American Journal Of Human Biology[JOURNAL]
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200 papers
Black South Africans Who Migrate Away From Their Rural Homes and Their Chances of Having Abdominal Obesity.
Myroniuk TW, Ginsburg C, White MJ … +3 more , McGarvey ST, Gómez-Olivé FX, Pheiffer CF
Am J Hum Biol · 2025 Jul · PMID 40671360 · Full text
INTRODUCTION: South Africa is experiencing a heterogeneous and rapid nutrition transition. Rural-origin Black South Africans frequently migrate to access employment opportunities in urbanized areas, which could place ind...
INTRODUCTION: South Africa is experiencing a heterogeneous and rapid nutrition transition. Rural-origin Black South Africans frequently migrate to access employment opportunities in urbanized areas, which could place individuals at risk for obesity due to accompanying dietary and lifestyle changes. METHODS: We utilize longitudinal data-four waves from 2018 to 2022-with detailed internal migration and health information, and negligible participant attrition from the Migrant Health Follow-Up Study, with origin households located in rural northeast South Africa-Agincourt. We employ lagged-dependent variable regressions to test whether (1) the number of waves one is away from their rural home (0-4) and (2) residing in a densely populated urban area (Gauteng province) relative to other locations or remaining in Agincourt over the four waves, are differentially associated with having abdominal obesity, indicated by the preferable measure of the waist circumference-to-height ratio (WHtR), at Wave 4-after adjusting for Wave 1 obesity and other variables, including fast food consumption. WHtR is operationalized as a binary indicator of abdominal obesity as well as a standardized, continuous one. Our analytic sample includes women (N = 895) and men (N = 1010). RESULTS: Our results show that internal migrant women and men face higher chances of having abdominal obesity at Wave 4 than their nonmigrant counterparts. For men, both the number of waves as a migrant and ever migrating to Gauteng are consistently, strongly associated with the chances of having abdominal obesity-considerably more so than women. CONCLUSION: As obesity rates rise throughout urbanizing low- and middle-income countries, this research emphasizes the importance of understanding the correlates of the risks of obesity that internal migrants will face.
Revealing Developmental Transitions in Perinatal and Infant Individuals Through Microanatomical Analysis.
Moreno MM, Doe DM, González NC … +3 more , Martínez DG, Martín AG, Cambra-Moo O
Am J Hum Biol · 2025 Jul · PMID 40658068 · Full text
OBJECTIVES: Identifying signs of birth in perinatal human remains of past populations is challenging due to the lack of direct markers of this event on bones. This research aims to identify distinct events in humeral cro...
OBJECTIVES: Identifying signs of birth in perinatal human remains of past populations is challenging due to the lack of direct markers of this event on bones. This research aims to identify distinct events in humeral cross-sections microanatomy related to perinatal development and to integrate the findings into infant mortality trends. MATERIAL AND METHODS: The sample consists of infants (N = 106) ranging from prenatal to 1.5 years, with microanatomical analysis of nine selected individuals. Age-at-death estimation and microanatomical characterization were conducted, combined with quantitative analysis of microanatomical features. RESULTS: Biological age-at-death presents high variability and overlap across prenatal to postnatal stages. Microanatomical analysis reveals a higher percentage of mineralized areas (60%-80%) within the total cross-sectional area in the youngest individuals up to the first neonatal month. CONCLUSIONS: Based on the integration of microanatomical analysis in an extensive infant sample, this study highlights the evidence of developmental transitions from prenatal to neonatal stages. These findings suggest that, unlike biological age estimation methods, the full-term period can be identified microanatomically in bone. This provides a valuable approach for analyzing fragmented skeletal remains, secondary deposits, and other funerary or osteological contexts, opening new pathways to understand gestational development and postnatal survival in past populations.
Strategy or Necessity? The Determinants of Marriage Between Relatives in the Barcelona Area, Sixteenth-Nineteenth Centuries.
Ruíz García J, Pujadas-Mora JM, López-Villanueva C
Am J Hum Biol · 2025 Jul · PMID 40657890 · Full text
Consanguineous marriages illustrate the complex interplay between environmental and social factors in family formation. However, there remains a significant lack of quantitative studies exploring this phenomenon in prein...
