Aaron Blackwell

Aaron Blackwell
Washington State University | WSU · Department of Anthropology

PhD University of Oregon, Biological Anthropology

About

134
Publications
14,707
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2,103
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Introduction
Aaron Blackwell currently works at the Department of Anthropology, Washington State University. Aaron does research in Biological Anthropology, Evolutionary Medicine, and Disease Ecology.
Additional affiliations
August 2018 - present
Washington State University
Position
  • Professor (Associate)
July 2012 - present
University of California, Santa Barbara
Position
  • Professor (Assistant)
January 2010 - June 2012
University of California, Santa Barbara
Position
  • PostDoc Position

Publications

Publications (134)
Article
Full-text available
Objectives: Growth standards and references currently used to assess population and individual health are derived primarily from urban populations, including few individuals from indigenous or subsistence groups. Given environmental and genetic differences, growth may vary in these populations. Thus, there is a need to assess whether international...
Article
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Infection with intestinal helminths results in immunological changes that influence co-infections, and might influence fecundity by inducing immunological states affecting conception and pregnancy.We investigated associations between intestinal helminths and fertility in women, using 9 years of longitudinal data from 986 Bolivian forager-horticultu...
Article
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Background: Amazonian populations are exposed to diverse parasites and pathogens, including protozoal, bacterial, fungal and helminthic infections. Yet much knowledge of the immune system is based on industrialised populations where these infections are relatively rare. Aim: This study examines distributions and age-related differences in 22 mea...
Article
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Helminths are parasitic nematodes and trematodes, grouped together because of morphological similarities and commonalities in the effects infections have on hosts. These include complications such as anemia and biasing of immune responses, which can alter susceptibility for other diseases. For pregnant women, these complications might have implicat...
Article
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Objectives: Despite well-known fitness advantages to males who produce and maintain high endogenous testosterone levels, such phenotypes may be costly if testosterone-mediated investment in reproductive effort trade-off against investment in somatic maintenance. Previous studies of androgen-mediated trade-offs in human immune function find mixed r...
Article
The original hygiene hypothesis proposed that certain diseases derive from low levels of early-life microbial exposure. Since then, the hypothesis has been applied to numerous inflammatory, autoimmune, and allergic conditions. The changes in hygiene linked to these diseases include numerous changes in biotic exposure and lifestyle. To this end, som...
Article
Objective: Immune function is multifaceted and characterizations based on single biomarkers may be uninformative or misleading, particularly when considered across ecological contexts. However, measuring the many facets of immunity in the field can be challenging, since many measures cannot be obtained on-site, necessitating sample preservation an...
Article
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Objective Cytomegalovirus (CMV) infection is associated with age-related chronic disease, and co-infection with Epstein-Barr virus (EBV) may compound disease risk. We aimed to assess the frequency of CMV infection and its relationship with age among EBV seropositive individuals in an Indigenous Amazonian population. Methods We report concentration...
Preprint
The human lineage entered a more carnivorous niche 2.6 mya. A range of evidence indicates this increased zoonotic pathogen pressure. This evidence includes increased zoonotic infections modern hunter-gatherers and bushmeat hunters relative to others living in the same environments, exceptionally low stomach pH compared to other primates, human-spec...
Article
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Background Soil-transmitted helminths (STHs) and humans share long co-evolutionary histories over which STHs have evolved strategies to permit their persistence by downregulating host immunity. Understanding the interactions between STHs and other pathogens can inform our understanding of human evolution and contemporary disease patterns. Methodol...
Preprint
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Background: Soil-transmitted helminth (STH) infections can catalyze immunological changes that affect the response to subsequent infections, particularly those that elicit strong inflammatory responses. As globalization heightens the risk that remote communities with high STH prevalence will encounter novel pathogens, understanding how STHs shape i...
Article
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Background Soil-transmitted helminths (STHs) and humans share long co-evolutionary histories over which STHs have evolved strategies to permit their persistence by downregulating host immunity. Understanding the interactions between STHs and other pathogens can inform our understanding of human evolution and contemporary disease patterns. Methodolo...
