American Journal Of Human Biology[JOURNAL]
Sun
200 papers
Peri-Pubertal Height Shifts and Stable Photoperiod-Associated Geographic Patterning Before and After COVID-19 in Japanese Children.
Yokoya M
Am J Hum Biol · 2026 Jul · PMID 42400118 · Publisher ↗
OBJECTIVES: Geographic variation in child body size in Japan has previously been associated with effective day length, a light-related measure. We tested whether this prefecture-level geographic structure remained stable...
OBJECTIVES: Geographic variation in child body size in Japan has previously been associated with effective day length, a light-related measure. We tested whether this prefecture-level geographic structure remained stable across the COVID-19-related disruption. METHODS: We conducted a prefecture-level ecological analysis using repeated cross-sectional summaries from Japan's School Health Statistics. For each sex and single-year age from 5 to 17 years, we compared a pre-pandemic baseline (2017-2019 mean) with a post-disruption period (2024-2025 mean). Effective day length above 5000 lx (ED5000) was treated as a prefecture-fixed exposure. Mean height was modeled as a function of mean weight and ED5000, and slope stability was tested using pooled models with an ED5000-by-period interaction term. RESULTS: Across ages 5-17 years in both sexes, mean height was generally higher in the post-period than in the pre-period, and mean weight also showed an upward shift across most ages, with the largest increases around peri-pubertal ages. ED5000 remained negatively associated with height conditional on weight in both periods, and there was no evidence that the ED5000-associated slope changed between periods at any age in either sex. In contrast, post-period differences in height appeared mainly as age-dependent upward shifts concentrated around peri-pubertal ages, peaking at ages 10-11 years in girls and 12-13 years in boys. CONCLUSIONS: These findings suggest that COVID-era disruptions were followed by age-specific increases in body size around puberty, consistent with changes in maturation tempo. In contrast, the ED5000-height association remained stable. Thus, period-related growth shifts occurred within a persistent geographic structure.
The Evolution of Digit Ratio (2D:4D) From 1998 to 2025: A Bibliometric Analysis.
Karaismailoglu S, Karaismailoglu E
Am J Hum Biol · 2026 Jul · PMID 42399719 · Publisher ↗
INTRODUCTION: The second-to-fourth digit ratio (2D:4D) has been extensively investigated as a potential biomarker of prenatal sex hormone exposure across biological, psychological, and behavioral sciences. Despite rapid...
INTRODUCTION: The second-to-fourth digit ratio (2D:4D) has been extensively investigated as a potential biomarker of prenatal sex hormone exposure across biological, psychological, and behavioral sciences. Despite rapid growth in this field, a comprehensive evaluation of its developmental course and conceptual framework has been limited. METHODS: This study provides a comprehensive bibliometric analysis of global 2D:4D research from 1998 to 2025. Bibliometrix (R software) and VOSviewer were employed to evaluate publication trends, influential authors, countries, institutions, journals, collaboration networks, keyword co-occurrence, and co-citation structures. RESULTS: A total of 1692 articles and reviews were included. The results reveal a steady growth in publications, with an average annual increase of 17.51%, alongside expanding international collaboration. Early studies focused on sexual dimorphism, prenatal androgen exposure, and developmental biology, whereas recent research emphasizes psychological traits, stress-related outcomes, and health associations. Keyword and co-citation analyses identified multiple thematic clusters, highlighting the interdisciplinary evolving nature of the field. CONCLUSION: Overall, this study demonstrates the historical evolution, current landscape, and emerging trends of 2D:4D research. The findings underscore the need for greater methodological standardization, increased use of longitudinal and cross-cultural designs, and closer integration of biological and translational models to advance future research.
Correction to "Associations of Obesity, Movement Behaviors, and Socioeconomic Status With Fundamental Movement Skills in Children: Results From the REACT Project".
Am J Hum Biol · 2026 Jul · PMID 42387830 · Publisher ↗
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Response to Letter to the Editor: Association of Air Pollution With Adiposity Rates in Active Runners and Inactive People.
Kutac P, Cipryan L, Jirik V … +6 more , Bunc V, Krajcigr M, Dankova M, Elavsky S, Jandackova VK, Jandacka D
Am J Hum Biol · 2026 Jul · PMID 42381274 · Publisher ↗
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Weight Perception Varies by Local Peer Body Size Norms Among US Adolescents.
