/ajhb.23684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/12/2021] [Accepted: 09/13/2021] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVES The 2D:4D ratio is influenced by prenatal testosterone (PT) and estrogen (PE) exposure in utero. This study sought to determine whether evidence of Manning's hypothesis can still be observed even in the postpartum period. We hypothesize that the offspring 2D:4D ratios will be inversely correlated with maternal postpartum circulating testosterone but positively correlated with estradiol. METHODS This study was conducted between December 2020 and April 2021 and was cross-sectional in nature. There were 272 mother-offspring pairs; the mothers were aged between 18 and 36 years while the median (IQR) age of their offspring was 111 (44-210) days. Offspring right (2D:4DR) and left (2D:4DL) digit ratios were measured using computer-assisted analysis. Sampling was done at 111 (44-210) days postpartum and blood was analyzed for total testosterone (TT), estradiol (E2) and sex hormone-binding globulins using the enzyme-linked immunosorbent assay technique. RESULTS The 2D:4DR of sons was significantly lower compared to daughters (p = .031). Mothers with sons had significantly increased levels of serum TT (p = .001) while mothers with daughters had significantly increased levels of E2 (p = .000). As hypothesized, the maternal serum free testosterone (FT%) was inversely correlated with their daughters' (r = -0.320, p = .003), and also with their sons' (r = -0.213, p = .047), 2D:4DL. Unexpectedly, daughters' 2D:4DL was inversely correlated with maternal circulating free E2 (r = -0.255, p = .015). CONCLUSIONS In humans, evidence of the relationship between maternal testosterone levels and their offspring's 2D:4D ratio may persist even into the postpartum period.
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Affiliation(s)
- Moses Banyeh
- Department of Biomedical Laboratory Science, School of Allied Health Sciences, University for Development Studies, Tamale, Ghana
| | - Nafiu Amidu
- Department of Biomedical Laboratory Science, School of Allied Health Sciences, University for Development Studies, Tamale, Ghana
| | - Lawrence Quaye
- Department of Biomedical Laboratory Science, School of Allied Health Sciences, University for Development Studies, Tamale, Ghana
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13
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Boutrus M, Gilani Z, Maybery MT, Alvares GA, Tan DW, Eastwood PR, Mian A, Whitehouse AJO. Brief Report: Facial Asymmetry and Autistic-Like Traits in the General Population. J Autism Dev Disord 2021; 51:2115-2123. [PMID: 32844273 DOI: 10.1007/s10803-020-04661-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Atypical facial morphology, particularly increased facial asymmetry, has been identified in some individuals with Autism Spectrum Conditions (ASC). Many cognitive, behavioural and biological features associated with ASC also occur on a continuum in the general population. The aim of the present study was to examine subthreshold levels of autistic traits and facial morphology in non-autistic individuals. Facial asymmetry was measured using three-dimensional facial photogrammetry, and the Autism-spectrum Quotient was used to measure autistic-like traits in a community-ascertained sample of young adults (n = 289). After accounting for covariates, there were no significant associations observed between autistic-like traits and facial asymmetry, suggesting that any potential facial morphology differences linked to ASC may be limited to the clinical condition.
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Affiliation(s)
- Maryam Boutrus
- Telethon Kids Institute, University of Western Australia, 100 Roberts Rd, Subiaco, WA, 6008, Australia. .,Cooperative Research Centre for Living with Autism (Autism CRC), Brisbane, Australia. .,School of Psychological Science, University of Western Australia, Perth, Australia.
| | - Zulqarnain Gilani
- Computer Sciences and Software Engineering, University of Western Australia, Perth, Australia.,School of Science, Edith Cowan University, Perth, Australia
| | - Murray T Maybery
- School of Psychological Science, University of Western Australia, Perth, Australia
| | - Gail A Alvares
- Telethon Kids Institute, University of Western Australia, 100 Roberts Rd, Subiaco, WA, 6008, Australia.,Cooperative Research Centre for Living with Autism (Autism CRC), Brisbane, Australia
| | - Diana W Tan
- Telethon Kids Institute, University of Western Australia, 100 Roberts Rd, Subiaco, WA, 6008, Australia.,School of Psychological Science, University of Western Australia, Perth, Australia
| | - Peter R Eastwood
- School of Human Sciences, Centre for Sleep Science, University of Western Australia, Perth, Australia.,Department of Pulmonary Physiology & Sleep Medicine, West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Perth,, Australia
| | - Ajmal Mian
- Computer Sciences and Software Engineering, University of Western Australia, Perth, Australia
| | - Andrew J O Whitehouse
- Telethon Kids Institute, University of Western Australia, 100 Roberts Rd, Subiaco, WA, 6008, Australia.,Cooperative Research Centre for Living with Autism (Autism CRC), Brisbane, Australia
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14
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McKenna BG, Huang Y, Vervier K, Hofammann D, Cafferata M, Al-Momani S, Lowenthal F, Zhang A, Koh JY, Thenuwara S, Brueggeman L, Bahl E, Koomar T, Pottschmidt N, Kalmus T, Casten L, Thomas TR, Michaelson JJ. Genetic and morphological estimates of androgen exposure predict social deficits in multiple neurodevelopmental disorder cohorts. Mol Autism 2021; 12:43. [PMID: 34108004 PMCID: PMC8190870 DOI: 10.1186/s13229-021-00450-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 06/01/2021] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Neurodevelopmental disorders (NDDs) such as autism spectrum disorder (ASD) display a strong male bias. Androgen exposure is profoundly increased in typical male development, but it also varies within the sexes, and previous work has sought to connect morphological proxies of androgen exposure, including digit ratio and facial morphology, to neurodevelopmental outcomes. The results of these studies have been mixed, and the relationships between androgen exposure and behavior remain unclear. METHODS Here, we measured both digit ratio masculinity (DRM) and facial landmark masculinity (FLM) in the same neurodevelopmental cohort (N = 763) and compared these proxies of androgen exposure to clinical and parent-reported features as well as polygenic risk scores. RESULTS We found that FLM was significantly associated with NDD diagnosis (ASD, ADHD, ID; all [Formula: see text]), while DRM was not. When testing for association with parent-reported problems, we found that both FLM and DRM were positively associated with concerns about social behavior ([Formula: see text], [Formula: see text]; [Formula: see text], [Formula: see text], respectively). Furthermore, we found evidence via polygenic risk scores (PRS) that DRM indexes masculinity via testosterone levels ([Formula: see text], [Formula: see text]), while FLM indexes masculinity through a negative relationship with sex hormone binding globulin (SHBG) levels ([Formula: see text], [Formula: see text]). Finally, using the SPARK cohort (N = 9419) we replicated the observed relationship between polygenic estimates of testosterone, SHBG, and social functioning ([Formula: see text], [Formula: see text], and [Formula: see text], [Formula: see text] for testosterone and SHBG, respectively). Remarkably, when considered over the extremes of each variable, these quantitative sex effects on social functioning were comparable to the effect of binary sex itself (binary male: [Formula: see text]; testosterone: [Formula: see text] from 0.1%-ile to 99.9%-ile; SHBG: [Formula: see text] from 0.1%-ile to 99.9%-ile). LIMITATIONS In the devGenes and SPARK cohorts, our analyses rely on indirect, rather than direct measurement of androgens and related molecules. CONCLUSIONS These findings and their replication in the large SPARK cohort lend support to the hypothesis that increasing net androgen exposure diminishes capacity for social functioning in both males and females.
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Affiliation(s)
| | - Yongchao Huang
- Department of Psychiatry, University of Iowa, Iowa City, USA
| | - Kévin Vervier
- Host-Microbiota Interactions Laboratory, Wellcome Sanger Institute, Hinxton, UK
| | | | - Mary Cafferata
- Department of Psychiatry, University of Iowa, Iowa City, USA
| | - Seima Al-Momani
- Department of Psychology, University of Nebraska, Omaha, USA
| | | | - Angela Zhang
- University of Washington School of Public Health, Seattle, USA
| | - Jin-Young Koh
- Molecular Otolaryngology and Renal Research Laboratories, University of Iowa, Iowa City, USA
| | | | - Leo Brueggeman
- Department of Psychiatry, University of Iowa, Iowa City, USA
| | - Ethan Bahl
- Department of Psychiatry, University of Iowa, Iowa City, USA
| | - Tanner Koomar
- Department of Psychiatry, University of Iowa, Iowa City, USA
| | | | - Taylor Kalmus
- Department of Psychology, University of Washington, Seattle, USA
| | - Lucas Casten
- Department of Psychiatry, University of Iowa, Iowa City, USA
| | - Taylor R Thomas
- Department of Psychiatry, University of Iowa, Iowa City, USA
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15
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Pruszkowska-Przybylska P, Sitek A, Rosset I, Sobalska-Kwapis M, Słomka M, Strapagiel D, Żądzińska E, Morling N. Associations between second to fourth digit ratio, cortisol, vitamin D, and body composition among Polish children. Sci Rep 2021; 11:7029. [PMID: 33782473 PMCID: PMC8007693 DOI: 10.1038/s41598-021-86521-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 03/16/2021] [Indexed: 01/17/2023] Open
Abstract
Associations between body characteristics (body composition: fat mass, muscle mass, cell, and water mass as well as body proportion—BMI), the 2D:4D digit ratio, and the concentrations of cortisol and vitamin (25-OH)D among Polish children have not been studied before. A total of 133 (73 girls and 60 boys) healthy Polish children aged 7–11 years were examined. The investigation was divided into three parts: measuring (the length of the second and fourth fingers in both hands, body composition, and body height and mass), questionnaires (socioeconomic status), and laboratory investigations (25-OH vitamin D and cortisol concentrations in saliva measured with ELISA methods). Boys with digit ratios below 1 had lower vitamin D concentration than those with digit ratios equal to or higher than 1 (Z = − 2.33; p = 0.019). Only boys with the male-typical pattern of 2D:4D digit ratio tended to have a lower 25-OH vitamin D concentration in saliva. Thus, it might indicate an effect of prenatal programming on the concentrations of steroid hormones in later life. Neither vitamin D, 2D:4D digit ratio nor the cortisol level was associated with the body components or proportions. More studies are needed to evaluate the molecular and genetic background of this phenomenon.
