Waist-to-Hip Ratio, but Not Body Mass Index, Is Associated with Testosterone and Estradiol Concentrations in Young Women

Testosterone mediates life-history trade-offs in female mammals

Hormones mediate life-history trade-offs. In female mammals, such trade-offs have been studied predominantly in the contexts of oestrogen, progesterone and prolactin. We evaluate the hypothesis that prenatal and postnatal testosterone levels structure and regulate trade-offs in females involving components of reproduction and survival. This hypothesis is predicated on the observation that testosterone confers competition-related and survival-related benefits, but also reproduction-related costs, to female mammals. The hypothesis is supported by field and laboratory data from diverse non-human animals, and data from healthy women. Most broadly, relatively low testosterone level in females has been associated with earlier, faster and higher offspring production, greater attractiveness to males, and reduced dominance or competitiveness, whereas higher testosterone level is associated with delayed and reduced reproduction but increased dominance, status, aggression, and resource accrual. The magnitude of testosterone-mediated trade-offs is expected to depend upon the strength of female-female competition, which represents some function of species-specific ecology, behaviour and mating system. Testosterone-associated trade-offs have, until now, been virtually ignored in studies of female life history, reproductive physiology, evolutionary endocrinology, and female-limited disease, probably due to researcher biases towards conceptualizing androgens as hormones with effects mainly restricted to males.

Sex differences in the risk of incident systemic sclerosis: a nationwide population-based study with subgroup analyses

Although higher prevalence of systemic sclerosis (SSc) in women than in men is well-known, it is unclear to what degree women are at higher risk of developing incident SSc. This study aims to assess the risk of incident SSc comparing women vs. men, and to identify subsets of individuals in whom the risk difference according to sex is more prominent. An analysis of a Korean nationwide cohort of 9,894,996 individuals was conducted. All individuals were followed up from 2009 to 2019. Cox proportional hazard models were used to assess the risk of incident SSc comparing women vs. men. Subgroup analysis was conducted by stratifying individuals according to multiple covariates. The absolute risk of SSc in men (i.e., background risk) was 0.004% (95% CI 0.003-0.004), and the absolute risk of SSc in women was 0.025% (95% CI 0.023-0.027). The absolute risk difference between women and men was 0.021% (95% CI 0.019-0.024). Women had a significantly higher risk of incident SSc than men (adjusted hazard ratio [aHR], 5.275; 95% confidence interval, 4.346-6.403). The effect size was more pronounced in middle-aged individuals (aHR 5.020 [< 40 years] vs. 5.868 [40-64 years] vs. 2.734 [≥ 65 years]; p-interaction < 0.001); those without abdominal obesity (aHR 5.863 vs. 3.658; p-interaction = 0.005); those who did not exercise regularly (aHR 5.701 vs. 3.932; p-interaction = 0.030); and those without hypertension (aHR 5.996 vs. 4.053; p-interaction = 0.010) or dyslipidemia (aHR 5.857 vs. 3.330; p-interaction = 0.001). Women had a 5-fold higher risk of incident SSc than men. The higher risk was more prominent in middle-aged individuals, those without abdominal obesity, those who do not exercise regularly, and do not have hypertension or dyslipidemia.

Autoimmune Hashimoto's Disease and Feminization Level-Testing the Immunocompetence Hypothesis

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.

Sex Doll Specifications versus Human Body Characteristics

Sex dolls have been criticized for reproducing unrealistic expectations about human bodies. Yet precise sex doll measurements are lacking in the literature nor has there been any systematic attempt to determine the extent to which sex dolls exaggerate human characteristics. To address this gap, we compared the specifications of sex dolls marketed in the USA with the characteristics of women and men living in the USA. Specifically, we tested if and to what degree female dolls were slimmer (H1) and male dolls more muscular (H2) than female and male humans, respectively. Furthermore, we tested if and to what degree female dolls' breasts (H3) and male dolls' penises (H4) were larger than those of women and men. We also tested if sex dolls' observed race/ethnicity was more often White than that of the US population (H5). In 2023, we collected the measures of all 757 full-body sex dolls marketed by the US retailer SexyRealSexDolls.com. Body measures from the US population were extracted from scientific literature. Descriptive and inferential statistical analyses were performed using R. All hypotheses were fully or partially confirmed, which indicated that sex dolls marketed in the USA are not realistic depictions of the US population but hypergendered (H1, H2), hypersexualized (H3, H4), and racially fetishized (H5). Implications of the lack of realism are discussed.