Cullin JM, Guilfoyle MM
Am J Hum Biol · 2026 Jul · PMID 42381265 · Full text
INTRODUCTION: Biological normalcy is a framework that examines relationships between statistical norms (e.g., variation, distribution) of biological traits and normative understandings of biology at the population level....
INTRODUCTION: Biological normalcy is a framework that examines relationships between statistical norms (e.g., variation, distribution) of biological traits and normative understandings of biology at the population level. We use this biocultural framework to test whether weight perception varies by local peer body size norms (BSNorm) in a nationally representative sample of US adolescents. METHODS: We used 2023 Youth Risk Behavior Survey data. Weight perception was assessed as "underweight," "about right," or "overweight." Local peer BSNorm was derived by calculating the proportion of peers with BMI ≥ 85th percentile within each locality. Linear regression tested the relationship between weight perception and BSNorm, controlling for sex, age, race/ethnicity, and BMI category (lower-range: < 5th percentile, mid-range: 5th-< 85th percentile, upper-mid-range: 85th-< 95th percentile, upper-range: ≥ 95th percentile). Subgroup analyses by sex and BMI category were performed. RESULTS: BSNorm was negatively associated with weight perception in the full sample (β = -0.60, p = 0.0005) and both sexes separately (females: β = -0.70, p = 0.0004; males: β = -0.50, p = 0.01). The association was primarily driven by adolescents in mid-range (β = -0.58, p < 0.0001) and mid-upper-range (β = -0.76, p = 0.037) BMI categories. By sex-specific weight categories, weight perception was negatively associated with BSNorm among females in the lower-range BMI category (β = -2.37, p = 0.015) as well as males (β = -0.44, p = 0.014) and females (β = -0.76, p < 0.0001) in the mid-range BMI category. There were no associations among adolescents in the upper-range BMI category. CONCLUSION: Overall, weight perception decreased as local peer BSNorm increased. This association held for both males and females and appears to be largely driven by adolescents in the mid- and upper-mid BMI ranges.
Increased Vulnerability to Dehydration Due to Heat Stress and Drought Across Reproductive States for Pastoralist Women in Northern Kenya.
Arshad S, Roba KT, Meriwether N … +11 more , Jacobson H, McGrosky A, Tavormina A, Bobbie N, Khosi G, Douglass M, Braun DR, Nzunza R, Ndiema E, Pontzer H, Rosinger AY
Am J Hum Biol · 2026 Jul · PMID 42381229 · Full text
OBJECTIVES: Extreme weather events, like drought and heat stress, make it harder to meet water needs in water-insecure settings, particularly vulnerable groups. This study examines how short-term (heat stress) and long-t...
OBJECTIVES: Extreme weather events, like drought and heat stress, make it harder to meet water needs in water-insecure settings, particularly vulnerable groups. This study examines how short-term (heat stress) and long-term (drought) water stress affects hydration status across reproductive states (pregnant, lactating, compared to non-pregnant/non-lactating) for Daasanach semi-nomadic pastoralist women in northern Kenya. METHODS: Drawing on unbalanced panel data, we analyzed 565 observations from 303 women (aged ≥ 16 years) in 2019-2024. Hydration was assessed via urine specific gravity (USG) with dehydration classified as USG > 1.020. Environmental heat stress was measured by ambient temperature and humidity, with sensitivity analyses using wet bulb globe temperature. RESULTS: Mixed effect logistic regression models indicated ambient temperature and humidity were significantly associated with greater odds of dehydration across all women. Holding heat stress constant, lactating but not pregnant women had higher odds of dehydration than non-pregnant/non-lactating women. A significant interaction between heat stress and reproductive status indicated that the probability of dehydration increased fastest for pregnant women as temperatures rose. Holding heat constant, dehydration probability increased during drought years compared to pre- and post-drought and was most pronounced among lactating women. CONCLUSIONS: Ambient heat stress increases dehydration risk among Daasanach women with effects compounded in pregnancy, though overall lactation was the period of greatest vulnerability to dehydration. Dehydration probability peaked during the drought illustrating how long-term periods of water scarcity also challenge water needs. Heat stress and droughts exacerbate maternal and infant health risks; thus, targeted hydration and cooling interventions are needed.
Correction to "Background, Rationale, and Methodological Overview of the REACT Project-Return-To-Action on Growth, Motor Development, and Health After the COVID-19 Pandemic in Primary School Children".