Consanguineous marriages illustrate the complex interplay between environmental and social factors in family formation. However, there remains a significant lack of quantitative studies exploring this phenomenon in preindustrial contexts. In this sense, this study examines the intensity and the structural and strategic determinants of consanguineous marriages in the Barcelona area between the 16th and 19th centuries, utilizing the unique Barcelona Historical Marriage Database. Methodologically, the isonymy method (spouses with matching surnames) was used to estimate the level of consanguinity (structural and strategic), while binary logistic regression models were constructed to analyze the social and territorial patterns of these marriages. The main findings indicate that consanguinity in the Barcelona area remained limited until the 19th century, mirroring European trends, though to a lesser degree. The nobility strategically adopted consanguineous marriages from the early modern period, while the peasantry largely avoided them, relying instead on primogeniture to preserve family assets. By the 19th century, the emerging bourgeoisie increasingly turned to consanguinity as a means of strengthening social networks and establishing class identity rather than merely preserving material heritage. Furthermore, the marriage market size and contextual factors-such as decreasing adult mortality and reduced dispensation costs-significantly influenced the rise of consanguineous unions.
Advances in Understanding Adaptive Hemoglobin Concentration at High Altitude.
Childebayeva A, Zhu K, Bigham AW
Am J Hum Biol · 2025 Jul · PMID 40650341 · Full text
Abstract loading — click title to view on PubMed.
Salivary/Serum Progesterone Ratio Differs Between Menstrual Cycle Phases but Not Between Populations: Implications for Health, Reproductive, and Behavioral Research.
Vitzthum VJ, Bellido D, Echalar L … +2 more , Caceres E, Thornburg J
Am J Hum Biol · 2025 Jul · PMID 40631468 · Full text
OBJECTIVES: Many investigations of human health, behaviors, and adaptations require an indicator of ovarian cycle functioning as a causal, outcome, or confounding variable in the study design and analyses. Because the dy...
OBJECTIVES: Many investigations of human health, behaviors, and adaptations require an indicator of ovarian cycle functioning as a causal, outcome, or confounding variable in the study design and analyses. Because the dynamic fluctuations in cycle hormones can rarely be adequately characterized by a single measurement, but repeated blood sampling can be onerous, salivary free progesterone (P) concentration is widely used in both clinical and research contexts as an alternative to total progesterone concentration in venous blood samples (P). However, some doubts have been raised about the use of P because of suggestions that Bolivian and other populations and/or individuals might differ markedly in the ratio of P to P (the apparent uptake fraction, UF). If there are such differences, several decades of comparative population research based on P would require reconsideration, and a seemingly useful tool in both clinical and research contexts would be lost or require additional extensive pre-use evaluations. Such impacts would fall disproportionally on clinical monitoring and research studies of menstruating persons, a segment of the population that has long been underrepresented in research and clinical trials, especially in low resource conditions. Therefore, we tested three hypotheses: (H1) UF differs by ovarian cycle phase; (H2) UF differs in Bolivian women from that of non-Bolivian women; and (H3) within a population, UF is consistently higher or lower in some individuals than in most others. METHODS: We collected mid-follicular and mid-luteal near-concurrent samples of venous blood and saliva from 36 healthy premenopausal Bolivian women. P and P were measured using commercial enzyme immunoassays. To test the study hypotheses, we used graphical and statistical methods to analyze these new data and to analyze data from several previously published studies. RESULTS: In our study sample of Bolivian women, P and P concentrations (n = 66 pairs) were significantly and highly correlated (Spearman's rho = 0.858; mixed model: intercept = 77.4 pmol/L [(p < 0.001), β = 0.0191 (p < 0.001)]). An individual's follicular-phase UF and luteal-phase UF were not significantly correlated (rho = -0.19, p = 0.462). Median UF equaled 8.1% for follicular and 2.3% for luteal phase pairs and were comparable to published values for other populations. CONCLUSIONS: Hypothesis 1 was supported. Consistent with prior reports for other populations, in these Bolivian women UF was higher and more variable in the follicular than in the luteal phase. The source(s) of phase-associated variation in UF deserves additional study, particularly the dynamic relationship to different conformers of corticosteroid-binding globulin (CBG). Hypothesis 2 was not supported. Paired P and P were highly correlated, and UF in these Bolivians was comparable to published values for other populations. Hypothesis 3 was not supported. There was no evidence that some individuals have consistently higher (or lower) UF than most other persons. In sum, these findings do not support the suggestions that the physiology underlying the relationship between P and P differs substantially and inexplicitly between populations and individuals. These results also reinforce the critical roles of fastidious attention to sample collection and handling, judicious assessment of assay results, and appropriate statistical methods when using ovarian steroid data in any project. We suggest some guidelines for meeting these requirements. Used with due consideration for its advantages and limitations, P reliably tracks P during the menstrual cycle and is a useful option in the biomarker toolkit. Just as it is costly to continue our work with tools not up to the task, so is it costly to discard useful tools without good reason. The development (and improvement through replication) of a robust toolkit for assessing changes in and the impacts of menstrual cycle hormones is foundational to reducing gender-based health disparities. (The linked file listed below under "Supporting Information" presents these findings in Spanish).
