Porotic hyperostosis as an indicator of anemia: An overview of correlation and cause
Anemia in prehistory remains a “paleopathological riddle”. The problems in diagnosis and interpretation are not surprising since anemia continues to be an issue of concern in contemporary populations. The word “anemia” is derived from the Greek, anaimia, meaning bloodlessness, and is a pathological condition in which the blood is deficient in red blood cells, in hemoglobin, or in total volume. Despite over one hundred years of research on the various forms of anemia, health care professionals, public health officials, and anthropologists continue to be unsure of the precise characteristics and nature of skeletal manifestations of anemia.
Further complicating the issue is the apparent correlation of anemia(s) with many other pathological conditions. Infectious pathogens are particularly confounding, because they have a symbiotic relationship with the hosts, and are as ubiquitous, in many respects, as the anemias.
This study reviews the history of the interpretation of skeletal lesions indicative of anemia and infection, with particular focus on recent scientific debates that interpret anemia as a positive factor. In this interpretation, instead of evaluating illness, lesions are construed as markers of “health”, and anemia is ultimately characterized as an adaptive response to prevent or diminish the activity or vigor of infections.
In my study, 96 individuals from three prehistoric sites in Tuscaloosa and Wilcox counties in Alabama are analyzed for standard markers of anemia and infection. An alternative method of analysis that employs visual representation of macroscopic, descriptive analysis and an expanded repertoire of skeletal markers of hypervascular activity in cranial and postcranial elements is proposed and subsequently applied to the sample of individuals. Cranial asymmetry is presented as a marker of metabolic distress when associated with other indicators such as porotic hyperostosis.
In the final phase of analysis and interpretation, anemia is reviewed within an “adaptive” framework. It is concluded that a much more detailed analysis is required for studies of anemia and infection. It is also concluded that rather than contributing to the adaptive fitness of the population, anemia is more likely an indication of physiological exhaustion and metabolic failure in most instances. Furthermore, skeletal lesions associated with anemia and infection are not well suited to questions of adaptation. This is because of two important points. The first is that skeletal lesions on postcranial elements in children less than five years of age may be caused by either infection or anemia or both together, and are virtually indistinguishable in many cases. The second problem is that while cranial lesions result from childhood bouts of anemia, lesions associated with infection can occur throughout ones life. In older individuals in whom there is evidence of healing or remodeling, there is no way to determine whether the anemia and infection occurred simultaneously or as separate events.
Anemia is not a true pathology. It is an abnormal physiological condition that can be symptomatic of many diseases, and can occur in tandem with these diseases. This study shows that a more synthetic approach is required in order to reveal cause and correlation relationships among indicators of metabolic discord and infectious disease, as well as many other pathological conditions.
0337: American history