American Journal of Human Biology最新文献

{"title":"Comparison of External Measurement Methods of the 2D:4D Digit Ratio","authors":"İlknur Çöllü,&nbsp;Mehmet Ali Malas","doi":"10.1002/ajhb.70337","DOIUrl":"10.1002/ajhb.70337","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objectives</h3>\u0000 \u0000 <p>External methods for measuring digit length differ in the hand surface and anatomical landmarks used, but the comparability of resulting 2D:4D ratios is unclear. This study compared 2D:4D ratios obtained using four external measurement methods and evaluated between-method differences, correlations, and reliability.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Digit lengths were measured in 231 Turkish university students (103 males, 128 females). Measurements were obtained directly with calipers from the dorsal and ventral surfaces and indirectly from photocopies and photographs. The 2D:4D ratio was calculated as second-digit length divided by fourth-digit length. Right and left hands were analyzed separately for effects of measurement method, sex, and hand side.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Males had lower 2D:4D ratios than females for all methods and hand sides except direct dorsal measurement of the left hand. Mean ratios were lowest with direct dorsal measurement and highest with direct ventral measurement. Differences among methods were significant for both hands (<i>p</i> &lt; 0.001). Between-method correlations ranged from <i>r</i> = 0.529–0.771 for the right hand and <i>r</i> = 0.440–0.776 for the left hand (all <i>p</i> &lt; 0.001). Intraobserver and interobserver reliability in the pilot sample was high (ICC = 0.85–0.95).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The 2D:4D ratio varies systematically according to the external measurement method used. Measurement protocols should therefore be reported explicitly, and absolute 2D:4D values obtained using different methods should be compared cautiously. These findings highlight the importance of standardizing measurement methods in 2D:4D research and suggest that the detection of sex differences may vary according to both the measurement method and hand side.</p>\u0000 </section>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 9","pages":""},"PeriodicalIF":1.9,"publicationDate":"2026-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149013178","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":"Sleep Duration and Sun Exposure in Portuguese Children: Associations With Obesity Indicators","authors":"Elizabete A. dos Santos,&nbsp;Aristides Machado-Rodrigues,&nbsp;Daniela Rodrigues,&nbsp;Maria-Raquel G. Silva,&nbsp;Helena Nogueira,&nbsp;Cristina Padez","doi":"10.1002/ajhb.70333","DOIUrl":"10.1002/ajhb.70333","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Introduction</h3>\u0000 \u0000 <p>Sleep duration, sun exposure, and obesity are important and potentially interconnected factors in child health. In this study, we aimed to analyze the associations between sleep duration, sun exposure, and obesity indicators in Portuguese children.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>This cross-sectional study included 4755 children aged 3–10 years from public and private schools across Portugal. Parents reported children's sleep duration, sun exposure, screen time, active play, and physical activity using validated questionnaires. Trained professionals measured weight and height to calculate Body Mass Index (BMI) and assessed skinfold thickness to estimate body fat percentage (%BF). Multiple linear regression analyses, stratified by sex and adjusted for demographic, behavioral, and anthropometric factors, analyzed associations between sun exposure and sleep duration.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>In partially adjusted models (Model 1), negative associations persisted among boys, and positive associations emerged in girls for average sleep duration (<i>β</i> = 2.11; 95% CI: 0.25 to 3.96; <i>p</i> = 0.026) and weekdays (<i>β</i> = 2.40; 95% CI: 0.47 to 4.33; <i>p</i> = 0.015). In fully adjusted models (Model 2), the negative association remained only for boys on Sundays (<i>β</i> = −4.57; 95% CI: −8.22 to −0.91; <i>p</i> = 0.014), with no significant associations in girls.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Sun exposure exhibits modest, sex-specific associations with sleep duration in children. These findings emphasize the importance of considering behavioral and environmental factors when designing interventions to promote healthy sleep, support growth, and prevent childhood obesity.