Transition analysis: a validation study with known-age modern American skeletons

Assessing the existence of the male-female health-survival paradox in the past: Dental caries in medieval London

OBJECTIVES

This study seeks to identify signals of the male-female health-survival paradox in medieval London.

MATERIALS AND METHODS

This study uses skeletal data on age, sex, dental caries (n = 592) and antemortem tooth loss (n = 819) from adult individuals from medieval London cemeteries (c. 1200-1540 CE). The association between age and dental caries was assessed using binary logistic regression. The associations among age, time period (pre- vs. post-Black Death), oral biomarker (dental caries or antemortem tooth loss), and sex were tested using hierarchical log-linear analysis.

RESULTS

The analyses reveal significantly higher odds of dental caries with increasing adult ages, more older adults after the Black Death, different age distributions of dental caries between the sexes, and a greater decrease in the prevalence of dental caries for females after the Black Death. These results appear not to be an artifact of trends in AMTL. However, this study does not yield evidence suggesting that females experienced both a survival advantage and a decline in oral health at late adult ages after the Black Death relative to males.

CONCLUSIONS

These results do not provide evidence of the existence of a male-female health-survival paradox, but they do corroborate existing evidence of improvements in health in general in the aftermath of the Black Death. The decreased prevalence of dental caries after the Black Death may reflect dietary improvements or the effects of selective mortality during the epidemic.

Testing the accuracy of the DRNNAGE software for age estimation in a modern Greek sample

Estimation of age-at-death from human skeletal remains is fundamental in forensic anthropology as part of the construction of the biological profile of the individual under study. At the same time, skeletal age-at-death estimation in adults is problematic due to the disparity between chronological and biological age, the important inter-individual variability at the rate of skeletal aging, and inherent biases in the available methodologies (e.g., age mimicry). A recent paper proposed a method for skeletal age-at-death estimation based on multiple anatomical traits and machine learning. A software was also created, DRNNAGE, for the easy implementation of this method. The authors of that study supported that their methods have very high repeatability and reproducibility, and the mean absolute error of the age estimation was ~6 years across the entire adult age span, which is particularly high and promising. This paper tests the proposed methodology on a modern documented Greek sample of 219 adult individuals from the Athens Collection, with age-at-death from 19 to 99 years old. The sample was split into males and females as well as into individuals under and over 50 years old. We also divided the sample in 10-year intervals. First, intra- and inter-observer error was estimated in order to assess repeatability and reproducibility of the variables employed for age-at-death estimation. Then, the validity (correct classification performance) of DRNNAGE for each anatomical region individually, as well as all combined, was evaluated on each demographic separately and on the pooled sample. According to the results, some of the variables showed very low repeatability and reproducibility, thus their use should be cautious. The DRNNAGE software showed overall highly accurate age-at-death estimates for individuals older than 50 years, but poor on younger adults, with only exception the cranial sutures, which performed surprisingly well for all age groups. Overall, these results support the importance of cross-validation and the use of population-specific methods in forensic anthropology.

Considerations for age estimation accuracy: Method-derived outcomes and practitioner interpretations

Recent research observed 92% accuracy for age-at-death estimations by U.S. forensic anthropologists. The present study compares this case report level accuracy to method level accuracy for the most commonly used methods in U.S. casework, drawing from the Forensic Anthropology Database for Assessing Methods Accuracy (FADAMA). Method application rate (i.e., how often a method is used in casework) was analyzed for n = 641 cases and identified 15 methods with an application rate >45 cases, and the present study focused further analyses on these 15 methods. Of the 15, only four yielded accuracies greater than or equal to the 92% documented for case-report level accuracy. The other 11 methods produced accuracy rates ranging from 54% to 91%, with six of these below 70% This disconnect between highly accurate age estimations at the case report level compared to the poor performance at method level suggests that practitioner interpretation and synthesis of the methods' outcomes is a critical step for increasing the accuracy rates of the age estimations as reported on the final case report. This inference was further supported by the study's results which indicated that practitioner interpretations of frequently used method combinations improve accuracy and age range width of age estimation. The study also performed a Fisher's Exact test to assess whether case report-level accuracy differed with the number of aging methods used in a case, and found no significant differences.

Ancient human dental calculus metadata collection and sampling strategies: Recommendations for best practices

OBJECTIVES

Ancient human dental calculus is a unique, nonrenewable biological resource encapsulating key information about the diets, lifestyles, and health conditions of past individuals and populations. With compounding calls its destructive analysis, it is imperative to refine the ways in which the scientific community documents, samples, and analyzes dental calculus so as to maximize its utility to the public and scientific community.

MATERIALS AND METHODS

Our research team conducted an IRB-approved survey of dental calculus researchers with diverse academic backgrounds, research foci, and analytical specializations.

RESULTS

This survey reveals variation in how metadata is collected and utilized across different subdisciplines and highlights how these differences have profound implications for dental calculus research. Moreover, the survey suggests the need for more communication between those who excavate, curate, and analyze biomolecular data from dental calculus.

DISCUSSION

Challenges in cross-disciplinary communication limit researchers' ability to effectively utilize samples in rigorous and reproducible ways. Specifically, the lack of standardized skeletal and dental metadata recording and contamination avoidance procedures hinder downstream anthropological applications, as well as the pursuit of broader paleodemographic and paleoepidemiological inquiries that rely on more complete information about the individuals sampled. To provide a path forward toward more ethical and standardized dental calculus sampling and documentation approaches, we review the current methods by which skeletal and dental metadata are recorded. We also describe trends in sampling and contamination-control approaches. Finally, we use that information to suggest new guidelines for ancient dental calculus documentation and sampling strategies that will improve research practices in the future.

Ageing and disease risk factors: A new paleoepidemiological methodology for understanding disease in the past

OBJECTIVES

To outline a methodology that enables the reconstruction of age-related disease risk in past societies.

MATERIALS

Modern epidemiological evidence considering risk factors for age-related disease is combined with contextual information about an archaeological society of interest.

METHODS

Data gathered is used to create a qualitative population-specific risk model for the disease of interest. To provide a case study, a risk model is constructed for Chronic Obstructive Pulmonary Disease (COPD) in the Eastern English Bronze Age.