Association Between Relative Leg Length and Insulin Resistance in Rural, Urban and Rural-Urban Migrant Populations of Peru.
Mucching-Toscano S, Moscoso-Porras M, Zafra-Tanaka JH … +4 more , Anza-Ramirez C, Bernabé-Ortiz A, Wells JCK, Miranda JJ
Am J Hum Biol · 2025 Jul · PMID 40631411 · Publisher ↗
OBJECTIVE: To determine the association between relative leg length and insulin resistance according to rural, urban, and rural-urban migrant groups. METHODS: Cross-sectional study using data from the PERU MIGRANT study...
OBJECTIVE: To determine the association between relative leg length and insulin resistance according to rural, urban, and rural-urban migrant groups. METHODS: Cross-sectional study using data from the PERU MIGRANT study (2007-2008). The exposure was relative leg length categorized as short, normal, or long, and the outcome was insulin resistance (logarithm of homeostatic model assessment log-HOMA2-IR). Linear regression models with log transformation, adjusted for sex, age, parental education, hip circumference, and physical activity level, were employed to estimate geometric mean ratios of insulin resistance across leg length categories. Interaction effects of population groups (rural, urban, and migrants) on insulin resistance were explored, along with mediation analysis of central obesity and excess body fat in the main relationship. RESULTS: Using data from 947 participants, 52.7% female, mean age 47.7 years (SD = 11.9), we found a robust inverse association between relative leg length and insulin resistance. The geometric mean of insulin resistance in subjects with long leg length was 43% (e: 0.57, 95% CI: 0.47-0.69) lower than those in the normal category. A significant interaction effect of the population group on relative leg length categories (p < 0.001) was observed, particularly in the migrant and rural groups. Excess body fat and abdominal obesity explained 33% and 12% of the association between relative leg length and insulin resistance, respectively. CONCLUSIONS: Longer leg length was associated with lower insulin resistance values, with a greater interaction effect observed among the rural-urban migrant and urban groups. These findings support the hypothesis that metabolic disorders in adults may be traceable to nutritional and developmental conditions early in life.
Validity of Adiposity Indices for Detecting High Body Fat Mass in Mexican Schoolchildren: Results From the NUTRENTO Project.
Marcos G, Celina RR, Guadalupe LR … +5 more , Luis MU, Gabriela OM, Patricia OD, Teodoro SD, Oscar GV
Am J Hum Biol · 2025 Jul · PMID 40631409 · Publisher ↗
INTRODUCTION: Body mass index (BMI) is a known indicator of adiposity. However, alternative measures have recently been proposed in children. We aimed to evaluate the validity of alternative adiposity indices (AIs)-BMI a...
INTRODUCTION: Body mass index (BMI) is a known indicator of adiposity. However, alternative measures have recently been proposed in children. We aimed to evaluate the validity of alternative adiposity indices (AIs)-BMI according to the World Health Organization (BMI-WHO) and the International Obesity Task Force (BMI-IOTF) standards, waist circumference (WC), and waist-to-height ratio (WHtR)-in detecting high body fat (HBF) in Mexican schoolchildren. METHODS: This cross-sectional analysis was conducted among 2189 schoolchildren in Hidalgo, Mexico. AIs including BMI-WHO, BMI-IOTF, WC, and WHtR were evaluated via anthropometry. Body fat (BF) was assessed using bioelectrical impedance analysis (BIA). The ability of the AIs to predict HBF was evaluated using sensitivity, specificity, and confidence intervals (95% CI). Agreements between AIs and BF were analyzed using Kappa correlation coefficients and Bland-Altman plots. RESULTS: In detecting HBF, BMI-WHO showed a sensitivity of 98.2% (95% CI: 97.0-99.0) and a specificity of 59.3% (95% CI: 56.7-61.9), and WHtR showed 98.0% (95% CI: 96.6-98.8) and 57.4% (95% CI: 54.8-59.9), respectively. Among boys, moderate agreement was observed between HBF and BMI-WHO (Kappa = 0.52), WHtR (Kappa = 0.50), and WC (Kappa = 0.47), all with p < 0.001. Among girls, moderate agreement was found with BMI-WHO (Kappa = 0.45) and WHtR (Kappa = 0.41), also with p < 0.001. Bland-Altman analysis showed good agreement between HBF and WHtR and intermediate agreement with BMI-WHO. CONCLUSION: BMI-WHO and WHtR demonstrate high validity for assessing HBF in schoolchildren. WHtR may serve as a practical alternative for routine screening and for evaluating the impact of interventions aimed at reducing risks associated with excessive BF accumulation.