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In high-income countries, one's relative socio-economic position and economic inequality may affect health and well-being, arguably via psychosocial stress. We tested this in a small-scale subsistence society, the Tsimane, by associating relative household wealth (n=871) and community-level wealth inequality (n=40, Gini = 0.15 – 0.53) with a range...
Article
Objective: The current study evaluates the feasibility of using clinical cranial computed tomography (CT) scans for assessing the presence and morphology of porous cranial lesions (cribra orbitalia, porotic hyperostosis). Methods: Observers (n = 4) conducted three independent evaluations of porous cranial lesions based on photographs , 2-D CT, and...
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Objective Anemia is an important global health challenge. We investigate anemia prevalence among Indigenous Shuar of Ecuador to expand our understanding of population‐level variation, and to test hypotheses about how anemia variation is related to age, sex, and market integration. Methods Hemoglobin levels were measured in a total sample of 1650 S...
Article
Significance Disgust likely evolved to regulate exposure to pathogen-related stimuli and behaviors. One key prediction, that individuals with greater pathogen disgust sensitivity (PDS) will be exposed to fewer pathogens and thus suffer fewer infections, has never been tested directly. To function adaptively, PDS must respond to the local cost/benef...
Article
Objectives: Flow cytometry is a powerful tool for investigating immune function, allowing for the quantification of leukocytes by subtype. Yet it has not been used extensively for field work due to perishable reagents and the need for immediate analysis of samples. To make flow cytometry more accessible, we devise and evaluate a field protocol for...
Article
A substantial body of research has illuminated psychological adaptations motivating pathogen avoidance, mechanisms collectively known as the behavioral immune system. Can knowledge about these mechanisms inform how people respond to widespread disease outbreaks, such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [coronavirus d...
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The intensifying pace of research based on cross-cultural studies in the social sciences necessitates a discussion of the unique challenges of multi-sited research. Given an increasing demand for social scientists to expand their data collection beyond WEIRD (Western, educated, industrialized, rich and democratic) populations, there is an urgent ne...
Article
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Background: In an energy-limited environment, caloric investments in one characteristic should trade-off with investments in other characteristics. In high pathogen ecologies, biasing energy allocation towards immune function over growth would be predicted, given strong selective pressures against early-life mortality. Methodology: In the presen...
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Background Altered hypothalamic–pituitary–adrenal (HPA) function and related changes in circulating glucocorticoids have been implicated in the pathogenesis of numerous diseases that involve dysregulated immune function. Glucocorticoid hormones have both direct and indirect modulatory effects on both pro‐ and anti‐inflammatory aspects of the immune...
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Background and objectives: Among placental mammals, females undergo immunological shifts during pregnancy to accommodate the fetus (i.e. fetal tolerance). Fetal tolerance has primarily been characterized within post-industrial populations experiencing evolutionarily novel conditions (e.g. reduced pathogen exposure), which may shape maternal respon...
Article
Background and objectives: Among placental mammals, females undergo immunological shifts during pregnancy to accommodate the fetus (i.e. fetal tolerance). Fetal tolerance has primarily been characterized within post-industrial populations experiencing evolutionarily novel conditions (e.g. reduced pathogen exposure), which may shape maternal respons...
Preprint
Full-text available
In high-income countries, relative wealth and inequality affect health by causing psychosocial stress. We test this hypothesis in a small-scale subsistence society, the Tsimane. We associated relative household wealth (n=1003) and community-level wealth inequality (n=35, Gini = 0.15 – 0.43) with a range of psychosocial and health outcomes (depressi...
Preprint
Full-text available
The intensifying pace of research based on cross-cultural studies in the social sciences necessitates a discussion of the unique challenges of multi-sited research. Given an increasing demand for social scientists to expand their data collection beyond WEIRD (western, educated, industrialized, rich, and democratic) populations, there is an urgent n...
Article
Full-text available
High social status is often associated with greater mating opportunities and fertility for men, but do women also obtain fitness benefits of high status? Greater resource access and child survivorship may be principal pathways through which social status increases women's fitness. Here, we examine whether peer-rankings of women's social status (ind...
Article
High social status is often associated with greater mating opportunities and fertility for men, but do women also obtain fitness benefits of high status? Greater resource access and child survivorship may be principal pathways through which social status increases women’s fitness. Here we examine whether peer-rankings of women’s social status (indi...
Article
Objectives: Despite public health concerns about hookworm infection in pregnancy, little is known about immune profiles associated with hookworm (Necator americanus and Ancylostoma duodenale) infection during pregnancy. Fetal tolerance requirements may constrain maternal immune response to hookworm, thereby increasing susceptibility to new infecti...
