Leprosy and mortality in the Medieval Danish village of Tirup.

Leprosy was a well-recognized and dreaded disease in Denmark in the Middle Ages (AD 1000-1536). A large fraction of the population was affected by leprosy in the 13th century. This paper analyzes the correlation between signs of leprosy and risk of dying in the small Danish village of Tirup (AD 1150-1350). Seven different dichotomous osteological lesions indicative of leprosy are analyzed, and it is possible to score at least one of these conditions on 135 skeletons of adult or adolescent people (aged 14 or more). Scores were transformed to a statistic, lambda, indicating the likelihood that the person to whom the skeleton belonged suffered from leprosy. The analyses indicate that the prevalence of leprosy among adult people in Tirup was 26% (95% confidence interval, 17-35%). The lambda statistic indicates that people who died with signs of leprosy did not differ in the distribution of age at death from those who did not have such signs. Skeletons showing dental enamel hypoplasia were less likely to come from skeletons with high lambda-values. The association between lambda and dental enamel hypoplasia indicates a relationship between stress in early childhood (ages 1-6 years) and subsequent development of signs of leprosy.