American Journal of Human Biology最新文献

{"title":"Silicone Wristbands for Measuring Human Exposure to Organic Chemicals: Uses and Benefits for Human Biological Research","authors":"Mecca E. Howe,&nbsp;Andrea S. Wiley,&nbsp;Yaw Edu Essandoh,&nbsp;Marta Venier","doi":"10.1002/ajhb.70187","DOIUrl":"10.1002/ajhb.70187","url":null,"abstract":"<p>Increasing human exposure to environmental contaminants is a growing concern and has become an important factor within human biological variation and health outcomes. Yet, traditional exposure assessment methods are often limited in their ability to capture the complexity and variation of chemical exposure, or are invasive, costly, and challenging to apply in field-based research. Here, we introduce silicone wristbands as an innovative and noninvasive tool for measuring personal passive chemical exposure and highlight opportunities for their use in human biological research. The wristbands sequester organic chemicals across multiple media (e.g., air, water, dust) and capture both inhalation and dermal absorption. We describe how they work, how to deploy them in the field, how to extract and analyze the chemical composition, and their methodological advantages for human biological research. A case study assessing exposure to flame retardants and the relationship to body size among girls in Costa Rica demonstrates the application for human biological research in a tropical and remote setting. We argue that wristbands provide a noninvasive method for assessing individual exposomes and understanding how environments are embodied and become a meaningful axis of human biological variation. Additionally, they motivate interdisciplinary, ethical, and community-engaged research in diverse and hard-to-reach populations, aligning with future directions of the field of human biology.</p>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12917870/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146229656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bitter Taste Perception in BaYaka Hunter-Gatherers","authors":"Sarai Keestra,&nbsp;Inez Derkx,&nbsp;Edmond Sylvestre Miabangana,&nbsp;Gaurav Sikka,&nbsp;Nikhil Chaudhary,&nbsp;Gul Deniz Salali","doi":"10.1002/ajhb.70218","DOIUrl":"10.1002/ajhb.70218","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objectives</h3>\u0000 \u0000 <p>This study examined variation in bitter taste perception among BaYaka hunter-gatherers from the Republic of Congo, comparing individuals from the same population that were born and grew up in a forest ecology to those from a logging town.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Bitter-tasting phenotype was assessed in 112 BaYaka individuals using a paper-strip taste-detection task with single-concentration strips of phenylthiocarbamide (PTC) and thiourea (thiocarbamide). Participants were grouped by the place where they were born and grew up: forest camps or the town. Logistic regression was used to test associations between location, sex, age, and bitter taste perception.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Town-born individuals were more likely to perceive both compounds as bitter than forest-born individuals (PTC: OR = 3.93, 95% CI: 1.75–9.17, <i>p</i> &lt; 0.01; thiourea: OR = 4.44, 95% CI: 1.97–10.42, <i>p</i> &lt; 0.01). No significant associations were found between bitter taste perception and sex or age.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Bitter-tasting phenotype differed among BaYaka individuals, with higher proportions of bitter tasters among those born and raised in town compared to those from forest camps. These results suggest that early-life ecological context may contribute towards variation in bitter taste perception, which we hypothesize might be due to differences in exposure to bitter wild plant compounds.</p>\u0000 </section>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12916250/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146221016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Absence of Sex Difference in Digit Ratio (2D:4D) Among the Elite Sportspersons: Further Evidence Among the Polish Swimmers","authors":"Marek Kociuba,&nbsp;Slawomir Kozieł,&nbsp;Zofia Ignasiak,&nbsp;Marek Rejman,&nbsp;Raja Chakraborty","doi":"10.1002/ajhb.70220","DOIUrl":"10.1002/ajhb.70220","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Variation in exposure to prenatal androgens was linked with athletic abilities and varied performance in different sports. The ratio between the second and fourth digit lengths (2D:4D) is a proxy indicator of prenatal testosterone exposure. A higher exposure leads to a lower 2D:4D and vice versa. Negative associations between digit ratio and several sports performances were consistent in earlier research.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Aim</h3>\u0000 \u0000 <p>The aim of the present study was to assess if 2D:4D was lower among the Polish competitive swimmers compared to non-sporting individuals and the heterogeneity in sex difference among different levels of swimmers and the non-sporting group.