Growth Status of Rural Youth 7-15 Years in Poland: Variation by Family Size in Decennial Surveys Spanning 1986-2016.
Bartowiak S, Konarski JM, Strzelczyk R … +1 more , Malina RM
Am J Hum Biol · 2025 Jul · PMID 40622021 · Publisher ↗
To evaluate variation in the growth status of rural school children 7-15 years by number of children in the family within and across four decennial surveys spanning 1986-2016. Heights and weights of children in the same...
To evaluate variation in the growth status of rural school children 7-15 years by number of children in the family within and across four decennial surveys spanning 1986-2016. Heights and weights of children in the same 10 communities were measured; BMI was calculated. Samples included 1416 boys and 1326 girls in 1986; 971 boys and 947 girls in 1996; 871 boys and 843 girls in 2006, and 658 boys and 711 girls in 2016. Number of children in the family and level of parental education were reported. MANCOVAs (with age of the child and with age and parental level of education as covariates) were used to evaluate variation in growth status by number of children in the family within each survey, and by number of children in the family across the four surveys. Family size declined across surveys. Variation in body size by family size was not consistent within the four surveys. Estimated secular gains in height, weight, and BMI across the 30-year interval were reasonably similar among boys and girls from families of 1, 2, 3, and 4+ children, while estimated gains between adjacent decadal surveys varied with the number of children in the family and between boys and girls.
Biological Mechanisms for Allen's Rule: DNA Methylation as Mediator of the Association Between In Utero Exposure to Environmental Heat and Tibial Growth in Childhood.
Straight B, Qiao X, Ngo D … +5 more , Hilton CE, Olungah CO, Lalancette C, Naugle A, Needham BL
Am J Hum Biol · 2025 Jul · PMID 40605395 · Full text
OBJECTIVES: Understanding human phenotypic plasticity in response to social, ecosystem, and climate interactions can be an important tool for designing social and public health strategies that increase climate change res...
OBJECTIVES: Understanding human phenotypic plasticity in response to social, ecosystem, and climate interactions can be an important tool for designing social and public health strategies that increase climate change resilience. Sensitivity of the tibia to environmental perturbations is well established; moreover, Allen's rule predicts relatively longer tibial length in hotter climates. In this study, we hypothesized DNA methylation (DNAm) changes as potential mechanisms for impacts of environmental heat exposure in utero persisting in childhood tibial growth in Kenyan Samburu pastoralist children ages 1.8-9.6 years living in a global climate change vulnerability hotspot. METHODS: DNAm data was measured from whole saliva using the Infinium MethylationEPIC BeadChip array. To test our hypothesis, we tested for differential DNAm and we performed high-dimensional mediation analysis using high-resolution (0.05 × 0.05) land surface temperature variables (LST) for each trimester of gestation and compared this to models using a coarser method (contrasting climate zones). RESULTS: We found differentially methylated CpG sites in both LST and comparison models, near genes relevant to linear growth, with some overlap between models, as expected. We identified 37 CpG sites mediating the association between LST > 37°C exposure in utero and tibial growth into childhood, and 13 CpG sites as mediators in comparison models. CONCLUSIONS: To our knowledge, these are the first results to identify biological mediators linking environmental heat to lower limb growth in children. The findings contribute evidence of epigenetic mechanisms relevant to Allen's rule and of the tibia as a key biomarker of early life conditions.
The Structure of the Ukrainian Population Based on Surname Distribution.