RESULTS

This enables the first rigorous approach to reconstructing age-related disease risk in the past. A risk model shows a high degree of COPD risk in the Eastern English Bronze Age, with a major contribution from indoor airborne pollution and agricultural practices.

SIGNIFICANCE

This represents a significant new approach in human paleopathology, facilitating understanding of the occurrence of a wide variety of diseases in the past, without the need for well-preserved skeletons of identified elderly individuals.

LIMITATIONS

The risk models generated are, of necessity, qualitative rather than quantitative, since we are unable to calculate the size of risk factors in the past with certainty.

SUGGESTIONS FOR FURTHER RESEARCH

The methodology could be applied to a wide variety of diseases and for many past societies.

Estimating adult age categories in commingled skeletons with Transition Analysis 3

OBJECTIVES

We estimate adult age frequencies from Unar 1 and Unar 2, two late Umm an-Nar (2400-2100 BCE) tombs in the modern-day Emirate of Ras al-Khaimah, United Arab Emirates. These collective tombs each contained hundreds of skeletons in commingled, fragmented, and variably cremated states. Previous studies placed the vast majority of this mortuary community in a generalized "adult" category, as have most analyses of similar tombs from this period. We sought to test how adult age estimation methods compare in identifying young, middle, and old-age individuals in commingled assemblages.

MATERIALS AND METHODS

We employed Transition Analysis 3 (TA3) and traditional age estimation methods to generate adult age frequencies for each tomb. We compared these frequencies between tomb contexts as well as by method.

RESULTS

Unar 1 and Unar 2 had similar adult age frequencies within each method, but TA3 age frequencies included significantly more middle and older adult individuals than those generated by traditional methods.

DISCUSSION

These results support findings of earlier iterations of transition analysis in regard to sensitivity in old adult age estimation, compared with traditional methods. Our findings indicate a potential use of TA3 in reconstructing age frequencies and mortality profiles in commingled skeletal assemblages. Increasing our understanding of everyday life in the distant past necessitates better understandings of adult age, and here, we illustrate how age estimation method choice significantly changes bioarchaeological interpretations of aging in Bronze Age Arabia.

RESEARCH HIGHLIGHTS

Adult age estimation using TA3 revealed significantly more middle and older adults than traditional methods in two commingled tombs. Similar mean maximum likelihood point estimates by side and across skeletal elements were found between tombs.

The Black Death in Hereford, England: A demographic analysis of the Cathedral 14th-century plague mass graves and associated parish cemetery

OBJECTIVES

This study explores the paleoepidemiology of the Black Death (1348-52 AD) mass graves from Hereford, England, via osteological analysis. Hereford plague mortality is evaluated in the local context of the medieval city and examined alongside other Black Death burials.

METHODS

The Hereford Cathedral site includes mass graves relating to the Black Death and a 12th-16th century parish cemetery. In total, 177 adult skeletons were analyzed macroscopically: 73 from the mass graves and 104 from the parish cemetery. Skeletal age-at-death was assessed using transition analysis, and sex and stress markers were analyzed.

RESULTS

The age-at-death distributions for the mass graves and parish cemetery were significantly different (p = 0.0496). Within the mass graves, young adults (15-24 years) were substantially over-represented, and mortality peaked at 25-34 years. From 35 years of age onwards, there was little variation in the mortality profiles for the mass graves and parish cemetery. Males and females had similar representation across burial types. Linear enamel hypoplasia was more prevalent within the mass graves (p = 0.0340) whereas cribra orbitalia and tibial periostitis were underrepresented.

CONCLUSIONS

Mortality within the Hereford mass graves peaked at a slightly older age than is seen within plague burials from London, but the overall profiles are similar. This demonstrates that young adults were disproportionately at risk of dying from plague compared with other age groups. Our findings regarding stress markers may indicate that enamel hypoplasia is more strongly associated with vulnerability to plague than cribra orbitalia or tibial periostitis.

Applicability of the six-phase method for auricular age estimation in an Indian population: A CT-based study

Age estimation plays a crucial role in human identification. Amongst numerous age markers located throughout the skeletal framework, the auricular surface of the ilium presents as a resilient structure, with different methods for auricular age estimation currently in practice. Amongst these methods, the Osborne method is believed to permit accurate age estimation through its use of robust age categories and discrete phase descriptors. The present study aimed to assess the applicability of the Osborne method in an Indian population through a computed tomographic (CT) examination of the auricular surface, an aspect presently unreported. In order to do so, CT scans of 380 individuals were collected and evaluated using the Osborne method. A CT-based examination indicated that surface texture described by Osborne is difficult to appreciate through 3D CT images. Indistinct definitions associated with certain features, and the mosaic display of features within each phase further prevents applying the method effectively. Overall accuracy percentages of 99.47% and 98.90% were obtained using the method in males and females, respectively, with corresponding inaccuracy values of 10.10 years and 9.04 years. Significantly reduced accuracy percentages were obtained with alternate, more robust age brackets presented within the original study, demonstrating the limited reliability associated with the method. Inaccuracy and bias values computed for each decade indicate the relative utility of the method in aging 40-59-year-old individuals. Low accuracy percentages, high error rates and different methodological hindrances encountered within the present study illustrate the limited applicability of the Osborne method in aging an Indian population.

Automated age-at-death estimation from 3D surface scans of the facies auricularis of the pelvic bone

This work presents an automated data-mining model for age-at-death estimation based on 3D scans of the auricular surface of the pelvic bone. The study is based on a multi-population sample of 688 individuals (males and females) originating from one Asian and five European identified osteological collections. Our method requires no expert knowledge and achieves similar accuracy compared to traditional subjective methods. Apart from data acquisition, the whole procedure of pre-processing, feature extraction and age estimation is fully automated and implemented as a computer program. This program is a part of a freely available web-based software tool called CoxAGE3D. This software tool is available at https://coxage3d.fit.cvut.cz/ Our age-at-death estimation method is suitable for use on individuals with known/unknown population affinity and provides moderate correlation between the estimated age and actual age (Pearson's correlation coefficient is 0.56), and a mean absolute error of 12.4 years.