Am J Hum Biol · 2026 Jun · PMID 42358101 · Publisher ↗
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Connectedness to Nature, Ceremonial Participation, and Mental and Physical Health Among Rural and Urban Wixárika in Jalisco, Mexico.
Shattuck EC, McKinnon L, Herrera IR … +5 more , Sagastume RC, de la Cruz Q, Hernández PTG, Sunil TS, Samson DR
Am J Hum Biol · 2026 Jun · PMID 42358098 · Publisher ↗
OBJECTIVES: Research in Western samples has repeatedly demonstrated a link between exposure to nature and natural stimuli and improved health. We sought to test these relationships in a sample of Indigenous Wixárika, who...
OBJECTIVES: Research in Western samples has repeatedly demonstrated a link between exposure to nature and natural stimuli and improved health. We sought to test these relationships in a sample of Indigenous Wixárika, whose traditional worldview is nature-based and conceives of all life as interconnected, in contrast to Western norms. METHODS: A total of 127 Wixárika adults (68.5% female, mean age = 33.6 years) were recruited from Guadalajara and a rural community, as part of a larger study on Wixárika health. Participants completed surveys including a Connectedness to Nature (CNS) scale, self-reported mental and physical health, and frequency of participation in traditional ceremonies, a proxy of adherence to a traditional worldview. Firth logistic regression was used to model the effects of CNS and ceremony participation on both health measures. RESULTS: Rural participants had worse health, but greater CNS scores (p < 0.001 for both) and more frequent ceremony participation than urban participants. Higher CNS scores were associated with better mental health (OR = 4.94, 95% CI = 1.60-16.45, p = 0.005) in rural participants, with no effect on either health measure in urban participants. CONCLUSION: Results partially supported our prediction that greater CNS would be associated with better health. Notably, the only statistically significant relationship was in rural Wixáritari. The effects of CNS on health may diminish in generally healthy individuals (i.e., Guadalajara residents). Future work should probe this possibility further. This work calls attention to potential discrepancies in the health/nature nexus in non-Western contexts and the need to explore different cultural understandings of nature.
Relationships Between Estradiol Levels and Vaginal Lactobacillus Abundance Across the Menstrual Cycles in Women.
Koczur K, Blukacz M, Galbarczyk A … +7 more , Golińska E, Klimek M, Słojewska K, Strus M, Ścibor M, Tubek-Krokosz A, Jasienska G
Am J Hum Biol · 2026 Jun · PMID 42338146 · Publisher ↗
OBJECTIVES: Microbiota of the urogenital tract is crucial for women's reproductive and sexual health and is largely dominated by Lactobacillus strains. A reduction of these bacteria within the vaginal microbial community...
OBJECTIVES: Microbiota of the urogenital tract is crucial for women's reproductive and sexual health and is largely dominated by Lactobacillus strains. A reduction of these bacteria within the vaginal microbial community has been linked to gynecological disorders and infections. It is assumed that the urogenital microbiota composition is influenced by estrogens; however, in most studies estrogen levels were not reliably measured. This study aimed to investigate the relationship between salivary estradiol levels and the abundance of Lactobacillus species in the vaginal microbiota of healthy, reproductive-age women across three menstrual cycles. METHODS: The participants were 39 women between 20 and 35 years with regular menstrual cycles. Over three cycles, participants collected daily saliva samples for measuring estradiol levels and vaginal swabs at several time points. Three model approaches were tested: immediate, delayed, and cumulative effect models. Additional day-specific analyses and adjustments for body fat or BMI were conducted. RESULTS: No statistically significant associations were found between estradiol concentrations and Lactobacillus abundance in any of the models. CONCLUSIONS: This study did not support a link between salivary estradiol levels and Lactobacillus abundance in healthy, reproductive-aged women with regular menstrual cycles. These findings do not imply that estradiol is not an important factor regulating the vaginal Lactobacillus, but suggest that variation in estradiol levels does not correlate with the abundance of these bacteria. Studies that measure estrogen levels in multiple samples rather than assume their concentrations based on menopausal status or cycle phase are necessary to better understand the hormonal regulation of vaginal microbiota.
Dam-Induced Displacement and Disruption Are Associated With Salivary Cortisol Concentration and Patterns of Diurnal Variation.
Lee CC, Miller AA, McDade TW … +1 more , Owuor PM
Am J Hum Biol · 2026 Jun · PMID 42331732 · Full text
OBJECTIVES: This study assesses the stress-related impacts of the construction of the Thwake Multipurpose Dam in Makueni, Kenya by examining salivary cortisol concentrations and patterns of diurnal variation. METHODS: On...