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Method</h3>\u0000 \u0000 <p>This cross-sectional study assessed 2D:4D among two groups of swimmers from the Polish national team and other higher level swimmers, and a control group (54 males and 34 females). Height, weight, and lengths of 2D and 4D were measured.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The control group showed a significant sex difference in the right hand 2D:4D; the females showed a higher ratio than the males (<i>t</i> = 2.17, <i>p</i> &lt; 0.05). However, no sex difference was evident in any of the swimmers' groups. The difference in 2D:4D among the three study groups was significant only for the left 2D:4D in males and only for the right 2D:4D in females. The female swimmers (both national and general) showed significantly lower right 2D:4D than the control females, whereas the male swimmers showed significantly lower left 2D:4D than the control males.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>The swimmers had lower 2D:4D than non-sporting individuals; the top level swimmers had the lowest 2D:4D. The female swimmers, particularly the elite group, showed “masculine” 2D:4D similar to their male counterparts. A plausible positive selection for a masculinised digit ratio (higher prenatal testosterone exposure) among the females in highly competitive professional sports was hypothesized.</p>\u0000 </section>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146214760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impaired Intestinal Function Among Indigenous Shuar Children of Amazonian Ecuador: Evidence From Lactulose:Mannitol Tests of Absorption and Permeability","authors":"Marcela Pfaff-Nash,&nbsp;Alejandro J. Ramirez,&nbsp;Elizabeth Y. Kim,&nbsp;Hannah N. Cantrell,&nbsp;Melissa A. Liebert,&nbsp;Felicia C. Madimenos,&nbsp;J. Josh Snodgrass,&nbsp;Lawrence S. Sugiyama,&nbsp;Samuel S. Urlacher","doi":"10.1002/ajhb.70219","DOIUrl":"10.1002/ajhb.70219","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objectives</h3>\u0000 \u0000 <p>Intestinal function is an important but often overlooked aspect of human biological variation, with the intestines serving as both a barrier against external pathogens/contaminants and the primary conduit of nutrient extraction from food. Impaired intestinal function among children is viewed as a key contributor to growth faltering globally. However, few studies have investigated children's intestinal function in rural settings or beyond infancy. To address this limitation, we conducted a pilot study to describe the intestinal function of school-age Indigenous Shuar children of Amazonian Ecuador and to assess the feasibility of implementing the widely utilized lactulose:mannitol (L:M) test of absorption and permeability with this group.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The urinary L:M test was performed with 23 rural-living Shuar children aged 4–12 years. Ultra-performance liquid chromatograph–high-resolution mass spectrometry was used to determine L:M ratios, lactulose recovery, and mannitol recovery. Age and sex patterns were investigated using linear regression models.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Children's mean L:M ratio was 0.33 ± 0.32, a ratio comparable to values reported for children in other low- and middle-income settings. 35%–91% of children were categorized as having impaired intestinal function using common cut-off values. Children's lactulose (0.14% ± 0.17%) and mannitol (2.60% ± 2.22%) recoveries did not differ by sex but increased with age (<i>p</i> &lt; 0.05) and indicated diminished intestinal absorptive capacity and increased permeability.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Intestinal function appears to be considerably impaired among school-age Shuar children living in a low-resource, rural setting. Children living in unsanitary, non-industrialized contexts may routinely experience intestinal permeability-related immune activation and malabsorption-related energy/nutrient loss. More research is needed to explore the breadth of global variation in children's intestinal function and to investigate its many evolutionary and public health implications.</p>\u0000 </section>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajhb.70219","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146214819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Variations in Physical Activity Across the Menstrual Cycle in Healthy Women: A Focus on Step Count and Activity Intensity","authors":"Sude Ozdemir,&nbsp;Andrzej Galbarczyk,&nbsp;Aleksandra Wachowicz,&nbsp;Kinga Słojewska,&nbsp;Magdalena Klimek,&nbsp;Grazyna Jasienska,&nbsp;Urszula M. Marcinkowska","doi":"10.1002/ajhb.70216","DOIUrl":"10.1002/ajhb.70216","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Introduction</h3>\u0000 \u0000 <p>Physical activity patterns across the menstrual cycle may reflect evolutionary adaptations that optimize reproductive success by aligning heightened activity with the fertile window and lowered activity in the luteal phase, when the female's body prepares for a possible pregnancy.