Survivorship and the second epidemiological transition in industrial-era London

OBJECTIVES

The second epidemiological transition describes a shift in predominant causes of death from infectious to degenerative (non-communicable) diseases associated with the demographic transition from high to low levels of mortality and fertility. In England, the epidemiological transition followed the Industrial Revolution, but there is little reliable historical data on cause of death beforehand. Because of the association between the demographic and epidemiological transitions, skeletal data can potentially be used to examine demographic trends as a proxy for the latter. This study uses skeletal data to examine differences in survivorship in London, England in the decades preceding and following initial industrialization and the second epidemiological transition.

MATERIALS AND METHODS

We use data (from n = 924 adults) from London cemeteries (New Churchyard, New Bunhill Fields, St. Bride's Lower Churchyard, and St. Bride's Church Fleet Street) in use prior to and during industrialization (c. 1569-1853 CE). We assess associations between estimated adult age at death and time period (pre-industrial vs. industrial) using Kaplan-Meier survival analysis.

RESULTS

We find evidence of significantly lower adult survivorship prior to industrialization (c. 1569-1669 and 1670-1739 CE) compared to the industrial period (c. 1740-1853 CE) (p < 0.001).

DISCUSSION

Our results are consistent with historical evidence that, in London, survivorship was improving in the later 18th century, prior to the recognized beginning of the second epidemiological transition. These findings support the use of skeletal demographic data to examine the context of the second epidemiological transition in past populations.

Estimating fertility using adults: A method for under-enumerated pre-adult skeletal samples

OBJECTIVES

Infant underrepresentation poses a great risk to accurate palaeodemographic findings when analyzing skeletal samples. Empirically derived palaeodemographic methods all require unbiased or minimally biased pre-adult representation for estimating demographic characteristics, including fertility. Currently, there are no reliable methods for estimating palaeodemographic parameters when pre-adults are underrepresented in skeletal samples, consequently such samples are often excluded from palaeodemographic analyses. The aim of this article is to develop a method for estimating total fertility rate (TFR) using reproductive aged adults, specifically for samples with suspected pre-adult under-enumeration.

METHODOLOGY

United Nations mortality data and TFR from the World Population Prospects was utilized. The correlation between known fertility and the proportion of individuals in key reproductive years (15-49 years) to total adult sample (15+ years) was assessed as an indirect means to estimate fertility.

RESULTS

It was determined that the proportion of reproductive aged adults is a reasonable proxy for fertility. A significant positive correlation was observed between the TFR and those who died aged 15-49 years of age as a proportion of those who died ≥15 years (D15-49/D15+). SE of the estimate revealed reasonable predictive accuracy. When applied to two modern non-agricultural populations, the method showed some variability in accuracy but good potential for an improved outcome over existing methods when pre-adults are underrepresented.

CONCLUSION

This research has provided a new method for estimating fertility in archeological skeletal samples with pre-adult under-enumeration. In combination with a contextually focused approach, this provides a significant step toward further use of biased samples in palaeodemography.

Antemortem tooth loss as a biomarker of poverty: Dental evidence of "weathering" in a contemporary U.S. skeletal sample

In societies where resources are unequally distributed, structural inequities can be physically embodied over lifetimes. Lived experiences including racism, sexism, classism, and poverty can lead to chronic stress that prematurely ages body systems. This study tests the hypothesis that members of structurally vulnerable groups will exhibit premature aging in the form of antemortem tooth loss (AMTL). Analyzing Black, Indigenous, and People of Color (BIPOC) and white skeletal donors from the University of Tennessee, we predict that individuals from structurally vulnerable groups will exhibit more AMTL than individuals with more social privilege. We find some evidence for increased AMTL in BIPOC individuals, but significantly more AMTL in low-socioeconomic-status white individuals than either BIPOC or high-SES white individuals. We maintain that high rates of AMTL provide evidence of embodied consequences of social policies and utilize the violence continuum to theorize the ways in which poverty and inequity are normalized in U.S. society.

Reference and target sample age distribution impacts between model types in dental developmental age estimation

The performance of age estimation methods may vary due to a combination of method- and sample-related factors. Method development and evaluation necessitates understanding what influences these factors have on age estimation outcomes. In the specific context of juvenile dental age estimation, we used a single dataset and complete factorial design to systematically test four potential sources of difference: age distributions of reference and target sample (uniform, unimodal, U-shaped), Bayesian (multivariate Bayesian cumulative probit) vs. classical regression modeling (multivariate adaptive regression splines i.e. MARS), and model selection bias. The dataset consisted of 850 sets of left mandibular molar scores from London children 5-18 years old. True age and estimated age intervals in target samples were compared for bias, root-mean-squared error, precision, and accuracy using locally weighted smoothing of performance measures across the age range and means of performance metrics between factor-level combinations. We found interactions of model type, reference distribution, and target distribution. MARS models showed consistent evidence of age mimicry. Central tendency of the reference sample corresponded with increased bias while central tendency of the target sample corresponded with reduced RMSE and reduced precision for both model types. We found evidence of model selection bias, mitigated through averaging model metrics. We conclude that reference and target sample distribution influences and model selection bias are sufficient to cause difference in model performance within a single population. We suggest using Bayesian modeling, drawing uniform reference and target samples, and calculating test error on a hold-out sample to mitigate these challenges in method development.

Mixed cumulative probit: a multivariate generalization of transition analysis that accommodates variation in the shape, spread and structure of data

Biological data are frequently nonlinear, heteroscedastic and conditionally dependent, and often researchers deal with missing data. To account for characteristics common in biological data in one algorithm, we developed the mixed cumulative probit (MCP), a novel latent trait model that is a formal generalization of the cumulative probit model usually used in transition analysis. Specifically, the MCP accommodates heteroscedasticity, mixtures of ordinal and continuous variables, missing values, conditional dependence and alternative specifications of the mean response and noise response. Cross-validation selects the best model parameters (mean response and the noise response for simple models, as well as conditional dependence for multivariate models), and the Kullback-Leibler divergence evaluates information gain during posterior inference to quantify mis-specified models (conditionally dependent versus conditionally independent). Two continuous and four ordinal skeletal and dental variables collected from 1296 individuals (aged birth to 22 years) from the Subadult Virtual Anthropology Database are used to introduce and demonstrate the algorithm. In addition to describing the features of the MCP, we provide material to help fit novel datasets using the MCP. The flexible, general formulation with model selection provides a process to robustly identify the modelling assumptions that are best suited for the data at hand.