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Affiliation(s)
| | - Aneta Sitek
- Department of Anthropology, Faculty of Biology and Environmental Protection, University of Lodz, 90-237, Lodz, Poland
| | - Iwona Rosset
- Department of Anthropology, Faculty of Biology and Environmental Protection, University of Lodz, 90-237, Lodz, Poland
| | - Marta Sobalska-Kwapis
- The Biobank Lab, Department of Molecular Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland.,BBMRI.Pl Consortium, Wrocław, Poland
| | - Marcin Słomka
- The Biobank Lab, Department of Molecular Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland.,BBMRI.Pl Consortium, Wrocław, Poland
| | - Dominik Strapagiel
- The Biobank Lab, Department of Molecular Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland.,BBMRI.Pl Consortium, Wrocław, Poland
| | - Elżbieta Żądzińska
- Department of Anthropology, Faculty of Biology and Environmental Protection, University of Lodz, 90-237, Lodz, Poland.,Biological Anthropology and Comparative Anatomy Research Unit, School of Medicine, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Niels Morling
- Section of Forensic Genetics, Department of Forensic Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Frederik V's Vej 11, 2100, Copenhagen, Denmark
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16
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Richards G, Medland SE, Beaton AA. Digit ratio (2D:4D) and handedness: A meta-analysis of the available literature. Laterality 2021; 26:421-484. [PMID: 33517845 DOI: 10.1080/1357650x.2020.1862141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The Geschwind-Behan-Galaburda and sexual differentiation models predict an association between elevated foetal androgen exposure and left-handedness whereas the callosal hypothesis predicts the opposite. We present a meta-analysis of correlations between handedness and digit ratio (2D:4D), a putative marker of prenatal testosterone. Left-handedness predicted low (male-typical) right-hand digit ratio (R2D:4D), high (female-typical) left-hand digit ratio (L2D:4D), and low R2D:4D-L2D:4D directional asymmetry (D[R-L]). Effect sizes were extremely small and not moderated by sex or method of measuring handedness or 2D:4D. The same general pattern was observed after excluding the very large study (110,329 males, 90,412 females) of Manning and Peters ([2009]. Digit ratio (2D:4D) and hand preference for writing in the BBC Internet Study. Laterality: Asymmetries of Body, Brain and Cognition, 14(5), 528-540. doi:10.1080/13576500802637872); however, no significant effects for R2D:4D were observed once these samples were removed. The results do not confirm any theory linking prenatal androgens with handedness, so we speculate they instead reflect the mechanical action of writing causing subtle changes in the musculature and/or fat pads of the fingers. Gripping a pen/pencil might cause an increase in 2D relative to 4D (and/or decrease in 4D relative to 2D) resulting in higher ratios on the writing-hand; furthermore, this could differ between left- and right-handers due to writing in the left-to-right direction (as in English) having asymmetrical effects depending on which hand is used.
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Affiliation(s)
- Gareth Richards
- School of Psychology, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK.,Centre for Research on Play in Education, Development & Learning, Faculty of Education, University of Cambridge, Cambridge, UK
| | - Sarah E Medland
- Psychiatric Genetics, QIMR Berghofer Medical Research Institute, Brisbane, Australia.,School of Psychology, University of Queensland, St Lucia, Australia.,School of Psychology and Counselling, Queensland University of Technology, Brisbane, Australia
| | - Alan A Beaton
- Department of Psychology, School of Human & Health Sciences, Swansea University, Swansea, UK.,Department of Psychology, Aberystwyth University, Aberystwyth, UK
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17
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Digit ratio (2D:4D) and amniotic testosterone and estradiol: an attempted replication of Lutchmaya et al. (2004). J Dev Orig Health Dis 2021; 12:859-864. [PMID: 33472723 DOI: 10.1017/s2040174420001294] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
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.
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18
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Guo J, Wu C, Zhang J, Li W, Lv S, Lu D, Qi X, Feng C, Liang W, Chang X, Zhang Y, Xu H, Cao Y, Wang G, Zhou Z. Prenatal exposure to multiple phenolic compounds, fetal reproductive hormones, and the second to fourth digit ratio of children aged 10 years in a prospective birth cohort. CHEMOSPHERE 2021; 263:127877. [PMID: 32835969 DOI: 10.1016/j.chemosphere.2020.127877] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/25/2020] [Accepted: 07/29/2020] [Indexed: 06/11/2023]
Abstract
Select phenols are known to possess hormone-disrupting properties, but no previous study has addressed the potential effects of prenatal exposure to phenol mixtures on fetal reproductive hormones and children's second to fourth digit (2D: 4D) ratio, a marker for in utero testosterone (T) exposure. We aimed to explore interrelations of prenatal phenol exposures individually and in mixtures, cord serum reproductive hormones, and 2D: 4D ratio of children aged 10 years. Urinary 11 phenol concentrations were determined from 392 pregnant women participating in a longitudinal birth cohort. We estimated associations of prenatal phenol exposures individually and in mixtures with cord reproductive hormones and children's 2D:4D ratio using three statistical approaches, including generalized linear models (GLMs), elastic net regression (ENR) models and Bayesian kernel machine regression (BKMR) models. In female newborns, the three models showed that maternal triclosan (TCS) concentrations were significantly negatively associated with cord serum T levels [regression coefficient (β) = -0.076, 95% confidence interval (CI): 0.138, -0.013; p = 0.018]. Additionally, maternal urinary bisphenol A (BPA) levels were related to decreases in 2D:4D ratio of the left hand in girls by GLMs (β = -0.003, 95% CI: 0.007, -0.001; p = 0.024) and ENR models, but not BKMR models. We provided evidence that prenatal TCS exposure predicted lower cord serum T levels, and maternal BPA exposure was related to decreased 2D:4D ratio of the left hand in females.
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Affiliation(s)
- Jianqiu Guo
- School of Public Health/Key Laboratory of Public Health Safety of Ministry of Education/Key Lab of Health Technology Assessment, National Health Commission of the People's Republic of China, Fudan University, No.130 Dong'an Road, Shanghai, 200032, China
| | - Chunhua Wu
- School of Public Health/Key Laboratory of Public Health Safety of Ministry of Education/Key Lab of Health Technology Assessment, National Health Commission of the People's Republic of China, Fudan University, No.130 Dong'an Road, Shanghai, 200032, China.
| | - Jiming Zhang
- School of Public Health/Key Laboratory of Public Health Safety of Ministry of Education/Key Lab of Health Technology Assessment, National Health Commission of the People's Republic of China, Fudan University, No.130 Dong'an Road, Shanghai, 200032, China
| | - Wenting Li
- School of Public Health/Key Laboratory of Public Health Safety of Ministry of Education/Key Lab of Health Technology Assessment, National Health Commission of the People's Republic of China, Fudan University, No.130 Dong'an Road, Shanghai, 200032, China
| | - Shenliang Lv
- School of Public Health/Key Laboratory of Public Health Safety of Ministry of Education/Key Lab of Health Technology Assessment, National Health Commission of the People's Republic of China, Fudan University, No.130 Dong'an Road, Shanghai, 200032, China
| | - Dasheng Lu
- Shanghai Municipal Center for Disease Control and Prevention, No. 1380 Zhongshan West Road, Shanghai, 200336, China
| | - Xiaojuan Qi
- Zhejiang Provincial Center for Disease Control and Prevention, No. 3399 Binsheng Road, Hangzhou, 310051, China
| | - Chao Feng
- Shanghai Municipal Center for Disease Control and Prevention, No. 1380 Zhongshan West Road, Shanghai, 200336, China
| | - Weijiu Liang
- Changning District Center for Disease Control and Prevention, No.39 Yunwushan Road, Shanghai, 200051, China
| | - Xiuli Chang
- School of Public Health/Key Laboratory of Public Health Safety of Ministry of Education/Key Lab of Health Technology Assessment, National Health Commission of the People's Republic of China, Fudan University, No.130 Dong'an Road, Shanghai, 200032, China
| | - Yubin Zhang
- School of Public Health/Key Laboratory of Public Health Safety of Ministry of Education/Key Lab of Health Technology Assessment, National Health Commission of the People's Republic of China, Fudan University, No.130 Dong'an Road, Shanghai, 200032, China
| | - Hao Xu
- Changning District Center for Disease Control and Prevention, No.39 Yunwushan Road, Shanghai, 200051, China
| | - Yang Cao
- Clinical Epidemiology and Biostatistics, School of Medical Sciences, Örebro University, Örebro, 70182, Sweden
| | - Guoquan Wang
- Shanghai Municipal Center for Disease Control and Prevention, No. 1380 Zhongshan West Road, Shanghai, 200336, China
| | - Zhijun Zhou
- School of Public Health/Key Laboratory of Public Health Safety of Ministry of Education/Key Lab of Health Technology Assessment, National Health Commission of the People's Republic of China, Fudan University, No.130 Dong'an Road, Shanghai, 200032, China.