Shuba V, Yasinskyi Y, Atramentova L
Am J Hum Biol · 2025 Jul · PMID 40600290 · Publisher ↗
OBJECTIVE: This paper examines the consequences of migration and other demographic processes for Ukraine's population through the analysis of surname distribution. MATERIALS AND METHODS: The dataset included 697 147 surn...
OBJECTIVE: This paper examines the consequences of migration and other demographic processes for Ukraine's population through the analysis of surname distribution. MATERIALS AND METHODS: The dataset included 697 147 surnames of 46 431 365 residents of Ukraine in 2001. The research methodology follows the approach of I. Barrai and applies the indicator CRSED proposed by J. Chen to assess the diversity of surnames in 25 regions of Ukraine in the context of historical population dynamics. RESULTS: A comparison of surname frequency distributions across regions reveals greater cultural and demographic stability in areas with high CRSED values. Low CRSED values correspond to regions with extensive and diverse immigration accompanied by high levels of migrant assimilation. DISCUSSION: The distribution of surnames in Ukraine reflects the influence of historical events, including colonization, industrialization, armed conflicts, and political transformations. The application of isonymy and CRSED indices enables the detection of underlying demographic and social processes that have shaped the modern population structure. The study offers new insights into the historical development of Ukraine's population and provides guidance for population policy planning.
Political Liberation, Hope, and Social Competition Are the Motor of Secular Trends in Height.
Scheffler C, Groth D, Hermanussen M
Am J Hum Biol · 2025 Jul · PMID 40589335 · Full text
BACKGROUND: Long-term improvements in physical living conditions correlate with long-term trends in height. AIM: To link temporal characteristics of the secular trend in height with the simultaneous political and economi...
BACKGROUND: Long-term improvements in physical living conditions correlate with long-term trends in height. AIM: To link temporal characteristics of the secular trend in height with the simultaneous political and economic dynamics. SAMPLE AND METHODS: Height of men of the German Armed Forces born between 1865 and 1975 was correlated with indicators of economic prosperity (GDP), nutrition and health (infant mortality), and indicators of social inhomogeneity (income inequality and household wealth share). The time periods before 1916, between 1916 and 1933, 1947, 1973, and after 1989 were separately analyzed. Coherence analysis was used to assess the changes in the temporal trends. RESULTS: Mean height of young adult men increased by 0.45 mm/year (before 1916), by 2.15 mm/year (1916-1933), by 1.87 mm/year in the early Federal Republic of Germany (FRG) until 1973, by 1.45 mm/year in the late FRG, and by 4 mm/year in East German conscripts after the reunification in 1989. The most substantial height increments occurred in periods of political upheaval and loss of state authority. CONCLUSION: The nonlinear pattern of secular height increments in Germany since the late 19th century suggests that political liberation, hope for a better life, and illusions of equity, freedom, justice, and the expectation of social advancement are associated with competitive growth, strategic growth adjustments, and finally, long-term and substantial secular trends in height.
Evaluation of the Relationship Between Aggression and Digit Ratio Through a Cross-Sectional Study Among Hitit University Students.
Koç F
Am J Hum Biol · 2025 Jul · PMID 40579991 · Publisher ↗
OBJECTIVES: The second-to-fourth digit ratio (2D:4D) is widely recognized as a biomarker of prenatal testosterone exposure and has been previously linked to aggression. This association demonstrates sex-specific variabil...
OBJECTIVES: The second-to-fourth digit ratio (2D:4D) is widely recognized as a biomarker of prenatal testosterone exposure and has been previously linked to aggression. This association demonstrates sex-specific variability and is further modulated by both biological and environmental influences. The present study aims to examine the relationship between 2D:4D and levels of aggression, including subtypes of aggression, among university students of Turkish ethnic origin residing in the Central Black Sea region of Turkey. Additionally, the study explores sex differences in these associations. METHOD: This cross-sectional study included 203 undergraduate students (108 females, 95 males) from Hitit University. Participants not affiliated with the university were excluded. The 2D:4D were measured using a digital caliper, and aggression levels were assessed using the Buss-Perry Aggression Questionnaire (BPAQ). Statistical analyses comprised the Mann-Whitney U test, Kruskal-Wallis test, and Spearman correlation analysis. RESULTS: In females, significant yet weak negative correlations were found between the lengths of the right-hand 2D, right-hand 4D, and left-hand 4D and both physical and verbal aggression scores (p < 0.05; r = 0.20-0.39). A weak negative correlation was also observed between the right-hand 4D and the total BPAQ score (p = 0.024, r = -0.218). Furthermore, weak positive correlations were identified between the left-hand 2D:4D and both physical aggression and total aggression scores. Among males, weak but significant positive correlations were identified between the right-hand 2D length and the left-hand 2D:4D and anger subscale scores (p = 0.043, p = 0.009; r = 0.20-0.39). Similarly, weak positive correlations were observed between the right-hand 2D and 2D:4D and hostility subscale scores (p = 0.031; r = 0.20-0.39). Additionally, a weak negative correlation was found between the right-hand 4D and verbal aggression (p = 0.017, r = -0.244). Finally, a weak but significant positive correlation was detected between the right-hand 2D:4D and the total BPAQ score (p = 0.012, r = 0.28). CONCLUSIONS: The findings indicate that digit ratio does not exhibit marked sexual dimorphism; however, the expression of aggressive behavior appears to differ by sex. In females, shorter digit lengths (2D and 4D) are negatively associated with specific subdimensions of aggression, whereas in males, higher 2D:4D is positively correlated with anger and hostility. Although these results diverge from trends commonly reported in the literature and reached statistical significance, the low correlation coefficients warrant cautious interpretation.