Studying ancient human oral microbiomes could yield insights into the evolutionary history of noncommunicable diseases

Noncommunicable diseases (NCDs) have played a critical role in shaping human evolution and societies. Despite the exceptional impact of NCDs economically and socially, little is known about the prevalence or impact of these diseases in the past as most do not leave distinguishing features on the human skeleton and are not directly associated with unique pathogens. The inability to identify NCDs in antiquity precludes researchers from investigating how changes in diet, lifestyle, and environments modulate NCD risks in specific populations and from linking evolutionary processes to modern health patterns and disparities. In this review, we highlight how recent advances in ancient DNA (aDNA) sequencing and analytical methodologies may now make it possible to reconstruct NCD-related oral microbiome traits in past populations, thereby providing the first proxies for ancient NCD risk. First, we review the direct and indirect associations between modern oral microbiomes and NCDs, specifically cardiovascular disease, diabetes mellitus, rheumatoid arthritis, and Alzheimer's disease. We then discuss how oral microbiome features associated with NCDs in modern populations may be used to identify previously unstudied sources of morbidity and mortality differences in ancient groups. Finally, we conclude with an outline of the challenges and limitations of employing this approach, as well as how they might be circumvented. While significant experimental work is needed to verify that ancient oral microbiome markers are indeed associated with quantifiable health and survivorship outcomes, this new approach is a promising path forward for evolutionary health research.

Dental size variation in admixed Latin Americans: Effects of age, sex and genomic ancestry

Dental size variation in modern humans has been assessed from regional to worldwide scales, especially under microevolutionary and forensic contexts. Despite this, populations of mixed continental ancestry such as contemporary Latin Americans remain unexplored. In the present study we investigated a large Latin American sample from Colombia (N = 804) and obtained buccolingual and mesiodistal diameters and three indices for maxillary and mandibular teeth (except third molars). We evaluated the correlation between 28 dental measurements (and three indices) with age, sex and genomic ancestry (estimated using genome-wide SNP data). In addition, we explored correlation patterns between dental measurements and the biological affinities, based on these measurements, between two Latin American samples (Colombians and Mexicans) and three putative parental populations: Central and South Native Americans, western Europeans and western Africans through PCA and DFA. Our results indicate that Latin Americans have high dental size diversity, overlapping the variation exhibited by the parental populations. Several dental dimensions and indices have significant correlations with sex and age. Western Europeans presented closer biological affinities with Colombians, and the European genomic ancestry exhibited the highest correlations with tooth size. Correlations between tooth measurements reveal distinct dental modules, as well as a higher integration of postcanine dentition. The effects on dental size of age, sex and genomic ancestry is of relevance for forensic, biohistorical and microevolutionary studies in Latin Americans.

Studying ancient human oral microbiomes could yield insights into the evolutionary history of noncommunicable diseases

Noncommunicable diseases (NCDs) have played a critical role in shaping human evolution and societies. Despite the exceptional impact of NCDs economically and socially, little is known about the prevalence or impact of these diseases in the past as most do not leave distinguishing features on the human skeleton and are not directly associated with unique pathogens. The inability to identify NCDs in antiquity precludes researchers from investigating how changes in diet, lifestyle, and environments modulate NCD risks in specific populations and from linking evolutionary processes to modern health patterns and disparities. In this review, we highlight how recent advances in ancient DNA (aDNA) sequencing and analytical methodologies may now make it possible to reconstruct NCD-related oral microbiome traits in past populations, thereby providing the first proxies for ancient NCD risk. First, we review the direct and indirect associations between modern oral microbiomes and NCDs, specifically cardiovascular disease, diabetes mellitus, rheumatoid arthritis, and Alzheimer's disease. We then discuss how oral microbiome features associated with NCDs in modern populations may be used to identify previously unstudied sources of morbidity and mortality differences in ancient groups. Finally, we conclude with an outline of the challenges and limitations of employing this approach, as well as how they might be circumvented. While significant experimental work is needed to verify that ancient oral microbiome markers are indeed associated with quantifiable health and survivorship outcomes, this new approach is a promising path forward for evolutionary health research.

The impact of age on the morphology of the 12th thoracic vertebral endplates

The current article explores the aging effects on the overall morphology of the endplates of the 12th thoracic vertebra (T12), while screening for sex differences. It further evaluates the suitability of T12 for estimating age-at-death in bioarcheaological contexts. We captured the morphology of the vertebral endplates, including the formation of osteophytes, in a novel continuous quantitative manner using digital photography. 168 Greek adults from the Athens Collection were used for modeling the aging effects and another 107 individuals from two Danish archaeological assemblages for evaluation. Regression analysis is based on generalized additive models for correlating age-at-death and morphological variation. Our proposed measurement method is highly reliable (R>0.98) and the main differences observed between sexes are size related. Aging has considerable effect on the endplate morphology of the T12 with the total area of the endplate, the area of the epiphyseal rim, and the shape irregularities of the endplate's external boundary being mostly affected. Multivariate regression shows that aging effects account up to 46% of the observed variation, although with differential expression between sexes. Correct age prediction on archaeological remains reached 33% with a prominent tendency for overestimation. The morphology of the T12 endplates is influenced by age and it can provide some insight with respect to the age-at-death of unidentified individuals, especially when other skeletal age markers are unavailable. Our proposed method provides an age-estimation framework for bioarchaeological settings, especially for estimating broader age ranges, such as discriminating between young and old adults.

Forensic Anthropology and Archaeology in Denmark

In this paper, we provide a brief overview of the status of forensic anthropology and forensic archeology in Denmark, as well as related information about education, research, and skeletal collections. Forensic anthropologists mainly deal with the examination of unidentified skeletal remains. Some special tasks include cranial trauma analysis of the recently deceased, advanced 3D visualization from CT scanning of homicide cases, and stature estimation of perpetrators using surveillance videos. Forensic anthropologists are employed at one of Denmark’s three departments of forensic medicine (in Copenhagen, Odense, and Aarhus) and have access to advanced imaging equipment (e.g., CT and MR scanning, surface scanners, and 3D printers) for use in both their requisitioned work and their research. Extensive research is conducted on different topics, such as the health and diseases of past populations, age estimation, and human morphology. Research is based on skeletal material from the archeological collections housed in Copenhagen and Odense or on CT data from the recently deceased. There is no full degree in forensic anthropology in Denmark, but elective courses and lectures are offered to students at different levels and to people from different professional backgrounds.

