Impact of urbanisation on population’s health in Mtskheta region – Georgia, from Late Bronze Age to Early Middle Ages

Abstract

Abstract

The emergence of urbanisation is considered to be an important period in human history as it is associated with an increase in population density, diversification of subsistence activites, and the establishment of ancient cities, often with poor sanitation. Each of these factors contributed to the spread of disease and a change in diet. Numerous investigations suggest that the impact of early urbanisation on population health and diet is not homogeneous everywhere but varies based on the particularities of the region in question. The Caucasus is one such region. Located between the Black and Caspian seas it has always been chracterized by vibrant cultural dynamism. It acted as a frontier between urban societies of the ancient Near East and the nomadic populations of the ancient Eurasian steppes. As such this is an excellent location to study the effect of urbanisstion on health and diet. This dissertation focuses on paleopathological examinations of skeletal materials from the region of Caucasus, specifically the Greater Mtskheta territories located in the central part of the south Caucasus. The anthropological material from Greater Mtskheta forms one of the largest collections in the region. Human skeletal materials from 13 cemeteries, from three important time-periods were examined: the Late Bronze/Early Iron Age pre-state society with rural-type settlements (15th–6th centuries BC); the Antique period with the emergence of urbanisation and the establishment of the Iberian kingdom (5th century BC–4th century AD); and the Early Middle Age period with developed urbanisation and the collapse of the Iberian kingdom (4th–7th centuries AD). To observe the changes in health and diet throughout these different periods, pathological conditions such as porotic hyperostosis and dental diseases—caries, periapical lesions, antemortem tooth loss and calculus—were examined. Besides these pathologies, molecular analysis of dental calculus was done for these three periods. Statistically, there were no significant differences in lesions and the degrees of activity of porotic hyperostosis. But there was a significant trend in prevalence of porotic hyperostosis across time-periods and between sex. This indicated that deterioration in health conditions during the transitional periods was gradual and did not severely affect the population. The incidences of caries, periapical lesions, antemortem tooth loss and calculus throughout the periods may be associated with changing diet. An insignificant decrease of caries lesions during the urbanisation period may suggest diversification of food production and less dependence of grain consumption, rich in hydrocarbonates, which are responsible for caries.

A statistically significant difference in the oral microbiome in pre-and urbanised-state societies may be associated to an increase of frequency of porotic lesions on the skulls and the rise of abscesses over time. The decrease and low incidences of caries throughout the periods may be associated with the absence of specific bacteria in the oral microbiome of the ancient population of Georgia. This study is part of a growing body of research into the impact of early urbanisation on population health and diet. Using certain pathological changes on human skulls, together with analysis of dental diseases, and combining these with the study of oral microbiomes, it contributes to future research on similar topics. This is particularly relevant for the Caucasus, where this type of research has not yet been conducted.