Association between Waist-Hip Ratio and Female Infertility in the United States: Data from National Health and Nutrition Examination Survey 2017-2020

INTRODUCTION

Obesity has previously been correlated with an elevated risk of reproductive system diseases in women. The waist-hip ratio (WHR) has been shown to be correlated with visceral fat, making it one of the most commonly used indicators of abdominal obesity. However, little is known about the relationship between WHR and infertility. Therefore, the aim of this study was to evaluate the effect of the WHR on infertility in women of childbearing age.

METHODS

The study used cross-sectional data from women aged 20-45 who participated in the National Health and Nutrition Examination Survey (NHANES), which was conducted between 2017 and 2020. We collected details of their waist circumference, hip circumference, fertility status, and several other essential variables. We used multivariate logistic regression analysis and subgroup analyses to assess the association between WHR and infertility.

RESULTS

There were 976 participants, with 12.0% (117/976) who experienced infertility. After adjusting for potential confounding factors, our multivariate logistic regression analysis revealed that every 0.1 unit increase in WHR resulted in a more than 35% higher risk of infertility (odds ratio [OR; 95% confidence interval [CI]: 1.35 [1.01∼1.81], p = 0.043). Compared to the group with WHR <0.85, the risk of infertility increased in the group with WHR ≥0.85, with an adjusted OR of 1.74 (95% CI: 1.06∼2.85). When WHR was treated as a continuous variable, it was observed that each 0.1 unit increase in WHR was associated with a relatively high risk in the secondary infertility population after adjusting all covariates, with an OR of 1.66 (95% CI: 1.14∼2.40, p = 0.01). When WHR was analyzed as a categorical variable, the group with WHR ≥0.85 exhibited a significantly higher risk of secondary infertility than the group with WHR <0.85, with the OR of 2.75 (95% CI: 1.35-5.59, p = 0.01) after adjusting for all covariates. Furthermore, the interaction analysis indicated that there was a significant interaction between age status on WHR and the risk of infertility.

CONCLUSION

WHR showed a positive correlation with the risk of infertility. This study highlights the importance of effectively managing abdominal fat and promoting the maintenance of optimal WHR levels to mitigate the progression of infertility, particularly for younger women.

Mean platelet volume and polycystic ovary syndrome: a systematic review and meta-analysis

OBJECTIVE

This meta-analysis evaluated the association between the mean platelet volume (MPV) and polycystic ovary syndrome (PCOS).

METHODS

A systematic literature search using PubMed, EMBASE, and Web of Science databases until June 2021 was conducted. Pooled standardized mean differences (SMD) and 95% confidence intervals (CI) were determined using a random effects model.

RESULTS

Ten studies involving 866 women with PCOS and 548 age- and body mass index-matched women without PCOS were included. The MPV was significantly increased in women with PCOS compared with non-PCOS women (SMD = 0.43, 95% CI = 0.13-0.72). Subgroup analyses showed that this trend was consistent in cross-sectional studies (SMD = 0.44, 95% CI = 0.03-0.86) and in Turkish women (SMD = 0.46, 95% CI = 0.13-0.79). Meta-regression analysis revealed a marginally positive correlation between the MPV and the homoeostasis model assessment of insulin resistance in women with PCOS. The sensitivity analysis showed that the effect estimate was robust and stable, and publication bias was not evidenced in the pooled analysis.

