Longitudinal analysis of cortisol changes during pubertal development in indigenous Qom girls.

Pubertal research has primarily focused on hypothalamic-pituitary-gonadal axis (HPG) regulation of puberty, though the hypothalamic-pituitary-adrenal axis (HPA) is increasingly considered critical. Heightened HPA function proxied by increasing cortisol levels may play a role in accelerated pubertal timing. However, the extent to which cortisol varies across ages and its relation to pubertal changes in linear growth are less well substantiated. We explored relationships between age, linear growth, adiposity, C-peptide (proxy for insulin), and cortisol across puberty, and we tested whether higher cortisol levels are associated with earlier ages at menarche and peak height velocity. We utilize longitudinal data (n = 777 urine samples) from Qom females ages 7-14 (n = 46) and test our pre-registered analysis using Bayesian longitudinal mixed effects models and joint modeling techniques. We find limited evidence supporting the overarching hypothesis that HPA upregulation is associated with pubertal maturation or timing. We find some evidence that HPA upregulation, as proxied by cortisol, may be more clearly related to differences in relative linear growth at early-mid puberty, as measured by height-for-age z-scores. Transdisciplinary perspectives on puberty, including the assumption that stressors acting via cortisol accelerate pubertal development, are discussed.

Birth mode and infectious morbidity risks in Qom children of Argentina.

OBJECTIVES: Cesarean delivery may increase childhood infectious morbidity risks via altered birth exposures and subsequent immune, microbial, and epigenetic development. Many Latin American indigenous populations experience dual burdens of infectious and chronic diseases, and are particularly vulnerable to rising rates of cesarean delivery and associated adverse outcomes. The Qom/Toba are an indigenous population in Argentina experiencing rapid lifestyle transitions. We hypothesized that cesarean delivery would be associated with increased risk of infectious symptoms in Qom children after adjusting for gestational and nutritional factors. METHODS: We conducted a secondary analysis of birth records and monthly anthropometric and illness data collected previously from 90 Qom children (aged 1-55 months). We tested for additive effects of birth mode on risk of gastrointestinal (GI) and respiratory illness (RI) in mixed-effects logistic regression models adjusting for child weight-for-age (WAZ), weaning, and gestational and maternal age. RESULTS: Cesarean deliveries accounted for 46% of births and were associated with maternal age < 20 and ≥ 30 years, gestational age < 39 weeks, and prenatal complications. GI and RI risks were reduced in association with cesarean delivery, greater WAZ, weaning, maternal age ≥ 30 years, and gestational age < 39 weeks. CONCLUSIONS: The relationship between cesarean delivery and reduced infectious risks may reflect statistical confounding with relatively rapid postnatal growth and greater adiposity. Postnatal growth trajectories may be important mediators of long-term morbidity risks associated with cesarean delivery. The frequency of cesarean deliveries among the Qom remains concerning given traditionally high rates of fertility and adolescent pregnancy.

Timing of pubertal growth and menarche in indigenous Qom girls of Argentina.

BACKGROUND: Pubertal timing is in part mediated by environmental factors, with greater energy availability often associated with earlier or more rapid development. Many indigenous populations are undergoing socioeconomic change that may affect pubertal development and related health risks, necessitating fundamental longitudinal research on growth and development in these populations. AIM: Growth velocity and time to menarche among peri-urban indigenous Qom (Toba) girls in Argentina are described. SUBJECTS AND METHODS: From 2011-2015, monthly anthropometrics and menstrual status were collected from 61 Qom girls aged 7-14. Growth velocity curves were generated using the 'Super-imposition by translation and rotation' (SITAR) method. Median time to menarche was estimated by Kaplan-Meier survival analysis. RESULTS: Mean ages at peak height, weight and BMI velocity were estimated at 10.8, 10.5 and 10.7 years and median age at menarche at 11.6 years (95% CI = 11.4-11.9). At menarche, 45% of girls were overweight or obese and only one participant was short-statured by international standards. CONCLUSION: Qom participants in this study exhibit relatively fast pubertal development as compared to other Latin American indigenous populations studied previously by others. Genetic and environmental factors influencing body size, diet and/or activity levels should be investigated further in this population.

Social Determinant Pathways to Hypertensive Disorders of Pregnancy Among Nulliparous U.S. Women.