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19
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Jones AL, Jaeger B, Schild C. No credible evidence for links between 2D:4D and COVID-19 outcomes: A probabilistic perspective on digit ratio, ACE variants, and national case fatalities. Early Hum Dev 2021; 152:105272. [PMID: 33227636 PMCID: PMC7670914 DOI: 10.1016/j.earlhumdev.2020.105272] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/04/2020] [Accepted: 11/10/2020] [Indexed: 10/26/2022]
Abstract
Research into COVID-19 susceptibility and outcomes are critical, but claims must be carefully evaluated to inform policy decisions. In a recent series of articles, Manning and Fink [1-3] use national-level data to describe associations between case-fatality ratios and male and female finger ratios (2D:4D), a suggested measure of prenatal androgen exposure, as well as angiotensin-converting enzyme (ACE) allele and genotype frequencies. The authors suggest that 2D:4D is linked with ACE variant prevalence, and that higher male 2D:4D is associated with higher case fatality ratios, and point to 2D:4D as a useful prognostic measure for COVID-19 susceptibility. A critical review and robust Bayesian analysis of the hypothesis is described here, finding no conclusive evidence of COVID-19 mortality and 2D:4D, nor associations between 2D:4D and ACE1 allele or ACE2 genotype frequency. This absence of evidence is present for data taken from the second wave of COVID-19 in October 2020. Problematic theoretical grounding, individual-level conclusions drawn from national-level data, and issues with statistical inference in the original articles are discussed. Taken together, the current data offer no clear utility of 2D:4D in determining COVID-19 outcomes.
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Affiliation(s)
- Alex L. Jones
- Swansea University, United Kingdom,Corresponding author
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20
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van Leeuwen B, Smeets P, Bovet J, Nave G, Stieglitz J, Whitehouse A. Do sex hormones at birth predict later-life economic preferences? Evidence from a pregnancy birth cohort study. Proc Biol Sci 2020; 287:20201756. [PMID: 33352071 PMCID: PMC7779492 DOI: 10.1098/rspb.2020.1756] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 11/27/2020] [Indexed: 12/12/2022] Open
Abstract
Economic preferences may be shaped by exposure to sex hormones around birth. Prior studies of economic preferences and numerous other phenotypic characteristics use digit ratios (2D : 4D), a purported proxy for prenatal testosterone exposure, whose validity has recently been questioned. We use direct measures of neonatal sex hormones (testosterone and oestrogen), measured from umbilical cord blood (n = 200) to investigate their association with later-life economic preferences (risk preferences, competitiveness, time preferences and social preferences) in an Australian cohort (Raine Study Gen2). We find no significant associations between testosterone at birth and preferences, except for competitiveness, where the effect runs opposite to the expected direction. Point estimates are between 0.05-0.09 percentage points (pp) and 0.003-0.14 s.d. We similarly find no significant associations between 2D : 4D and preferences (n = 533, point estimates 0.003-0.02 pp and 0.001-0.06 s.d.). Our sample size allows detecting effects larger than 0.11 pp or 0.22 s.d. for testosterone at birth, and 0.07 pp or 0.14 s.d. for 2D : 4D (α = 0.05 and power = 0.90). Equivalence tests show that most effects are unlikely to be larger than these bounds. Our results suggest a reinterpretation of prior findings relating 2D : 4D to economic preferences, and highlight the importance of future large-sample studies that permit detection of small effects.
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Affiliation(s)
- Boris van Leeuwen
- Department of Economics, Tilburg University, Tilburg, The Netherlands
| | - Paul Smeets
- Department of Finance, Maastricht University, Maastricht, The Netherlands
| | - Jeanne Bovet
- Department of Psychology, Northumbria University, Newcastle upon Tyne, UK
| | - Gideon Nave
- Department of Marketing, The Wharton School, University of Pennsylvania, Philadelphia, PA, USA
| | - Jonathan Stieglitz
- Institute for Advanced Study in Toulouse, University of Toulouse 1 Capitole, Toulouse, France
| | - Andrew Whitehouse
- Telethon Kids Institute, University of Western Australia, Crawley, Western Australia, Australia
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21
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Digit ratio, a proposed marker of the prenatal hormone environment, is not associated with prenatal sex steroids, anogenital distance, or gender-typed play behavior in preschool age children. J Dev Orig Health Dis 2020; 12:923-932. [PMID: 33336644 DOI: 10.1017/s2040174420001270] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Prenatal hormones have been proposed as key factors impacting child development as well as long-term health and disease. Digit ratio (the ratio of the lengths of the second to fourth digits; 2D:4D) has been proposed as a sexually dimorphic, noninvasive marker of prenatal androgen exposure that can be reliably measured in children and adults. To date, few longitudinal pregnancy cohort studies have examined childhood digit ratio in relation to other relevant measures including prenatal hormones and androgen-sensitive outcomes. To augment the current literature on this topic, we measured right-hand digit ratio in 4-year-old children participating in The Infant Development and the Environment Study, a multicenter longitudinal cohort study that has been following mother-child dyads since the first trimester of pregnancy (n = 321). We assessed sex differences in digit ratio and fit multivariable linear regression models to examine digit ratio in relation to: (1) child sex; (2) maternal sex steroid hormone concentrations in early pregnancy; (3) newborn anogenital distance, another proposed measure of sensitivity to prenatal androgens; and (4) gender-typical play behavior as measured by the Preschool Activities Inventory (PSAI) at age 4. We observed no sex difference in digit ratio; the mean 2D:4D was 0.97 ± 0.05 mm in both sexes. Furthermore, digit ratio was not associated with maternal sex steroid concentrations in early pregnancy, anogenital distance in either sex, or PSAI scores in either sex in covariate-adjusted models. In conclusion, we observed no evidence that early childhood digit ratio was associated with child sex or hormone-sensitive measures in this cohort.
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22
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Effects of hand preference on digit lengths and digit ratios among children and adults. Early Hum Dev 2020; 151:105204. [PMID: 33059164 DOI: 10.1016/j.earlhumdev.2020.105204] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 01/21/2023]
Abstract
BACKGROUND Prenatal sex hormones may not exclusively determine effects of hand preference on digit ratios. Genetic determination is an alternative possibility. AIM To study the likelihood of similar effects of hand preference on digit lengths and digit ratios. METHODS We selected similar numbers of left-handers and right-handers in samples of kindergarten children (N = 101, age range: 3.5-7 years) and adults (N = 189, age range: 17-28 years) and measured digit lengths (excluding the thumb) directly on the palmar hand. RESULTS Compared to right-handers, left-handers had longer digits and lower third-to-fourth (3D:4D) digit ratios among children, whereas an opposite pattern of handedness differences occurred among adults. CONCLUSIONS Effects of hand preference on digit lengths and ratios might be genetically/ontogenetically determined. Also discussed are implications of this set of findings for digit ratio research.
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Richards G, Browne WV, Aydin E, Constantinescu M, Nave G, Kim MS, Watson SJ. Digit ratio (2D:4D) and congenital adrenal hyperplasia (CAH): Systematic literature review and meta-analysis. Horm Behav 2020; 126:104867. [PMID: 32998030 DOI: 10.1016/j.yhbeh.2020.104867] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 09/18/2020] [Accepted: 09/19/2020] [Indexed: 01/15/2023]
Abstract
The ratio of length between the second and fourth fingers (2D:4D) is commonly used as an indicator of prenatal sex hormone exposure. Several approaches have been used to try to validate the measure, including examining 2D:4D in people with congenital adrenal hyperplasia (CAH), a suite of conditions characterised by elevated adrenal androgen production secondary to defective steroidogenesis. We present a systematic review and meta-analysis that examines the relationship between these two variables. Twelve articles relating to nine CAH cohorts were identified, and 2D:4D comparisons have been made between cases and controls in eight of these cohorts. Altogether, at least one 2D:4D variable has been compared between n = 251 females with CAH and n = 358 unaffected females, and between n = 108 males with CAH and n = 204 unaffected males. A previous meta-analysis (Hönekopp and Watson, 2010) reported lower right hand (R2D:4D) and left hand (L2D:4D) digit ratios in patients with CAH relative to sex-matched controls. Our meta-analysis showed the same pattern, with medium effect sizes for R2D:4D and small effect sizes for L2D:4D. Differences of small magnitude were also observed for M2D:4D, and no significant effects were observed for D[R-L]. Notably, the only effects that remained statistically significant when stratified by sex were R2D:4D in males and L2D:4D in females, and the average effect size had reduced by 46.70% since the meta-analysis of Hönekopp and Watson (2010). We also found that individual comparisons in this literature were considerably underpowered, and that patterns of sexual dimorphism in 2D:4D were similar in CAH samples as in typically developing populations. Findings are discussed in relation to the prenatal androgen hypothesis as well as alternative explanations.
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Affiliation(s)
- Gareth Richards
- School of Psychology, Faculty of Medical Sciences, Newcastle University, UK; Autism Research Centre, Department of Psychiatry, University of Cambridge, UK.
| | | | - Ezra Aydin
- Autism Research Centre, Department of Psychiatry, University of Cambridge, UK
| | - Mihaela Constantinescu
- Gender Development Research Centre, University of Cambridge, UK; School of Psychology, University of East London, UK
| | - Gideon Nave
- Marketing Department, The Wharton School, University of Pennsylvania, USA
| | - Mimi S Kim
- Keck School of Medicine, University of Southern California, USA
| | - Steven J Watson
- School of Psychology, Faculty of Medical Sciences, Newcastle University, UK; Department of Psychology of Conflict, Risk and Safety, University of Twente, Netherlands
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Baxter A, Wood EK, Witczak LR, Bales KL, Higley JD. Sexual Dimorphism in Titi Monkeys' Digit (2D:4D) Ratio is Associated with Maternal Urinary Sex Hormones During Pregnancy. Dev Psychobiol 2020; 62:979-991. [PMID: 31372988 PMCID: PMC7871332 DOI: 10.1002/dev.21899] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/15/2019] [Accepted: 06/28/2019] [Indexed: 12/23/2022]
Abstract
The second-to-fourth digit (2D:4D) ratio is a sexually-dimorphic biomarker for prenatal sex hormone exposure. We investigated whether titi monkeys (Plecturocebus cupreus) exhibit sexually-dimorphic 2D:4D ratio, and whether variation in 2D:4D ratio correlates with maternal testosterone and estrogen levels during early pregnancy. Subjects were 61 adult titi monkeys (32 males, 29 females). For 26 subjects, maternal urine samples were collected approximately 15-20 weeks before birth and assayed for testosterone and estrone conjugate (E1 C). Titi monkeys exhibited a human-like pattern of sexual dimorphism in right-hand 2D:4D ratio, with females exhibiting higher 2D:4D ratio than males (β = -0.29, p = 0.023). For left-hand 2D:4D ratio, high levels of maternal E1 C predicted low offspring 2D:4D ratio (β = -0.48, p = 0.009). For right-hand 2D:4D ratio, high levels of testosterone (β = -0.53, p = 0.005) and testosterone-to-E1 C ratio (β = -0.41, p = 0.028) predicted low offspring 2D:4D ratio. For 2D:4D ratio asymmetry (right-hand - left-hand), high levels of testosterone (β = -0.43, p = 0.03) and testosterone-to-E1 C ratio (β = -0.53, p = 0.003) predicted low (right-biased) asymmetry. This is the first report of sexually-dimorphic 2D:4D ratio in New World monkeys, and the results support a growing literature suggesting prenatal sex hormones may modulate offspring 2D:4D ratio.