Article
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Objectives: A core assumption of life history theory and the immunocompetence handicap hypothesis (ICHH) is that testosterone (T) upregulates energetic investment in mating effort at the expense of immunity. This tenet, along with observed positive relationships between estrogens and immunity, may contribute to the higher observed morbidity and mo...
Article
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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...
Data
Independent variable selection & category construction. (DOCX)
Data
Summary results for Models 1a-9f & age interactions. Full results for all regression models and age interactions in select models. (XLSX)
Data
Supplementary Figures. Scatter plots of WHO and Tsimane-derived HAZ scores showing differences in age interactions with CF and number of siblings. (PDF)
Article
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"We appreciate Ocobock's interest in methodological rigor. We largely agree with her commentary, which suggests that departures from standard protocols might have contributed to the high resting metabolic rate (RMR) measured for Tsimane. Indeed, our paper acknowledges many of the key departures from gold-standard indirect calorimetry methods of RMR...
Article
A comparison of men who migrated from Bangladesh to the United Kingdom at different ages, alongside men who were lifelong residents of both countries, reveals that early environments determine levels of reproductive hormones and secondary sexual characteristics.
Article
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Shamans can have efficacy at healing through botanical remedies and in observational and advisory functions through cognitive strengths, while shamanic acts of strangeness are likely honest signals of these qualities. Given this potential for shamanic practices to have true efficacy and the capacity for honest signaling, we expect efficacy will inf...
Article
Physiology and behavior are best thought of as two aspects of the same biological process, shaped simultaneously by natural selection. Like behavioral strategies, ecological conditions may affect physiological strategies, leading to changes in immunity and hormonal regulation. These alternate strategies help explain the health correlations of depri...
Article
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Objectives: Numerous studies link low objective and subjective socioeconomic status (SES) to chronic activation of the hypothalamic pituitary adrenal (HPA) axis. Here, we examine associations between objective and subjective SES and diurnal salivary cortisol, a primary HPA component, as well as demographic and ecological predictors associated with...
Article
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Objectives: Humans-and several other apes-exhibit a unique pattern of post-natal adrenal maturation; however, the causes and consequences of variation in adrenal development are not well understood. In this study, we examine developmental and age-related maturation of the adrenal gland (measured via dehydroepiandrosterone-sulfate [DHEA-S]) for pot...
Article
Food insecurity relates to fat storage, but cannot explain fat storage in excess of levels optimal for buffering – that is, obesity. However, factors related to food unpredictability in the past, including stress, disease, micronutrient content of food, and physical activity, may cue physiological processes that change intake or fat deposition even...
Article
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The Tsimane Health and Life History Project, an integrated bio-behavioral study of the human life course, is designed to test competing hypotheses of human life-history evolution. One aim is to understand the bidirectional connections between life history and social behavior in a high-fertility, kin-based context lacking amenities of modern urban l...
Article
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The apolipoprotein E4 (E4) allele is present worldwide, despite its associations with higher risk of cardiovascular morbidity, accelerated cognitive decline during aging, and Alzheimer 'S: disease (AD). The E4 allele is especially prevalent in some tropical regions with a high parasite burden. Equatorial populations also face a potential dual burde...
Article
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Heart disease and type 2 diabetes are commonly believed to be rare among contemporary subsistence-level human populations, and by extension prehistoric populations. Although some caveats remain, evidence shows these diseases to be unusual among well-studied hunter-gatherers and other subsistence populations with minimal access to healthcare. Here w...
Article
Objectives: Resting metabolic rate (RMR) reflects energetic costs of homeostasis and accounts for 60 to 75% of total energy expenditure (TEE). Lean mass and physical activity account for much RMR variability, but the impact of prolonged immune activation from infection on human RMR is unclear in naturalistic settings. We evaluate the effects of in...
Article
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Background: Market integration (MI)-increasing production for and consumption from a market-based economy-is drastically altering traditional ways of life and environmental conditions among indigenous Amazonian peoples. The effects of MI on the biology and health of Amazonian children and adolescents, however, remain unclear. Aim: This study exa...
Data
Full-text available
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