American Journal of Human Biology最新文献

{"title":"Evolution of the Human Life Cycle, Revisited","authors":"Barry Bogin, B. Holly Smith","doi":"10.1002/ajhb.70018","DOIUrl":"https://doi.org/10.1002/ajhb.70018","url":null,"abstract":"<p>We are honored to be among the “Invited Commentaries on Influential Papers” for the 50th Anniversary of the Human Biology Association. The <i>AJHB</i> Editor, Bill Leonard, wrote that “These contributions will span the broad scope of research encompassed by the field of human population biology, including theoretical advancements … evolutionary/adaptive dimensions of human biology … insights into human health disparities … and methodological innovations …” (Leonard <span>2024</span>). Bill placed our article (Bogin and Smith <span>1996</span>) in the “evolutionary/adaptive” category. Human growth, as studied and taught in the 1970s and 80s, was not a particularly evolutionary field. Existing textbooks were written by physicians, with the medical student in mind or as a practical guide for parents. At the University of Michigan Center for Human Growth and Development (CHGD), where Bill and Holly studied and crossed paths with Barry at lectures, emphasis was placed on human variation, plasticity and health disparities. In paleontology, growth and development was seen through the 19th century lens of “heterochrony” as resurrected by Gould (<span>1977</span>), with its subset of hypothetical processes by which morphology and size might evolve. Neither of those paths lead toward a model of when and what shaped the human life cycle.</p><p>By the early 1990s, however, decades of work on <i>Pan troglodytes</i> growth and development (Krogman <span>1930</span>; Schultz <span>1940</span>, <span>1960</span>; Gavan <span>1953</span>; Nissen and Riesen <span>1964</span>) and ethology (see Goodall <span>1986</span>) had described ways in which chimpanzees resembled humans (e.g., tool use, group hunting, sharing meat, strong mother-infant bonds, male–male affiliations) and the ways they did not (e.g., extremely prolonged nursing, dental and skeletal maturation almost twice as fast as humans, lack of an adolescent growth spurt). In addition, the anthropology of human societies had been enriched by a new human ecology that had an eye to growth, work, demography, and energy production and consumption by age, sex, and gender (Draper <span>1976</span>; Howell <span>1979</span>; Lee <span>1979</span>; Leonard <span>1994</span>; Hill and Hurtado <span>1996</span>). An evolutionary paradigm coming from comparative biology and the relatively new discipline of ‘life history,’ which studied how organisms evolved to allocate time and energy to growth, maintenance and reproduction, was bringing breadth and rigor into interpretations of life cycle and behavior (Stearns <span>1992</span>; Charnov <span>1993</span>).</p><p>Our pre-1996 independent research formed the basis of our working together. Barry started toward research in biological development and evolution in 1969 via a job in the lab of Richard L. Miller, a developmental biologist who was the first to discover fertilization by sperm chemotaxis in an animal (Miller <span>1966</span>). It was Barry's junior year at","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"37 3","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajhb.70018","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143554592","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":"Regulatory T-Cells During Pregnancy Relate to Women's Own Childhood History of Microbial Exposure","authors":"Molly M. Fox,&nbsp;Adiba Hassan,&nbsp;Kyle S. Wiley,&nbsp;Dayoon Kwon,&nbsp;Delaney A. Knorr","doi":"10.1002/ajhb.70013","DOIUrl":"https://doi.org/10.1002/ajhb.70013","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objectives</h3>\u0000 \u0000 <p>Previous studies found that children with siblings, farm residence, and other proxies of greater microbial contacts had lower rates of hyper-responsive immune disorders. Yet, scientific debate persists regarding whether the human immune system is educated in early life primarily as a function of pathogenic or benign microbial exposures, or both. Furthermore, pregnancy relies on women's intrinsic immunosuppressive function, yet it remained unknown how immunoregulation in pregnant women relates to early-life microbial exposures. Here, we conduct a preliminary examination of whether childhood microbial exposures prime women's pregnancy-related immunoregulatory capacity.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We administered retrospective questionnaires to estimate 55 pregnant women's early-life exposure to pathogenic (e.g., illness) and benign (e.g., pets; rural residence) microbes. Tolerogenic regulatory T-cells (Tregs) and Treg subtypes were measured by flow cytometry from peripheral blood.