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Affiliation(s)
- Alexander Baxter
- Department of Psychology, Brigham Young University, Provo, Utah
- Department of Psychology, University of California, Davis, California
- California National Primate Research Center, Davis, California
| | | | - Lynea R Witczak
- Department of Psychology, University of California, Davis, California
- California National Primate Research Center, Davis, California
| | - Karen L Bales
- Department of Psychology, University of California, Davis, California
- California National Primate Research Center, Davis, California
| | - J Dee Higley
- Department of Psychology, Brigham Young University, Provo, Utah
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25
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Yamaguchi N, Yasui T, Kaji T, Sogawa E, Yoshida A, Yonetani N, Irahara M. Usefulness of measurement of proximal phalanx length by using ultrasonography in newborn infants. J OBSTET GYNAECOL 2020; 41:739-745. [PMID: 33054451 DOI: 10.1080/01443615.2020.1798903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The purpose of this study was to compare digit lengths and proximal phalanx lengths in newborn infants by using ultrasonography (USG) and to examine sex differences between the ratio of the second digit (2D) and fourth digit (4D) of digit length and that of proximal phalanx length and the associations of digit length and proximal phalanx length with birth weight and birth height. Sixty newborn infants (28 males and 32 females) were recruited. Digit lengths were measured by using a transparent ruler and proximal phalanx lengths were measured by using USG. There were significant correlations between digit length and proximal phalanx length in the left and right hands. There was no significant correlation between 2D:4D ratios of digit lengths and 2D:4D ratios of proximal phalanx lengths measured by using USG. In males, birth height was significantly associated with right fourth proximal phalanx length and with left second and fourth proximal phalanx lengths. Birth weight was significantly associated with proximal phalanx length in males. Proximal phalanx length measured by using USG was significantly associated with digit length in newborn infants. Hormonal exposure before birth may be involved in the associations of proximal phalanx length with birth weight and height in males.Impact statementWhat is already known on this subject? The ratio of the second digit (2D) and fourth digit (4D) has been used postnatally to provide a retrospective indication of the foetal hormonal environment. Digit lengths have been measured by using a direct method, photocopies, digital scans and radiographs, but the results of a study on measurement of digit lengths by using ultrasonography (USG) have not been reported.What do the results of this study add? Proximal phalanx length measured by using USG was significantly associated with digit length in newborn infants. In males, birth height was significantly associated with right fourth proximal phalanx length and with left second and fourth proximal phalanx lengths. Birth weight was significantly associated with proximal phalanx length in males.What are the implications of these findings for clinical practice and/or further research? Measurement of proximal phalanx length by using USG may be useful for a study on gender differences in foetal development and the foetal hormonal environment. Hormonal exposure before birth may be involved in the associations of proximal phalanx length with birth weight and height in males.
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Affiliation(s)
- Natsumi Yamaguchi
- Department of Cardiology, Tokushima Graduate School of Medical Science, Tokushima, Japan
| | - Toshiyuki Yasui
- Department of Reproductive and Menopausal Medicine, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Takashi Kaji
- Department of Obstetrics and Gynecology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Eishi Sogawa
- Department of Obstetrics and Gynecology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Atsuko Yoshida
- Department of Obstetrics and Gynecology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Naoto Yonetani
- Department of Obstetrics and Gynecology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Minoru Irahara
- Department of Obstetrics and Gynecology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
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26
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Rostovtseva VV, Mezentseva AA, Windhager S, Butovskaya ML. Second-to-fourth digit ratio and facial shape in Buryats of Southern Siberia. Early Hum Dev 2020; 149:105138. [PMID: 32750625 PMCID: PMC7374133 DOI: 10.1016/j.earlhumdev.2020.105138] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 07/08/2020] [Accepted: 07/14/2020] [Indexed: 11/29/2022]
Abstract
BACKGROUND The 2nd-to-4th digit ratio (2D:4D) is a putative predictor of a prenatal exposure to sex hormones. 2D:4D is sexually dimorphic (males < females). Studies, linking digit ratio and full facial shapes among Europeans, show that a low 2D:4D is associated with a set of male-specific facial features. Buryats - Mongolian people from Southern Siberia - demonstrate a different pattern of facial sexual dimorphism than Europeans (narrower and more vertically elongated faces in men as opposed to women). AIM The aim of the present study was to investigate the association between facial shape and the 2D:4D in comparison to the pattern of facial sexual dimorphism in Buryats. SUBJECTS Buryats: 88 men and 80 women aged 20 ± 2 years. OUTCOME MEASURES To assess relationship between facial shape and 2D:4D we used a geometric morphometric approach based on standardized full-face frontal photographs and direct measurements of the digit lengths among right-handed individuals. RESULTS The results revealed that 2D:4D was associated with facial morphology in Buryat men, and to a lesser extent in women. Narrower faces, elongated in the vertical direction, and a narrower lower facial outline, were characteristic of Buryat men with low 2D:4D ratios, which corresponded to the male-like facial shapes in Buryats. CONCLUSIONS In Europeans, such facial features were reported for men with a high 2D:4D, which corresponded more to female-like European facial shapes. Hence, our results show that sex-specific morphogenesis in humans is multidirectional, and that digit ratio is capable of predicting sex-specific facial traits even in populations with differing sexually-dimorphic morphology.
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Affiliation(s)
- Victoria V. Rostovtseva
- Institute of Ethnology and Anthropology, Russian Academy of Sciences, Leninskiy pr-t 32a, Moscow 119334, Russia,Corresponding author
| | - Anna A. Mezentseva
- Department of Ethnology, Lomonosov Moscow State University, Lomonosovskiy pr-t 27/4, Moscow 119192, Russia
| | - Sonja Windhager
- Department of Evolutionary Anthropology, University of Vienna, Althanstrasse 14, Vienna 1090, Austria
| | - Marina L. Butovskaya
- Institute of Ethnology and Anthropology, Russian Academy of Sciences, Leninskiy pr-t 32a, Moscow 119334, Russia,National Research University Higher School of Economics, Myasnitskaya str. 20, Moscow 101000, Russia
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27
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Körner LM, Schaper ML, Pause BM, Heil M. Parent-Reports of Sex-Typed Play Preference in Preschool Children: Relationships to 2D:4D Digit Ratio and Older Siblings' Sex. ARCHIVES OF SEXUAL BEHAVIOR 2020; 49:2715-2724. [PMID: 32222854 PMCID: PMC7497428 DOI: 10.1007/s10508-020-01662-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 02/11/2020] [Accepted: 02/13/2020] [Indexed: 05/06/2023]
Abstract
Sex-typed play behavior shows large sex differences and seems to be affected by prenatal sex hormones. For example, a smaller, more male-typical ratio between the second and fourth digit length (2D:4D), a proposed marker for prenatal testosterone exposure, has been shown to be related to sex-typed play preference in childhood. Nevertheless, it is still being debated whether 2D:4D displays a stable sex difference throughout childhood, as there are few longitudinal studies. In the present study, children's 2D:4D was measured on both hands on four occasions from early infancy to early childhood (T1: 5 months, T2: 9 months, T3: 20 months, and T4: 40 months) providing the rare possibility to test the temporal stability of the sex difference. Parents completed the Preschool Activities Inventory at T4 and reported on the number of older brothers and sisters as a measure for socialization influences. Parents described boys as playing more masculine and less feminine than girls. Boys had smaller 2D:4D than girls at all measurements (T1-T4) and on both hands (right/left). Nevertheless, 2D:4D increased significantly from T3 to T4 in both sexes. Girls, but not boys, who were described as playing more masculine and less feminine had more masculine 2D:4D ratios at T1-T4 on both hands (except for right 2D:4D at T2 and T3) and had more older brothers and fewer older sisters. These data underline the stability of the sex difference in 2D:4D and show the importance of both biological and social influences on sex-typed play behavior.