OBJECTIVES: This study assesses the stress-related impacts of the construction of the Thwake Multipurpose Dam in Makueni, Kenya by examining salivary cortisol concentrations and patterns of diurnal variation. METHODS: One set of evening, waking, and 30-min post-waking saliva samples was collected across 221 women who were displaced by the dam or who lived upstream or downstream of the dam development site. Salivary cortisol concentration was analyzed using a commercially available assay kit. Multivariable linear regression was used to assess the relationship between displacement status and waking cortisol concentration, evening cortisol concentration, cortisol awakening response, and diurnal difference. RESULTS: Log-transformed evening cortisol concentration (displaced: β = 0.365, p = 0.018; downstream: β = 0.675, p = 0.007) and diurnal difference (displaced: β = 0.034, p = 0.049) were significantly associated with displacement status. CONCLUSIONS: Both displaced and downstream communities demonstrate stress-related hormonal differences associated with dam-induced disruption. Future policy and research addressing the health impacts of hydroelectric dam development should include downstream communities in addition to those directly displaced by development.
Ethnic Variability in Anthropometric Trajectories Across the Lifespan: Findings From a Nationwide Survey in Peru.
Saavedra-Garcia L, Hernández-Vásquez A, Guerra Valencia J
Am J Hum Biol · 2026 Jun · PMID 42316584 · Publisher ↗
INTRODUCTION: Anthropometric indicators are widely used for nutritional assessment and cardiometabolic risk, but their age-related patterns may differ by ethnicity, potentially limiting the applicability of global thresh...
INTRODUCTION: Anthropometric indicators are widely used for nutritional assessment and cardiometabolic risk, but their age-related patterns may differ by ethnicity, potentially limiting the applicability of global thresholds. To examine age-related trajectories of BMI and seven nonconventional anthropometric indicators by ethnicity in Peruvian adults. METHODS: A cross-sectional analysis was conducted using nationally representative data from the 2021-2023 Demographic and Health Survey (ENDES). Adults aged 20-80 years with complete anthropometric data and self-reported ethnicity (Quechua-Aymara, Afro-Peruvian, Other) were included (n = 77 592). Eight indicators were analyzed: BMI, tri-ponderal mass index (TMI), a body shape index (ABSI), body roundness index (BRI), relative fat mass (RFM), weight-adjusted waist index (WWI), waist-to-BMI ratio, and conicity index. Generalized Additive Models for Location, Scale, and Shape (GAMLSS) were used to estimate smoothed percentile curves (3rd, 50th, and 97th) across age and ethnicity. RESULTS: Percentile curves revealed distinct age-related trajectories by ethnicity. Quechua-Aymara men had lower values across percentiles for BMI, TMI, RFM, and BRI, but not consistently for ABSI, WWI, and conicity index. In women, patterns were more heterogeneous, with earlier and lower peaks for Quechua-Aymara at lower percentiles, while Afro-Peruvian and Other women showed gradual increases. For ABSI, WWI, and conicity index, men showed a linear increase with age, while women showed rising trajectories only at the upper percentiles. The waist-to-BMI ratio displayed a J-shaped pattern in both sexes, with more ethnic variability at lower percentiles in women. CONCLUSION: Ethnic disparities in anthropometric trajectories highlight the limitations of global thresholds and support the need for population-specific reference standards.
Longitudinal Changes and Correlates of 24-Hour Movement Behaviors in Brazilian Older Adults.
Oliveira CBT, Lopes DSD, Câmara M … +6 more , Ribeiro LFC, de Oliveira FDA, Barreira TV, Waters DL, Cabral LLP, Costa EC
Am J Hum Biol · 2026 Jun · PMID 42311027 · Publisher ↗
BACKGROUND: The 24 h movement behavior cycle (24hMB) has been increasingly studied in older adults. However, longitudinal changes in the 24hMB cycle and its potential correlates are poorly understood, particularly in low...