Sex Ratio at Birth in Northern Ireland During the COVID-19 Pandemic: A Comparison With Published Data From the Republic of Ireland, England and Wales.
Masukume G, Cleaver P, Philip RK … +2 more , Grech V, Non AL
Am J Hum Biol · 2025 Jul · PMID 40579861 · Full text
OBJECTIVES: The COVID-19 pandemic has been linked in several countries to fluctuations in the proportion of male live births/total live births, known as the sex ratio at birth (SRB). This study investigates how the pande...
OBJECTIVES: The COVID-19 pandemic has been linked in several countries to fluctuations in the proportion of male live births/total live births, known as the sex ratio at birth (SRB). This study investigates how the pandemic influenced SRB patterns in Northern Ireland compared to published data from neighboring regions, including the Republic of Ireland with which it shares an open land border, and England and Wales, across the sea. METHODS: Monthly live birth data for Northern Ireland from 2015 to 2021 were obtained from the Northern Ireland Statistics and Research Agency. A time series analysis predicted the SRB for 2020 using data from 2015 to 2019. Predicted and observed SRB values were compared for 2020. RESULTS: In August 2020, 5 months after the pandemic declaration, the SRB fell significantly to 49.13%, the period's lowest, below the 95% prediction interval (50.09%-51.85%). In December 2020, 9 months after the declaration, the SRB rose to 54.48%, exceeding the prediction interval (49.75%-51.57%). This overall SRB pattern resembled that in England and Wales but differed from the Republic of Ireland. CONCLUSION: The decline in SRB in August 2020, occurring 3-5 months after the pandemic declaration, suggests the pandemic disproportionately affected male fetuses in Northern Ireland. The rise in December, 9 months after the declaration, may relate to increased sexual activity in March 2020 following lockdown in a subset of the population. Northern Ireland's SRB pattern aligns more with England and Wales than the Republic of Ireland, indicating that socio-political ties in the United Kingdom may be more influential for pandemic response than geographical proximity.
Market Integration and Secular Changes in Anthropometric Characteristics in Two Maya Communities From Yucatan, Mexico.
Azcorra H, Castillo-Burguete MT, Lara-Riegos J … +5 more , Sarabia-Herrera V, Salazar-Rendón JC, Mendez-Dominguez N, Aelion CM, Leatherman T
Am J Hum Biol · 2025 Jul · PMID 40579812 · Publisher ↗
OBJECTIVE: To compare the changes in children's height, weight, and BMI from two Maya communities during 1986-2023 in order to analyze if their differences in degrees of participation in market economy are reflected in s...