BACKGROUND: Hypertensive disorders of pregnancy are a leading cause of maternal morbidity and mortality in the United States and impact Black mothers at disproportionately higher rates. Hypertensive disparities among racialized groups are rooted in systemic inequalities, and we hypothesize that clinical markers of allostatic load capture embodied disparities in stressors that can link upstream social determinants of health with downstream hypertensive outcomes. METHODS: We analyzed observational cohort data from the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be (n = 6,501) and developed a structural equation model linking latent social determinants of health, longitudinal markers of allostatic load across gestation, and hypertensive pregnancy outcomes in a multigroup framework. RESULTS: Non-Hispanic Black mothers-to-be (n = 1,155) showed higher rates of hypertensive disorders of pregnancy (32%) than non-Hispanic white women (n = 5,346, 23%). Among both groups, the social environment showed stronger direct effects on allostatic markers than via behaviorally mediated dietary, exercise, or smoking pathways. Demographic aspects of the social environment (e.g., household income, partnered status) were the most salient predictor of hypertensive risk and showed stronger effects among Black women. CONCLUSIONS: Embodied stress rooted in the social environment is a major path driving maternal hypertensive disparities in the United States, with effects that vary across racialized groups. These pathway findings underscore the greater impact of systemic stressors relative to individual health behaviors. More comprehensive and detailed analyses of sociostructural domains are needed to identify promising avenues for policy and intervention to improve maternal health.

Prevalence and duration of SARS-CoV-2 fecal shedding in breastfeeding dyads following maternal COVID-19 diagnosis.

Background: There is a paucity of data on the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in feces of lactating women with coronavirus disease 2019 (COVID-19) and their breastfed infants as well as associations between fecal shedding and symptomatology. Objective: We examined whether and to what extent SARS-CoV-2 is detectable in the feces of lactating women and their breastfed infants following maternal COVID-19 diagnosis. Methods: This was a longitudinal study carried out from April 2020 to December 2021 involving 57 breastfeeding maternal-infant dyads: 33 dyads were enrolled within 7 d of maternal COVID-19 diagnosis, and 24 healthy dyads served as controls. Maternal/infant fecal samples were collected by participants, and surveys were administered via telephone over an 8-wk period. Feces were analyzed for SARS-CoV-2 RNA. Results: Signs/symptoms related to ears, eyes, nose, and throat (EENT); general fatigue/malaise; and cardiopulmonary signs/symptoms were commonly reported among mothers with COVID-19. In infants of mothers with COVID-19, EENT, immunologic, and cardiopulmonary signs/symptoms were most common, but prevalence did not differ from that of infants of control mothers. SARS-CoV-2 RNA was detected in feces of 7 (25%) women with COVID-19 and 10 (30%) of their infants. Duration of fecal shedding ranged from 1-4 wk for both mothers and infants. SARS-CoV-2 RNA was sparsely detected in feces of healthy dyads, with only one mother's and two infants' fecal samples testing positive. There was no relationship between frequencies of maternal and infant SARS-CoV-2 fecal shedding (P=0.36), although presence of maternal or infant fever was related to increased likelihood (7-9 times greater, P≤0.04) of fecal shedding in infants of mothers with COVID-19.

COVID-19 stay-at-home restrictions increase the alignment in sleep and light exposure between school days and weekends in university students.

Younger adults have a biological disposition to sleep and wake at later times that conflict with early morning obligations like work and school; this conflict leads to inadequate sleep duration and a difference in sleep timing between school days and weekends. The COVID-19 pandemic forced universities and workplaces to shut down in person attendance and implement remote learning and meetings that decreased/removed commute times and gave students more flexibility with their sleep timing. To determine the impact of remote learning on the daily sleep-wake cycle we conducted a natural experiment using wrist actimetry monitors to compare activity patterns and light exposure in three cohorts of students: pre-shutdown in-person learning (2019), during-shutdown remote learning (2020), and post-shutdown in-person learning (2021). Our results show that during-shutdown the difference between school day and weekend sleep onset, duration, and midsleep timing was diminished. For instance, midsleep during school days pre-shutdown occurred 50 min later on weekends (5:14 ±â€…12 min) than school days (4:24 ±â€…14 min) but it did not differ under COVID restrictions. Additionally, we found that while the interindividual variance in sleep parameters increased under COVID restrictions the intraindividual variance did not change, indicating that the schedule flexibility did not cause more irregular sleep patterns. In line with our sleep timing results, school day vs. weekend differences in the timing of light exposure present pre- and post-shutdown were absent under COVID restrictions. Our results provide further evidence that increased freedom in class scheduling allows university students to better and consistently align sleep behavior between school days and weekends.