BACKGROUND: The 24 h movement behavior cycle (24hMB) has been increasingly studied in older adults. However, longitudinal changes in the 24hMB cycle and its potential correlates are poorly understood, particularly in low to middle-income countries. This study investigated longitudinal changes of 24hMB and their potential correlates in Brazilian older adults. METHODS: The 24hMB was assessed in community-dwelling older adults aged 60-80 years using hip accelerometry (ActiGraph GT3X+) over 1 week at baseline and follow-up. Outcomes included nocturnal sleep time (NST), sedentary time, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA). Longitudinal changes and associations between changes in 24hMB and potential baseline correlates (age, sex, body mass index, post-secondary education, and multimorbidity) were examined using generalized estimating equations. RESULTS: A total of 86 participants were analyzed (67.4 ± 5.3 years; mean follow-up: 4.0 ± 0.4 years). No changes were observed in NST (p > 0.05). However, sedentary time increased (36 ± 86 min/day), while LPA (16 ± 63 min/day) and MVPA (9 ± 20 min/day) decreased over 4 years (p < 0.05). Older age was associated with reduced NST and increased sedentary time over time. Female sex was associated with reduced NST and increased sedentary time and MVPA. No associations were found between multimorbidity, BMI, and education level and changes in 24hMB (p > 0.05). CONCLUSION: After a 4-year period, older adults experienced an overall increase in sedentary time and a decrease in physical activity, while NST remained stable. The correlates associated with changes in NST, sedentary time, and physical activity may help inform targeted interventions to improve 24hMB.
Maternal Education, Reproductive Behavior, and Fertility Outcomes in Pakistan: Evidence From the Pakistan Demographic and Health Survey 2017-2018.
Qiu X, Ibupoto MH
Am J Hum Biol · 2026 Jun · PMID 42303467 · Publisher ↗
INTRODUCTION: This study examines the association between maternal education, human reproductive behavior, and fertility adaptation in Pakistan, using nationally representative data from the Pakistan Demographic and Heal...
INTRODUCTION: This study examines the association between maternal education, human reproductive behavior, and fertility adaptation in Pakistan, using nationally representative data from the Pakistan Demographic and Health Survey (PDHS) 2017-2018. It aims to assess how different levels of maternal education influence fertility outcomes, particularly children ever born, while controlling for key demographic, socioeconomic, and reproductive factors. METHODS: The study utilizes cross-sectional data from ever-married women aged 15-49 years (N = 14 500). Fertility behavior is measured using children ever born (CEB) as a count variable. Maternal education is categorized into four levels: no education, primary, secondary, and higher education. Descriptive and bivariate analyses are conducted to examine fertility differentials, followed by multivariate regression models, including Poisson and Negative Binomial regression, to estimate adjusted incidence rate ratios (IRRs). Logistic regression is additionally employed to assess high fertility (CEB ≥ 4). All analyses account for the complex survey design using sampling weights. RESULTS: The findings reveal a strong and statistically significant inverse relationship between maternal education and fertility behavior. Women with higher education have substantially lower fertility compared to those with no education. Specifically, higher education is associated with nearly a 49% reduction in children ever born (IRR = 0.51, p < 0.001), while secondary education reduces fertility by approximately 28%. The results indicate a clear dose-response relationship, with stronger effects observed at higher levels of education. Additionally, age at marriage, urban residence, wealth status, and modern contraceptive use are significantly associated with reduced fertility. These findings remain robust across multiple model specifications. CONCLUSIONS: Maternal education emerges as a critical determinant of fertility behavior in Pakistan, operating through multiple pathways, including delayed marriage, increased contraceptive use, and enhanced reproductive autonomy. The findings highlight the importance of expanding access to secondary and higher education for women as a key strategy for lower fertility intensity and improved reproductive outcomes. The findings contribute to understanding how maternal education shapes reproductive behavior and fertility outcomes within the broader sociocultural and ecological context of a high-fertility population.
Patterns of Chronic Stress in Diurnal Salivary Cortisol Already Predict Epigenetic Age Acceleration in Young Adults in the Cebu Longitudinal Health and Nutrition Survey.
Post SR, Ryan CP, Lee NR … +8 more , Carba DB, Bechayda SA, MacIsaac JL, Dever K, Lin DTS, Atashzay P, Kobor MS, Kuzawa CW
Am J Hum Biol · 2026 Jun · PMID 42303423 · Publisher ↗
Epigenetic clocks estimate biological aging through age-related DNA methylation patterns and are known to accelerate in response to adversity. While cortisol links stress experiences to cellular aging, the relationship b...