OBJECTIVE: To compare the changes in children's height, weight, and BMI from two Maya communities during 1986-2023 in order to analyze if their differences in degrees of participation in market economy are reflected in secular changes in growth measures. MATERIAL AND METHODS: We compared the changes in height, weight, and BMI of 1463 children (6-12 years) from two communities (Dzeal and Yalcoba) differing by speed and degree of market integration along three points in time: 1986/1987, 1996-1998/2000 and 2022/2023. Linear regression models were adjusted to estimate the changes in height-for-age (HAZ) and BMI-for-age Z-scores (BMIZ) in each community by age group and sex using the period of measurement as the independent variable. RESULTS: Increases in HAZ between 1986/1987 and 2022/2023 were greater in children from the community with slower integration into the market economy (Dzeal). Differences in total increases between 1986/1987 and 2022/2023 in HAZ between communities were 0.50 (boys) and 1.19 (girls) standard deviations (SD) score in the 6-8-year-old group and 0.40 (boys) and 0.41 SD (girls) in children aged 9-12. Total increases in BMIZ were 0.81 SD (boys) and 1.07 SD (girls) in children (6-8 years) from the community with rapid integration (Yalcoba); changes in children with slower integration were not significant. CONCLUSION: The rapid integration of the community into the market economy seems to favor larger secular increases in children's BMI and smaller increases in linear growth.
Correction to "Maximal Fat Oxidation Rate in Healthy Young Adults. Influence of Cardiorespiratory Fitness Level and Sex".
Am J Hum Biol · 2025 Jun · PMID 40566652 · Publisher ↗
Abstract loading — click title to view on PubMed.
Defining and Using Gender/Sex in Human Biology: Where Are We? Where Should We Be?
SturtzSreetharan C, DuBois LZ, Brewis A
Am J Hum Biol · 2025 Jun · PMID 40566648 · Publisher ↗
Sex and gender categories are often used by human biologists in hypothesis generation, research design, data analysis, and interpretation. Many studies in human biology thus differentiate samples by "sex" and/or "gender....
Sex and gender categories are often used by human biologists in hypothesis generation, research design, data analysis, and interpretation. Many studies in human biology thus differentiate samples by "sex" and/or "gender." But it is unclear to what extent, if any, these terms are defined or clearly operationalized. Through analysis of recent publications in the American Journal of Human Biology we assessed how these terms are defined and used in human biological research. Through systemic coding of the text of all original research studies published in AJHB in 2023, we identified inconsistencies in the definition and application of these terms. We find that sex and gender are often conflated and often lack a clear definition. In addition, the reader must glean definitions and methods of operationalization. We tie these observations to theories of language as social action- the idea that language represents experience, creates organization, and differentiates. Thus more precise gender/sex language use in research reporting increases precision in science, but also matters for dissemination of human biological research. We discuss pressing opportunities for human biologists to lead translational science writing by moving toward such precise yet nuanced uses of sex and gender in their research reporting.
The Homo erectus Female Revisited.
Aiello LC
Am J Hum Biol · 2025 Jun · PMID 40552455 · Full text
The Energetic Consequences of Being a Homo erectus Female was published in the American Journal of Human Biology over two decades ago. This paper drew attention to the high body-size-related reproductive costs of an H. e...
The Energetic Consequences of Being a Homo erectus Female was published in the American Journal of Human Biology over two decades ago. This paper drew attention to the high body-size-related reproductive costs of an H. erectus female if she retained the same reproductive schedule of smaller-bodied earlier hominins modeled on the schedule for modern Pan. The main conclusion was that the energetic cost per offspring would be significantly reduced by adopting a modern human reproductive schedule with a shorter lactation period and an overall shorter interbirth interval. To make this possible and support the energetic requirements of the larger body size, there would have had to be a fundamental shift in subsistence behavior involving a higher-quality diet and intergenerational cooperation in food acquisition. This paper re-evaluates these conclusions based on recent energetic research developments. Although the modeling parameters have changed, the conclusions are still valid. Their implications are discussed in light of modern research on the increase in body and brain size and the evolution of cooperative subsistence behavior.
From Testosterone to Racialization to Knobby Knees: 15 Years of Gender/Sex.
van Anders SM
Am J Hum Biol · 2025 Jun · PMID 40545909 · Full text
This paper discusses ~15 years of my research on gender/sex. I first discuss how "sex versus gender" is an overlay onto "nature versus nurture" ideologies, and the ways these are unempirical (if not anti-empirical), inac...