Fatty acid composition in the mature milk of Bolivian forager-horticulturalists: controlled comparisons with a US sample.

Breast milk fatty acid (FA) composition varies greatly among individual women, including in percentages of the long-chain polyunsaturated FAs (LCPUFA) 20:4n-6 (arachidonic acid, AA) and 22:6n-3 (docosahexaenoic acid, DHA), which are important for infant neurological development. It has been suggested that owing to wide variation in milk LCPUFA and low DHA in Western diets, standards of milk FA composition should be derived from populations consuming traditional diets. We collected breast milk samples from Tsimane women at varying lactational stages (6-82 weeks). The Tsimane are an indigenous, natural fertility, subsistence-level population living in Amazonia Bolivia. Tsimane samples were matched by lactational stage to samples from a US milk bank, and analysed concurrently for FA composition by gas-liquid chromatography. We compared milk FA composition between Tsimane (n = 35) and US (n = 35) mothers, focusing on differences in LCPUFA percentages that may be due to population-typical dietary patterns. Per total FAs, the percentages of AA, DHA, total n-3 and total n-6 LCPUFA were significantly higher among Tsimane mothers. Mean percentages of 18:2n-6 (linoleic acid) and trans FAs were significantly higher among US mothers. Tsimane mothers' higher milk n-3 and n-6 LCPUFA percentages may be due to their regular consumption of wild game and freshwater fish, as well as comparatively lower intakes of processed foods and oils that may interfere with LCPUFA synthesis.

Traditional and biomedical maternal and neonatal care practices in a rural Indigenous population of the Bolivian Amazon.

In recent decades, Bolivia has expanded maternal and child health insurance coverage to improve access to prenatal and early life health care. Nationally, however, maternal and child health disparities persist along a rural-urban divide. Research is needed among rural populations to better understand local barriers to health care access and usage. Particularly among Indigenous populations, disparities may be compounded by differences in preferences for and access to traditional versus biomedical health care. We examined prenatal care and birth practices among Tsimane forager-farmers of El Beni, Bolivia. From 2012-2013, we interviewed 151 Tsimane mothers (0-35 months postpartum) from nine villages about birth and neonatal care practices, prenatal care, and pharmaceutical usage during labour and postpartum recovery. Results demonstrate local disparities in biomedical care usage by ease of access (e.g. proximity to market town, Spanish fluency), and maternal experience (e.g. parity and prior offspring death or miscarriage). While 59% of interviewed mothers had received at least one prenatal screening, services performed in screenings were limited. Nearly all women continue to birth at home with family assistance. Inconsistent access to health care services may be exacerbated by regional, generational, and educational disparities within the population.

Psychosocial and energetic factors on human female pubertal timing: a systematized review.

Childhood psychosocial stressors have been proposed to favour fast life history strategies promoting earlier puberty in females. However, studies demonstrating this association often do not elucidate causal mechanisms, nor account for greater childhood energetic availability - also known to promote rapid growth and earlier puberty. To assess the extent to which such confounding has been considered, we conducted a systematized review to identify studies examining measures of both prepubertal growth (e.g. weight, height) and psychosocial stressors (e.g. adversity, father absence) in relation to female pubertal timing. A total of 1069 non-duplicated studies were identified across five databases. Twenty studies met selection criteria for critical review following independent screening of titles, abstracts and manuscripts. Within these studies, measures indicative of rapid childhood growth were more consistently associated with earlier pubertal timing than were measures of psychosocial stress. We discuss future research directions to investigate the impact of psychosocial stress on pubertal timing more robustly, including methodological and mechanistic considerations, and contextualization of findings by socioecological environments.

SARS-CoV-2 specific antibody trajectories in mothers and infants over two months following maternal infection.