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Results show that proxies for both pathogenic and benign exposures were positively associated with Treg concentrations.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>These findings offer insights that may help elucidate the relative contributions of early-life pathogenic (“hygiene hypothesis”) and benign (“old friends hypothesis”) microbial exposures toward the expansion of the Treg compartment. Human evolutionary history is characterized by changing microbial exposures as human residency patterns, living environments, and subsistence strategies changed. In this context, our findings suggest the possibility of less gestational pathology in human evolutionary past conditions typified by richer diversity of microbial exposure.</p>\u0000 </section>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"37 3","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143521998","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":"Health and Mortality in the 19th-Century Rural United States: The Second Epidemiological Transition in Madison County, New York","authors":"Sharon N. DeWitte,&nbsp;Eric E. Jones,&nbsp;Catherine Livingston","doi":"10.1002/ajhb.70017","DOIUrl":"https://doi.org/10.1002/ajhb.70017","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objectives</h3>\u0000 \u0000 <p>A number of studies have examined changes in mortality and health during industrialization in both the United States and Western Europe; however, most of this work has focused on urban communities. Despite theories regarding differences between rural and urban patterns of mortality at this time, few analyses of data from rural communities have been done. Our goal is to examine trends in mortality, <i>c</i>. 1850–1880, for a rural county in central New York State at a time when farming, the economic base of this county, was becoming commercialized and industrialization was impacting the wider region.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Materials and Methods</h3>\u0000 \u0000 <p>Using census mortality records from Madison County, NY (1850–1880), we examine trends in hazards of death, survivorship, and cause of death. In order to contribute a rural perspective to this area of study, we examine trends from the mortality records at several scales: town-specific, groups of towns based on population density, and the county as a whole.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Our results suggest that the hazards of death decreased and survivorship increased at the county level across this 30-year period. In general, the rates of communicable diseases decreased and the rates of non-communicable diseases increased. Individual towns had variable outcomes, and higher population density towns had better apparent outcomes than those with medium and lower densities.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Overall, mortality patterns changed noticeably during this period. These changes were likely at least partially a result of changing economic conditions, but may also have been affected by socio-spatial factors and access to healthcare, both of which continue to impact rural communities today.</p>\u0000 </section>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"37 3","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajhb.70017","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143522026","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":"Correction to “Population History and Anthropometric Variation of West Coast Irish Islands”","authors":"","doi":"10.1002/ajhb.70014","DOIUrl":"https://doi.org/10.1002/ajhb.70014","url":null,"abstract":"<p>\u0000 <span>Relethford, J. H.</span> <span>Population History and Anthropometric Variation of West Coast Irish Islands</span>. <i>American Journal of Human Biology</i> <span>2025</span>; <span>37</span>:e24177.\u0000 </p><p>FIGURE 3 | Principal coordinates plot of Mahalanobis <i>D</i>² between the means of the six Irish populations and England. Each axis has been scaled by the square root of its corresponding eigenvalue following Harpending and Jenkins (1973) to show the proportional contribution of each axis. The two axes account for 79% of the total variation (axis I=53%, axis II=26%).</p><p>I apologize for this error.</p>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"37 2","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajhb.70014","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489823","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":"Intrasexual Selection for Upper Limb Length in Homo sapiens","authors":"Neil R. Caton,&nbsp;David M. G. Lewis","doi":"10.1002/ajhb.70010","DOIUrl":"https://doi.org/10.1002/ajhb.70010","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objectives</h3>\u0000 \u0000 <p>Sexual selection via contest competition has equipped countless organisms with weaponry in their <i>appendages</i> to overpower their opponents. Here, we tested (1) whether greater upper limb length—measured as span controlling for biacromial width—confers an advantage in contest competition among adult humans, (2) several possible means by which upper limb length might increase success in intrasexual contest competition, and (3) whether, consistent with male–male contest competition creating stronger selection pressures than female–female contest competition, male <i>Homo sapiens</i> have greater upper limb length.