</p>\u0000 </section>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 9","pages":""},"PeriodicalIF":1.9,"publicationDate":"2026-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13591200/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149013154","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":"Neighborhood Social Fragmentation and Excessive Body Weight Among Children—A View From a Portuguese Inner City","authors":"Ana Cláudia Lourenço,&nbsp;Helena Nogueira,&nbsp;Daniela Rodrigues,&nbsp;Augusta Gama,&nbsp;Aristides M. Machado-Rodrigues,&nbsp;Maria Raquel G. Silva,&nbsp;Cristina Padez","doi":"10.1002/ajhb.70335","DOIUrl":"10.1002/ajhb.70335","url":null,"abstract":"<div>\u0000 \u0000 <p>This cross-sectional study examined the association between neighborhood social fragmentation and excessive body weight in childhood. The sample included 832 children aged 3–10 years living in the municipality of Porto, Portugal. Excessive body weight was classified using International Obesity Task Force sex- and age-specific cut-offs. Neighborhood social fragmentation was assessed using a composite index derived from 2021 Portuguese Census data at the statistical section level. Associations were estimated using sex-stratified multivariable logistic regression adjusted for relevant confounders. No association was observed between neighborhood social fragmentation and excessive body weight among boys. In contrast, girls living in the least fragmented neighborhoods had lower odds of excessive body weight compared with those in the most fragmented neighborhoods (OR = 0.55, 95% CI = 0.32–0.94, <i>p</i> = 0.030). These findings suggest that neighborhood social structure may be differently associated with childhood body weight by sex and may contribute to observed gender disparities in excess body weight among children.</p>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 9","pages":""},"PeriodicalIF":1.9,"publicationDate":"2026-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149013184","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":"Science and Videogames: From Scientific Dissemination to Knowledge Production","authors":"Rafael Bisso-Machado","doi":"10.1002/ajhb.70334","DOIUrl":"10.1002/ajhb.70334","url":null,"abstract":"<div>\u0000 \u0000 <p>Videogames are played by 42% of the global population. As an interactive medium, they require participants to engage actively in the constant construction of knowledge. Their relevance to human biology has been increasing and expanding, ranging from scientific dissemination to knowledge production. This article examines each of the videogames' possible scientific uses, including “commercial” games used for teaching and scientific dissemination, games created by scientists for science dissemination and science education, online games that enable players to help solve scientific problems, and citizen science platforms such as Foldit. The example of Demis Hassabis, whose achievements in using AI to predict and design the structure of proteins earned him a Noble Prize in Chemistry, started his research on AI when he was a game designer. This further demonstrates how videogames can contribute to scientific innovation. Together, these examples show that videogames can be powerful tools for both scientific dissemination and knowledge production.</p>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 9","pages":""},"PeriodicalIF":1.9,"publicationDate":"2026-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148978777","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":"Cardiometabolic Health in P'urépecha Migrant-Sending Communities in Michoacan, Mexico","authors":"Isaura Cruz,&nbsp;Amanda L. Thompson","doi":"10.1002/ajhb.70319","DOIUrl":"10.1002/ajhb.70319","url":null,"abstract":"<p>Migration–health research frequently attributes cardiometabolic risk among migrants to post-migration dietary and lifestyle change, despite limited empirical evidence from migrant-sending communities. This assumption is particularly salient in studies of indigenous populations, where pre-migration contexts are often treated as culturally traditional and implicitly protective. Using a mixed-methods biocultural design, this study examines cardiometabolic risk among never-migrant P'urépecha adults living in migrant-sending communities in Michoacán, Mexico, to assess whether commonly used sociocultural indicators are associated with cardiometabolic outcomes and to situate origin-community health within broader population trends. We collected anthropometric measures, cardiometabolic biomarkers, and survey data from 193 adults and integrated these data with ethnographic observations of local food environments and comparisons to national surveillance benchmarks from ENSANUT. Cardiometabolic risk was widespread. Seventy-five percent of participants were overweight or obese, 59% were hypertensive, 34% exhibited dysglycemia (HbA1c ≥ 5.7% or medication use), and 77% met criteria for metabolic syndrome. In multivariable analyses, age and sex were consistently associated with cardiometabolic risk, while income, perceived stress, language proficiency, and