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Affiliation(s)
- Lisa M Körner
- Department of Experimental Psychology, Institute of Experimental Psychology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany.
| | - Marie Luisa Schaper
- Department of Experimental Psychology, Institute of Experimental Psychology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Bettina M Pause
- Department of Experimental Psychology, Institute of Experimental Psychology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Martin Heil
- Department of Experimental Psychology, Institute of Experimental Psychology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
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28
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Chirchir H. Trabecular bone in domestic dogs and wolves: Implications for understanding human self‐domestication. Anat Rec (Hoboken) 2020; 304:31-41. [DOI: 10.1002/ar.24510] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 05/13/2020] [Accepted: 05/13/2020] [Indexed: 12/17/2022]
Affiliation(s)
- Habiba Chirchir
- Department of Biological Sciences Marshall University Huntington West Virginia USA
- Human Origins Program, Department of Anthropology National Museum of Natural History, Smithsonian Institution Washington District of Columbia USA
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29
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Jones AL, Satchell LP, Jaeger B, Schild C. (Mis-)understanding COVID-19 and digit ratio: Methodological and statistical issues in Manning and Fink (2020). Early Hum Dev 2020; 148:105095. [PMID: 32499091 PMCID: PMC7256504 DOI: 10.1016/j.earlhumdev.2020.105095] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 05/26/2020] [Indexed: 11/29/2022]
Affiliation(s)
- Alex L. Jones
- Department of Psychology, Swansea University, UK,Corresponding author.
| | | | - Bastian Jaeger
- Department of Social Psychology, Tilburg University, Netherlands
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30
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Yamada Y, Ebara T, Yamaguchi C, Miyachi T, Shoji N, Matsuki T, Kano H, Hirosawa M, Kamijima M. Sexual difference in 2nd-to-4th digit ratio among 1.5-year-old Japanese children: A cross-sectional study of Aichi regional adjunct cohort of the Japan Environment and Children's Study (JECS-A). Early Hum Dev 2020; 146:105050. [PMID: 32387816 DOI: 10.1016/j.earlhumdev.2020.105050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 04/08/2020] [Accepted: 04/21/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND A sex difference in the second-to-fourth digit ratio (2D:4D, males < females) has been described in Japanese fetuses and children, and its possible links to autism spectrum disorders (ASDs) have been discussed. Accordingly, this sexual difference in representative neonates merits examination. AIMS This study aimed to examine 2D:4D measurements and sexual differences in Japanese toddlers aged 1.5 years. STUDY DESIGN AND SUBJECTS The digit lengths used to calculate 2D:4D were measured using an easy-to-use photography method. A total of 1045 JECS-A (the Aichi regional sub-cohort of the Japan Environment and Children's Study) children (males, 523; females, 522) aged 1.5 years were analyzed. RESULTS The mean ages for the males and females were 575.3 ± 13.1 and 575.9 ± 17.1 days, respectively. Histograms of left and right 2D:4D were normally distributed regardless of sex (left male, 0.909 ± 0.048; left female, 0.913 ± 0.049, d = 0.08; right male, 0.938 ± 0.055; right female, 0.937 ± 0.049, d = 0.02). Because of high dispersion in the data, t-tests did not support a significant sex difference in 2D:4D. Post-hoc statistical power was calculated as 0.124 and the effect size for the sex difference in 2D:4D was 0.036. CONCLUSIONS This study failed to confirm sexual differences in 2D:4D in 1.5-year-old Japanese children. This may be because digit measurement is difficult in this group, resulting in reduced effect sizes, or because rapid growth attenuates the in utero sexual dimorphism. This evidence is useful for the light it casts on the extreme male brain theory of ASDs.
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Affiliation(s)
- Yasuyuki Yamada
- Juntendo University, Graduate School of Health and Sports Science, Inzai, Chiba 2701695, Japan; Nagoya City University, Department of Occupational and Environmental Health, Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Aichi 4678601, Japan
| | - Takeshi Ebara
- Nagoya City University, Department of Occupational and Environmental Health, Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Aichi 4678601, Japan.
| | - Chikae Yamaguchi
- Nagoya City University, Graduate School of Nursing, Mizuho-ku, Nagoya, Aichi 4678601, Japan
| | - Taishi Miyachi
- Nagoya City University, Department of Pediatrics and Neonatology, Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Aichi 4678601, Japan
| | - Naoto Shoji
- Nagoya City University, Department of Occupational and Environmental Health, Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Aichi 4678601, Japan; Asahi University, School of Health Sciences, Mizuho, Gifu 5010296, Japan
| | - Taro Matsuki
- Nagoya City University, Department of Occupational and Environmental Health, Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Aichi 4678601, Japan
| | - Hirohisa Kano
- Nagoya City University, Department of Occupational and Environmental Health, Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Aichi 4678601, Japan
| | - Masataka Hirosawa
- Juntendo University, Graduate School of Health and Sports Science, Inzai, Chiba 2701695, Japan
| | - Michihiro Kamijima
- Nagoya City University, Department of Occupational and Environmental Health, Graduate School of Medical Sciences, Mizuho-ku, Nagoya, Aichi 4678601, Japan
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31
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Kowal M, Sorokowski P, Żelaźniewicz A, Nowak J, Orzechowski S, Żurek G, Żurek A, Juszkiewicz A, Wojtycka L, Sieniuć W, Poniatowska M, Tarnowska K, Kowalska K, Drabik K, Łukaszek P, Krawczyk K, Stefaniak T, Danek N. No relationship between the digit ratios (2D:4D) and salivary testosterone change: Study on men under an acute exercise. Sci Rep 2020; 10:10068. [PMID: 32572079 PMCID: PMC7308391 DOI: 10.1038/s41598-020-66915-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 03/16/2020] [Indexed: 01/08/2023] Open
Abstract
The digit ratio (2D:4D) is said to be a potential marker of exposure to prenatal sex steroids. Some studies suggest that the 2D:4D is also linked with the testosterone response to challenging situations due to organizational effect of prenatal hormonal milieu on adult endocrine functioning. However, up to date, there were only four studies (conducted on small samples) that examined the 2D:4D and the testosterone response to a challenging situation (i.e. physical exertion or aggressive context). Here, we examined the relationship between the 2D:4D and the testosterone change under an acute exercise among 97 men. We found that the digit ratios (the right 2D:4D, the left 2D:4D, and the right minus left 2D:4D) were neither predictors of pre-exercise testosterone, nor the change in testosterone level after a cycling task. Our results add a contradictory to previous studies evidence in a discussion on the links of the 2D:4D and the testosterone change.
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Affiliation(s)
- Marta Kowal
- Institute of Psychology, University of Wrocław, Wrocław, Poland
| | - Piotr Sorokowski
- Institute of Psychology, University of Wrocław, Wrocław, Poland.
| | | | - Judyta Nowak
- Department of Human Biology, University of Wrocław, Wrocław, Poland
| | | | - Grzegorz Żurek
- University School of Physical Education in Wrocław, Wrocław, Poland
| | - Alina Żurek
- Institute of Psychology, University of Wrocław, Wrocław, Poland
| | | | - Lidia Wojtycka
- Institute of Psychology, University of Wrocław, Wrocław, Poland
| | | | | | | | - Kaja Kowalska
- Institute of Psychology, University of Wrocław, Wrocław, Poland
| | | | | | | | | | - Natalia Danek
- University School of Physical Education in Wrocław, Wrocław, Poland
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32
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Tabachnik M, Sheiner E, Wainstock T. The association between second to fourth digit ratio, reproductive and general health among women: findings from an Israeli pregnancy cohort. Sci Rep 2020; 10:6341. [PMID: 32286380 PMCID: PMC7156723 DOI: 10.1038/s41598-020-62599-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 03/15/2020] [Indexed: 12/17/2022] Open
Abstract
The ratio between the length of second and fourth digits (2D:4D) is a putative biomarker for prenatal testosterone and estrogen exposure. The aim of the study was to examine the association between 2D:4D and women’s general and reproductive health. This analysis was conducted within a prospective pregnancy cohort study. The study population included 187 women. 2D:4D was measured directly in both hands using a digital caliper. Multivariable linear and logistic models were used to study the associations between digit ratio and the studied health characteristics. Mean age of the participants was 30.7 ± 4.9 years. The mean age at menarche was 12.9 ± 1.4 years. Right hand 2D:4D mean ± SD was 0.965 ± 0.03. Left hand 2D:4D mean ± SD was 0.956 ± 0.03. An association was found between right 2D:4D and age at menarche, with older age in women with 2D:4D ≥ mean versus 2D:4D < mean (13.2 ± 1.5 and 12.8 ± 1.3 respectively, b = 0.48, 95%CI:0.06–0.91) while controlling for ethnicity. Higher 2D:4D was also associated with heavier menses bleeding and dysmenorrhea. There is an association between 2D:4D and sub optimal reproductive characteristics, including later age at menarche, heavier menses bleeding and dysmenorrhea. These findings support the association between the intrauterine period and reproductive characteristics. Further studies are required to support our findings.
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Affiliation(s)
- Maya Tabachnik
- The Department of Public Health, Faculty of Health Sciences, Ben-Gurion University of the Negev, POB 653, Beer-Sheva, 84105, Israel.
| | - Eyal Sheiner
- Department of Obstetrics and Gynecology, Soroka University Medical Center, Ben-Gurion University of the Negev, POB 151, Beer-Sheva, 84101, Israel
| | - Tamar Wainstock
- The Department of Public Health, Faculty of Health Sciences, Ben-Gurion University of the Negev, POB 653, Beer-Sheva, 84105, Israel
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33
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Nitschke JP, Bartz JA. Lower digit ratio and higher endogenous testosterone are associated with lower empathic accuracy. Horm Behav 2020; 119:104648. [PMID: 31785282 DOI: 10.1016/j.yhbeh.2019.104648] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 11/22/2019] [Accepted: 11/23/2019] [Indexed: 01/10/2023]
Abstract
Empathy is a cornerstone of human sociality. It has important consequences for our interpersonal relationships and for navigating our social world more generally. Although research has identified numerous psychological factors that can influence empathy, evidence suggests that empathy may also be rooted in our biology and, in particular, the gonadal steroid hormone testosterone. To date, much of the research linking testosterone and empathy has focused on the 2D:4D ratio (i.e., the ratio of the lengths of the index and ring fingers), and the results have been mixed. These mixed results, however, may be due to reliance on self-report measures to assess empathy, which can be vulnerable to self-presentation, as well as social-cultural norms about gender/sex differences in empathy. Moreover, although some have argued that digit ratio is an indicator of prenatal androgen exposure, the evidence for this to date is weak. Here, we aimed to follow up on this prior work, using a naturalistic empathic accuracy task in which participants dynamically track, in real-time, the emotional state of targets. We show that lower digit ratio (Study 1; N = 107) and higher circulating testosterone (Study 2; N = 76) are associated with poorer empathic accuracy performance; critically, these effects hold when controlling for sex/gender. In neither study, however, did we find effects on self-reported empathy. Our results highlight the limitations of self-report measures and support the notion that endogenous testosterone levels as well as 2D:4D ratio are related to key social-cognitive competencies like empathic accuracy.
