The spatial distribution of cribra orbitalia in the medieval Netherlands: a relationship with malaria?

Abstract

Cribra orbitalia, orbital roof porosity, is one of the most frequently scored skeletal lesions in archaeological remains from the Netherlands. Cribra orbitalia is generally associated with childhood anaemia, but the underlying cause of this red blood cell disorder is still debated. Gowland and Westen (2012) showed a clear correlation between cribra orbitalia prevalence and certain geographic areas in the UK, linking this to malaria. As the Netherlands was plagued by malaria as well, this parasitic infection may have been an important contributing factor to the prevalence of anaemia in the medieval period. To contribute to this complex debate on the aetiology, and to study the hypothesis of malaria as an important causative agent, this research investigates the spatial distribution of cribra orbitalia in the medieval Netherlands. In total, 1629 individuals from 19 different medieval sites have been studied for the presence or absence of cribra orbitalia and severity of the lesions (1 to 3, Stuart-Macadam 1985). Results show a greater prevalence of cribra orbitalia in the areas deemed malarial based on palaeogeographic and 20th century malaria distribution data (10.9% vs. 23.1%, p<0.001). Yet, even though the mean scores are slightly higher in the malarial area, the severity of the lesions does not significantly vary. This study suggests that malaria may have been an important contributing factor to the prevalence of cribra orbitalia and that it was likely an influential disease in the low-lying coastal areas of the Netherlands with a substantial impact on health and life expectancy.