The effect of leprotic infection on the risk of death in medieval rural Denmark

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This study of the effect of leprotic infection on the risk of death of the individuals buried at Øm Kloster illustrates the complexity of paleopathological and paleodemographic studies of past health using skeletal material. Based on the nature of the disease, the dynamics of preindustrial medieval populations, and the heterogeneous factors affecting each individual’s likelihood of disease and then death, the results of this analysis suggest that certain individuals that manifested leprotic infection in the skeleton were at a higher risk of death than other individuals at the same age. It is difficult to determine exactly how many among the living individuals suffered from leprotic infection as everyone in the population was most likely exposed to and may have carried the bacterium, but a great number may not have reacted osteologically owing to differential immune responses based on sex, age of transmission, social status, and yet unknown genetic factors. More than anything, most individuals may have died from other causes (other illnesses, trauma, child birth, etc.) before any skeletal manifestation of the disease could have occurred. To reach valid, unbiased, and un-confounded conclusions about the dynamics of health, we must understand the disease and the risk of dying with and without the disease. This knowledge should then be applied to models that consider the complexity of heterogeneity and competing hazards. From this point of view, it is important to grasp the significance of the methodology used here in that such a model—with improvements—is applicable to other populations and other diseases.

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