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34
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Parslow E, Ranehill E, Zethraeus N, Blomberg L, von Schoultz B, Hirschberg AL, Johannesson M, Dreber A. The digit ratio (2D:4D) and economic preferences: no robust associations in a sample of 330 women. JOURNAL OF THE ECONOMIC SCIENCE ASSOCIATION 2019; 5:149-169. [PMID: 31894199 PMCID: PMC6917633 DOI: 10.1007/s40881-019-00076-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 09/19/2019] [Accepted: 09/24/2019] [Indexed: 06/10/2023]
Abstract
Many studies report on the association between 2D:4D, a putative marker for prenatal testosterone exposure, and economic preferences. However, most of these studies have limited sample sizes and test multiple hypotheses (without preregistration). In this study we mainly replicate the common specifications found in the literature for the association between the 2D:4D ratio and risk taking, the willingness to compete, and dictator game giving separately. In a sample of 330 women we find no robust associations between any of these economic preferences and 2D:4D. We find no evidence of a statistically significant relation for 16 of the 18 total regressions we run. The two regression specifications which are statistically significant have not previously been reported and the associations are not in the expected direction, and therefore they are unlikely to represent a real effect.
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Affiliation(s)
- Elle Parslow
- Department of Economics, Stockholm School of Economics, P.O Box 6501, 11383 Stockholm, Sweden
| | - Eva Ranehill
- Department of Economics, University of Gothenburg, Gothenburg, Sweden
| | - Niklas Zethraeus
- Department of Learning, Informatics, Management and Ethics, Karolinska Institutet, Solna, Sweden
| | - Liselott Blomberg
- Karolinska University Hospital, Karolinska Institutet, Solna, Sweden
| | - Bo von Schoultz
- Karolinska University Hospital, Karolinska Institutet, Solna, Sweden
| | | | - Magnus Johannesson
- Department of Economics, Stockholm School of Economics, P.O Box 6501, 11383 Stockholm, Sweden
| | - Anna Dreber
- Department of Economics, Stockholm School of Economics, P.O Box 6501, 11383 Stockholm, Sweden
- Department of Economics, University of Innsbruck, Innsbruck, Austria
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Králík M, Hupková A, Zeman T, Hložek M, Hlaváček L, Slováčková M, Čuta M, Urbanová P. Family effects on the digit ratio (2D:4D): The role of the interbirth interval. Am J Hum Biol 2019; 31:e23260. [PMID: 31183942 DOI: 10.1002/ajhb.23260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 02/26/2019] [Accepted: 05/12/2019] [Indexed: 11/11/2022] Open
Abstract
OBJECTIVES Family represents the closest social environment that immediately affects human ontogeny from an early prenatal period. This study aimed to assess sibship influences on the second-to-fourth digit length ratio (2D:4D ratio). METHODS The source sample represented 329 children aged 6.5 to 15.8 years (Czech Republic), including a subsample of 75 sibling pairs. A combination of (a) between-family design (cross-sectional sample) and (b) within-family design (pairs of siblings) was used to study the effect of family variables and interbirth interval (IBI) on the 2D:4D ratio. RESULTS Birth order, number of siblings (except for younger sisters), and sex ratio in siblings were significantly related to the 2D:4D ratio on the right, left, or both hands. At the same time, the relationships were opposite in males and females for birth order, number of older brothers and number of children in the family--increasing values in these variables increased digit ratio in males but decreased digit ratio in females. Mean difference in 2D:4D ratio (DIFF) within pairs (older minus younger sibling) differed from zero only in the "older sister--younger brother" group, where DIFF did not depend on IBI. On the contrary, in remaining pair types the DIFF tended to change with IBI, the strongest in the "older brother--younger sister" pairs. CONCLUSIONS Family variables, especially number of older brothers, should be considered as important confounding factors in 2D:4D ratio studies. However, the effect of these variables might be modified by IBI.
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Affiliation(s)
- Miroslav Králík
- Laboratory of Morphology and Forensic Anthropology (LaMorFA), Department of Anthropology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Adela Hupková
- Laboratory of Morphology and Forensic Anthropology (LaMorFA), Department of Anthropology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Tomáš Zeman
- Laboratory of Neurobiology and Molecular Psychiatry, Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Martin Hložek
- Department of Archaeology and Museology, Faculty of Arts, Masaryk University, Brno, Czech Republic
| | - Lukáš Hlaváček
- Palacký University Olomouc, Conference Services, Olomouc, Czech Republic
| | - Marie Slováčková
- Laboratory of Morphology and Forensic Anthropology (LaMorFA), Department of Anthropology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Martin Čuta
- Laboratory of Morphology and Forensic Anthropology (LaMorFA), Department of Anthropology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Petra Urbanová
- Laboratory of Morphology and Forensic Anthropology (LaMorFA), Department of Anthropology, Faculty of Science, Masaryk University, Brno, Czech Republic
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Bovet J. Evolutionary Theories and Men's Preferences for Women's Waist-to-Hip Ratio: Which Hypotheses Remain? A Systematic Review. Front Psychol 2019; 10:1221. [PMID: 31244708 PMCID: PMC6563790 DOI: 10.3389/fpsyg.2019.01221] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 05/08/2019] [Indexed: 01/20/2023] Open
Abstract
Over the last 25 years, a large amount of research has been dedicated to identifying men's preferences for women's physical features, and the evolutionary benefits associated with such preferences. Today, this area of research generates substantial controversy and criticism. I argue that part of the crisis is due to inaccuracies in the evolutionary hypotheses used in the field. For this review, I focus on the extensive literature regarding men's adaptive preferences for women's waist-to-hip ratio (WHR), which has become a classic example of the just-so storytelling contributing to the general mistrust toward evolutionary explanations of human behavior. The issues in this literature originate in the vagueness and incompleteness of the theorizing of the evolutionary mechanisms leading to mate preferences. Authors seem to have rushed into testing and debating the effects of WHR on women's attractiveness under various conditions and using different stimuli, without first establishing (a) clear definitions of the central evolution concepts (e.g., female mate value is often reduced to an imprecise concept of "health-and-fertility"), and (b) a complete overview of the distinct evolutionary paths potentially at work (e.g., focusing on fecundability while omitting descendants' quality). Unsound theoretical foundations will lead to imprecise predictions which cannot properly be tested, thus ultimately resulting in the premature rejection of an evolutionary explanation to human mate preferences. This paper provides the first comprehensive review of the existing hypotheses on why men's preferences for a certain WHR in women might be adaptive, as well as an analysis of the theoretical credibility of these hypotheses. By dissecting the evolutionary reasoning behind each hypothesis, I show which hypotheses are plausible and which are unfit to account for men's preferences for female WHR. Moreover, the most cited hypotheses (e.g., WHR as a cue of health or fecundity) are found to not necessarily be the ones with the strongest theoretical support, and some promising hypotheses (e.g., WHR as a cue of parity or current pregnancy) have seemingly been mostly overlooked. Finally, I suggest some directions for future studies on human mate choice, to move this evolutionary psychology literature toward a stronger theoretical foundation.
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Affiliation(s)
- Jeanne Bovet
- Stony Brook University, Stony Brook, NY, United States
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Slama N, Warner M, Mocarelli P, Brambilla P, Eskenazi B. The 2nd to 4th digit length ratio (2D:4D) among children of Seveso women exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin. Early Hum Dev 2019; 131:45-50. [PMID: 30849682 PMCID: PMC6435417 DOI: 10.1016/j.earlhumdev.2019.02.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/19/2019] [Accepted: 02/26/2019] [Indexed: 10/27/2022]
Abstract
BACKGROUND Exposure to endocrine-disrupting chemicals (EDCs) during sensitive developmental windows, such as in utero, may influence disease later in life but direct measurement of fetal hormones is not feasible. The ratio of the length of the second finger digit to the fourth digit (2D:4D), a sexually dimorphic trait, is a biomarker of androgen levels and the androgen/estrogen balance in utero. However, it is unclear whether in utero EDC exposure might alter 2D:4D ratio. AIMS We examined 2D:4D ratio in Seveso children in relation to in utero exposure to a potent EDC, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) using linear regression. STUDY DESIGN The Seveso Women's Health Study (SWHS) is a historical cohort study, following the health of women exposed to TCDD during a 1976 explosion in Seveso, Italy. Individual-level TCDD was measured for SWHS in serum collected soon after the accident. In 2014, the SWHS children born after the explosion were enrolled in the Seveso Second Generation Study. SUBJECTS 594 SWHS children born post-explosion to 397 mothers. OUTCOME MEASURES Right hand 2D:4D ratio. RESULTS On average, 2D:4D ratio for males was significantly lower than for females (p < 0.05). Overall, in utero TCDD exposure, either as maternal initial serum TCDD concentration or as TCDD extrapolated to pregnancy was not significantly associated with 2D:4D ratio in Seveso children. Results from all adjusted sensitivity analyses remained non-significant. CONCLUSIONS Our results suggest in utero exposure to TCDD is not associated with alteration in 2D:4D ratio.
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Affiliation(s)
- Natalie Slama
- Center for Environmental Research & Children’s Health (CERCH), University of California, School of Public Health, Center for Environmental Research and Children’s Health, 1995 University Avenue, Suite 265, Berkeley, CA 94720-7392
| | - Marcella Warner
- Center for Environmental Research & Children’s Health (CERCH), University of California, School of Public Health, Center for Environmental Research and Children’s Health, 1995 University Avenue, Suite 265, Berkeley, CA 94720-7392
| | - Paolo Mocarelli
- Department of Laboratory Medicine, University of Milano-Bicocca, School of Medicine, Hospital of Desio, Desio-Milano, Italy
| | - Paolo Brambilla
- Department of Laboratory Medicine, University of Milano-Bicocca, School of Medicine, Hospital of Desio, Desio-Milano, Italy
| | - Brenda Eskenazi
- Center for Environmental Research & Children's Health (CERCH), School of Public Health, University of California, Berkeley, CA, United States of America.