CONCLUSIONS

This meta-analysis revealed that women with PCOS have a significantly increased MPV than women without PCOS, which is probably associated with insulin resistance.INPLASY registration number: INPLASY2021100021.

Sex-Specific Causal Relations between Steroid Hormones and Obesity-A Mendelian Randomization Study

Steroid hormones act as important regulators of physiological processes including gene expression. They provide possible mechanistic explanations of observed sex-dimorphisms in obesity and coronary artery disease (CAD). Here, we aim to unravel causal relationships between steroid hormones, obesity, and CAD in a sex-specific manner. In genome-wide meta-analyses of four steroid hormone levels and one hormone ratio, we identified 17 genome-wide significant loci of which 11 were novel. Among loci, seven were female-specific, four male-specific, and one was sex-related (stronger effects in females). As one of the loci was the human leukocyte antigen (HLA) region, we analyzed HLA allele counts and found four HLA subtypes linked to 17-OH-progesterone (17-OHP), including HLA-B*14*02. Using Mendelian randomization approaches with four additional hormones as exposure, we detected causal effects of dehydroepiandrosterone sulfate (DHEA-S) and 17-OHP on body mass index (BMI) and waist-to-hip ratio (WHR). The DHEA-S effect was stronger in males. Additionally, we observed the causal effects of testosterone, estradiol, and their ratio on WHR. By mediation analysis, we found a direct sex-unspecific effect of 17-OHP on CAD while the other four hormone effects on CAD were mediated by BMI or WHR. In conclusion, we identified the sex-specific causal networks of steroid hormones, obesity-related traits, and CAD.

Waist circumference, hip circumference, arm span, and waist-to-hip ratio high risk of polycystic ovarian syndrome

BACKGROUND AND AIMS

Polycystic ovarian syndrome is a reproductive problem of women with high prevalence cases accompanied by obesity conditions. Obesity condition can be seen from the size of waist circumference, hip circumference, arm span, and waist-to-hip ratio. This study aims to find out the risk factors between waist circumference size, hip circumference, arm span, and waist-to-hip ratio with polycystic ovarian syndrome.

METHODS

This research is an analytical observation using a case-control approach conducted at Sekar Fertility Clinic and Poly Obgyn Dr Moewardi General Hospital Surakarta. Subjects were 150 consisting of 75 polycystic ovarian syndrome women and 75 normal fertile women. Sampling techniques used in this study are purposive sampling, researchers doing anthropometric measurements in the form of waist circumference, hip circumference, arm span, and waist-to-hip ratio simultaneously. The results were analyzed using Statistic Product and Service Solution 25.

RESULTS

The results of the study obtained waist circumference with polycystic ovarian syndrome (b = 3.002; CI 95% = 3.41-123.5; p = 0.001), hip circumference (b = -2.671; CI 95% = 0.01-0.37; p = 0.002), arm span (b = 5.318; CI 95% = 32.23-129.58; p < 0.001) and waist-to-hip ratio (b = 1.761; CI 95% = 1.02-33.01; p = 0.047).

CONCLUSION

Waist circumference size, hip circumference, arm span, and waist-to-hip ratio correlate to a high risk of polycystic ovarian syndrome. Arm span is more dominant as an indicator of high risk to polycystic ovarian syndrome compared to waist circumference, hip circumference, and waist-to-hip ratio.

Sex-specific genetic factors affect the risk of early-onset periodontitis in Europeans

AIMS

Various studies have reported that young European women are more likely to develop early-onset periodontitis compared to men. A potential explanation for the observed variations in sex and age of disease onset is the natural genetic variation within the autosomal genomes. We hypothesized that genotype-by-sex (G × S) interactions contribute to the increased prevalence and severity.

MATERIALS AND METHODS

Using the case-only design, we tested for differences in genetic effects between men and women in 896 North-West European early-onset cases, using imputed genotypes from the OmniExpress genotyping array. Population-representative 6823 controls were used to verify that the interacting variables G and S were uncorrelated in the general population.