Forensic archaeology is a relatively new field of expertise in Denmark, and relevant cases are rare, with only one or two cases per year. No forensic archeologists are officially employed in any of the departments of forensic medicine. Until recently, the Special Crime Unit of the police handled crime scene investigations involving excavations, but with the option of enlisting the help of outside specialists, such as archaeologists, anthropologists, and pathologists. An official excavation work group was established in 2015 under the lead of the Special Crime Unit of the police with the aim of refining the methods and procedures used in relevant criminal investigations. The group is represented by five police officers from the Special Crime Scene Unit, a police officer from the National Police Dog Training center, the two archaeologists from Moesgaard Museum, a forensic anthropologist from the Department of Forensic Medicine (University of Copenhagen), and a forensic pathologist from the Department of Forensic Medicine (University of Aarhus).

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.

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.

The computational age-at-death estimation from 3D surface models of the adult pubic symphysis using data mining methods

Age-at-death estimation of adult skeletal remains is a key part of biological profile estimation, yet it remains problematic for several reasons. One of them may be the subjective nature of the evaluation of age-related changes, or the fact that the human eye is unable to detect all the relevant surface changes. We have several aims: (1) to validate already existing computer models for age estimation; (2) to propose our own expert system based on computational approaches to eliminate the factor of subjectivity and to use the full potential of surface changes on an articulation area; and (3) to determine what age range the pubic symphysis is useful for age estimation. A sample of 483 3D representations of the pubic symphyseal surfaces from the ossa coxae of adult individuals coming from four European (two from Portugal, one from Switzerland and Greece) and one Asian (Thailand) identified skeletal collections was used. A validation of published algorithms showed very high error in our dataset-the Mean Absolute Error (MAE) ranged from 16.2 and 25.1 years. Two completely new approaches were proposed in this paper: SASS (Simple Automated Symphyseal Surface-based) and AANNESS (Advanced Automated Neural Network-grounded Extended Symphyseal Surface-based), whose MAE values are 11.7 and 10.6 years, respectively. Lastly, it was demonstrated that our models could estimate the age-at-death using the pubic symphysis over the entire adult age range. The proposed models offer objective age estimates with low estimation error (compared to traditional visual methods) and are able to estimate age using the pubic symphysis across the entire adult age range.

DXAGE 2.0 - adult age at death estimation using bone loss in the proximal femur and the second metacarpal

The accurate age at death assessment of unidentified adult skeletal individuals is a critical research task in forensic anthropology, being a key feature for the determination of biological profiles of individual skeletal remains. We have previously shown that the age-related decrease of bone mineral density (BMD) in the proximal femur could be used to assess age at death in women (Navega et al., J Forensic Sci 63:497-503, 2018). The present study aims to generate models for age estimation in both sexes through bone densitometry of the femur and radiogrammetry of the second metacarpal. The training sample comprised 224 adults (120 females, 104 males) from the "Coimbra Identified Skeletal Collection," and different models were generated through least squares regression and general regression neural networks (GRNN). The models were operationalized in a user-friendly online interface at https://osteomics.com/DXAGE2/ . The mean absolute difference between the known and estimated age at death ranges from 9.39 to 13.18 years among women and from 10.33 to 15.76 among men with the least squares regression models. For the GRNN models, the mean absolute difference between documented and projected age ranges from 8.44 to 12.58 years in women and from 10.56 to 16.18 years in men. DXAGE 2.0 enables age estimation in incomplete and/or fragmentary skeletal remains, using alternative skeletal regions, with reliable results.

Adult Skeletal Age-at-Death Estimation through Deep Random Neural Networks: A New Method and Its Computational Analysis

Age-at-death assessment is a crucial step in the identification process of skeletal human remains. Nonetheless, in adult individuals this task is particularly difficult to achieve with reasonable accuracy due to high variability in the senescence processes. To improve the accuracy of age-at-estimation, in this work we propose a new method based on a multifactorial macroscopic analysis and deep random neural network models. A sample of 500 identified skeletons was used to establish a reference dataset (age-at-death: 19–101 years old, 250 males and 250 females). A total of 64 skeletal traits are covered in the proposed macroscopic technique. Age-at-death estimation is tackled from a function approximation perspective and a regression approach is used to infer both point and prediction interval estimates. Based on cross-validation and computational experiments, our results demonstrate that age estimation from skeletal remains can be accurately (~6 years mean absolute error) inferred across the entire adult age span and informative estimates and prediction intervals can be obtained for the elderly population. A novel software tool, DRNNAGE, was made available to the community.

Interpreting error in the estimation of skeletal growth profiles from past populations: An example demonstrating skeletal growth in historic African American communities

OBJECTIVES

The study of growth in the past is a critical component of bioarcheological analyses. However, our understanding of growth in the past is subject to a number of methodological challenges. This study aims to model the skeletal growth of past populations by considering the challenges associated with the data collection process and the challenges associated with the age estimation procedures.

MATERIALS AND METHODS

We use skeletal remains from two historic African American cemeteries in the American South to model femoral diaphyseal length-for-age. We estimate the age of each individual using dental development techniques and present growth curves as both a product of the maximum likelihood (MLE) age estimate and the estimated posterior age distribution. Growth was compared against a reference sample from the University of Colorado Child Research Council Study.

RESULTS

The results of our analyses showed that femoral diaphyseal length in two historic African American communities is small-for-estimated age as compared to a modern reference sample. However, the magnitude and characterization of this difference is variable when taking into account the broader posterior age distribution.

DISCUSSION

Both samples may be small-for-age due to physiological stress associated with racism, inequality, and the compounding effects of early urbanization. However, the interpretation of growth in the past is muddled when considering the relationship between the study sample and the reference sample, when accounting for uncertainty in the age estimation procedure, and the error-inducing steps taken during the data collection process. Future interpretation of skeletal growth in the past must include a full account of the possible sources of error in order to present an accurate representation of growth.

