Doctoral Dissertation Research: Enamel Defects, Well-Being and Mortality in a Medieval Danish Village

The reconstruction of the demography and health of past populations has been one of the major endeavors in physical anthropology, not only to understand how specific populations lived and developed, but to better understand the general biological interactions between humans and their environments. Developmental defects within tooth enamel called accentuated striae (AS), which form during periods of physiological stress, have been used in previous studies of skeletons as a measure of the past population's nutrition and disease experience, since studies of living people have shown that tooth defects are associated with periods of nutritional stress and disease. However, the assumption that a higher number of AS in a skeletal sample indicates a population with poorer nutrition and a higher disease load is confounded by two factors. First, it is not clear that the presence of AS in an individual's dentition necessarily means that the individual had a higher risk of death than other individuals, since the individual would have to have survived a stress event in order to acquire the defect. Second, even if AS are associated with a higher risk of death, the fact that individual levels of nutrition and disease vary within a population will result in a skeletal sample that is highly selected for the 'weakest' individuals, thus elevating the apparent levels of nutritional stress and disease in the once-living population. This study uses survival analysis methods to test for a relationship between AS and age at death in skeletons from a medieval Danish village to determine whether those individuals with a higher risk of death (those dying at younger ages) had a higher incidence of AS. Using survival analysis corrects for the selective skeletal sample that results from a population with heterogeneous levels of health. The project may show that the relationship of AS to health is much more complex, but also more informative, than previously thought, and will contribute to a method that continues to be used in paleodemographic research to understand the relationship between skeletal pathology and health and between health and preindustrial population processes.