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Rodriguez-Ruiz C, Muñoz-Reyes JA, Iglesias-Julios M, Sanchez-Pages S, Turiegano E. Sex Affects the Relationship Between Third Party Punishment and Cooperation. Sci Rep 2019; 9:4288. [PMID: 30862895 PMCID: PMC6414674 DOI: 10.1038/s41598-019-40909-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 02/22/2019] [Indexed: 11/09/2022] Open
Abstract
Prosocial third-party punishment (3PP) is a punitive behavior against antisocial individuals, which might explain extended cooperativeness in humans. 3PP shows sexual dimorphism, being more frequent in men than in women. We studied whether sexually dimorphic features related to sexual hormones during development (facial dimorphism and 2D:4D) influence the tendency to engage in 3PP in a sample of 511 women and 328 men. After playing a Prisoner's Dilemma, participants had to decide whether to penalize the defection of a third player who had exploited his/her counterpart's cooperation. In line with previous studies, we observe that men are more prone to engage in 3PP than women. We find that this sex difference is due to cooperative men being more likely to punish than cooperative women. In addition, men with higher facial masculinity are less likely to engage in 3PP, whereas no features influence 3PP in women. We discuss the possibility that sex differences in the motivations and fitness implications underlying 3PP might be driving the observed results.
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Affiliation(s)
| | - José Antonio Muñoz-Reyes
- Laboratorio de Comportamiento Animal y Humano, Centro de Estudios Avanzados, Universidad de Playa Ancha, Valparaíso, Chile
| | - Marta Iglesias-Julios
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | | | - Enrique Turiegano
- Biology Department, Universidad Autónoma de Madrid. C/Darwin 2, 28029, Madrid, Spain.
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Relationship between umbilical cord sex hormone binding globulin, sex steroids, and age at menarche: a prospective cohort study. Fertil Steril 2019; 110:965-973. [PMID: 30316444 DOI: 10.1016/j.fertnstert.2018.06.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 05/03/2018] [Accepted: 06/04/2018] [Indexed: 12/16/2022]
Abstract
OBJECTIVE To study the role of the prenatal environment in regulating reproductive development by measuring the prospective association between umbilical cord concentrations of sex hormone binding globulin (SHBG; principal regulator of sex steroid activity), bioavailable sex steroids, and age at menarche. DESIGN Prospective population-based cohort. SETTING Not applicable. PATIENT(S) In 286 female members of the Western Australian Pregnancy (Raine) cohort, concentrations of SHBG and steroids (estrogens: estrone, estradiol, estriol and estetrol [E4]; androgens: total testosterone, Δ4-androstenedione, androstenedione and dehydroepiandrosterone) were measured by liquid chromatography-tandem mass spectrometry from archived umbilical cord blood samples collected at birth. Bioavailable concentrations of testosterone and estradiol were calculated along with total composite measures of androgen and estrogen bioactivity. SHBG was measured by ELISA. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Age of menarche was calculated from date of menarche, collected prospectively by questionnaire sent home with participants at the year 10 follow-up. RESULT(S) Higher maternal education, higher body mass index, and the presence of antepartum hemorrhage were all significantly associated with earlier age at menarche. The bioavailable sex steroid measures accounted for 8.3% of the variance in age at menarche. Further, both SHBG and E4 concentrations accounted for a significant proportion of unique variance in age at menarche. CONCLUSION(S) Lower SHBG and higher E4 concentrations in umbilical cord blood were associated with earlier age at menarche. These results suggest that the prenatal sex steroid environment contributes toward pubertal development and age at menarche.
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Sanwald S, Widenhorn-Müller K, Wernicke J, Sindermann C, Kiefer M, Montag C. Depression Is Associated With the Absence of Sex Differences in the 2D:4D Ratio of the Right Hand. Front Psychiatry 2019; 10:483. [PMID: 31379616 PMCID: PMC6660250 DOI: 10.3389/fpsyt.2019.00483] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 06/19/2019] [Indexed: 11/20/2022] Open
Abstract
The 2D:4D digit ratio reflects prenatal testosterone relative to estradiol exposure of a developing embryo. Higher levels of prenatal testosterone have been related to lower 2D:4D ratios. In addition, higher 2D:4D ratios have been associated with female gender, neuroticism, and depression severity. Therefore, the present study investigated whether 2D:4D ratios differ between inpatients with major depression and matched healthy controls and whether 2D:4D ratios correlate with depression severity. We examined 139 inpatients diagnosed with major depression according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria and 137 healthy controls regarding 2D:4D ratios of both hands and BDI-II scores. While we observed significant sex differences in the 2D:4D ratio of the right hand in the healthy control group (women on average showed a significantly higher 2D:4D ratio), no such differences were found in the group of depressed patients. The 2D:4D digit ratios did not correlate with depression severity even when examined for group and sex separately. We conclude that major depression is associated with an absence of sex differences in the 2D:4D ratio.
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Affiliation(s)
- Simon Sanwald
- Department of Psychiatry, Ulm University, Ulm, Germany
| | | | - Jennifer Wernicke
- Department of Molecular Psychology, Institute of Psychology and Education, Ulm University, Ulm, Germany
| | - Cornelia Sindermann
- Department of Molecular Psychology, Institute of Psychology and Education, Ulm University, Ulm, Germany
| | - Markus Kiefer
- Department of Psychiatry, Ulm University, Ulm, Germany
| | - Christian Montag
- Department of Molecular Psychology, Institute of Psychology and Education, Ulm University, Ulm, Germany
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Testosterone measured from amniotic fluid and maternal plasma shows no significant association with directional asymmetry in newborn digit ratio (2D:4D). J Dev Orig Health Dis 2018; 10:362-367. [PMID: 30376903 DOI: 10.1017/s2040174418000752] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Foetal sex hormones can have powerful and far-reaching effects on later phenotype. However, obtaining accurate measurements is difficult for ethical reasons, and researchers often employ proxy variables to examine their effects. The relative length of the second and fourth fingers (digit ratio or 2D:4D) is frequently used for this purpose, as it is hypothesized to index variance in prenatal androgen and oestrogen exposure. Most studies employing this method examine digit ratio for the right hand (R2D:4D) and/or left hand (L2D:4D), though the mean value (M2D:4D) (i.e., the average of R2D:4D and L2D:4D) and directional asymmetry (D[R-L]) (i.e., R2D:4D minus L2D:4D) are also commonly used. As no published studies have examined M2D:4D or D[R-L] in relation to testosterone measured from amniotic fluid, we conducted a secondary analysis of data published by Ventura et al. The sample comprises 106 mothers from Portugal who underwent amniocentesis during the second trimester and their neonates. Newborn M2D:4D was negatively correlated with amniotic testosterone in females (P<0.05) but not in males; no significant association was observed between amniotic testosterone and D[R-L] in either sex. In addition, we examined testosterone measured from maternal circulation during the second trimester, and found that it was not a significant predictor of M2D:4D or D[R-L] in male or female infants. Further research should aim to measure the ratio of testosterone to oestradiol present in amniotic fluid and maternal plasma, to examine whether either is a predictor of digit ratio variables at different stages of postnatal development.
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Del Giudice M, Barrett ES, Belsky J, Hartman S, Martel MM, Sangenstedt S, Kuzawa CW. Individual differences in developmental plasticity: A role for early androgens? Psychoneuroendocrinology 2018; 90:165-173. [PMID: 29500952 PMCID: PMC5864561 DOI: 10.1016/j.psyneuen.2018.02.025] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 02/20/2018] [Accepted: 02/22/2018] [Indexed: 11/16/2022]
Abstract
Developmental plasticity is a widespread property of living organisms, but different individuals in the same species can vary greatly in how susceptible they are to environmental influences. In humans, research has sought to link variation in plasticity to physiological traits such as stress reactivity, exposure to prenatal stress-related hormones such as cortisol, and specific genes involved in major neurobiological pathways. However, the determinants of individual differences in plasticity are still poorly understood. Here we present the novel hypothesis that, in both sexes, higher exposure to androgens during prenatal and early postnatal life should lead to increased plasticity in traits that display greater male variability (i.e., a majority of physical and behavioral traits). First, we review evidence of greater phenotypic variation and higher susceptibility to environmental factors in males; we then consider evolutionary models that explain greater male variability and plasticity as a result of sexual selection. These empirical and theoretical strands converge on the hypothesis that androgens may promote developmental plasticity, at least for traits that show greater male variability. We discuss a number of potential mechanisms that may mediate this effect (including upregulation of neural plasticity), and address the question of whether androgen-induced plasticity is likely to be adaptive or maladaptive. We conclude by offering suggestions for future studies in this area, and considering some research designs that could be used to empirically test our hypothesis.
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Affiliation(s)
- Marco Del Giudice
- Department of Psychology, University of New Mexico, Albuquerque, NM, USA.
| | - Emily S Barrett
- School of Public Health, Rutgers University, Piscataway, NJ, USA
| | - Jay Belsky
- Department of Human Ecology, University of California - Davis, Davis, CA, USA
| | - Sarah Hartman
- Department of Human Ecology, University of California - Davis, Davis, CA, USA
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Alonso J, Di Paolo R, Ponti G, Sartarelli M. Facts and Misconceptions about 2D:4D, Social and Risk Preferences. Front Behav Neurosci 2018; 12:22. [PMID: 29487510 PMCID: PMC5816919 DOI: 10.3389/fnbeh.2018.00022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 01/25/2018] [Indexed: 11/30/2022] Open
Abstract
We study how the ratio between the length of the second and fourth digit (2D:4D) correlates with choices in social and risk preferences elicitation tasks by building a large dataset from five experimental projects with more than 800 subjects. Our results confirm the recent literature that downplays the link between 2D:4D and many domains of economic interest, such as social and risk preferences. As for the former, we find that social preferences are significantly lower when 2D:4D is above the median value only for subjects with low cognitive ability. As for the latter, we find that a high 2D:4D is not correlated with the frequency of subjects' risky choices.