Epigenetic clocks estimate biological aging through age-related DNA methylation patterns and are known to accelerate in response to adversity. While cortisol links stress experiences to cellular aging, the relationship between circadian cortisol and epigenetic age acceleration (EAA) remains unclear. To address this gap, we use data from the Cebu Longitudinal Health and Nutrition Survey (CLHNS) to explore linear relationships between diurnal salivary cortisol and a suite of epigenetic clocks. In 2005, when cohort members were 20-22 years old, saliva samples were obtained to measure bedtime cortisol, waking cortisol, and the cortisol awakening response (CAR). Additionally, DNA methylation was measured in whole blood to calculate EAA with multiple epigenetic clocks: principal components-based first-generation clocks trained on chronological age (PC Horvath, PC Hannum), second-generation clocks trained on chronological age and health markers (PC PhenoAge, PC GrimAge, PC DNAmTL), and DunedinPACE, a clock trained on the pace of change in aging-related biomarkers. Elevated bedtime cortisol and a blunted CAR-markers of chronic stress-significantly predicted EAA across second-generation clocks and DunedinPACE, even when stratifying by sex and adjusting for immune cell fractions. After multiple hypothesis test correction, elevated bedtime cortisol remained a significant predictor of EAA, although effect sizes were small. Associations were attenuated by adjusting for immune cell fractions, suggesting that links between chronic stress and EAA may operate through stress-related changes to the composition of the immune system. These findings indicate that, in the CLHNS cohort, cortisol-based measures of chronic stress already predict acceleration of multiple epigenetic clocks in young adulthood.
Seasonal and Sex Differences in Children's Body Composition Under In-Term PA Versus Vacation Non-PA Periods: A 40-Month Natural-Experiment Observation.
Pan X, Gao Y, Jiang L … +6 more , Li M, Zhao D, Chen J, Wang C, Mao X, Zhang Y
Am J Hum Biol · 2026 Jun · PMID 42297628 · Publisher ↗
OBJECTIVES: To characterize seasonal body composition changes in Chinese schoolchildren, contrasting in-term periods (school-based physical activity [PA] active) with vacations (PA suspended), and to test whether BMI, bo...
OBJECTIVES: To characterize seasonal body composition changes in Chinese schoolchildren, contrasting in-term periods (school-based physical activity [PA] active) with vacations (PA suspended), and to test whether BMI, body fat percentage (BFP), and weight respond uniformly across sex and season. METHODS: Natural-experiment observational analysis of a school-monitored cohort enriched for elevated baseline adiposity (92.0% overweight or obese, Chinese WS/T 586); the research team was not involved in the school-delivered PA program's design or delivery. We measured 342 children (212 boys, 130 girls; mean age 10.2 y) from two Beijing primary schools at up to 10 time points over 40 months (September 2021-December 2024) by bioelectrical impedance (1178 observations). Three 12-week windows were defined (in-term, winter vacation, summer vacation); paired changes were tested by Wilcoxon tests and era-stratified trajectories by linear mixed-effects models, with GAMM smooths for visualization only. RESULTS: Across 268 in-term paired observations, BMI declined 0.42 ± 1.10 kg/m (Cohen d = -0.38), an active reversal while the PA program ran. Both vacations produced gains (winter ΔBMI +0.78, summer +0.95 kg/m). Effect sizes diverged across indicators: summer d(weight) = +1.48 > d(BMI) = +0.71 > d(BFP) = +0.57. Summer BFP rose 2.6-fold more in girls than boys (+2.32 vs. +0.91 pp., p = 0.032). CONCLUSIONS: Under this in-term/vacation alternation, children's body composition showed marked seasonal directionality, with active reversal in term and gains during vacations. The indicator-specific effect-size divergence and the 2.6-fold female-skewed summer BFP response are consistent with sex-stratified, tissue-specific dynamics aligning with peri-pubertal sexual dimorphism.
Relationships Among Maternal Epstein-Barr Virus Antibodies, COVID-19, and Stress in Mothers up to 1-Year Postpartum.
Anastasi E, Glass DJ, Pan TD … +16 more , Brindle E, Caffe B, Smith CB, Kunkle AE, Kent MA, Navarrete AD, Pace CDW, Eisenberg DTA, Pace RM, Williams JE, Ley SH, Barbosa-Leiker C, McGuire MA, McGuire MK, Meehan CL, Martin MA
Am J Hum Biol · 2026 Jun · PMID 42286962 · Full text
OBJECTIVES: Both psychosocial stress and current infection can increase the likelihood of reactivation of latent Epstein-Barr virus (EBV). Pregnancy and infection with SARS-CoV-2 can be stressful and modulate immune func...
