Evaluating life history trade-offs through the presence of linear enamel hypoplasia at Pueblo Bonito and Hawikku: A biocultural study of early life stress and survival in the Ancestral Pueblo Southwest

How Does Social Inequality Alter Relationships Between Porous Cranial Lesions and Mortality? Examining the Relationship Between Skeletal Indicators of Stress, Socioeconomic Status, and Survivorship in a Pediatric Autopsy Sample

BACKGROUND

In prior exploration of modern and archeological populations, lower SES has been associated with an increased risk of mortality. However, SES is often difficult to ascertain in archeological populations. Thus, explorations of skeletal lesions and their association with mortality may be subject to confounding factors that alter the strength and/or direction of this association.

METHODS

The present study uses data from a modern, documented coronial pediatric dataset to examine the association between porous cranial lesions (PCLs) (cribra orbitalia [CO] and porotic hyperostosis [PH]) and age at death while controlling for SES, as inferred through housing type, with manufactured or apartment housing identified as reflecting individuals from lower SES backgrounds in this context. We include 887 (535 males, 352 females) individuals aged 0.5-20.9 years from New Mexico who died between 2011 and 2022. Kaplan-Meier survival analysis was used to assess survivorship as related to PCLs and SES.

RESULTS

Low SES is associated with lower survivorship. CO does not have a significant association with age at death when not controlling for SES; PH alone is associated with older age at death. Disadvantaged individuals with PCLs have significantly reduced survivorship than those with higher SES.

DISCUSSION AND CONCLUSIONS

The findings of this study demonstrate that low SES results in reduced survivorship, and those with low SES and PCLs have worse survivorship than less disadvantaged individuals with PCLs. Thus, the strong contribution of SES to mortality necessitates the consideration of the sociocultural context as a confounding factor when examining associations between variables of interest (such as lesions) and mortality in both past and present populations.

Frailty or resilience? Hazard-based and cumulative phenotype approaches to discerning signals of health inequality in medieval London

Bioarchaeology uses human skeletal remains to reconstruct varied experiences of individuals and populations in the past, including patterns of health across time periods and cultural contexts. In the past three decades, bioarchaeological studies have highlighted the concept of "frailty," operationalizing it as increased risk of mortality or cumulative phenotypes. Using data from medieval London cemeteries, we integrate these two approaches to frailty in past populations. First, we estimate the risks of mortality and survivorship (hazard and survival analyses) associated with 10 biomarkers and use these results to construct population-specific frailty and resilience indices. Then, we apply the indices to adult individuals to explore frailty and resilience differentials between males and females in medieval London. Findings suggest that the male-female morbidity-mortality paradox observed in modern populations may not have existed in this context, which may be explained by preferential cultural buffering of men in this patriarchal, urban setting.

The relationship between cause of death and skeletal markers of physiological stress in the Hamann-Todd collection

OBJECTIVES

Socioeconomic status, past stress events, and other factors may contribute to the cumulative burden of physiological stress, which influences an individual's susceptibility to mortality and cause of death (COD). Here, we explore the association between skeletal evidence of stress and COD in the Hamann-Todd Osteological Collection (HTOC), a predominantly low socioeconomic status sample from the late 19th and early 20th century.

MATERIALS AND METHODS

Skeletal markers of stress including linear enamel hypoplasia (LEH), stature, and antemortem tooth loss (AMTL) were analyzed in 298 individuals in the HTOC. Recorded CODs were grouped into six broad categories and contrasted with stress indicators, ages-at-death, and demographic variables, using various parametric and non-parametric statistical tests.

RESULTS

COD varied by socially ascribed race and sex within the sample. Overall, infectious diseases were more prevalent than degenerative diseases. Individuals that died of infectious diseases had significantly lower ages-at-death compared to degenerative diseases (p < 0.001). There was no association between LEH and COD (χ2 = 4.449, p = 0.487). Stature varied significantly across COD categories for males (F = 2.534, p = 0.032), but not females (F = 1.733, p = 0.132). Controlling for age-at-death, AMTL prevalence was associated with COD (H = 18.53, p = 0.002), with cardiovascular disease being associated with higher prevalence of AMTL.

