ABSTRACTObjectivesBoth psychosocial stress and current infection can increase the likelihood of reactivation of latent Epstein–Barr virus (EBV). Pregnancy and infection with SARS‐CoV‐2 can be stressful and modulate immune function. However, it is unknown how SARS‐CoV‐2 infection and stress further interact among postpartum women to affect EBV antigen and antibody expression.MethodsWe examined associations among COVID‐19 diagnosis, self‐reported stress, and EBV immunoglobulin G (IgG) in previously collected data from 45 breastfeeding US women (1–18 months postpartum) during the height of the COVID‐19 pandemic. Between June 2020 and March 2021, stress survey data and capillary dried blood HemaSpot samples were collected from 25 SARS‐CoV‐2 infected and 20 non‐infected participants at multiple time points over the course of 60 days. Samples (N = 104) were later assayed for EBV IgG. Statistical methods were pre‐registered, and relationships among SARS‐CoV‐2 infection, stress, and EBV IgG were analyzed via mixed‐effects regression models, adjusting for time postpartum and time elapsed since enrollment.ResultsThere was a statistically significant association between self‐reported stress and EBV IgG levels, with higher average stress associated with higher average EBV IgG. EBV IgG relative concentration did not vary independently with COVID‐19 positivity status or the number of COVID‐19 symptoms.ConclusionsResults suggest that EBV IgG relative concentrations were elevated across sample participants by stress, but not by the relatively mild cases of COVID‐19 the mothers experienced.

ABSTRACTObjectivesThis study assesses the stress‐related impacts of the construction of the Thwake Multipurpose Dam in Makueni, Kenya by examining salivary cortisol concentrations and patterns of diurnal variation.MethodsOne set of evening, waking, and 30‐min post‐waking saliva samples was collected across 221 women who were displaced by the dam or who lived upstream or downstream of the dam development site. Salivary cortisol concentration was analyzed using a commercially available assay kit. Multivariable linear regression was used to assess the relationship between displacement status and waking cortisol concentration, evening cortisol concentration, cortisol awakening response, and diurnal difference.ResultsLog‐transformed evening cortisol concentration (displaced: β = 0.365, p = 0.018; downstream: β = 0.675, p = 0.007) and diurnal difference (displaced: β = 0.034, p = 0.049) were significantly associated with displacement status.ConclusionsBoth displaced and downstream communities demonstrate stress‐related hormonal differences associated with dam‐induced disruption. Future policy and research addressing the health impacts of hydroelectric dam development should include downstream communities in addition to those directly displaced by development.

ABSTRACTObjectivesMorphological differences between parous and nulliparous women have long been interpreted as reproductive signatures. However, such patterns may instead reflect demographic composition. This study aimed to reassess parity‐related morphological variation by reducing confounding from age and BMI using propensity score matching (PSM).MethodsAnthropometric data from 1339 Korean women aged 20–39 years were analyzed. Forty‐five direct and derived body dimensions, collected following ISO 7250‐1:2017, were compared between parous and nulliparous women before and after 1:1 nearest‐neighbor PSM on age and BMI. Group differences were examined for torso breadths, depths, circumferences, and proportional indices.ResultsUnadjusted analyses reproduced well‐known findings: parous women showed greater abdominal breadths and depths, larger circumferences, and adiposity patterns commonly attributed to childbirth. After PSM, however, most differences—including widely cited markers of lower‐body enlargement and postpartum contour change—were substantially attenuated or statistically nonsignificant. Only a small number of proportional indices (e.g., underbust/weight, waist/weight, elbow/weight) retained modest differences, indicating that parity leaves limited, anatomically localized morphological signatures rather than broad structural changes.ConclusionsDemographic composition, rather than reproductive biology alone, accounts for much of the observed variation in cross‐sectional datasets. Matching‐based approaches clarify the independent contribution of parity, strengthen causal inference in anthropometric research, and underscore the need to consider population structure when interpreting life‐history‐related variation in adult female morphology.

ABSTRACTObjectiveThis study aims to investigate whether urinary cortisol can be reliably measured after long‐term storage at −20°C, using urine samples collected in 1993 from rural Bangladeshi women, and assayed after 16 and 30 years (2009 and 2023).MethodsSpecimens were collected by participants, placed in coolers with ice packs, transported to a field lab, and then refrigerated for up to 1 week before processing. Specific gravity was measured, and a 6.5 mL sample was archived at −20°C. Urinary cortisol was assayed in 2009 as part of a prior study using enzyme‐linked immunosorbent assay (ELISA). In 2023, cortisol was measured in a subsample of 200 specimens using the same assay.ResultsOf the 200 specimens, 7 (3.5%) were measured with low precision. Cortisol could not be detected in nine specimens (4.5%). In the remaining 184 specimens, urinary log cortisol levels measured in 2009 and 2023 were positively correlated (r = 0.973, 95% CI: 0.964–0.980; p < 0.0001 and nonparametric rs = 0.795; p < 0.0001). A paired t‐test revealed a bias toward slightly greater values in the 2023 measurements (p < 0.0001).ConclusionThese results suggest that urinary cortisol remains largely intact and measurable in specimens stored at −20°C for three decades, and there is a strong correlation between cortisol measured after 16 and 30 years in storage.