OBJECTIVES: Both psychosocial stress and current infection can increase the likelihood of reactivation of latent Epstein-Barr virus (EBV). Pregnancy and infection with SARS-CoV-2 can be stressful and modulate immune function. However, it is unknown how SARS-CoV-2 infection and stress further interact among postpartum women to affect EBV antigen and antibody expression. METHODS: We examined associations among COVID-19 diagnosis, self-reported stress, and EBV immunoglobulin G (IgG) in previously collected data from 45 breastfeeding US women (1-18 months postpartum) during the height of the COVID-19 pandemic. Between June 2020 and March 2021, stress survey data and capillary dried blood HemaSpot samples were collected from 25 SARS-CoV-2 infected and 20 non-infected participants at multiple time points over the course of 60 days. Samples (N = 104) were later assayed for EBV IgG. Statistical methods were pre-registered, and relationships among SARS-CoV-2 infection, stress, and EBV IgG were analyzed via mixed-effects regression models, adjusting for time postpartum and time elapsed since enrollment. RESULTS: There was a statistically significant association between self-reported stress and EBV IgG levels, with higher average stress associated with higher average EBV IgG. EBV IgG relative concentration did not vary independently with COVID-19 positivity status or the number of COVID-19 symptoms. CONCLUSIONS: Results suggest that EBV IgG relative concentrations were elevated across sample participants by stress, but not by the relatively mild cases of COVID-19 the mothers experienced.
The Relationship Between 2D:4D Digit Ratio and Polycystic Ovary Syndrome: A Systematic Review.
Güner Emül T, Kaplan Serin E
Am J Hum Biol · 2026 Jun · PMID 42249717 · Full text
OBJECTIVES: This systematic review aimed to synthesize current evidence on the association between 2D:4D ratios and PCOS. METHODS: A comprehensive literature search was performed in PubMed, Web of Science, Scopus, and Co...
OBJECTIVES: This systematic review aimed to synthesize current evidence on the association between 2D:4D ratios and PCOS. METHODS: A comprehensive literature search was performed in PubMed, Web of Science, Scopus, and Cochrane Library databases between May and June 2025. Two independent researchers conducted study screening, data extraction, and quality appraisal using the Joanna Briggs Institute critical appraisal tools. RESULTS: Eleven studies published between 2005 and 2024, with sample sizes ranging from 40 to 400 participants, were included. Study designs were cross-sectional or case-control, and measurement techniques involved calipers, photocopies, or digital analysis. Nine studies reported significantly lower 2D:4D ratios in women with PCOS compared to healthy controls, supporting the hypothesis of increased prenatal androgen exposure. However, two studies found no significant association, likely due to methodological heterogeneity, small sample sizes, or diagnostic inconsistencies. CONCLUSION: The majority of included studies suggest that lower 2D:4D ratios may reflect elevated prenatal androgen exposure in women with PCOS, indicating its potential as a non-invasive biomarker. Nonetheless, variability in diagnostic criteria, measurement methods, and study populations limits generalizability. Further large-scale, standardized research is required to determine clinical utility and to establish population-specific reference values.
Tracing the Origins of Human Disease: A Phylogenomic Toolkit for Identifying Evolutionary Trade-Offs.
Strizzi CT, Natterson-Horowitz B
Am J Hum Biol · 2026 Jun · PMID 42244396 · Publisher ↗
Evolutionary trade-offs, in which adaptations that confer fitness advantages simultaneously create disease vulnerabilities, are widely recognized across human biology. Such trade-offs have traditionally been identified t...