DISCUSSION

These findings show that some skeletal stress indicators are associated with COD in the HTOC, but the causal pathways of these relationships are not clear. This study adds to growing bodies of literature exploring relationships between past stress events and susceptibility to mortality and long-term consequences of poor living conditions for past individuals.

High prevalence of adult and nonadult scurvy in an early agricultural transition site from Mainland Southeast Asia was associated with decreased survivorship

OBJECTIVES

The osteological paradox recognizes that the presence of lesions is not always directly related with increased mortality. When combined with the clinical, historical, and epidemiological literature on scurvy, survivorship analysis, a form of statistical analysis to assess the relationship between the presence of diseases in the archeological record and survival, helps determine the overall burden of the disease both in terms of morbidity and mortality. This article explores the relationship between scurvy and survivorship in 26 adults from Man Bac, a Neolithic site from northern Vietnam together with prepublished evidence of scurvy in the nonadult population (n = 44).

METHODS

Diagnosis of scurvy included differential diagnosis combined with the Snoddy, A. M. E., Buckley, H. R., Elliott, G. E., Standen, V. G., Arriaza, B. T., & Halcrow, S. E. (2018). Macroscopic features of scurvy in human skeletal remains: A literature synthesis and diagnostic guide. American Journal of Physical Anthropology, 167(4), 876-895. https://doi.org/10.1002/ajpa.23699 threshold criteria and the Brickley, M. B., & Morgan, B. (2023). Assessing diagnostic certainty for scurvy and rickets in human skeletal remains. American Journal of Biological Anthropology, 181, 637-645 diagnostic certainty approaches. Kaplan-Meier survival curves were produced to assess the relationship between the presence of probable scurvy and age-at-death.

RESULTS

The prevalence of probable scurvy in adults (35%) was considerably lower than reported for the nonadults (80%). Almost all lesions observed in the adults were in a mixed stage of healing. Kaplan-Meier analysis demonstrated no difference in survivorship between infants and children (<15 years) with or without probable scurvy, whereas a meaningful difference was observed for the adults and adolescents (15+ years).

CONCLUSIONS

The findings demonstrate that scurvy considerably decreased survivorship to older age categories. The degree of lesion remodeling, however, indicates that scurvy was not necessarily the direct cause of death but contributed to an overall disease burden that was ultimately fatal.

What's luck got to do with it? A generative model for examining the role of stochasticity in age-at-death, with implications for bioarchaeology

INTRODUCTION

The role of "luck" in determining individual exposure to health insults is a critical component of the processes that shape age-at-death distributions in mortality samples but is difficult to address using traditional bioarcheological analysis of skeletal materials. The present study introduces a computer simulation approach to modeling stochasticity's contribution to the mortality schedule of a simulated cohort.

METHODS

The present study employs an agent-based model of 15,100 individuals across a 120 year period to examine the predictive value of birth frailty on age-at-death when varying the likelihood of exposure to health insults.

RESULTS

Birth frailty, when accounting for varying exposure likelihood scenarios, was found to account for 18.7% of the observed variation in individual age-at-death. Analysis stratified by exposure likelihood demonstrated that birth frailty alone explains 10.2%-12.1% of the variation observed across exposure likelihood scenarios, with the stochasticity associated with exposure to health insults (i.e., severity of health insult) and mortality likelihood driving the majority of variation observed.

CONCLUSIONS

Stochasticity of stressor exposure and intrinsic stressor severity are underappreciated but powerful drivers of mortality in this simulation. This study demonstrates the potential value of simulation modeling for bioarchaeological research.