Performance of three mathematical models for estimating age-at-death from multiple indicators of the adult skeleton

The mathematical method which will achieve the most accurate and precise age-at-death estimate from the adult skeleton is often debated. Some research promotes Bayesian analysis, which is widely considered better suited to the data construct of adult age-at-death distributions. Other research indicates that methods with less mathematical complexity produce equally accurate and precise age-at-death estimates. One of the advantages of Bayesian analysis is the ability to systematically combine multiple indicators, which is reported to improve the age-at-death estimate. Few comparisons exist between Bayesian analysis and less complex mathematical models when considering multiple skeletal indicators. This study aims to evaluate the performance of a Bayesian approach compared to a phase-based averaging method and linear regression analysis using multiple skeletal indicators. The three combination methods were constructed from age-at-death data collected from 330 adult skeletons contained in the Raymond A Dart and Pretoria Bone Collections in South Africa. These methods were tested and compared using a hold-out sample of 30 skeletons. As is frequently reported in literature, a balance between accuracy and precision was difficult to obtain from the three selected methods. However, the averaging and regression analysis methods outperformed the Bayesian approach in both accuracy and precision. Nevertheless, each method may be suited to its own unique situation-averaging to inform first impressions, multiple linear regression to achieve statistically defensible accuracies and precisions and Bayesian analysis to allow for cases where category adjustments or missing indicators are necessary.

Temporal, spatial and gender-based dietary differences in middle period San Pedro de Atacama, Chile: A model-based approach

To explore the possible emergence and lived consequences of social inequality in the Atacama, we analyzed a large set (n = 288) of incredibly well preserved and contextualized human skeletons from the broad Middle Period (AD 500-1000) of the San Pedro de Atacama (Chile) oases. In this work, we explore model-based paleodietary reconstruction of the results of stable isotope analysis of human bone collagen and hydroxyapatite. The results of this modeling are used to explore local phenomena, the nature of the Middle Period, and the interaction between local situations and the larger world in which the oases were enmeshed by identifying the temporal, spatial, and biocultural correlates and dimensions of dietary difference. Our analyses revealed that: 1) over the 600-year period represented by our sample, there were significant changes in consumption patterns that may evince broad diachronic changes in the structure of Atacameño society, and 2) at/near 600 calAD, there was a possible episode of social discontinuity that manifested in significant changes in consumption practices. Additionally, while there were some differences in the level of internal dietary variability among the ayllus, once time was fully considered, none of the ayllus stood out for having a more (or less) clearly internally differentiated cuisine. Finally, sex does not appear to have been a particularly salient driver of observed dietary differences here. While we do not see any de facto evidence for complete dietary differentiation (as there is always overlap in consumption among individuals, ayllus, and time periods, and as isotopic analysis is not capable of pinpointing different foods items or preparations), there are broad aspects of dietary composition changing over time that are potentially linked to status, and foreignness. Ultimately, these stand as the clearest example of what has been termed "gastro-politics," potentially tied to the emergence of social inequality in the San Pedro oases.

Correlation of the human pubic symphysis surface with age-at-death: a novel quantitative method based on a bandpass filter

Age-at-death estimation from skeletal remains typically utilizes the roughness of pubic symphysis articular surfaces. This study presents a new quantitative method adapting a tool from geometric morphometrics, bandpass filtering of partial warp bending energy to extract only age-related changes of the surfaces. The study sample consisted of 440 surface-scanned symphyseal pubic bones from men between 14 and 82 years of age, which were landmarked with 102 fixed and surface semilandmarks. From the original sample, 371 specimens within Procrustes distance of 0.05 of the side-specific average were selected. For this subsample, age was correlated with total bending energy (calculated as summed squared partial warps amplitudes) for a wide range of plausible bandpass filters. For our subsample's 188 right-side surfaces, the correlation between age and bandpass filtered versions of bending energy peaks relatively sharply at r = -0.648 for ages up through 49 years against the first seven partial warp amplitudes only. The finding for left symphyses is similar. The results demonstrate that below the age 50, the symphyseal surface form changes most systematically related to age may be best detected by a lowpass-filtered version of bending energy: signals at the largest geometric scales of roughness rather than its full spectrum. Combining this method with information from other skeletal features could further improve age-at-death estimation based on the symphyseal pubic surface.

Using a multimethod life history approach to navigate the osteological paradox: A case study from Prehispanic Nasca, Peru

OBJECTIVES

We leverage recent bioarchaeological approaches and life history theory to address the implications of the osteological paradox in a study population. The goal of this article is to evaluate morbidity and mortality patterns as well as variability in the risk of disease and death during the Late Intermediate period (LIP; 950-1450 C.E.) in the Nasca highlands of Peru. We demonstrate how the concurrent use of multiple analytical techniques and life history theory can engage the osteological paradox and provide salient insights into the study of stress, frailty, and resilience in past populations.

MATERIALS AND METHODS

Crania from LIP burial contexts in the Nasca highlands were examined for cribra orbitalia (n = 325) and porotic hyperostosis (n = 270). All age groups and both sexes are represented in the sample. Survivor/nonsurvivor analysis assessed demographic differences in lesion frequency and severity. Hazard models were generated to assess differences in survivorship. The relationship between dietary diversity and heterogeneity in morbidity was assessed using stable δ¹⁵ N and δ¹³ C isotope values for bone collagen and carbonate. One hundred and twenty-four crania were directly AMS radiocarbon dated, allowing for a diachronic analysis of morbidity and mortality.

RESULTS

The frequency and expression of both orbital and vault lesions increases significantly during the LIP. Survivor/nonsurvivor analysis indicates cranial lesions co-vary with frailty rather than robusticity or longevity. Hazard models show (1) decreasing survivorship with the transition into the LIP, (2) significantly lower adult life expectancy for females compared to males, and (3) individuals with cranial lesions have lower survivorship across the life course. Stable isotope results show very little dietary diversity. Mortality risk and frequency of pathological skeletal lesions were highest during Phase III (1300-1450 C.E.) of the LIP.

CONCLUSION

Results provide compelling evidence of increasing physiological stress and mortality in the Nasca highlands during the LIP, but also reveal substantial heterogeneity in frailty and the risk of death. Certain members of society experienced a heavier disease burden and higher mortality compared to their contemporaries. Elevated levels of disease and lethal trauma among females account for some of the sex differences in survivorship but cannot explain the large degree of female-biased mortality. We hypothesize that parental investment in males or increased female fertility rates may explain these differences.