cultural/ethnic identification were not independently associated with outcomes. Although bivariate differences by language group were observed, these associations disappeared after adjustment for age. When interpreted alongside ethnographic observations and population-level benchmarks, these findings reveal that cardiometabolic risk is already embedded within the everyday environments of indigenous migrant-sending communities. The lack of consistent associations between commonly used sociocultural indicators and health outcomes suggests that shared community-level exposures may be more important than individual measures of language or cultural identification in shaping cardiometabolic health. By integrating biomarker, survey, and ethnographic data, this study demonstrates the value of a biocultural approach for understanding health before migration and provides a critical point of comparison for future migration-health research.</p>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 9","pages":""},"PeriodicalIF":1.9,"publicationDate":"2026-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13572770/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148964062","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":"Seven Decades: How We Evolved to Live Longer. By Michael D. Gurven, Princeton: Princeton University Press, 2025. 536 pp. $35 (paperback). ISBN: 978-0-69-123199-0","authors":"B. Natterson-Horowitz","doi":"10.1002/ajhb.70331","DOIUrl":"https://doi.org/10.1002/ajhb.70331","url":null,"abstract":"","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 9","pages":""},"PeriodicalIF":1.9,"publicationDate":"2026-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148943343","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":"Second-to-Fourth Digit (2D:4D) Ratio as A Risk Factor for Osteoporosis and Osteoarthritis: A Systematic Review","authors":"Özlem Elvan,&nbsp;Birgül Vural Doğru,&nbsp;Emine Kaplan Serin","doi":"10.1002/ajhb.70330","DOIUrl":"10.1002/ajhb.70330","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Background&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;The second-to-fourth digit (2D:4D) ratio is an established marker of prenatal sex hormone exposure and has been associated with various health outcomes across the lifespan. Increasing evidence suggests that developmental factors reflected by the 2D:4D ratio may contribute to susceptibility to musculoskeletal disorders, including osteoarthritis (OA) and osteoporosis (OP).&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Aim&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;This systematic review aimed to synthesize the available evidence regarding the association between 2D:4D ratio and the risk of OA and OP.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Methods&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;This systematic review was conducted according to the PRISMA guidelines and registered in PROSPERO (CRD420261439840). A comprehensive literature search was performed in PubMed, Web of Science, and Scopus between April and May 2026. Observational studies investigating the relationship between 2D:4D ratio and OA or OP related outcomes were included. Study selection, data extraction, and methodological quality assessment were independently performed by three reviewers. Methodological quality was evaluated using the Joanna Briggs Institute critical appraisal tools.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Results&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Nine studies met the inclusion criteria, comprising eight studies on OA and one study on OP. Most studies reported that lower 2D:4D ratios or Type III finger patterns were associated with increased OA risk, greater radiographic severity, and a higher likelihood of severe knee OA requiring joint replacement. Associations were particularly evident for knee and hand OA, with several studies reporting stronger associations in women than in men. In contrast, evidence regarding OP was limited, as only one eligible study specifically investigated OP. Methodological heterogeneity was observed across studies regarding digit ratio assessment methods and disease definitions.