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Affiliation(s)
- Judit Alonso
- Departamento de Fundamentos de Análisis Económico, Universidad de Alicante, San Vicente del Raspeig/Sant Vicent del Raspeig, Alicante, Spain
| | - Roberto Di Paolo
- Departamento de Fundamentos de Análisis Económico, Universidad de Alicante, San Vicente del Raspeig/Sant Vicent del Raspeig, Alicante, Spain
| | - Giovanni Ponti
- Departamento de Fundamentos de Análisis Económico, Universidad de Alicante, San Vicente del Raspeig/Sant Vicent del Raspeig, Alicante, Spain.,Department of Economics, The University of Chicago, Chicago, IL, United States.,Dipartimento di Economia e Finanza, Libera Università Internazionale degli Studi Sociali Guido Carli (LUISS), Rome, Italy
| | - Marcello Sartarelli
- Departamento de Fundamentos de Análisis Económico, Universidad de Alicante, San Vicente del Raspeig/Sant Vicent del Raspeig, Alicante, Spain
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Xie Z, Page L, Hardy B. Investigating Gender Differences under Time Pressure in Financial Risk Taking. Front Behav Neurosci 2018; 11:246. [PMID: 29326566 PMCID: PMC5736567 DOI: 10.3389/fnbeh.2017.00246] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 11/28/2017] [Indexed: 11/13/2022] Open
Abstract
There is a significant gender imbalance on financial trading floors. This motivated us to investigate gender differences in financial risk taking under pressure. We used a well-established approach from behavior economics to analyze a series of risky monetary choices by male and female participants with and without time pressure. We also used second to fourth digit ratio (2D:4D) and face width-to-height ratio (fWHR) as correlates of pre-natal exposure to testosterone. We constructed a structural model and estimated the participants' risk attitudes and probability perceptions via maximum likelihood estimation under both expected utility (EU) and rank-dependent utility (RDU) models. In line with existing research, we found that male participants are less risk averse and that the gender gap in risk attitudes increases under moderate time pressure. We found that female participants with lower 2D:4D ratios and higher fWHR are less risk averse in RDU estimates. Males with lower 2D:4D ratios were less risk averse in EU estimations, but more risk averse using RDU estimates. We also observe that men whose ratios indicate a greater prenatal exposure to testosterone exhibit a greater optimism and overestimation of small probabilities of success.
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Affiliation(s)
- Zhixin Xie
- Queensland Behavioral Economics Group, School of Economics and Finance, Queensland University of Technology, Brisbane, QLD, Australia
| | - Lionel Page
- Queensland Behavioral Economics Group, School of Economics and Finance, Queensland University of Technology, Brisbane, QLD, Australia
| | - Ben Hardy
- School of Finance and Management, SOAS University of London, London, United Kingdom
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Kaltwasser L, Mikac U, Buško V, Hildebrandt A. No Robust Association between Static Markers of Testosterone and Facets of Socio-Economic Decision Making. Front Behav Neurosci 2017; 11:250. [PMID: 29326567 PMCID: PMC5742355 DOI: 10.3389/fnbeh.2017.00250] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 12/11/2017] [Indexed: 11/13/2022] Open
Abstract
Digit ratio (2D:4D) and facial width-to-height ratio (WHR) are supposedly static indicators of testosterone exposition during prenatal and pubertal lifetime, respectively. Both measures have been linked to aggressive and assertive behavior in laboratory economic games, as well as in real world scenarios. Most of the research-often limited to male subjects-considers the associations between these behaviors, traits, and hormonal markers separately for 2D:4D and WHR. Reported associations are weak and volatile. In the present study we had independent raters assess 2D:4D and WHR in a sample of N = 175 participants who played the ultimatum game (UG). Respondent behavior in UG captures the tendency to reject unfair offers (negative reciprocity). If unfair UG offers are seen as provocations, then individuals with stronger testosterone exposition may be more prone to reject such offers. Economists argue that negative reciprocity reflects altruistic punishment, since the rejecting individual is sacrificing own resources. However, recent studies suggest that self-interest, in terms of status defense plays a substantial role in decisions to reject unfair offers. We also assessed social preferences by social value orientation and assertiveness via self-report. By applying structural equation modeling we estimated the latent level association of 2D:4D and WHR with negative reciprocity, assertiveness and prosociality in both sexes. Results revealed no robust association between any of the trait measures and hormonal markers. The measures of 2D:4D and WHR were not related with each other. Multigroup models based on sex suggested invariance of factor loadings allowing to compare hormone-behavior relationships of females and males. Only when collapsing across sex greater WHR was weakly associated with assertiveness, suggesting that individuals with wider faces tend to express greater status defense. Only the right hand 2D:4D was weakly associated with prosocial behavior, indicating that individuals with lower prenatal testosterone exposure are more cooperative. Rejection behavior in UG was not related with 2D:4D nor WHR in any of the models. There were also no curvilinear associations between 2D:4D and prosociality as theorized in the literature. Our results suggest that previous studies over-estimated the role of static markers of testosterone in accounting for aggression and competition behavior in males.
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Affiliation(s)
- Laura Kaltwasser
- Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Una Mikac
- Faculty of Humanities and Social Sciences, University of Zagreb, Zagreb, Croatia
| | - Vesna Buško
- Faculty of Humanities and Social Sciences, University of Zagreb, Zagreb, Croatia
| | - Andrea Hildebrandt
- Department of Psychology, Ernst-Moritz-Arndt-Universität Greifswald, Greifswald, Germany
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Affiliation(s)
- Gareth Richards
- Autism Research Centre, Department of Psychiatry, University of Cambridge, UK.
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47
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Manning JT, Fink B. Are there any "direct" human studies of digit ratio (2D:4D) and measures of prenatal sex hormones? Early Hum Dev 2017; 113:73-74. [PMID: 28927753 DOI: 10.1016/j.earlhumdev.2017.09.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 09/05/2017] [Indexed: 10/18/2022]
Affiliation(s)
- John T Manning
- Applied Sports, Technology, Exercise and Medicine (A-STEM), Swansea University, Swansea, United Kingdom
| | - Bernhard Fink
- Institute of Psychology, University of Goettingen, Goettingen, Germany.
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Richards G. What is the evidence for a link between digit ratio (2D:4D) and direct measures of prenatal sex hormones? Early Hum Dev 2017; 113:71-72. [PMID: 28807670 DOI: 10.1016/j.earlhumdev.2017.08.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 08/07/2017] [Accepted: 08/08/2017] [Indexed: 11/25/2022]
Affiliation(s)
- Gareth Richards
- Autism Research Centre, Department of Psychiatry, University of Cambridge, UK.
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Georgiev AV, Ryan CP, Gettler LT, McDade TW, Kuzawa CW. Second‐to‐fourth digit ratio (2D:4D) is unrelated to measures of somatic reproductive effort among young men from Cebu, the Philippines. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2017; 163:437-445. [DOI: 10.1002/ajpa.23215] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 02/24/2017] [Accepted: 03/10/2017] [Indexed: 12/18/2022]
Affiliation(s)
| | - Calen P. Ryan
- Department of AnthropologyNorthwestern UniversityEvanston Illinois
| | - Lee T. Gettler
- Department of AnthropologyUniversity of Notre DameNotre Dame Indiana
- The Eck Institute for Global HealthUniversity of Notre DameNotre Dame Indiana
| | - Thomas W. McDade
- Department of AnthropologyNorthwestern UniversityEvanston Illinois
- Institute for Policy ResearchNorthwestern UniversityEvanston Illinois
| | - Christopher W. Kuzawa
- Department of AnthropologyNorthwestern UniversityEvanston Illinois
- Institute for Policy ResearchNorthwestern UniversityEvanston Illinois
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Jamnadass ESL, Keelan JA, Russell-Smith SN, Hickey M, Maybery MT, Whitehouse AJO. Umbilical cord androgens and estrogens in relation to verbal and nonverbal abilities at age 10 in the general population. PLoS One 2017; 12:e0173493. [PMID: 28278304 PMCID: PMC5344490 DOI: 10.1371/journal.pone.0173493] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 02/21/2017] [Indexed: 11/18/2022] Open
Abstract
Sex differences in verbal and nonverbal abilities are a contentious area of research. Prenatal steroids have been shown to have masculinizing effects on the brain that may affect the development of nonverbal and verbal abilities in later life. The current study examined a wide range of biologically active sex steroids (both androgens and estrogens) in umbilical cord blood at birth in a large pregnancy cohort in relation to performance on nonverbal (Raven's Coloured Progressive Matrices) and verbal (Clinical Evaluation of Language Fundamentals-3 and the Peabody Picture Vocabulary Test-III) measures at age 10 years. Overall, Androgen and Estrogen composites in cord blood were not found to be predictive of performance on verbal and nonverbal measures at age 10. These data suggest that late gestation sex steroids do not exert a major effect on nonverbal and verbal abilities in middle childhood.
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Affiliation(s)
- Esha S. L. Jamnadass
- School of Psychology, University of Western Australia, Perth, Western Australia, Australia
- Telethon Kids Institute, University of Western Australia, Perth, Western Australia, Australia
- * E-mail:
| | - Jeffrey A. Keelan
- School of Women’s and Infant’s Health, University of Western Australia, Perth, Western Australia, Australia
| | | | - Martha Hickey
- Department of Obstetrics and Gynaecology, University of Melbourne and the Royal Women’s Hospital, Melbourne, Victoria, Australia
| | - Murray T. Maybery
- School of Psychology, University of Western Australia, Perth, Western Australia, Australia
| | - Andrew J. O. Whitehouse
- Telethon Kids Institute, University of Western Australia, Perth, Western Australia, Australia
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