Evolutionary trade-offs, in which adaptations that confer fitness advantages simultaneously create disease vulnerabilities, are widely recognized across human biology. Such trade-offs have traditionally been identified through forward reasoning: investigators with deep knowledge of a particular disease recognize that an associated gene or pathway also serves an adaptive function and propose a trade-off hypothesis on this basis. While productive, this approach is opportunistic and disease-specific. No systematic method exists for working in reverse: starting from a disease and tracing its genetic underpinnings to the adaptive biology under historical selection. Here we present a six-step integrative toolkit for identifying disease-specific evolutionary trade-offs. The toolkit proceeds from (1) curating disease-associated gene sets using publicly available genomic platforms, through (2) profiling expression and pathway involvement, (3) identifying statistically enriched biological processes, (4) mapping genes to their evolutionary origins via phylostratigraphy, (5) linking gene emergence to macroevolutionary innovations, to (6) formulating testable trade-off hypotheses with experimental readouts. We discuss the toolkit's strengths and limitations, including conditions under which it is most and least informative, its relationship to developmental and life-history trade-offs, and the caveats inherent in phylostratigraphic dating and database composition. A cross-domain catalog of established trade-offs illustrates the breadth of trade-off biology across human disease. To demonstrate the toolkit in practice, we apply it to atherosclerosis, showing that its disease-susceptibility gene set is enriched in a lipid-immune integration program whose phylostratigraphic distribution converges temporally with the independently dated origin of the vertebrate endothelium (~540-510 MYA). By connecting present-day disease susceptibilities to historical adaptive benefits through an accessible, reproducible pipeline, this toolkit offers a practical method for human biologists investigating the evolutionary origins of disease vulnerability.
Mental Health and Physiological Biomarkers Under Legal Uncertainty: Evidence From Asylum Centers in Serbia.
Jankovic-Rankovic J, Oka RC, Meyer JS … +1 more , Gettler LT
Am J Hum Biol · 2026 Jun · PMID 42244380 · Full text
OBJECTIVES: Asylum, grounded in international law, provides protection to individuals fleeing persecution, war, or violence by ensuring legal residency, fundamental rights, and pathways to integration, while reflecting t...
OBJECTIVES: Asylum, grounded in international law, provides protection to individuals fleeing persecution, war, or violence by ensuring legal residency, fundamental rights, and pathways to integration, while reflecting the global commitment to human dignity, justice, and solidarity. Using data from asylum seekers and non-asylum seekers within a shared context of displacement in three asylum centers in Serbia, we examined the associations between the asylum process, mental health, and physiological markers. METHODS: In this mixed-methods study of asylum seekers (aged 18-55 years, n = 242), we collected key socio-demographic information, migration- and asylum-related variables, and self-reported measures of mental well-being, along with physiological markers relevant to exposure to chronic psychosocial stress (fingernail cortisol and blood pressure measures). RESULTS: We found that asylum seekers reported better mental and physical health and lower PTSD-related symptoms (assessed with the RHS-15 and IES-R) compared to non-asylum seekers, while there was no significant difference between the groups in recent perceived stress (measured by PSS scores). We also found that asylum seekers had higher nail cortisol levels as well as higher systolic and diastolic blood pressure compared to their non-asylum seeker peers. CONCLUSION: Although our study is cross-sectional, it emphasizes that the asylum process is more than just a legal or bureaucratic procedure. It is a significant social determinant of health. The physiological stress observed in asylum seekers highlights an urgent need for systemic reforms and targeted health interventions to reduce both the psychological and physiological effects of forced displacement, extended legal uncertainty, and structural constraints.
Measuring Dynamic Inflammation Regulation in Low-Resource Settings: Results From a Sample of Adults in the Dominican Republic.
Krause KC, Jiménez SPM, Duperval F … +3 more , St Juste F, Miller AA, McDade TW
Am J Hum Biol · 2026 Jun · PMID 42226028 · Publisher ↗
INTRODUCTION: Inflammatory signaling mediates several homeostatic mechanisms that shape health, and quantifying inflammation regulation patterns using ex vivo cell culture systems-response to activation and sensitivity t...
INTRODUCTION: Inflammatory signaling mediates several homeostatic mechanisms that shape health, and quantifying inflammation regulation patterns using ex vivo cell culture systems-response to activation and sensitivity to inhibition-improves upon baseline measures of chronic inflammation. The purpose of this report is to demonstrate the feasibility of implementing an ex vivo cell culture system in a low-resource setting in the Dominican Republic. METHODS: This study implements an ex vivo cell culture system to measure stimulated inflammation and glucocorticoid (GC) sensitivity using finger stick capillary blood collected from 202 adults in the Dominican Republic (age: 18-61 years). RESULTS: Median cytokine responses (pg/mL) to incubation with lipopolysaccharide (LPS) were robust for IL6 (58.0), IL1β (21.3), and TNFα (23.1). Median cytokine responses to incubation with LPS and GC-capturing sensitivity to inhibition-were attenuated for IL6 (20.2), IL1β (8.4), and TNFα (7.0). CONCLUSION: Minimally invasive cell culture protocols offer novel research opportunities for measuring inflammation regulation and health in low-resource settings across diverse eco-social milieus.
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