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We collected fight statistics and facial and body photographs from professional combatants (<i>N</i> = 715) in the Ultimate Fighting Championship (UFC; Study 1). Sexual dimorphism in upper limb length was then examined via diverse and demographically representative samples from four studies (total <i>N</i> = 6915), from Croatian adolescents and older Singaporean adults to United States Army personnel born across all major world regions (Studies 2a–2d).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>First, we found that greater upper limb length is associated with increased success in intrasexual contest competition, an effect driven by both the capacity to grapple opponents to submission and to knock opponents unconscious (Study 1). Second, we found unequivocal, cross-cultural evidence of unique sexual dimorphism in upper limb length <i>after controlling for allometry</i>: across four studies, men exhibited longer upper limbs than women (Studies 2a–2d).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Upper limb length may have been shaped by intrasexual selection, with implications across the biological, anthropological, and psychological sciences.</p>\u0000 </section>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"37 2","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajhb.70010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438812","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":"Bioethics Recommendations to Increase Culturally Informed Global Health Survey Research: A Framework for Centering Community Engagement","authors":"Madeleine J. Getz,&nbsp;Alicia M. DeLouize,&nbsp;Felicia C. Madimenos,&nbsp;Glorieuse Uwizeye,&nbsp;Zaneta M. Thayer,&nbsp;Luseadra J. McKerracher,&nbsp;Alejandra Núñez-de la Mora,&nbsp;J. Josh Snodgrass","doi":"10.1002/ajhb.70011","DOIUrl":"https://doi.org/10.1002/ajhb.70011","url":null,"abstract":"<div>\u0000 \u0000 <p>Global health projects—a source of inspiration and collaboration for applied human biology—benefit scholars, governments, NGOs, and aid organizations. While such research is intended to improve population health, direct benefits to individuals and communities are often excluded from published works and/or not considered in study designs and framing. This exclusion is increasingly recognized as a colonial legacy that hinders global health equity, particularly for Indigenous and other marginalized populations. Collaboration and community engagement are avenues for addressing these injustices, but they require planning, intention, and resources. Drawing on our collective experience and ongoing dialogues about community engagement in human biology, we propose six recommendations to increase equity in global health research. These include: (1) Incorporating trusted local specialists and stakeholders at all project levels; (2) disseminating health information to participants in strengths-based and culturally meaningful ways and contributing to solutions wherever possible; (3) investing in local healthcare, research, and infrastructure; (4) making study results/data available to stakeholders; (5) working within data frameworks that respect community sovereignty; and, (6) applying culturally informed bioethics frameworks. Our discussion highlights persistent needs to address community rights and benefits and to dismantle colonial legacies within global health and human biology while recognizing structural barriers to implementing these needed changes, particularly within the context of global health projects wherein human biologists are not the main power brokers or resource holders. When interfacing with global health, human biologists must continue to pursue health equity and decolonization through implementing critical, culturally informed bioethics frameworks centering community engagement.</p>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"37 2","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143431452","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":"Differential Sex Trends in Infant, Neonatal, and Child Mortality Before and After Decentralization in Pakistan","authors":"Mukhtiar Hussain Ibupoto,&nbsp;Athar Ali Shah,&nbsp;Anqi Sang","doi":"10.1002/ajhb.70012","DOIUrl":"https://doi.org/10.1002/ajhb.70012","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Background</h3>\u0000 \u0000 <p>Differential sex child mortality is an important indicator of gender-based discrimination. Decentralization refers to the distribution of power from the federal to the provincial governments in Pakistan. Present research highlights the sex differential sex trends in infant, neonatal, and child mortality before and after decentralization.