Infants exposed to caregivers infected with SARS-CoV-2 may have heightened infection risks relative to older children due to their more intensive care and feeding needs. However, there has been limited research on COVID-19 outcomes in exposed infants beyond the neonatal period. Between June 2020 - March 2021, we conducted interviews and collected capillary dried blood spots from 46 SARS-CoV-2 infected mothers and their infants (aged 1-36 months) for up to two months following maternal infection onset (COVID+ group, 87% breastfeeding). Comparative data were also collected from 26 breastfeeding mothers with no known SARS-CoV-2 infection or exposures (breastfeeding control group), and 11 mothers who tested SARS-CoV-2 negative after experiencing symptoms or close contact exposure (COVID- group, 73% breastfeeding). Dried blood spots were assayed for anti-SARS-CoV-2 S-RBD IgG and IgA positivity and anti-SARS-CoV-2 S1 + S2 IgG concentrations. Within the COVID+ group, the mean probability of seropositivity among infant samples was lower than that of corresponding maternal samples (0.54 and 0.87, respectively, for IgG; 0.33 and 0.85, respectively, for IgA), with likelihood of infant infection positively associated with the number of maternal symptoms and other household infections reported. COVID+ mothers reported a lower incidence of COVID-19 symptoms among their infants as compared to themselves and other household adults, and infants had similar PCR positivity rates as other household children. No samples returned by COVID- mothers or their infants tested antibody positive. Among the breastfeeding control group, 44% of mothers but none of their infants tested antibody positive in at least one sample. Results support previous research demonstrating minimal risks to infants following maternal COVID-19 infection, including for breastfeeding infants.

Milk From Women Diagnosed With COVID-19 Does Not Contain SARS-CoV-2 RNA but Has Persistent Levels of SARS-CoV-2-Specific IgA Antibodies.

Background: Limited data are available regarding the balance of risks and benefits from human milk and/or breastfeeding during and following maternal infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Objective: To investigate whether SARS-CoV-2 can be detected in milk and on the breast after maternal coronavirus disease 2019 (COVID-19) diagnosis; and characterize concentrations of milk immunoglobulin (Ig) A specific to the SARS-CoV-2 spike glycoprotein receptor binding domain (RBD) during the 2 months after onset of symptoms or positive diagnostic test. Methods: Using a longitudinal study design, we collected milk and breast skin swabs one to seven times from 64 lactating women with COVID-19 over a 2-month period, beginning as early as the week of diagnosis. Milk and breast swabs were analyzed for SARS-CoV-2 RNA, and milk was tested for anti-RBD IgA. Results: SARS-CoV-2 was not detected in any milk sample or on 71% of breast swabs. Twenty-seven out of 29 (93%) breast swabs collected after breast washing tested negative for SARS-CoV-2. Detection of SARS-CoV-2 on the breast was associated with maternal coughing and other household COVID-19. Most (75%; 95% CI, 70-79%; n=316) milk samples contained anti-RBD IgA, and concentrations increased (P=.02) during the first two weeks following onset of COVID-19 symptoms or positive test. Milk-borne anti-RBD IgA persisted for at least two months in 77% of women. Conclusion: Milk produced by women with COVID-19 does not contain SARS-CoV-2 and is likely a lasting source of passive immunity via anti-RBD IgA. These results support recommendations encouraging lactating women to continue breastfeeding during and after COVID-19 illness.

Variation among populations in the immune protein composition of mother's milk reflects subsistence pattern.

LAY SUMMARY: Adaptive immune proteins in mothers' milk are more variable than innate immune proteins across populations and subsistence strategies. These results suggest that the immune defenses in milk are shaped by a mother's environment throughout her life. BACKGROUND AND OBJECTIVES: Mother's milk contains immune proteins that play critical roles in protecting the infant from infection and priming the infant's developing immune system during early life. The composition of these molecules in milk, particularly the acquired immune proteins, is thought to reflect a mother's immunological exposures throughout her life. In this study, we examine the composition of innate and acquired immune proteins in milk across seven populations with diverse disease and cultural ecologies. METHODOLOGY: Milk samples (n = 164) were collected in Argentina, Bolivia, Nepal, Namibia, Philippines, Poland and the USA. Populations were classified as having one of four subsistence patterns: urban-industrialism, rural-shop, horticulturalist-forager or agro-pastoralism. Milk innate (lactalbumin, lactoferrin and lysozyme) and acquired (Secretory IgA, IgG and IgM) protein concentrations were determined using triple-quadrupole mass spectrometry. RESULTS: Both innate and acquired immune protein composition in milk varied among populations, though the acquired immune protein composition of milk differed more among populations. Populations living in closer geographic proximity or having similar subsistence strategies (e.g. agro-pastoralists from Nepal and Namibia) had more similar milk immune protein compositions. Agro-pastoralists had different milk innate immune protein composition from horticulturalist-foragers and urban-industrialists. Acquired immune protein composition differed among all subsistence strategies except horticulturist-foragers and rural-shop. CONCLUSIONS AND IMPLICATIONS: Our results reveal fundamental variation in milk composition that has not been previously explored in human milk research. Further study is needed to understand what specific aspects of the local environment influence milk composition and the effects this variation may have on infant health outcomes.