The accuracy of age estimation using transition analysis in the Hamann-Todd collection

OBJECTIVES

Reconstructing demography of past populations using skeletal data is challenging when analyzing adults because the process of biological aging does not always reflect the individual's chronological age. A proposed solution to address the limitations of traditional age estimation methods is transition analysis (TA), a multifactorial method of age estimation. However, despite its methodological refinement, TA has varying degrees of accuracy when applied to different known-age skeletal samples. This study assesses TA's accuracy by comparing age estimates to known age at death in the Hamann-Todd Collection.

MATERIALS AND METHODS

We contrasted the maximum likelihood age estimates generated by the ADBOU program to the known ages of 221 individuals. The absolute error was calculated for the entire sample, and compared between sex and ancestry.

RESULTS

The mean absolute error in the sample is 11.6 (SD = 10.3) years, with white individuals' errors (14.1 years) being significantly higher than black individuals' (9.1 years; p < 0.001). No significant differences were found between sexes (p = 0.621). A weak to moderate positive correlation was found between known age and absolute error for white males (R = 0.607; p < 0.001), white females (R = 0.509; p < 0.001), and black males (R = 0.371; p = 0.006). The accuracy of TA age estimates varied when each anatomical region was analyzed independently, but the combination of all three anatomical regions yielded the most accurate age estimates.

DISCUSSION

These findings further support that TA accuracy depends on the prior distribution used and, in the Hamann-Todd Collection, the accuracy for white individuals is more influenced by this limitation than when black individuals are analyzed.

An evaluation of the Acsádi and Nemeskéri Complex Method of adult age estimation in a modern South African skeletal sample

The Acsádi and Nemeskéri Complex Method is a multifactorial adult age estimation method that makes use of weighting systems. The Complex Method employs the use of four skeletal elements in assessing age, including the degree of endocranial suture closure, age-related changes to the pubic symphyseal surface, and the internal structural changes observable in the proximal humerus and femur. Acsádi and Nemeskéri reported a very optimistic error margin of ±2.5 years when all four skeletal elements were used. Despite these promising results, the Complex Method's effectiveness has been questioned, suggesting that it results in a constant over- and underestimation of age in younger and older groups, respectively. In this study, the Complex Method was tested on a modern South African skeletal sample (n = 313) with individuals of known age-at-death. Results from this study to some extent justify the critique levelled against the Complex Method's tendency to over- and underestimate age. Nevertheless, the Complex Method still performed surprisingly well for certain skeletal element combinations. Contrary to Acsádi and Nemeskéri's findings, the use of all four skeletal elements did not provide more accurate age estimates. For the most part, combinations making use of three or two skeletal elements outperformed the use of all four skeletal indicators. Results from this study indicate caution in using a blanket approach when it comes to deciding on the best combination of skeletal elements used in multifactorial methods. It is suggested that the Complex Method may be optimised by making use of sex- and population-specific skeletal element combinations and weighting systems in the future.

A paleodemographic assessment of mortality and fertility rates during the second demographic transition in rural central Indiana

OBJECTIVES

Since its inception, skeletally based paleodemographic research has emphasized the utility of biocultural models for interpreting the dynamic relationship between the sociocultural and ecological forces accompanying demographic transitions and shaping populations' health and well-being. While the demographic transition associated with the Neolithic Revolution has been a common focus in bioarcheology, the present study analyzes human skeletal remains from a large 19th century cemetery in central Indiana to examine population dynamics during the second demographic transition, a period generally characterized by decreasing fertility rates and improvements in life expectancy. This study demonstrates the potential to methodologically identify regional variations in the timing and interactions between broad-scale socioeconomic changes and technological advancements that characterized the time period through observed changes in survivorship and fertility based on age-at-death distributions.

MATERIALS AND METHODS

This study uses three temporally distinct samples (AD 1827-1869; 1870-1889; 1890-1935) from the Bethel Cemetery (n = 503). Kaplan-Meier survival analyses with a log- rank tests are utilized to evaluate survivorship and mortality over time. Next, Cox proportional hazard analyses are employed to examine the interaction between sex and time as covariates. Finally, the D0-14/D ratio is applied to estimate fertility for each of the three temporally bounded cohorts.

RESULTS

The Kaplan-Meier survival analyses and Cox proportional hazard modeling revealed statistically significant differences in survivorship between the three time periods. Age-specific mortality rates are reduced among adult female and male age classes in this rural community over the course of the 19th and early 20th centuries, resulting in the increasing life expectancies associated with the second demographic transition. While mortality in early adulthood was common during the first time period and decreases thereafter, sex was not identified as a meaningful covariate. The proportion of juveniles in the three temporal samples indicate that fertility rates were higher than national averages for the better part of the 19th century and subsequently declined around the turn of 20th century for this community.

CONCLUSIONS

The results indicate temporal differences between the three periods, demonstrating increased survivorship and decreased mortality and fertility over time. These findings corroborate two key features of the second demographic transition characterized by the move from high rates of both fertility and mortality to reduced rates and a general easing of demographic pressures. The observed trends likely reflect improvements in health, coinciding the industrial advance and economic development within and around Indianapolis. While the socioeconomic factors characterizing the Industrial Revolution drove demographic shifts that parallel an equally important epidemiological transition, potential regional differences are discussed to highlight variability in the timing of demographic transitions. The paleodemographic methods utilized in this study demonstrate improved accuracy and efficacy, which ultimately advances researchers' potential to disentangle population-specific socioeconomic factors that may contribute to asymmetrical experiences of health and mortality.

A dual process model for paleopathological diagnosis

OBJECTIVES

This paper aims to provide an explicit theoretical model for the cognitive processes involved in paleopathological diagnosis.

METHODS

The approach adopted is a dual process model (DPM). DPMs recognize that cognition is a result of both Type 1 (intuitive) and Type 2 (analytical) processes. DPMs have been influential for understanding decision-making in a range of fields, including diagnosis in clinical medicine. Analogies are drawn between diagnosis in a clinical and a paleopathological setting.

