Doctoral Dissertation Improvement Award: City Living And Biological Frailty

While increased population density and the growth of cities are often thought to be important sources of social and economic opportunity, the potential negative effects of urbanization can sometimes harm human health. In living societies, increasing settlement and population density can be accompanied by greater exposure and susceptibility to dangerous infectious diseases, social inequality, unsanitary living conditions, and unstable food supplies. Paleodemography; the study of human populations in the archaeological past based on skeletal remains - can provide important insights into the complex relationships between people, their social and physical environments, and their diseases even in the absence of written historical records. This project will investigate the effects of urbanization on human health and the risk of death in medieval Denmark (c. AD 1050-1536) to disentangle the social and biological influences on human health in changing populations. In paleodemography, 'frailty' is defined as an individual's age-adjusted risk of death. Frailty can vary owing to individual differences in susceptibility to disease and death that may have underlying genetic, social, or environmental causes. New statistical analyses of skeletal samples from medieval Denmark will be used to determine how patterns of variation in frailty and risk of death in the past differed as a result of increased urbanization during the medieval period. This project will inform us about the role of urbanization in past preindustrial populations that dealt with the same illnesses and conditions that continue to influence people today, and as such will provide insight into how to avoid emerging health risks. Broader impacts of this study include museum exhibitions, public science outreach efforts (particularly aimed at promoting the role of women in scientific research), and continued international collaborations.

This dissertation project brings together established paleodemographic approaches and a new model of frailty, along with newly-developed statistical methods, to investigate the relationship between childhood and adult frailty and the risk of death from skeletal data in order to determine the effects of urbanization on age-at-death distributions from medieval Denmark. Skeletal remains from the Ole Wormsgade urban cemetery, Sejet rural parish cemetery, and the monastic cemetery of Om Kloster, which represent samples of the people who occupied the area in and near the medieval port city of Horsens on the eastern coast of Jutland, Denmark, will be examined. These samples will be analyzed to determine: (1) how frailty and age-at-death patterns differed as a result of urbanization over the medieval period, (2) how males and females were affected differently by their social and physical environments within and across the three samples, and (3) what the relationship was between childhood frailty and resulting adult frailty and mortality. These goals will be met by estimating disease prevalence and the associated risk of death in relation to boney indicators of childhood stress, infection, and malnutrition.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.