Palaeopathology and beyond

WARNING: contains a photo of archaeological human remains.

Hello everyone,

I’m Laura Castells and I am the new osteoarchaeologist for the COMMIOS project. As Charlie explained, us osteoarchaeologists are concerned with the analysis of human remains which usually involves the assessment of sex, the estimation of age and stature and the analysis of trauma and pathologies observable on the remains.

But this is just the beginning.

There are two ways to analyse that data: we can deep-dive into the analysis of one individual in what we call ‘osteobiographies’ or we can bring together all the available data for all the individuals and try to tease out population and chronological trends (i.e. who was suffering from what and what this might tell us about social structures and dynamics). But are these two ‘perspectives’ truly independent? Are we individual monoliths who develop diseases, or are we part of a much bigger network and thus our health is influenced by what happened before us and what happens around us?  

This is where pathology stops being recorded for curiosity’s sake and starts being a tool to understand life and societal dynamics. But for it to become a valuable tool, we must first understand how these diseases develop and, this my friends, is the first huge boulder in our path.

Two boulders, really: the first is that bone responds in very limited ways to injury or disease, so it’s very possible that different pathologies may result in similar-looking lesions. This means that we have to depend on the lesion distribution throughout the skeleton, the biological characteristics of the individual and their societal and archaeological context to be able to offer a diagnosis (which, in many cases, even when bone preservation is excellent, will be tentative). An example of this is periosteal new bone formation or periosteal lesions: a layer of new bone with an open and sponge-like appearance which appears when the periosteum (the connective tissue that envelops every bone) is irritated. Periostosis can appear as a marker of unspecific infection or inflammation (Dewitte and Bekvalac, 2011) or it can be associated with a specific pathology like leprosy (Ortner, 2003). Whilst the lesions themselves can be very similar (Figures 1 and 2A), it is their distribution and the combination of periostosis with additional bone changes in leprosy that allows the distinction to be made between them.

Right femur, thigh bone, of a juvenile individual from the Roman cemetery of Santa Caterina (Barcelona, Spain). In the middle of the shaft it has a darker patch of porous bone diagnosed as an unspecific periosteal lesion

Figure 1: Unspecific periosteal lesion (arrow) on a right femur of a juvenile individual (UF 726) from the Roman period cemetery of Santa Caterina (Barcelona) curated at the Barcelona History Museum (MUHBA). (Photo by LCN).

A. Distal halves of tibia and fibula, shin bones, of a young individual from the Roman cemetery of Santa Caterina (Barcelona). The bones are covered in a layer of bone with open holes characteristic of periosteal lesions. 
B. First, second and third metatarsals,   long bones of the foot, of the same individual. The bones have been remodeled, tapering towards the end, and are half the size they are expected to be. 
The combination of the periosteal new bone and the deformation of the metatarsals suggest a likely diagnosis of leprosy.

Figure 2: A. Periosteal lesions (black arrows) at right tibia and fibula of a young adult individual (UF710) from the Roman period cemetery of Santa Caterina curated at the Barcelona History Museum (MUHBA). B. These periosteal lesions were accompanied by remodeling and resorption of the metatarsals (and facial lesions not shown here), thus the diagnosis of leprosy is the most likely. For reference to the right, a drawing of the normal shape of bones (modified from Standard Anatomy, CC BY-NC 4.0). The numbers in the image and the drawing indicate 1st, 2nd and 3rd metatarsals. (Photo by LCN).

So far, so good – we can, mostly, do this.

The second boulder is that (sadly) for most of the lesions that we see on bone, we have only a simple understanding of their cause and how they develop. So, it’s not uncommon for the interpretation of a lesion to change or be associated with a myriad of conditions. Good examples of these are cribra orbitalia and porotic hyperostosis, which are clusters of pores at the orbital roof and the cranial surface, respectively (Figure 3). These have traditionally been associated with iron deficiency anaemia, but more recently been linked to a plethora of metabolic deficiencies associated with malnutrition and poor living conditions (Walker et al., 2009), possible childhood anaemia (Brickley, 2018), malaria (Schats, 2021), and respiratory infections (O’Donnell et al., 2020), among others.