New Equations for the Estimation of the Age of the Formation of the Harris Lines

Harris Lines (HLs) are transverse, sclerotic lines that can be visualized by X-ray imaging and that occur in long bones, most commonly in the tibia and femur. HLs are associated with disrupted bone mineralization during endochondral ossification, affecting the normal growth process. The etiology of HLs is debated, with some claims linking their presence to detrimental factors such as inflammation, malnutrition, alcohol abuse, and diseases. The age at which HLs form can be estimated based on their location, which allows for a retrospective assessment of the individual's health status during childhood or youth. The current study is concerned with providing new equations to estimate the age of Harris Line occurrences using a simple calculating tool. Bone growth curves were derived based on a dataset provided by Byers in 1991 using non-linear estimation. The best model was chosen with the Akaike Information Criterion. New and old methods were compared through Bland-Altman plots. As a result, we managed to produce reliable, well-fitted growth curves, concordant with previous methods.

Beyond dirty teeth: Integrating dental calculus studies with osteoarchaeological parameters

The study of ancient human dental calculus (mineralized dental plaque, also known as tartar) is becoming increasingly important in osteoarchaeology, human palaeoecology and environmental archaeology. Microremains of different origin (e.g. starch granules, pollen, phytoliths, feather barbules) as well as biomolecules and chemical compounds retrieved from its mineral matrix may represent an important link between past humans and their physical, biological and social environment, but they are rarely fully linked to the evidence from skeletal remains. This paper critically reviews the lines of evidence retrieved from dental calculus in relation to osteoarchaeological parameters, employing macroscopic, microscopic and biomolecular approaches, assessing synergy potential and limitations. The scope of this paper is also to contribute to the building of a much needed theoretical framework in this emerging subfield.

Paleodemography: From archaeology and skeletal age estimation to life in the past

Much of paleodemography, an interdisciplinary field with strong ties to archaeology, among other disciplines, is oriented toward clarifying the life experiences of past people and why they changed over time. We focus on how human skeletons contribute to our understanding of preindustrial demographic regimes, including when changes took place that led to the world as we know it today. Problems with existing paleodemographic practices are highlighted, as are promising directions for future work. The latter requires both better age estimates and innovative methods to handle data appropriately. Age-at-death estimates for adult skeletons are a particular problem, especially for adults over 50 years that undoubtedly are mistakenly underrepresented in published studies of archaeological skeletons. Better age estimates for the entirety of the lifespan are essential to generate realistic distributions of age at death. There are currently encouraging signs that after about a half-century of intensive, and sometimes contentious, research, paleodemography is poised to contribute much to understandings of evolutionary processes, the structure of past populations, and human-disease interaction, among other topics.

Twenty-first century bioarchaeology: Taking stock and moving forward

This article presents outcomes from a Workshop entitled "Bioarchaeology: Taking Stock and Moving Forward," which was held at Arizona State University (ASU) on March 6-8, 2020. Funded by the National Science Foundation (NSF), the School of Human Evolution and Social Change (ASU), and the Center for Bioarchaeological Research (CBR, ASU), the Workshop's overall goal was to explore reasons why research proposals submitted by bioarchaeologists, both graduate students and established scholars, fared disproportionately poorly within recent NSF Anthropology Program competitions and to offer advice for increasing success. Therefore, this Workshop comprised 43 international scholars and four advanced graduate students with a history of successful grant acquisition, primarily from the United States. Ultimately, we focused on two related aims: (1) best practices for improving research designs and training and (2) evaluating topics of contemporary significance that reverberate through history and beyond as promising trajectories for bioarchaeological research. Among the former were contextual grounding, research question/hypothesis generation, statistical procedures appropriate for small samples and mixed qualitative/quantitative data, the salience of Bayesian methods, and training program content. Topical foci included ethics, social inequality, identity (including intersectionality), climate change, migration, violence, epidemic disease, adaptability/plasticity, the osteological paradox, and the developmental origins of health and disease. Given the profound changes required globally to address decolonization in the 21st century, this concern also entered many formal and informal discussions.