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>This study examined variation in physical activity patterns across five arbitrary phases of the ovulatory menstrual cycle in 77 healthy women (age: 20–36 years). Based on ovulation tests and the date of the next menstruation, the menstrual cycle was divided into five physiologically distinct phases: menstrual, follicular, peri-ovulatory, luteal, and premenstrual. Daily physical activity was measured using a wristband accelerometer that tracked step count and activity duration at various intensities: sedentary, light, moderate, and intense, and the total 24-h duration of activity. Differences among phases were analyzed by repeated measures ANOVA, with corrections for multiple comparisons.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Step counts were higher in the follicular phase compared to the premenstrual phase (mean 10.2 vs. 8.9, respectively, <i>p</i> = 0.001), and total activity time was higher during the follicular phase than in the premenstrual phase (mean 99.3 vs. 90.8, <i>p</i> = 0.004). No other significant differences were observed.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Step count and total active time peaks in the follicular phase and declines during the premenstrual phase. Our study highlights the importance of accurately identifying phases of the menstrual cycle and analyzing various activity intensities for understanding physical activity behavior across the menstrual cycle.</p>\u0000 </section>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146214746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Taxonomic Legacies and Biological Diversity: Reflections on Terminology in “Racial and Ethnic Differences in Bone Mass in Pediatric Populations”","authors":"Barış Özener","doi":"10.1002/ajhb.70226","DOIUrl":"10.1002/ajhb.70226","url":null,"abstract":"","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146208312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing Sleep Architecture in Rural Eastern Cape Villagers of South Africa Using ŌURA Ring Data","authors":"Erica Kilius,&nbsp;Ming Fei Li,&nbsp;David R. Samson","doi":"10.1002/ajhb.70215","DOIUrl":"10.1002/ajhb.70215","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objectives</h3>\u0000 \u0000 <p>To examine the sleep architecture (proportion of Light, Rapid Eye Movement (REM), and Deep Sleep) of rural villagers using noninvasive, wearable ŌURA rings.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>From June to August 2023, we collected sleep data from 30 participants (16 men, 14 women, 370 nights) using ŌURA rings. Regression models were used to investigate the effect of gender, age, household size, livestock presence, and temperature on sleep patterns and sleep architecture.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Average Total Sleep Time (TST) in the community was 7.6 h (SD: 1.01). Average proportion (%) Light Sleep was 59.9%, % REM Sleep was 17.9%, and % Deep Sleep was 22.2%. Men who cared for livestock had significantly higher % Light Sleep and lower % REM sleep compared to men who did not have livestock. Presence of livestock did not significantly affect men or women's % Deep Sleep. Temperature was positively associated with % Light and negatively associated with % REM and % Deep Sleep.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>We found that men who were responsible for livestock tended to have more % Light Sleep and less % REM Sleep than men without livestock. Livestock presence did not affect women's % Light or REM sleep stages, and % Deep Sleep remained unchanged between groups. Temperature was associated with changes in all sleep stages. Our findings highlight the need for naturalistic studies investigating sleep architecture in non-industrialized settings.</p>\u0000 </section>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12908102/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146203777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prenatal Hormonal Markers in Individuals With Joint Hypermobility: The Role of the 2D:4D Digit Ratio","authors":"Rabia Zorlular,&nbsp;Ali Zorlular","doi":"10.1002/ajhb.70217","DOIUrl":"10.1002/ajhb.70217","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objectives</h3>\u0000 \u0000 <p>Exposure to sex hormones during the early stages of fetal development in the prenatal period is thought to affect the length ratio of the second and fourth fingers (2D:4D). The 2D:4D ratio remains a subject of significant interest, particularly in relation to diseases and conditions linked to gender differences. This study aims to compare the 2D:4D ratio of individuals with generalized joint hypermobility (GJH) to the ratio of individuals without GJH in a population of both male and female participants.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The study was conducted on 180 individuals (100 females), including 85 with GJH and 95 without GJH (controls). Joint hypermobility was assessed using the Beighton score. The 2D:4D ratio was calculated using a digital caliper. In addition, the height, weight, and body mass index of the participants were calculated.