RESULTS

In clinical medicine, both Type 1 and Type 2 processes play a part in diagnosis. In paleopathology the role of Type 1 processes has been unacknowledged. However, like clinical diagnosis, paleopathological diagnosis is inherently a result of a combination of both Type 1 and Type 2 processes. A model is presented by which Type 1 processes can be explicitly incorporated into a scientific approach to diagnosis from skeletal remains, and in which diagnosis is formalized as a process of hypothesis testing.

SIGNIFICANCE

Accurately modelling our diagnostic processes allows us to understand the biases and limitations in our work and potentially helps us to improve our procedures, including how we impart diagnostic skills in pedagogical settings.

LIMITATIONS

This work provides a theoretical model for paleopathological diagnosis. However, such models are by their nature dynamic and developing rather than static entities; it is hoped that this work stimulates further debate and discussion in this important area.

Demographic uniformitarianism: the theoretical basis of prehistoric demographic research and its cross-disciplinary challenges

A principle of demographic uniformitarianism underpins all research into prehistoric demography (palaeodemography). This principle-which argues for continuity in the evolved mechanisms underlying modern human demographic processes and their response to environmental stimuli between past and present-provides the cross-disciplinary basis for palaeodemographic reconstruction and analysis. Prompted by the recent growth and interest in the field of prehistoric demography, this paper reviews the principle of demographic uniformitarianism, evaluates how it relates to two key debates in palaeodemographic research and seeks to delimit its range of applicability to past human and hominin populations. This article is part of the theme issue 'Cross-disciplinary approaches to prehistoric demography'.

Technical note: preliminary insight into a new method for age-at-death estimation from the pubic symphysis

Age-at-death estimation methods are important in forensic anthropology. However, age assessment is problematic due to inter-individual variation. The subjectivity of visual scoring systems can affect the accuracy and reliability of methods as well. One of the most studied skeletal regions for age assessment is the pubic symphysis. Few studies on Spanish pubic symphysis collections have been conducted, making further research necessary as well as the sampling of more forensic skeletal collections. This study is a preliminary development of an age-at-death estimation method from the pubic symphysis based on a new simple scoring system. A documented late twentieth century skeletal collection (N = 29) and a twenty-first century forensic collection (N = 76) are used. Sixteen traits are evaluated, and a new trait (microgrooves) is described and evaluated for the first time in this study. All traits are scored in a binary manner (present or absent), thus reducing ambiguity and subjectivity. Several data sets are constructed based on different age intervals. Machine learning methods are employed to evaluate the scoring system's performance. The results show that microgrooves, macroporosity, beveling, lower extremity, ventral and dorsal margin decomposition, and lipping are the best preforming traits. The new microgroove trait proves to be a good age predictor. Reliable classification results are obtained for three age intervals (≤ 29, 30-69, ≥ 70). Older individuals are reliably classified with two age intervals (< 80, ≥ 80). The combination of binary attributes and machine learning algorithms is a promising tool for gaining objectivity in age-at-death assessment.

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

OBJECTIVES

Due to the indelible nature of enamel, bioarchaeologists use linear enamel hypoplasia (LEH) to detect early investments in surviving stress and have identified an association between LEH presence and constraints in growth and maintenance as well as an increased susceptibility to future stress events. This study evaluates heterogenous frailty and susceptibility to death in relation to episodes of early life stress, as reflected by LEH presence, in the Ancestral Pueblo Southwest. This study hypothesizes that LEH presence will be associated with decreased survivorship and an increased likelihood of mortality in both samples.

MATERIALS AND METHODS

This study uses two samples, one from Pueblo Bonito (A.D. 800-1200; n = 28) and the second from Hawikku (A.D. 1300-1680; n = 103). Kaplan-Meier survival analysis with a log-rank test was used to evaluate the effect of LEH presence on survivorship for the two samples.

RESULTS

Survival analysis reveals statistically significant differences in mortality risk between individuals with and without LEH for the Hawikku sample, but no significant differences for the Pueblo Bonito sample.

CONCLUSION

The results demonstrate differences in the response to early life stress at the Hawikku and Pueblo Bonito sites, likely reflecting context. The Pueblo Bonito sample represents a high-status group, and survival following LEH may be the result of cultural buffering. Hawikku dates to a period associated with increased levels of disease and malnutrition as well as Spanish colonization. This environment may have exacerbated mortality risk for individuals in the region who survived early life stress and signifies the consequences of European colonialism in the New World.

Cranial suture closure as an age indicator: A review

Cranial suture closure has been recognized for over a century as a useful trait for age estimation. Although this indicator has become a standard feature of age assessment protocols in skeletal remains, serious questions have been raised about its reliability. This article attempts to provide a comprehensive review of cranial suture closure as an age indicator from several perspectives, including its anatomy and history, as well as issues relating to validation, statistics, and the potential of technological advancements to improve outcomes. We further suggest a path forward for the use of cranial suture closure as an estimator of age. Although its unreliability has been widely reported, cranial suture closure still appears to have value as an aging method, and it is hoped that the information contained in this article can serve as a stepping stone toward more effective use of this indicator. The cranium is often more durable than other skeletal elements in both archaeological and forensic circumstances, so maximizing the effectiveness of cranial indicators is an important goal. It is hoped that recent advancements in technology and in analytical approaches to the cranial sutures could breathe some new life into this feature as an indicator of age.

Tuberculosis in medieval and early modern Denmark: A paleoepidemiological perspective

Millions of people worldwide have sickened and died from tuberculosis in recent centuries. Yet for most of human existence, the impact of tuberculosis on society is largely unknown. It is, indeed, unknowable without methods suitable for estimating disease prevalence in skeletal samples. Here such a procedure is applied to medieval and early modern Danish skeletons, and it shows how disease prevalence varied with differences in socioeconomic conditions. The approach is based on sensitivity and specificity estimates from modern skeletons. To augment our understanding of tuberculosis in Danish history, 713 adult skeletons were examined, all from Ribe. Tuberculosis increased from 17% to 40% in the medieval to early modern periods in Ribe. Low status (29%) people were more likely to contract the disease than those of high status (10%). The general model, derived from the modern expression of tuberculosis, fits the early modern sample better than it does the medieval skeletons. Differences in the model's fit indicate the skeletal expression changed over time. Notably, rib lesions increased in frequency from the medieval to early modern periods. The approach developed here can provide insights into host-pathogen relationships and disease expression in future work with tuberculosis and other diseases that affect the skeleton.