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methodology</h3>\u0000 \u0000 <p>The research utilizes the four waves of the Demographic and Health Survey from 1990 to 2018, applying Cox proportional regression in STATA. The sample size includes 164 005 total live births and 24 089 deaths across all years, with 8204 neonatal, 5107 infants, and 11 778 child deaths.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>This study provides crucial insights into the gendered patterns of neonatal, infant, and child mortality in Pakistan before and after key policy reforms. This study reveals persistent gender disparities in neonatal, infant, and child mortality in Pakistan before and after policy reforms. While girls initially had a biological survival advantage, this diminished at higher birth orders, where they faced increased mortality risks. Despite some improvements post-reform, gender-based discrimination and son preference continue to disadvantage female children, particularly in larger families.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>The findings highlight the need for targeted policies to address healthcare inequities and discriminatory practices. Strengthening gender-sensitive interventions is crucial to improving female child survival and achieving long-term progress in reducing mortality disparities.</p>\u0000 </section>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"37 2","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143431453","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":"Chronic Stress and Severe Water Insecurity During the Historic 2022 Drought in Northern Kenya Were Associated With Inflammation Among Daasanach Seminomadic Pastoralists","authors":"Kedir Teji Roba,&nbsp;Hannah Jacobson,&nbsp;Amanda McGrosky,&nbsp;Srishti Sadhir,&nbsp;Leslie B. Ford,&nbsp;Marcela Pfaff,&nbsp;Elizabeth Y. Kim,&nbsp;Rosemary Nzunza,&nbsp;Matthew Douglass,&nbsp;David R. Braun,&nbsp;Emmanuel Ndiema,&nbsp;Samuel S. Urlacher,&nbsp;Herman Pontzer,&nbsp;Asher Y. Rosinger","doi":"10.1002/ajhb.70009","DOIUrl":"https://doi.org/10.1002/ajhb.70009","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objective</h3>\u0000 \u0000 <p>Extreme climatic events, like droughts, are increasing in frequency and severity. Droughts disrupt community livelihoods and resources with serious implications for human biology. This study investigated how chronic stress, measured by fingernail cortisol concentration (FCC), and water insecurity status were predictive of C-reactive protein (CRP), a biomarker of inflammation, during a historic drought among Daasanach seminomadic pastoralists.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Data were collected at the height of the 2022 drought from 128 Daasanach household heads aged 16–80 years in northern Kenya using household surveys, anthropometric measurements, and dried blood spots to assess CRP levels and fingernails to assess FCC. We employed mixed-effects linear and logistic regression models to examine the relationships between log-transformed FCC, high water insecurity status measured via the Household Water Insecurity Experiences (HWISE ≥ 24) scale, and serum-equivalent CRP (log-transformed and dichotomized at mild, low-grade inflammation ≥ 1 mg/L) adjusted for covariates.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The mean serum-equivalent CRP was 4.1 mg/L and 56.3% of Daasanach adults had at least mild, low-grade inflammation. Linear models indicated that ln(FCC) was positively associated with ln(CRP) (<i>β</i> = 0.56, SE = 0.12; <i>p</i> &lt; 0.001). Further, logistic models demonstrated that ln(FCC) (OR = 2.69, 95% CI: 1.84–3.95; <i>p</i> &lt; 0.001) and high water insecurity (OR = 2.23, 95% CI: 1.34–3.72; <i>p</i> = 0.002) were both associated with greater odds of low-grade inflammation.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>This study provides evidence for how chronic stress and severe water insecurity may impact inflammation levels among pastoralists during drought. Since inflammation is central to cardiometabolic disease etiology, this is an additional reason to mitigate the negative health impacts of droughts and water insecurity exacerbated by climate change.