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The 2D:4D ratio was significantly higher in individuals with GJH compared to controls. In males, the 2D:4D ratio was higher in both the right and left hands in the GJH group compared to controls (<i>p</i> &lt; 0.05). In females, the 2D:4D ratio was also significantly higher in both hands in the GJH (<i>p</i> &lt; 0.05). The Beighton total score showed moderate positive correlations with right- and left-hand 2D:4D ratios (<i>r</i> = 0.49 and <i>r</i> = 0.38, respectively; <i>p</i> &lt; 0.001).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>The 2D:4D ratio can be used as a potential biomarker for GJH. It is thought that the concentration of sex hormones in the prenatal period (2D:4D ratio) may affect joint hypermobility (connective tissue).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Trial Registration</h3>\u0000 \u0000 <p>ClinicalTrials.gov: NCT07157930</p>\u0000 </section>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146203764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Inverse Association Between Betel Quid Use and Diabetes in Rural Bangladesh","authors":"Kristin K. Sznajder,&nbsp;Mary K. Shenk,&nbsp;Laura Perez,&nbsp;Nurul Alam,&nbsp;Rubhana Raqib,&nbsp;Anjan Kumar,&nbsp;Farjana Haque,&nbsp;Tami Blumenfield,&nbsp;Siobhán M. Cully,&nbsp;Katherine Wander","doi":"10.1002/ajhb.70203","DOIUrl":"10.1002/ajhb.70203","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objectives</h3>\u0000 \u0000 <p>Betel quid is used as a mild stimulant in many parts of South and East Asia and the Pacific. In observational studies, its use has been associated with elevated risk for diabetes, but studies in animal models suggest some component(s) of betel quid could reduce risk.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We assessed associations between betel quid use and diabetes (glycated hemoglobin, HbA_1c ≥ 6.5%) among a cross-sectional sample of 410 men and 717 non-pregnant women in Matlab, Bangladesh.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>In multivariable logistic regression, betel quid use was inversely associated with diabetes among men (aOR: 0.45; 95% CI: 0.26, 0.79) but not women (aOR: 0.88; 95% CI: 0.51, 1.52). There was a dose–response relationship between frequency of betel quid use and diabetes among men (aOR: 0.73; 95% CI: 0.59, 0.89), but not women (aOR: 0.96; 95% CI: 0.77, 1.18). Betel quid use was inversely associated with diabetes as an ordinal variable (no diabetes/prediabetes/diabetes) among men (aOR: 0.55; 95% CI: 0.36, 0.82) and women (aOR: 0.66; 95% CI: 0.47, 0.94). Structural equation modeling suggested that some of the inverse association was mediated by food source (market vs. household production).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>These models support the hypothesis that betel quid use could decrease, rather than increase, risk for diabetes in the Bangladeshi context, particularly among men (who have more frequent betel quid use than women). Heterogeneity in betel quid preparation across settings, multifactorial effects of betel quid use, and publication bias may contribute to differences between these findings and other observational studies.</p>\u0000 </section>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12903070/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146183319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Second to Fourth Digit Ratio (2D:4D) in Female Patients With Systemic Sclerosis: Evidence for Prenatal Androgen Exposure","authors":"Ramazan Fazil Akkoc,&nbsp;Ahmet Karatas,&nbsp;Burak Oz","doi":"10.1002/ajhb.70224","DOIUrl":"10.1002/ajhb.70224","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objectives</h3>\u0000 \u0000 <p>Systemic sclerosis (SSc) demonstrates marked female predominance, suggesting hormonal influences in disease pathogenesis. The second-to-fourth digit ratio (2D:4D), a biomarker of prenatal androgen exposure, has been associated with various autoimmune conditions. This study investigated whether 2D:4D ratios differ between female SSc patients and healthy controls.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>This case–control study enrolled 33 women with SSc (2013 ACR/EULAR criteria) and 30 age-matched healthy female controls. Second and fourth digit lengths were measured bilaterally using digital calipers, and 2D:4D ratios were calculated. Between-group differences were analyzed using Welch's t-test and Mann–Whitney U test.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>SSc patients demonstrated significantly lower 2D:4D ratios than controls bilaterally (right hand: 0.950 ± 0.029 vs. 1.022 ± 0.012, <i>p</i> &lt; 0.001; left hand: 0.951 ± 0.030 vs. 1.022 ± 0.012, <i>p</i> &lt; 0.001). Effect sizes were substantial (Cohen's d &gt; 2.8). The lower ratios resulted from longer fourth digits rather than shorter second digits, consistent with elevated prenatal androgen exposure.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Female SSc patients exhibit significantly lower 2D:4D ratios than healthy controls, suggesting higher prenatal testosterone exposure. These findings support the hypothesis that the prenatal hormonal environment may contribute to autoimmune disease susceptibility.</p>\u0000 </section>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 2","pages":""},"PeriodicalIF":1.7,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146196039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}