ABSTRACTThe menstrual cycle is increasingly described as a “vital sign of the female body,” with the literature suggesting cycle‐related brain and behavioral changes. With growing interest in the effects that the menstrual cycle has on the brain, body and mind, characterizing what constitutes healthy cycle‐related change has become a central goal of behavioral neuroendocrinology. Considering the epistemological importance of research in behavioral neuroendocrinology for shaping our understanding of cycle‐related effects in menstruating people, a critical examination of how the menstrual cycle is operationalized and studied in this field is warranted. In this narrative review, we first describe some methodological gold standards for investigating the menstrual cycle as an acontextual sex‐related neurohormonal phenomenon, while highlighting ongoing limitations. We then introduce alternative conceptualizations that operationalize the menstrual cycle as context‐contingent and demonstrate the importance of environmental experiences, particularly stress, in influencing cycle‐related brain and behavioral changes. Grounded in a feminist/queer approach to sex/gender difference, we propose a conceptualization of the menstrual cycle that integrates gendered sources of stress and discuss the potential of this approach to enable a more representative operationalization that better accounts for its inherent variability.

ABSTRACTObjectiveHandgrip strength (HGS) provides a dynamic indicator of overall strength and physical fitness. Population‐based investigations of anemia and iron deficiency as predictors of HGS are limited; most studies rely on elderly and/or clinical samples. We assessed iron deficiency, anemia, body mass index (BMI), and body fat percentage as predictors of HGS among a representative cross‐sectional sample of adult residents of Matlab, Bangladesh.MethodsWe collected HGS, anthropometric measurements, and whole blood specimens from a representative, population‐based sample of adults in Matlab. We used hemoglobin to identify anemia and soluble transferrin receptor to identify iron deficiency. We estimated mixed‐effects generalized linear models of HGS.ResultsIron deficiency, but not anemia, was negatively associated with HGS among both men and women. Among men, but not women, underweight BMI was negatively associated with HGS, and overweight BMI was positively associated with HGS.ConclusionsIron nutrition is important for muscles' capacity for work and overall physical fitness, regardless of the presence of anemia. Among men (but not women) in this setting, BMI categories seem to capture differences in muscle tissue as well as adiposity.

ABSTRACTObjectiveTo characterize the metacarpophalangeal pattern profile (MCPP) of healthy children and adolescents from São Paulo, Brazil, and to establish percentile curves by chronological age (CA), bone age (BA), and sex using the LMS method. Additionally, to compare these findings with previous population‐based data and to apply the derived standards to patients with skeletal dysplasias.MethodsLeft hand and wrist radiographs were obtained from healthy individuals and age‐matched patients with confirmed skeletal dysplasias. Tubular bone lengths were compared across CA and BA, against prior normative studies, and with dysplastic cohorts using Student's t‐test. Patient Z‐scores were calculated from LMS parameters generated from the healthy population.ResultsWe analyzed 974 radiographs from healthy subjects and 83 from patients (18 hypochondroplasia, 27 achondroplasia, 14 osteogenesis imperfecta, 24 Turner syndrome). In healthy participants, hand bone lengths correlated significantly with CA and BA. Compared with international reference data, differences in mean metacarpal and phalangeal lengths were noted. Patients with achondroplasia and hypochondroplasia exhibited markedly reduced Z‐scores relative to controls, whereas those with Turner syndrome showed reductions of up to 1.8 SD in the fourth metacarpal. Patients with osteogenesis imperfecta demonstrated no significant deviations.ConclusionThis study established MCPP reference percentiles for Brazilian children and adolescents using the LMS method. Bone measurements showed consistent associations with CA and BA. Although differences were observed relative to international cohorts, the generated standards effectively discriminated dysplastic phenotypes, particularly achondroplasia and hypochondroplasia, supporting the use of MCPP analysis as an adjunct tool for evaluating short stature and suspected skeletal dysplasias.

ABSTRACTObjectivesAltitude shapes human morphology as highland populations must cope with cold and hypoxic environments. Although Andean highlanders have been proposed to exhibit larger and deeper ribcages, this idea is mainly based on research using disarticulated skeletal elements or non‐South American controls. The objective of this research is to study 3D ribcage configuration of native South American populations considering altitude and worldwide ribcage variation.MethodsRibcages of 37 adult South Americans (17 highlanders, 20 lowlanders) were reconstructed and analyzed using 3D geometric morphometrics. Shape variation was assessed through Procrustes MANOVA and PCA, while centroid size was used to test for size differences. Comparisons were also made with a sample of 92 adult worldwide lowlanders.ResultsSouth American highlanders and lowlanders show similar ribcage shapes, both exhibiting a deeper thorax than worldwide lowlanders. No significant differences in absolute ribcage size were detected between South American highlanders and lowlanders. However, a marked sexual dimorphism was observed in both groups, with males having wider and significantly larger ribcages than females.ConclusionsThe pronounced ribcage depth in native South Americans could represent a population‐specific trait maintained through long‐term interactions, potentially advantageous in high‐altitude settings but neutral in the lowlands. In addition, we propose that South American highlanders have a larger ribcage relative to their smaller body size compared to lowlanders. Finally, the larger and stockier male ribcage morphology in South Americans supports the notion of greater respiratory capacity and metabolic demands in males.