Inferior view of the frontal bone of a young adult male individual from the post-medieval cemetery of Sant Cugat del Rec (Barcelona). At the roof of the eye orbits, it shows a cluster of porous of less than a millimeter in diameter diagnosed as cribra orbitalia.

Figure 3: Bilateral cribra orbitalia (black arrows) in a young adult male individual (M3) from the post-medieval cemetery of Sant Cugat del Rec (Barcelona) curated at the Barcelona History Museum (MUHBA). (Photo by LCN).

How do we disentangle this? I hear you ask.

Well.

With patience (first) and then considering where the knowledge of the pathology stands in terms of clinical, physiological and metabolic research, and (again) bringing together as much information about the individual as possible. For example: are there other lesions in other parts of the skeleton? How old was the individual? What do we know about their living conditions? And sometimes, we’ll need to stop here and recognise the limitations of our understanding and that maybe the best we can say (for now) is that these porotic lesions may be non-specific lesions associated with nutrient deficiency which can easily increase susceptibility to infection and, indeed, each feed of the other.  

Add another boulder, I hear you request?

Sure, let me present to you the Osteological Paradox. Until Wood and colleague’s (1992) paper, the interpretation of pathology had been considered fairly straight forward: more pathology – worse health. However, they argued that the relationship between health, risk of death and mortality was slightly more conceptually complex when they noted that: ‘the presence of a healed lesion indicates survival of a disease process earlier in life and thus may signify an individual whose frailty is low compared with those who died at earlier ages’ (Wood et al. 1992, 352). Or in other words: were those who died without any visible pathology actually healthy? Did they die of a disease that left no mark on the bone? Or did they die of a condition that could have left marks on the bone but the person died before the bone became affected?

Oh, the joys of being an osteoarchaeologist.

How does this not deter us from doing research in palaeopathology?

Now that I read what I have written, I find this to be a good question. But one that I can only answer for myself.

I believe that, despite the conceptual and technical complexities, palaeopathology and analysis of archaeological human remains is still the most direct way we have of exploring communities and individuals: who they were and how they lived. Basically, because we are asking them. So, for my part, I recognise, embrace and work with these boulders, because this is the only way to really explore what I am most interested in: how identity and life history, socio-economic context and environment of an individual may impact their health.  

This may seem a bit of a jump, so to help us we use theoretical approaches (often borrowed from medical and social sciences as well as public health, ta) to frame our analysis and interpretation. Here I will only explore two, intersectionality and syndemics, but there are others, such as Developmental Origins of Health and Disease (Gowland, 2015) and One Health + One Health Approach (e.g.Urban et al., 2021), which are well worth keeping in mind.

First, intersectionality recognises that identity is the combination of multiple axes of identity that exist within a single individual such as age, sex and sexuality, gender, socio-economic status, ability, ethnic group. These overlap and interplay creating and preserving social inequality and discrimination (Crenshaw, 1989), thus contributing to the individual life experience and, equally important in our discipline, impacting the individual’s health (Mant et al., 2021). Meanwhile, syndemics recognises the compounding effects of biological, environmental and social factors such as poverty, poor nutrition and stress on community and individual health (Larsen and Crespo, 2022, Perry and Gowland, 2022). The combination of intersectional and syndemic approaches, therefore, considers that our own health, as well as that of those who lived many centuries before us, is not an isolated factor but is the result of the interaction between biological, social and environmental factors and variables.   

Fair enough, but what does this really mean for COMMIOS?