</p>\u0000 </section>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"37 2","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajhb.70009","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143362349","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":"The Concentration of Docosahexaenoic Acid (DHA) and Arachidonic Acid (AA) in Human Milk Is Associated With the Size of Maternal Social Network","authors":"Magdalena Babiszewska-Aksamit,&nbsp;Marek Szołtysik,&nbsp;Anna Apanasewicz,&nbsp;Magdalena Piosek,&nbsp;Patrycja Winczowska,&nbsp;Agnieszka Cierniak,&nbsp;Dariusz P. Danel,&nbsp;Anna Ziomkiewicz","doi":"10.1002/ajhb.70006","DOIUrl":"https://doi.org/10.1002/ajhb.70006","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Introduction</h3>\u0000 \u0000 <p>Social factors, such as kin and non-kin support in helping the mother of a newborn baby, impact the duration of lactation and may affect human milk composition. Recent studies suggest that maternal stress negatively affects the level of polyunsaturated fatty acids in human milk, which are crucial for infant vision and brain development. We suggest that social support may have the potential to attenuate a negative effect of stress on the composition of human milk fatty acids.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>We studied 129 exclusively breastfeeding mothers and their healthy, term infants to explore the relationship between support from significant others (structural and functional) and the concentration of docosahexaenoic acid (DHA, <i>N</i> = 49) and arachidonic acid (AA, <i>N</i> = 129) in human milk. We also examined whether maternal stress reactivity (log Cort. AUC) may be related to these fatty acids. Gas chromatography was used to analyze the concentration of DHA and AA in human milk samples.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Analyses revealed a positive association between the number of helpers (structural support) and the concentration of DHA and AA. Maternal stress reactivity was not a statistically significant predictor of DHA and AA contents in milk and was unrelated to the number of helpers.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>Our results show for the first time that human milk composition, particularly DHA and AA concentrations, may be associated with the size of mothers' immediate social network of kin and non-kin helpers. This result is consistent with evolutionary studies that emphasize the role of cooperative breeding in human reproduction.</p>\u0000 </section>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"37 2","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143362350","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":"Low-to-Moderate Daytime Physical Activities Predicted Higher-Quality Sleep Among Habitually Active Agropastoralists","authors":"Ming Fei Li,&nbsp;Puseletso Lecheko,&nbsp;Tumelo Phuthing,&nbsp;Tsepo Lesholu,&nbsp;David R. Samson","doi":"10.1002/ajhb.70008","DOIUrl":"https://doi.org/10.1002/ajhb.70008","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Introduction</h3>\u0000 \u0000 <p>The positive effects of physical activity (PA) on sleep are widely promoted by public health organizations and supported by abundant empirical evidence. Nonetheless, there remains a dearth of studies investigating the association between daytime PA and nighttime sleep among non-urban and nonindustrial populations that habitually engage in PA as part of their subsistence strategy.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Here, we examined the bidirectional relationship between PA and sleep. We also looked at age, gender, and occupation-level differences in moderate-to-vigorous-intensity PA (MVPA), low-intensity PA (LPA), and sedentary activity durations among Basotho and Xhoxa agropastoralists residing in rural villages in the Eastern Cape, South Africa. We analyzed activity and sleep data collected from 113 individuals using MotionWatch actigraphy wristwatches across three field seasons (7111 individual days).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Percentage daily total MVPA decreased with age, though older participants maintained low activity levels and did not suffer from poorer sleep compared to younger participants. Herders spent more percentage of their day in higher-intensity activity than non-herders. Overall, women had greater daily percentage MVPA and lower percentage sedentary activity than men. Durations of total MVPA and LPA decreased total sleep time (TST) and improved sleep quality (increased sleep efficiency (SE), decreased fragmentation, and decreased percentage wake after sleep onset). Daytime PA measures were not affected by sleep duration or quality from the previous night.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Among this group of habitually active agropastoralists, low-to-moderate-intensity PA durations consistently predicted higher sleep quality. Our findings showed that sleep quality was more strongly affected by PA than sleep duration.</p>\u0000 </section>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"37 2","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajhb.70008","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143248730","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}