Conflict or congruence? Maternal and infant-centric factors associated with shorter exclusive breastfeeding durations among the Tsimane.

Six months of exclusive breastfeeding (EBF) is considered optimal for infant health, though globally most infants begin complementary feeding (CF) earlier-including among populations that practice prolonged breastfeeding. Two frameworks for understanding patterns of early CF emerge in the literature. In the first, maternal and infant needs trade-off, as "maternal-centric" factors-related to time and energy demands, reproductive investment, cultural influences, and structural barriers- favor supplanting breastfeeding with earlier and increased CF. A second framework considers that "infant-centric" factors-related to infant energetic needs-favor CF before six months to supplement breastfeeding. We apply these two frameworks in examining early CF among the Tsimane-a high-fertility, high-mortality, forager-horticulturalist population residing in the Bolivian Amazon. Data were collected from a mixed-longitudinal sample of 161 Tsimane mother-infant pairs from August 2012-April 2013. Tsimane mothers generally reported introducing CF because of perceived infant needs. However, CF is introduced with continued intensive breastfeeding, and generally coupled with premastication. Risks of earlier CF relative to the minimum hazard (estimated at 5 births) were elevated for lower and higher parity mothers, but were significantly greater only after 9 births. Seventeen percent of mothers reported introducing CF because of low milk supply. Introducing CF because of low milk was most common from 0 to 3 months of age and among higher parity mothers, which may reflect physiological constraints. Maternal reproductive trade-offs and perceived infant needs may help explain the low prevalence of EBF to six months among other populations in which breastfeeding is not structurally or culturally constrained.

Evidence for a peak shift in a humoral response to helminths: age profiles of IgE in the Shuar of Ecuador, the Tsimane of Bolivia, and the U.S. NHANES.

BACKGROUND: The peak shift model predicts that the age-profile of a pathogen's prevalence depends upon its transmission rate, peaking earlier in populations with higher transmission and declining as partial immunity is acquired. Helminth infections are associated with increased immunoglobulin E (IgE), which may convey partial immunity and influence the peak shift. Although studies have noted peak shifts in helminths, corresponding peak shifts in total IgE have not been investigated, nor has the age-patterning been carefully examined across populations. We test for differences in the age-patterning of IgE between two South American forager-horticulturalist populations and the United States: the Tsimane of Bolivia (n=832), the Shuar of Ecuador (n=289), and the U.S. NHANES (n=8,336). We then examine the relationship between total IgE and helminth prevalences in the Tsimane. METHODOLOGY/PRINCIPAL FINDINGS: Total IgE levels were assessed in serum and dried blood spots and age-patterns examined with non-linear regression models. Tsimane had the highest IgE (geometric mean =8,182 IU/ml), followed by Shuar (1,252 IU/ml), and NHANES (52 IU/ml). Consistent with predictions, higher population IgE was associated with steeper increases at early ages and earlier peaks: Tsimane IgE peaked at 7 years, Shuar at 10 years, and NHANES at 17 years. For Tsimane, the age-pattern was compared with fecal helminth prevalences. Overall, 57% had detectable eggs or larva, with hookworm (45.4%) and Ascaris lumbricoides (19.9%) the most prevalent. The peak in total IgE occurred around the peak in A. lumbricoides, which was associated with higher IgE in children <10, but with lower IgE in adolescents. CONCLUSIONS: The age-patterning suggests a peak shift in total IgE similar to that seen in helminth infections, particularly A. lumbricoides. This age-patterning may have implications for understanding the effects of helminths on other health outcomes, such as allergy, growth, and response to childhood vaccination.