An Investigation of Micro-CT Analysis of Bone as a New Diagnostic Method for Paleopathological Cases of Osteomalacia

Assessing the association of skeletal indicators of stress with mean age-at-death in sub-adults

OBJECTIVES

The present study investigated the association of skeletal indicator of stress presence with mean age-at-death as a means of understanding whether commonly studied indicators are indeed indicative of increased frailty.

MATERIALS AND METHODS

Using a medieval Gaelic population from Ballyhanna (Co. Donegal), the present study assessed the association between skeletal indicators of stress and mean age-at-death using the Kaplan-Meier survival function with log rank test to determine whether these indicators were associated with younger age-at-death, and therefore increased frailty, in sub-adults only (0 to 18 years, N = 139) and through comparison to an all-ages cohort (N = 318).

RESULTS

Only linear enamel hypoplasia was found to be associated with significantly decreased survivorship across the all-ages cohort but, conversely, was associated with increased survivorship when analysis was restricted to sub-adults. All other indicators assessed were associated with increased age-at-death for both all-age cohorts and sub-adult cohorts (cribra orbitalia), increased age-at-death when assessing all ages only (porotic hyperostosis and healed periosteal lesions); or were sufficiently rare in adults to prevent comparative analysis (stunting and micronutrient deficiency). Increased survivorship in individuals with higher numbers of co-morbid skeletal indicators was observed for both sub-adults alone and all age cohort.

DISCUSSION

These findings suggest that these commonly recorded skeletal indicators may be more accurately viewed simply as records of stressor exposure and subsequent survival only, rather than providing evidence that these sub-adults are frailer than their similarly aged-at-death peers. Thus, the demographic and sociocultural context is essential to the interpretation of observed skeletal indicators of stress.

Applications of Microct Imaging to Archaeobotanical Research

The potential applications of microCT scanning in the field of archaeobotany are only just beginning to be explored. The imaging technique can extract new archaeobotanical information from existing archaeobotanical collections as well as create new archaeobotanical assemblages within ancient ceramics and other artefact types. The technique could aid in answering archaeobotanical questions about the early histories of some of the world's most important food crops from geographical regions with amongst the poorest rates of archaeobotanical preservation and where ancient plant exploitation remains poorly understood. This paper reviews current uses of microCT imaging in the investigation of archaeobotanical questions, as well as in cognate fields of geosciences, geoarchaeology, botany and palaeobotany. The technique has to date been used in a small number of novel methodological studies to extract internal anatomical morphologies and three-dimensional quantitative data from a range of food crops, which includes sexually-propagated cereals and legumes, and asexually-propagated underground storage organs (USOs). The large three-dimensional, digital datasets produced by microCT scanning have been shown to aid in taxonomic identification of archaeobotanical specimens, as well as robustly assess domestication status. In the future, as scanning technology, computer processing power and data storage capacities continue to improve, the possible applications of microCT scanning to archaeobotanical studies will only increase with the development of machine and deep learning networks enabling the automation of analyses of large archaeobotanical assemblages.

Technical note: Application and potentiality of quantitative ultrasonometry for the evaluation of bone mineral density status

The evaluation of bone mineral density (BMD) is an important task in paleopathology. Techniques commonly applied in bone quantity assessment, such as DXA or radiogrammetry (XR), suffer from several limitations when applied to skeletal remains. In recently published research, we developed a new methodology and new reference curves for the evaluation of BMD on human skeletal remains, applying for the first time Quantitative Ultrasonometry (QUS), a user-friendly, portable, and reliable clinical technique. This study aims to apply this new methodology to an archeological sample and to compare the results with those obtained through XR. We apply QUS and XR to a sample of 104 adults from Medieval Italian cemeteries. Fragility fractures were recorded. Descriptive statistics and comparisons between sexes, age-at-death cohorts, and individuals with and without fragility fractures were performed. Moreover, univariate and multivariate logistic regression models were used to define the parameters most predictive of fracture risk in past populations. The comparison between sexes showed no significant results concerning BMD parameters, whereas a decrease in BMD with increasing age is confirmed. The comparison between fracture and non-fracture individuals and the logit model demonstrated that QUS parameters, especially UBPI, are more reliable predictors of fracture risk in comparison to XR. Our results confirmed that QUS is a valuable technique that can be efficiently applied to archeological remains, also considering its portability. We also propose a modification of the previously published QUS standard curves, to easily assess osteopenia and osteoporosis in archeological material.

The role of dietary calcium in the etiology of childhood rickets in the past and the present

For more than two centuries, lack of sunlight has been understood to cause vitamin D deficiency and documented as a primary cause of rickets. As such, evidence of rickets in the archeological record has been used as a proxy for vitamin D status in past individuals and populations. In the last decade, a clinical global consensus has emerged wherein it is recognized that dietary calcium deficiency also plays a role in the manifestation of rickets and classic skeletal deformities may not form if dietary calcium is normal even if vitamin D is deficient. This disease is now clinically called "nutritional rickets" to reflect the fact that rickets can take calcium deficiency-predominant or vitamin D deficiency-predominant forms. However, there are currently no paleopathological studies wherein dietary calcium deficiency is critically considered a primary etiology of the disease. We review here the interplay of calcium, vitamin D, and phosphorous in bone homeostasis, examine the role of dietary calcium in human health, and critically explore the clinical literature on calcium deficiency-predominant rickets. Finally, we report a case of rickets from the late Formative Period (~2500-1500 years ago) of the Atacama Desert and argue the disease in this infant is likely an example of calcium deficiency-predominant rickets. We conclude that most archeological cases of rickets are the result of multiple micronutrient deficiencies that compound to manifest in macroscopic skeletal lesions. For clinicians, these factors are important for implementing best treatment practice, and for paleopathologists they are necessary for appropriate interpretation of health in past communities.

Differential diagnosis of metabolic disease in a commingled sample from 19th century Hisban, Jordan

OBJECTIVE

This research attempts a differential diagnosis of skeletal lesions in a commingled sample from Hisban, Jordan, focusing on non-adults in the assemblage.

MATERIALS

2,883 well-preserved skeletal elements and 9 relatively complete skulls representing an MNI of 32 non-adults (<18 years old).

METHODS

All skeletal elements were observed macroscopically and pathophysiological processes underlying any lesions or other anomalies were assessed, followed by a comparative approach to rule out potential diagnoses.

RESULTS

The skeletal lesions observed were caused by inflammation due to chronic hemorrhaging, marrow hyperplasia due to an increase in hemopoiesis, rapid bone growth, and the impact of biomechanical strain on poorly mineralized elements. Rickets, scurvy, and acquired anemias best fit this pattern of lesions, although inflammation from other sources such as trauma or infection could not be definitively ruled out.

CONCLUSIONS

The in utero and postnatal environments at Hisban were conducive to the development of vitamin C and D deficiencies from birth until 2 years of age. The analysis of commingled remains requires an ontological shift in the importance of the individual to the population in paleopathology.

SIGNIFICANCE

This investigation demonstrates the efficacy of a combined biological and comparative approach in differential diagnosis in complicated commingled collections. In addition, it emphasizes the importance of the mother-infant dyad in understanding metabolic disease.

LIMITATIONS

Histological and radiographic analyses were not included in this diagnostic study due to COVID-19 travel restrictions.

SUGGESTIONS FOR FURTHER RESEARCH

Isotopic analysis to investigate childhood diet and histological and radiographic analyses to assess survival of deficiencies.

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.