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Conclusion&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Current evidence suggests that lower 2D:4D ratios are associated with OA-related outcomes, particularly in knee and hand OA, with several studies indicating stronger associations in women. These findings suggest that variation in 2D:4D may reflect developmental and sex-dependent patterns of musculoskeletal health rather than a causal relationship. However, evidence regarding OP remains insufficient to draw definitive conclusions. Further large-scale prospective studies using standardized assessment methods are","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 9","pages":""},"PeriodicalIF":1.9,"publicationDate":"2026-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13550950/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148908025","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":"Short- and Long-Term Impact of Exogenous Hormones on Thermoregulation in Women","authors":"Cara Wall-Scheffler,&nbsp;Martin Hora","doi":"10.1002/ajhb.70325","DOIUrl":"10.1002/ajhb.70325","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objectives</h3>\u0000 \u0000 <p>How the body changes its methods of thermoregulation as part of the female ovarian cycle is a crucial aspect of human adaptive strategies to negotiate variable environments and tasks. The use of exogenous hormones to manage the ovarian cycle is a regular part of modern life but its long-term impact on thermoregulation, particularly while moving, continues to be understudied.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Here, we specifically track adults (<i>N</i> = 35) including men, women of known ovarian phases, and women on an estrogen-progesterone combination pill, doing the same walking and resting protocol while their core body temperature was monitored continuously and their blood perfusion was monitored regularly. Blood perfusion was normalized to maximum blood flow, and lines were fit to the blood flow during exercise and during rest; the slope of these lines was used to analyze blood flow of the different endocrine groups.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Women on the pill showed significantly higher core temperatures (<i>x¯</i> = 38.16°C) than women not on the pill (luteal <i>x¯</i> = 37.85°C; follicular <i>x¯</i> = 37.69°C) and men (<i>x¯</i> = 37.80°C) (<i>p</i> = 0.02). Women in the luteal phase showed the most shallow slopes of blood perfusion (between −0.14 and 0.07), whereas all other endocrine groups showed slopes ranging from −0.31 to 0.15. Endocrine group significantly impacted the slope of blood perfusion during resting and walking (<i>p</i> = 0.059).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Given the different core temperatures, the similarity in the amount and pattern of blood perfusion between women on the pill and women in the follicular phase was not enough to substantially lower the core temperature of women on the pill. Another mechanism besides blood flow is necessary to explain the substantial difference in core body temperature maintained by women on the pill throughout the experimental period. These results suggest that core temperature does not automatically trigger blood perfusion as a mechanism of cooling for women on the pill. Additionally, women in the luteal phase must use other, non-vascular, mechanisms to cool the body during exercise. Finally, the thermoregulatory responses of people on a combination pill do not match the thermoregulatory responses of people in the luteal phase; studies which conflate these two should use caution in their interpretation.</p>\u0000 </section>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 9","pages":""},"PeriodicalIF":1.9,"publicationDate":"2026-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13548345/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148901463","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":"Direct and Indirect Effects of Adolescent Motherhood on Under-Five Mortality in Pakistan: Evidence From a Nationally Representative Survey","authors":"Naeem Rabbani,&nbsp;Zhongliang Zhou,&nbsp;Rashed Nawaz,&nbsp;Neelum Khalid","doi":"10.1002/ajhb.70332","DOIUrl":"10.1002/ajhb.70332","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Background&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Adolescent motherhood is associated with adverse child survival outcomes, particularly in low- and middle-income settings. Maternal and child health (MCH) service utilization may represent an important pathway linking adolescent motherhood with child survival, but evidence from Pakistan remains limited. This study examined the association between adolescent motherhood and under-five mortality and assessed the statistical indirect association through MCH service utilization.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Methods&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;We analyzed nationally representative data from the 2018 Pakistan Demographic and Health Survey, including 8159 mother–child observations. Under-five mortality was examined as a time-to-event outcome. We used multivariable generalized structural equation modeling with a Weibull proportional hazards specification to estimate associations between adolescent motherhood, MCH service utilization, and under-five mortality. We constructed the MCH service utilization index from indicators of antenatal care, skilled delivery care, and postnatal care. Indirect associations were evaluated using 5000 bootstrap replications and 95% bias-corrected bootstrap confidence intervals. All analyses were conducted using STATA version 17.1.