This paper discusses ~15 years of my research on gender/sex. I first discuss how "sex versus gender" is an overlay onto "nature versus nurture" ideologies, and the ways these are unempirical (if not anti-empirical), inaccurate, and unjust. I provide definitions of gender/sex, as well as gender and sex, and the pitfalls of "getting sex right" ideologies that aim to provide a singular universal definition of sex that belies its multiplicity, dynamism, and social situatedness. I discuss how these ideologies are often rooted in "bio/logics" that seek to define sex in ways that restrict human rights, especially for gender/sex minorities. I focus on my own research on testosterone (T) beyond masculinity that highlights the importance of gender/sex. This includes thinking about T in terms of social and biomaterial construction, including a "gender → T pathway" and "chronic gender". I then describe how discussions of T are also rooted in racism, racialization, colonialism, and settler colonialism. In addition, I delineate how this makes not just for "sex versus gender" dichotomies and gender binaries, but ladders or helices that include gender/sex and race/ethnicity, among other social locations. I also point to gender/sex as an important lens for understanding bodily formations beyond T, that include a new "knobby knee hypothesis". In discussing these topics, I focus on an array of important feminist science principles, including epistemic injustice, pre-theory, intersectionality, and diffraction. I close by discussing how gender/sex can provide an avenue for bioscientific research that is more empirical, accurate, and just.
Higher Resting Metabolism Is Associated With Increased Free Triiodothyronine Among Female Reindeer Herders in Northern Finland.
Ocobock C, Stenbäck V, Niclou AM … +4 more , Soppela P, Turunen M, Walkowiak J, Herzig KH
Am J Hum Biol · 2025 Jun · PMID 40542509 · Full text
BACKGROUND: Thyroid hormones (TH) regulate metabolism and are shaped by environmental factors-ambient temperature in particular. Previous work among indigenous and non-indigenous populations in Russia revealed that there...
BACKGROUND: Thyroid hormones (TH) regulate metabolism and are shaped by environmental factors-ambient temperature in particular. Previous work among indigenous and non-indigenous populations in Russia revealed that there are seasonal shifts in TH dynamics such that total and free triiodothyronine (fT) and free thyroxine (fT) increase during winter. Elevated TH levels in these populations were positively correlated with the elevated resting metabolic rate (RMR) commonly seen among indigenous cold climate populations. METHODS: Here we examined the relationship between TH levels (fT3, fT4, and thyroid stimulating hormone) and resting metabolism among reindeer herders (N = 35) and office workers (N = 16) from northern Finland in January 2019 and February of 2023. RMR was measured using indirect calorimetry at both time points and a TH analysis was conducted from venous blood samples collected before RMR measurements in 2023 only. RESULTS: Controlling for fat free mass, female reindeer herders had significantly higher RMRs than male reindeer herders and significantly higher RMRs than predictive equation estimates. Female herders also had significantly higher fT and TSH than male herders and female officer workers. Female herders exhibited a significant positive correlation between fT and RMR; significant correlations were not found among male herders or female office workers. CONCLUSION: This preliminary study demonstrates variation in the relationship between TH levels and resting metabolism among reindeer herders and office workers in Northern Finland. These results highlight potential sex-based differences in TH and metabolism dynamics, particularly among female reindeer herders, that require further research.
The Maternal Capital Hypothesis: Giving Mothers Central Place in Evolutionary Perspectives on Developmental Plasticity and Health.
Wells JCK
Am J Hum Biol · 2025 Jun · PMID 40536109 · Full text
The "developmental origins of health and disease" paradigm has revolutionized biomedical research and raised new questions in the public domain. Not only individual disease risk, but also population health inequalities,...
The "developmental origins of health and disease" paradigm has revolutionized biomedical research and raised new questions in the public domain. Not only individual disease risk, but also population health inequalities, may be profoundly shaped by experience early in life. The maternal capital hypothesis, published in 2010, is an evolutionary conceptual framework for understanding developmental plasticity on an intergenerational time-scale. The central proposition is that societal adversities can become embodied in maternal phenotype, and hence undermine the health and life opportunities of their offspring. The offspring calibrates its early developmental trajectory to maternal phenotype, not to the external environment. The framework emphasizes societal stresses from which individual mothers cannot opt out, such as malnutrition, poverty, gender inequality, colonialism, racism, war, and interpersonal violence. Conversely, mothers with greater capital can better defend themselves against these stresses and buffer their offspring. In this commentary, I revisit why the hypothesis was developed and summarize how it has stimulated further work. I review evidence for the role of maternal phenotype in the intergenerational basis of health inequalities; theoretical issues that the hypothesis can help clarify; implications for policy and intergenerational justice; and experimental studies that show that promoting maternal capital can have health benefits for both mothers and offspring. There is no intention to blame mothers when arguing that maternal phenotype plays a unique role in intergenerational cycles of disadvantage. Rather, promoting maternal capital may not only improve maternal and child health, but also combat gender and racial inequality.
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