Melanie A Martin

• MA, PhD
• Professor (Assistant) at University of Washington

Poor sleep represents a central health disparity for people experiencing homelessness, and any intervention to alleviate the impacts of homelessness should aim to improve sleep. We measured actimetry-based sleep in homeless adults spending their nights in four types of shelters in Seattle, WA, during the summer and winter. Homeless participants exp...

En este trabajo se presentan resultados sobre el estado nutricional en comunidades qom y wichí de la provincia de Formosa. Nuestro enfoque se enmarca en la antropología biológica e intenta entender el crecimiento infantil como un resultado del diálogo entre lo biológico y lo sociocultural. Los qom y los wichí son pueblos originarios de la región de...

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 vari...

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 dete...

While the importance of human milk in shaping infant immune function is well established, the impact of at-the-nipple (ATN) breastfeeding on maternal immune status has been understudied. Since lactation evolved to support infant survival and boost maternal fitness, we predict that ATN breastfeeding will confer benefits on maternal immune function....

Pre-registration of analysis plan.

This repository contains R code and instructions to automatically collate and calculate quality control indices across multiple output files generated from BioTek microplate readers with Gen5 software. This is applicable for researchers conducting laboratory assays with this specific equipment and software. The worked example was developed for outp...

The hypothalamic-pituitary-adrenal (HPA) and gonadal (HPG) axes partially regulate the timing of child-to-adult phenotypic transitions. 'Hormonal Coupling' describes relationships between 2+ hormones (e.g., cortisol, testosterone), leveraged to understand why HPA-HPG crosstalk is expected in adolescence. Evolutionary theorists suggest the HPA and H...

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 attendanc...

Childhood psychosocial stressors have been proposed to favor 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 exten...

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 c...

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 exte...

Background Human milk oligosaccharides (HMOs) are an abundant class of compounds found in human milk and have been linked to the development of the infant and specifically the brain, immune system, and gut microbiome. Objectives Advanced analytical methods were used to obtain relative quantitation of many structures in approximately 2000 samples f...

Background and objectives Cesarean section may lead to suboptimal breastfeeding outcomes, though evidence has been mixed. Factors, such as premature birth, birth weight and maternal age may independently increase risk of cesarean and hinder breastfeeding initiation, while maternal preferences, support and sociostructural barriers may influence brea...

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 20...

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....

Selective and neutral forces shape human microbiota assembly in early life. The Tsimane are an indigenous Bolivian population with infant care-associated behaviors predicted to increase mother-infant microbial dispersal. Here, we characterize microbial community assembly in 47 infant-mother pairs from six Tsimane villages, using 16S rRNA gene ampli...

Little is known about the relative contributions of selective and neutral forces on human-associated microbiota assembly. Here, we characterize microbial community assembly in 52 Tsimane infant-mother pairs, using longitudinally collected stool and tongue swab samples profiled with 16S rRNA gene amplicon sequencing. The Tsimane are an indigenous Bo...

Biological anthropology in 2018 encapsulated what past scholars envisioned for its future: a multidisciplinary approach to understanding human and nonhuman primate evolution and diversity using the most innovative techniques and rigorous standards available. This year also built on a tradition of introspection about what biological anthropology enc...

Anthropometric measures are commonly converted to age stratified z-scores to examine variation in growth outcomes in mixed-age and sex samples. For many study populations, z-scores will differ if calculated from World Health Organization (WHO) growth standards or within-population references. The specific growth reference used may influence statist...

Independent variable selection & category construction. (DOCX)

Summary results for Models 1a-9f & age interactions. Full results for all regression models and age interactions in select models. (XLSX)

Supplementary Figures. Scatter plots of WHO and Tsimane-derived HAZ scores showing differences in age interactions with CF and number of siblings. (PDF)

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 assoc...

Background: Traditional diets are often credited for the robust cardiometabolic health of subsistence populations. Yet, rural subsistence populations are undergoing nutrition transitions that have been linked to the increase in chronic noncommunicable diseases. Few studies have presented detailed dietary estimates in transitioning populations. Ob...

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 a...

Current age-based breastfeeding recommendations are supported by ample evidence and improve maternal and infant health. However, mixed-feeding trajectories-from complementary feeding introduction to full weaning-vary widely across populations. While numerous sociocultural factors influence this variation, comparative primate and human biological an...

Phthalates are a class of plasticizing chemicals produced in high volume and widely found in consumer products. Evidence suggests that phthalates may have non-monotonic effects on reproductive hormone activity. With exposure to phthalates virtually ubiquitous among industrialized populations, identifying unexposed and/or minimally exposed human pop...

Interregional encounters frequently result in dietary, health, and cultural changes for participating groups. This paper investigates the patterns and pathways of dietary change among the Mulia Dani of highland western New Guinea, who at the time of data collection had been in contact with Christian missionaries and the global food market for 29 ye...

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-of...

Background: Premastication, the transfer of pre-chewed food, is a common infant and young child feeding practice among the Tsimane, forager-horticulturalists living in the Bolivian Amazon. Research conducted primarily with Western populations has shown that infants harbor distinct oral microbiota from their mothers. Premastication, which is less c...

No abstract is available for this article.

Rarefaction of 16S rRNA gene sequences of 24 saliva and two premasticated food samples

Change of phylogenetic distance between mothers and infants Average dissimilarity distances between each infant and all mothers are negatively correlated with infant age, r = 0.64, p = 0.025. Average dissimilarity distances between a mother and all infants are not correlated with maternal age, r = − 0.33, p = 0.293.

Supplemental Tables

Average relative abundance of 15 genera previously linked to gingivitis Graph depicts values in log scale (log10(x) + 10). Asterisks denote significant differences in abundance between maternal and infant samples (∗p < 0.05, ∗∗p < 0.01).

No abstract is available for this article.

This PDF file includes: Materials and Methods Supplementary Results Figures S1-S8 Tables S1-S7 Captions for databases S1 to S2 References Other Supplementary Materials for this manuscript includes the following: Database S1: AFRdata.csv Database S2: IPIdata.csv

Parasitic worms influence human fecundity Parasitic worms infect 2 billion people globally. Mostly, such infections are symptomless and individual worm burdens are low. Blackwell et al. monitored the fecundity of Tsimane women in Bolivia. These women have on average of 10 children in their lifetimes. However, if they had successive hookworm infecti...

Co-infection may affect transmission and recovery from infection, but remains an understudied element of disease ecology, particularly with regard to antagonism between parasites sharing a host. Helminth and giardia infections are often endemic in the same populations and both occupy the small intestine; yet few studies have examined interactions b...

Hosts are commonly infected with multiple species of parasites and pathogens. These species may interact both directly, through competition for resources and establishment, and indirectly, by eliciting immune responses that may be agonistic or synergistic. During human evolution, hominin ancestors harbored multiple species of symbiotic microorganis...

Primates harbor diverse communities of gut bacteria that enhance host energy extraction, regulate metabolism and energy storage, protect against pathogens, and modulate immune responses. The Dynamic host-gut bacterial relationship begins at birth, when maternal and environmental bacteria colonize sterile infant GI Tracts. Host diet and exposure to...

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...

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 sh...