When studying archaeological human remains such as the communities from Iron Age Britain, it is a reality that some of these axes and factors will be invisible to us. But we can still try to grasp as many aspects of identity as possible by combining the information obtained from macroscopic analysis of the remains (i.e. age at death, biological sex and pathology) and combine it with the mobility, diet and kinship information obtained from isotope and ancient DNA data. Equally, we can explore social and environmental contexts by gathering information on burial and archaeological context, as well as environmental data. In juggling all this data, we can start exploring questions such as:

  • Given the diversity in burial practice, can we get a better picture of who was buried where, and if, for example, type of burial is related to social status?
  • Can we see differences in social structures? And if so, do these different structures have any impact on the health of their members?
  • In the British Iron Age there are communities living all over the islands: is it the same to live in Iron Age Cornwall as Yorkshire? Which are the health trade-offs for those communities living in harsh environments (such as wetlands or areas with arid soils)?

So, to go back to the beginning: humans are certainly not monoliths but the result of complex interactions between ourselves and our environment (understood in its broadest terms). Therefore, palaeopathology is not about identifying interesting diseases, but it is the exploration of what these pathologies (in combination with every other bit of data) can tell us about those who lived before us.       

References

BRICKLEY, M. B. 2018. Cribra orbitalia and porotic hyperostosis: A biological approach to diagnosis. American Journal of Physical Anthropology, 167, 896-902.

CRENSHAW, K. 1989. Demarginalizing the Intersection of Race and Sex: A Black Feminist Critique of Antidiscrimination Doctrine, Feminist Theory and Antiracist Politics. The University of Chicago Legal Forum, 140.

DEWITTE, S. N. & BEKVALAC, J. 2011. The association between periodontal disease and periosteal lesions in the St. Mary Graces cemetery, London, England A.D. 1350-1538. American Journal of Physical Anthropology,, 146, 609-18.

GOWLAND, R. L. 2015. Entangled lives: Implications of the developmental origins of health and disease hypothesis for bioarchaeology and the life course. American Journal of Physical Anthropology, 158, 530-540.

LARSEN, C. S. & CRESPO, F. 2022. Paleosyndemics: A Bioarchaeological and Biosocial Approach to Study Infectious Diseases in the Past. Centaurus, 64.

MANT, M., COVA, C. & BRICKLEY, M. B. 2021. Intersectionality and trauma analysis in bioarchaeology. American Journal of Physical Anthropology.

O’DONNELL, L., HILL, E. C., ANDERSON, A. S. A. & EDGAR, H. J. H. 2020. Cribra orbitalia and porotic hyperostosis are associated with respiratory infections in a contemporary mortality sample from New Mexico. American Journal of Physical Anthropology, 173, 721-733.

ORTNER, D. J. 2003. Identification of pathological conditions in human skeletal remains, Academic Press.

PERRY, M. A. & GOWLAND, R. L. 2022. Compounding vulnerabilities: Syndemics and the social determinants of disease in the past. International Journal of Paleopathology, 39, 35-49.

SCHATS, R. 2021. Cribriotic lesions in archaeological human skeletal remains. Prevalence, co-occurrence, and association in medieval and early modern Netherlands. International Journal of Paleopathology, 35, 81-89.

URBAN, C., BLOM, A. A., PFRENGLE, S., WALKER-MEIKLE, K., STONE, A. C., INSKIP, S. A. & SCHUENEMANN, V. J. 2021. One Health Approaches to Trace Mycobacterium leprae’s Zoonotic Potential Through Time. Frontiers in Microbiology, 12.

WALKER, P. L., BATHURST, R. R., RICHMAN, R., GJERDRUM, T. & ANDRUSHKO, V. A. 2009. The causes of porotic hyperostosis and cribra orbitalia: A reappraisal of the iron-deficiency-anemia hypothesis. American Journal of Physical Anthropology, 139, 109-125.

WOOD, J. W., MILNER, G. R., HARPENDING, H. C., WEISS, K. M., COHEN, M. N., EISENBERG, L. E., HUTCHINSON, D. L., JANKAUSKAS, R., CESNYS, G., ČESNYS, G., KATZENBERG, M. A., LUKACS, J. R., MCGRATH, J. W., ROTH, E. A., UBELAKER, D. H. & WILKINSON, R. G. 1992. The Osteological Paradox: Problems of Inferring Prehistoric Health from Skeletal Samples [and Comments and Reply]. Current Anthropology, 33, 343-370.