&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Results&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Overall, 4.09% of children died before age five, and 37.55% were born to adolescent mothers. After adjustment for prespecified covariates, adolescent motherhood was associated with higher under-five mortality (HR = 2.05, &lt;i&gt;p&lt;/i&gt; &lt; 0.001) and lower MCH service utilization (&lt;i&gt;β&lt;/i&gt; = −0.02, &lt;i&gt;p&lt;/i&gt; = 0.044). Higher MCH service utilization was associated with lower under-five mortality (HR = 0.26, &lt;i&gt;p&lt;/i&gt; &lt; 0.001). After accounting for MCH service utilization, adolescent motherhood remained associated with higher under-five mortality (HR = 1.99, &lt;i&gt;p&lt;/i&gt; &lt; 0.001). The indirect association through MCH service utilization was positive and statistically supported (&lt;i&gt;β&lt;/i&gt; = 0.0223; bootstrap SE = 0.0103; 95% [BCCI: 0.0038–0.0398]).&lt;/p&gt;\u0000 &lt;/section&gt;\u0000 \u0000 &lt;section&gt;\u0000 \u0000 &lt;h3&gt; Conclusion&lt;/h3&gt;\u0000 \u0000 &lt;p&gt;Adolescent motherhood was associated with higher under-five mortality and lower MCH service utilization, while greater MCH service utilization was associated with lower under-five mortality. The findings suggest that differences in MCH service utilization account for part of the observed association between adolescent motherhood and under-five mortality. Improving access to and utilization of MCH services, alongside interventions addressing adolescent pregnancy and broader social determinants of child health, may contribute to improve","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 9","pages":""},"PeriodicalIF":1.9,"publicationDate":"2026-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148907925","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":"Secular Trend in Age at Menarche and Associated Determinants in the Valencian Population (Spain)","authors":"Andrea Beneito,&nbsp;Blanca Sarzo,&nbsp;Raul Beneyto,&nbsp;Reem Abumallouh,&nbsp;Natalia Marin,&nbsp;Oihane Alvarez,&nbsp;Ana Molina-Barceló,&nbsp;Mercedes Vanaclocha-Espí,&nbsp;Carmen Freire,&nbsp;Ferran Ballester,&nbsp;Ana Esplugues,&nbsp;Maria-Jose Lopez-Espinosa","doi":"10.1002/ajhb.70322","DOIUrl":"10.1002/ajhb.70322","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Objective</h3>\u0000 \u0000 <p>To assess secular trend in age at menarche spanning nearly eight decades and to explore variations in these patterns according to selected sociodemographic and anthropometric determinants in the Valencian Community, Spain.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Materials and Methods</h3>\u0000 \u0000 <p>This population-based study included 417 260 participants born between 1931 and 2008. First, secular trend in age at menarche were assessed using time-series models across 5-year birth cohorts for the overall population. Then, 5-year birth cohorts were combined into two groups based on the data availability for the determinant analyses: an earlier-born group (1941–1975), whose age at menarche was reported retrospectively in adulthood, and a later-born group (1991–2005), whose age at menarche was collected during childhood and/or adolescence. Bayesian linear regression models were fitted for each group, adjusting for 5-year birth cohort and continent of birth in all models, and additionally for educational level in the earlier-born group and body mass index (BMI) in the later-born group.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Mean age at menarche decreased by 1.9 years, from 13.1 to 11.1, between the 1931–1935 and 2006–2008 birth cohorts, with a steeper decline after 1975. Compared with European-born participants, those born in South/Central America (<i>β</i> [95% CI]: 0.33 [0.30, 0.36] years) and Africa (0.52 [0.45, 0.58] years) experienced later menarche in the earlier-born group, whereas those born in South/Central America experienced earlier menarche in the later-born group (−0.18 [−0.28, −0.09] years). In the later-born group, lower BMI was associated with later menarche (0.96 [0.74, 1.18] years) whereas higher BMI with earlier onset (−0.53 [−0.57, −0.48] years).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>There was a marked decline in age at menarche in the Valencian Community. Factors associated with age at menarche included continent of birth (with cohort-specific effects) and BMI.</p>\u0000 </section>\u0000 </div>","PeriodicalId":50809,"journal":{"name":"American Journal of Human Biology","volume":"38 9","pages":""},"PeriodicalIF":1.9,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13535273/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148876761","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}