RESULTS

In total, 20 loci indicated G × S associations (P < 0.0005), 3 of which were previously suggested as risk genes for periodontitis (ABLIM2, CDH13, and NELL1). We also found independent G × S interactions of the related gene paralogs MACROD1/FLRT1 (chr11) and MACROD2/FLRT3 (chr20). G × S-associated SNPs at CPEB4, CDH13, MACROD1, and MECOM were genome-wide-associated with heel bone mineral density (CPEB4, MECOM), waist-to-hip ratio (CPEB4, MACROD1), and blood pressure (CPEB4, CDH13).

CONCLUSIONS

Our results indicate that natural genetic variation affects the different heritability of periodontitis among sexes and suggest genes that contribute to inter-sex phenotypic variation in early-onset periodontitis.

Endometriosis and polycystic ovary syndrome are diametric disorders

Evolutionary and comparative approaches can yield novel insights into human adaptation and disease. Endometriosis and polycystic ovary syndrome (PCOS) each affect up to 10% of women and significantly reduce the health, fertility, and quality of life of those affected. PCOS and endometriosis have yet to be considered as related to one another, although both conditions involve alterations to prenatal testosterone levels and atypical functioning of the hypothalamic-pituitary-gonadal (HPG) axis. Here, we propose and evaluate the novel hypothesis that endometriosis and PCOS represent extreme and diametric (opposite) outcomes of variation in HPG axis development and activity, with endometriosis mediated in notable part by low prenatal and postnatal testosterone, while PCOS is mediated by high prenatal testosterone. This diametric disorder hypothesis predicts that, for characteristics shaped by the HPG axis, including hormonal profiles, reproductive physiology, life-history traits, and body morphology, women with PCOS and women with endometriosis will manifest opposite phenotypes. To evaluate these predictions, we review and synthesize existing evidence from developmental biology, endocrinology, physiology, life history, and epidemiology. The hypothesis of diametric phenotypes between endometriosis and PCOS is strongly supported across these diverse fields of research. Furthermore, the contrasts between endometriosis and PCOS in humans parallel differences among nonhuman animals in effects of low versus high prenatal testosterone on female reproductive traits. These findings suggest that PCOS and endometriosis represent maladaptive extremes of both female life-history variation and expression of sexually dimorphic female reproductive traits. The diametric disorder hypothesis for endometriosis and PCOS provides novel, unifying, proximate, and evolutionary explanations for endometriosis risk, synthesizes diverse lines of research concerning the two most common female reproductive disorders, and generates future avenues of research for improving the quality of life and health of women.

Birth size and morphological femininity in adult women

BACKGROUND

Women's morphological femininity is perceived to develop under the influence of sex hormones and to serve as a cue of estradiol level, fertility and health in mating context. However, as the studies on direct relationship between femininity and sex steroid levels have reported mixed results, it is still not well understood what factors contribute to inter-women variation in morphological femininity. Epidemiological studies show that indicators of adverse conditions during intrauterine growth and development in utero, such as low birthweight or relative thinness at birth, influence women's physiology ovarian functioning and may be associated with life-time exposure to estradiol in women. Thus, here we tested if birth parameters are also related with the level of morphological femininity in adult women.

RESULTS

One hundred sixty-five healthy women of mean age 28.47 years (SD = 2.39) participated in the study. Facial femininity was estimated based on facial width-to-height ratio (fWHR) and facial shape sexual dimorphism measured in the photos. Body femininity was estimated based on waist-to-hip ratio (WHR) and breast size. Birth weight and birth length were obtained from medical records and ponderal index at birth was calculated. No relationship between birth parameters and facial or body femininity in women of reproductive age was found, also when controlled for adult sex steroid levels and BMI.

CONCLUSIONS

The results suggest that, although previous research showed that birth parameters predict reproductive development and adult oestradiol level, they do not explain the variance in morphological femininity in women of reproductive age, trait that is thought to be a cue of a woman's estradiol level and fertility in mating context.

Motion and Gender-Typing Features Interact in the Perception of Human Bodies

The human body conveys socially relevant information, including a person's gender. Several studies have shown that both shape and motion inform gender judgments of bodies. However, while body shape seems to influence more the judgment of female bodies, body motion seems to play a major role in the judgments of male bodies. Yet, the interdependence of morphologic and dynamic cues in shaping gender judgment and attractiveness evaluation in body perception is still unclear. In two experiments, we investigated how variations of implied motion and shape interact in perceptual and affective judgments of female and male bodies. In Experiment 1, participants were asked to provide ratings for masculinity and femininity of virtual renderings of human bodies with variable gender-typing features and implied motion. We found evidence of a tendency to perceive bodies in static poses as more feminine and bodies in dynamic poses as more masculine. In Experiment 2, participants rated the same pictures for dynamism and pleasantness. We found that male bodies were judged more dynamic than female bodies with the same pose. Also, female bodies were liked more in static than in dynamic poses. A mediation analysis allowed us to further shed light on the relationship between gender-typing features and motion, suggesting that the less is the movement conveyed by a female body, the greater is an observer's sensitivity to its femininity, and this leads to a more positive evaluation of its pleasantness. Our findings hint to an association between stillness and femininity in body perception, which can stem from either the evolutionary meaning of sexual selection and/or the influence of cultural norms.

Women's attractiveness is linked to expected age at menopause

A great number of studies have shown that features linked to immediate fertility explain a large part of the variance in female attractiveness. This is consistent with an evolutionary perspective, as men are expected to prefer females at the age at which fertility peaks (at least for short-term relationships) in order to increase their reproductive success. However, for long-term relationships, a high residual reproductive value (the expected future reproductive output, linked to age at menopause) becomes relevant as well. In that case, young age and late menopause are expected to be preferred by men. However, the extent to which facial features provide cues to the likely age at menopause has never been investigated so far. Here, we show that expected age at menopause is linked to facial attractiveness of young women. As age at menopause is heritable, we used the mother's age at menopause as a proxy for her daughter's expected age of menopause. We found that men judged faces of women with a later expected age at menopause as more attractive than those of women with an earlier expected age at menopause. This result holds when age, cues of immediate fertility and facial ageing were controlled for. Additionally, we found that the expected age at menopause was not correlated with any of the other variables considered (including immediate fertility cues and facial ageing). Our results show the existence of a new correlate of women's facial attractiveness, expected age at menopause, which is independent of immediate fertility cues and facial ageing.

CAN BODY PROPORTIONS SERVE AS A PREDICTOR OF RISK-TAKING BEHAVIOURS IN WOMEN AND MEN?

The second to fourth digit ratio (2D:4D) is claimed to be a biomarker of prenatal sex steroids. This study compared 2D:4D and waist-hip ratio (WHR) in men and women with nose deformity caused by injuries suggesting risky behaviour with those of unaffected controls. This kind of facial trauma was accepted as an indicator of risk-taking behaviour. The study involved 100 patients (50 women aged 30.74±8.09 years and 50 men aged 30.98±10.86 years) who underwent rhinoplasty due to nose trauma in a hospital in Łódź, Poland, in 2015. For comparison purposes, a control sample of 70 women (aged 23.03±3.36 years) and 70 men (aged 22.87±3.46 years) was recruited. In both groups the following measurements were taken: body height, waist and hip circumferences, II and IV digit lengths and body weight. The results showed that women and men who had suffered nose injury had significantly higher values of WHR than controls. The 2D:4D in women with post-traumatic nose deformity was significantly different than the ratio in control women (p<0.0001) and presented the male pattern. It is concluded that in women risky behaviours seem to be associated with prenatal sex hormone influence, while differences in WHR suggest that this tendency is also related to postnatal hormonal factors. Risky behaviours in men should be linked to postnatal hormonal changes rather than to increased prenatal androgen exposure.